Move the package content into `com.unity.uiwidgets` folder.

com.unity.uiwidgets/Runtime/widgets/banner.cs.meta

-fileFormatVersion: 2
-guid: e2e859ca92594b5d98bcce5ce505ca7b
+fileFormatVersion: 2
+guid: e2e859ca92594b5d98bcce5ce505ca7b
 timeCreated: 1552882905

com.unity.uiwidgets/Runtime/widgets/basic.cs.meta

-fileFormatVersion: 2
-guid: 69241aaa538e4e2baa651ffa39d6f355
+fileFormatVersion: 2
+guid: 69241aaa538e4e2baa651ffa39d6f355
 timeCreated: 1536564821

com.unity.uiwidgets/Runtime/widgets/binding.cs.meta

-fileFormatVersion: 2
-guid: 39d3379616cb4c64afdedd889e3ac2a2
+fileFormatVersion: 2
+guid: 39d3379616cb4c64afdedd889e3ac2a2
 timeCreated: 1536213633

com.unity.uiwidgets/Runtime/widgets/bottom_navigation_bar_item.cs.meta

-fileFormatVersion: 2
-guid: 7000f1f897684e08a0831ca5d920589f
+fileFormatVersion: 2
+guid: 7000f1f897684e08a0831ca5d920589f
 timeCreated: 1553162159

com.unity.uiwidgets/Runtime/widgets/container.cs.meta

-fileFormatVersion: 2
-guid: 7c96e4ace3a14122bc2107afe55771da
+fileFormatVersion: 2
+guid: 7c96e4ace3a14122bc2107afe55771da
 timeCreated: 1536831109

com.unity.uiwidgets/Runtime/widgets/dismissible.cs.meta

-fileFormatVersion: 2
-guid: abd926e0982c44ca80edbb282a52b90b
+fileFormatVersion: 2
+guid: abd926e0982c44ca80edbb282a52b90b
 timeCreated: 1552033946

com.unity.uiwidgets/Runtime/widgets/form.cs.meta

-fileFormatVersion: 2
-guid: 3ce8dad5676b40ec862b142dd03b9f64
+fileFormatVersion: 2
+guid: 3ce8dad5676b40ec862b142dd03b9f64
 timeCreated: 1552545243

com.unity.uiwidgets/Runtime/widgets/heroes.cs.meta

-fileFormatVersion: 2
-guid: ae21d125110c4c989fd2ce9e5a0bc1c0
+fileFormatVersion: 2
+guid: ae21d125110c4c989fd2ce9e5a0bc1c0
 timeCreated: 1554263028

com.unity.uiwidgets/Runtime/widgets/image.cs.meta

-fileFormatVersion: 2
-guid: d1d313d74f6044198caad151f52721b8
+fileFormatVersion: 2
+guid: d1d313d74f6044198caad151f52721b8
 timeCreated: 1536219326

com.unity.uiwidgets/Runtime/widgets/overscroll_indicator.cs.meta

-fileFormatVersion: 2
-guid: b87c58140c4b442e82a27b804f8502c7
+fileFormatVersion: 2
+guid: b87c58140c4b442e82a27b804f8502c7
 timeCreated: 1554348404

com.unity.uiwidgets/Runtime/widgets/sliver_persistent_header.cs.meta

-fileFormatVersion: 2
-guid: 1e795962fe2d4c3291bbbe4bb1146a80
+fileFormatVersion: 2
+guid: 1e795962fe2d4c3291bbbe4bb1146a80
 timeCreated: 1553067038

com.unity.uiwidgets/Runtime/widgets/ticker_provider.cs.meta

-fileFormatVersion: 2
-guid: aa6922a60d7945ffb3b92dede5941836
+fileFormatVersion: 2
+guid: aa6922a60d7945ffb3b92dede5941836
 timeCreated: 1536807803

com.unity.uiwidgets/Runtime/widgets/value_listenable_builder.cs

-using Unity.UIWidgets.foundation;
-
-namespace Unity.UIWidgets.widgets {
-    public delegate Widget ValueWidgetBuilder<T>(BuildContext context, T value, Widget child);
-
-    public class ValueListenableBuilder<T> : StatefulWidget {
-        public ValueListenableBuilder(
-            ValueListenable<T> valueListenable,
-            ValueWidgetBuilder<T> builder,
-            Widget child = null
-        ) {
-            D.assert(valueListenable != null);
-            D.assert(builder != null);
-            this.valueListenable = valueListenable;
-            this.builder = builder;
-            this.child = child;
-        }
-
-        public readonly ValueListenable<T> valueListenable;
-
-        public readonly ValueWidgetBuilder<T> builder;
-
-        public readonly Widget child;
-
-        public override State createState() {
-            return new _ValueListenableBuilderState<T>();
-        }
-    }
-
-    class _ValueListenableBuilderState<T> : State<ValueListenableBuilder<T>> {
-        T value;
-
-        public override void initState() {
-            base.initState();
-            this.value = this.widget.valueListenable.value;
-            this.widget.valueListenable.addListener(this._valueChanged);
-        }
-
-        public override void didUpdateWidget(StatefulWidget _oldWidget) {
-            ValueListenableBuilder<T> oldWidget = _oldWidget as ValueListenableBuilder<T>;
-            if (oldWidget.valueListenable != this.widget.valueListenable) {
-                oldWidget.valueListenable.removeListener(this._valueChanged);
-                this.value = this.widget.valueListenable.value;
-                this.widget.valueListenable.addListener(this._valueChanged);
-            }
-
-            base.didUpdateWidget(oldWidget);
-        }
-
-        public override void dispose() {
-            this.widget.valueListenable.removeListener(this._valueChanged);
-            base.dispose();
-        }
-
-        void _valueChanged() {
-            this.setState(() => { this.value = this.widget.valueListenable.value; });
-        }
-
-        public override Widget build(BuildContext context) {
-            return this.widget.builder(context, this.value, this.widget.child);
-        }
-    }
+using Unity.UIWidgets.foundation;
+
+namespace Unity.UIWidgets.widgets {
+    public delegate Widget ValueWidgetBuilder<T>(BuildContext context, T value, Widget child);
+
+    public class ValueListenableBuilder<T> : StatefulWidget {
+        public ValueListenableBuilder(
+            ValueListenable<T> valueListenable,
+            ValueWidgetBuilder<T> builder,
+            Widget child = null
+        ) {
+            D.assert(valueListenable != null);
+            D.assert(builder != null);
+            this.valueListenable = valueListenable;
+            this.builder = builder;
+            this.child = child;
+        }
+
+        public readonly ValueListenable<T> valueListenable;
+
+        public readonly ValueWidgetBuilder<T> builder;
+
+        public readonly Widget child;
+
+        public override State createState() {
+            return new _ValueListenableBuilderState<T>();
+        }
+    }
+
+    class _ValueListenableBuilderState<T> : State<ValueListenableBuilder<T>> {
+        T value;
+
+        public override void initState() {
+            base.initState();
+            this.value = this.widget.valueListenable.value;
+            this.widget.valueListenable.addListener(this._valueChanged);
+        }
+
+        public override void didUpdateWidget(StatefulWidget _oldWidget) {
+            ValueListenableBuilder<T> oldWidget = _oldWidget as ValueListenableBuilder<T>;
+            if (oldWidget.valueListenable != this.widget.valueListenable) {
+                oldWidget.valueListenable.removeListener(this._valueChanged);
+                this.value = this.widget.valueListenable.value;
+                this.widget.valueListenable.addListener(this._valueChanged);
+            }
+
+            base.didUpdateWidget(oldWidget);
+        }
+
+        public override void dispose() {
+            this.widget.valueListenable.removeListener(this._valueChanged);
+            base.dispose();
+        }
+
+        void _valueChanged() {
+            this.setState(() => { this.value = this.widget.valueListenable.value; });
+        }
+
+        public override Widget build(BuildContext context) {
+            return this.widget.builder(context, this.value, this.widget.child);
+        }
+    }
 }

com.unity.uiwidgets/Runtime/widgets/visibility.cs.meta

-fileFormatVersion: 2
-guid: f24846c5a2354d9a8b02bf83f3e8398e
+fileFormatVersion: 2
+guid: f24846c5a2354d9a8b02bf83f3e8398e
 timeCreated: 1552895385

com.unity.uiwidgets/Runtime/widgets/will_pop_scope.cs.meta

-fileFormatVersion: 2
-guid: 624e6292cdfc4b43ac439df81ae8efee
+fileFormatVersion: 2
+guid: 624e6292cdfc4b43ac439df81ae8efee
 timeCreated: 1552547854

com.unity.uiwidgets/Runtime/ui/txt/layout.cs

-using UnityEngine;
-
-namespace Unity.UIWidgets.ui {
-    static class Layout {
-        // Measure the length of the span of the text. Currently, this is only used to compute the length
-        // of ellipsis, assuming that the ellipsis does not contain any tab, tab is not considered for simplicity
-        public static float measureText(string text, TextStyle style) {
-            char startingChar = text[0];
-            float totalWidth = 0;
-            if (char.IsHighSurrogate(startingChar) || EmojiUtils.isSingleCharEmoji(startingChar)) {
-                float advance = style.fontSize * EmojiUtils.advanceFactor + style.letterSpacing;
-                for (int i = 0; i < text.Length; i++) {
-                    char ch = text[i];
-                    if (char.IsHighSurrogate(ch) || EmojiUtils.isSingleCharNonEmptyEmoji(ch)) {
-                        totalWidth += advance;
-                    }
-                }
-            }
-            else {
-                Font font = FontManager.instance.getOrCreate(style.fontFamily, style.fontWeight, style.fontStyle).font;
-                font.RequestCharactersInTextureSafe(text, style.UnityFontSize, style.UnityFontStyle);
-                for (int i = 0; i < text.Length; i++) {
-                    char ch = text[i];
-                    if (font.getGlyphInfo(ch, out var glyphInfo, style.UnityFontSize, style.UnityFontStyle)) {
-                        totalWidth += glyphInfo.advance + style.letterSpacing;
-                    }
-                    else {
-                        totalWidth += style.letterSpacing;
-                    }
-
-                    if (LayoutUtils.isWordSpace(ch)) {
-                        totalWidth += style.wordSpacing;
-                    }
-                }
-            }
-
-            return totalWidth;
-        }
-
-        public static int computeTruncateCount(float offset, string text, int start, int count, TextStyle style,
-            float advanceLimit, TabStops tabStops) {
-            char startingChar = text[start];
-            float currentAdvance = offset;
-            if (char.IsHighSurrogate(startingChar) || EmojiUtils.isSingleCharEmoji(startingChar)) {
-                float advance = style.fontSize * EmojiUtils.advanceFactor + style.letterSpacing;
-                for (int i = 0; i < count; i++) {
-                    char ch = text[start + i];
-                    if (char.IsHighSurrogate(ch) || EmojiUtils.isSingleCharNonEmptyEmoji(ch)) {
-                        currentAdvance += advance;
-                        if (currentAdvance > advanceLimit) {
-                            return count - i;
-                        }
-                    }
-                }
-            }
-            else {
-                Font font = FontManager.instance.getOrCreate(style.fontFamily, style.fontWeight, style.fontStyle).font;
-                for (int i = 0; i < count; i++) {
-                    char ch = text[start + i];
-                    if (ch == '\t') {
-                        currentAdvance = tabStops.nextTab(currentAdvance);
-                    }
-                    else if (font.getGlyphInfo(ch, out var glyphInfo, style.UnityFontSize, style.UnityFontStyle)) {
-                        currentAdvance += glyphInfo.advance + style.letterSpacing;
-                    }
-                    else {
-                        currentAdvance += style.letterSpacing;
-                    }
-
-                    if (LayoutUtils.isWordSpace(ch)) {
-                        currentAdvance += style.wordSpacing;
-                    }
-
-                    if (currentAdvance > advanceLimit) {
-                        return count - i;
-                    }
-                }
-            }
-
-            return 0;
-        }
-
-        public static float computeCharWidths(float offset, string text, int start, int count, TextStyle style,
-            float[] advances, int advanceOffset, TabStops tabStops) {
-            char startingChar = text[start];
-            float totalWidths = 0;
-            if (char.IsHighSurrogate(startingChar) || EmojiUtils.isSingleCharEmoji(startingChar)) {
-                float advance = style.fontSize * EmojiUtils.advanceFactor + style.letterSpacing;
-                for (int i = 0; i < count; i++) {
-                    char ch = text[start + i];
-                    if (char.IsHighSurrogate(ch) || EmojiUtils.isSingleCharNonEmptyEmoji(ch)) {
-                        advances[i + advanceOffset] = advance;
-                        totalWidths += advance;
-                    }
-                    else {
-                        advances[i + advanceOffset] = 0;
-                    }
-                }
-            }
-            else {
-                Font font = FontManager.instance.getOrCreate(style.fontFamily, style.fontWeight, style.fontStyle).font;
-                // TODO: it is kind of a waste to require the entire string for this style, but SubString causes alloc
-                font.RequestCharactersInTextureSafe(text, style.UnityFontSize, style.UnityFontStyle);
-                for (int i = 0; i < count; i++) {
-                    char ch = text[start + i];
-                    if (ch == '\t') {
-                        advances[i + advanceOffset] = tabStops.nextTab(offset + totalWidths) - (offset + totalWidths);
-                    }
-                    else if (font.getGlyphInfo(ch, out var glyphInfo, style.UnityFontSize, style.UnityFontStyle)) {
-                        advances[i + advanceOffset] = glyphInfo.advance + style.letterSpacing;
-                    }
-                    else {
-                        advances[i + advanceOffset] = style.letterSpacing;
-                    }
-
-                    if (LayoutUtils.isWordSpace(ch)) {
-                        advances[i + advanceOffset] += style.wordSpacing;
-                    }
-
-                    totalWidths += advances[i + advanceOffset];
-                }
-            }
-
-            return totalWidths;
-        }
-
-        public static float doLayout(float offset, string text, int start, int count, TextStyle style,
-            float[] advances, float[] positions, TabStops tabStops, out UnityEngine.Rect bounds) {
-            float advance = 0;
-            Font font = FontManager.instance.getOrCreate(style.fontFamily, style.fontWeight, style.fontStyle).font;
-
-            char startingChar = text[start];
-            bounds = new UnityEngine.Rect();
-            if (char.IsHighSurrogate(startingChar) || EmojiUtils.isSingleCharEmoji(startingChar)) {
-                advance = _layoutEmoji(text, start, count, style, font, advances, positions, ref bounds);
-            }
-            else {
-                // According to the logic of Paragraph.layout, it is assured that all the characters are requested
-                // in the texture before (in computing line breaks), so skip it here for optimization.
-                // The only exception is the ellipsis, which did not appear in line breaking. It is taken care of
-                // only when needed.
-
-                // font.RequestCharactersInTextureSafe(buff.text, style.UnityFontSize, style.UnityFontStyle);
-
-//                int wordstart = start == buff.size
-//                    ? start
-//                    : LayoutUtils.getPrevWordBreakForCache(buff, start + 1);
-                int wordend;
-                for (int iter = start; iter < start + count; iter = wordend) {
-                    wordend = LayoutUtils.getNextWordBreak(text, iter, start + count);
-                    advance = _layoutWord(offset, iter - start, text, iter,
-                        wordend - iter, style, font, advances, positions, advance,
-                        tabStops, ref bounds);
-                }
-            }
-
-            // bounds relative to first character
-            bounds.x -= positions[0];
-            return advance;
-        }
-
-        static float _layoutWord(float offset, int layoutOffset,
-            string text, int start, int wordCount, TextStyle style, Font font, float[] advances,
-            float[] positions, float initAdvance, TabStops tabStops, ref UnityEngine.Rect bounds) {
-            float wordSpacing =
-                wordCount == 1 && LayoutUtils.isWordSpace(text[start]) ? style.wordSpacing : 0;
-
-            float x = initAdvance;
-            float letterSpace = style.letterSpacing;
-            float letterSpaceHalfLeft = letterSpace * 0.5f;
-            float letterSpaceHalfRight = letterSpace - letterSpaceHalfLeft;
-
-            for (int i = 0; i < wordCount; i++) {
-                initAdvance = x;
-                var ch = text[start + i];
-                if (i == 0) {
-                    x += letterSpaceHalfLeft + wordSpacing;
-                    advances[i + layoutOffset] = letterSpaceHalfLeft + wordSpacing;
-                }
-                else {
-                    advances[i - 1 + layoutOffset] += letterSpaceHalfRight;
-                    advances[i + layoutOffset] = letterSpaceHalfLeft;
-
-                    x += letterSpace;
-                }
-
-                if (font.getGlyphInfo(ch, out var glyphInfo, style.UnityFontSize, style.UnityFontStyle)) {
-                    _updateBounds(glyphInfo, x, ref bounds);
-                }
-
-                positions[i + layoutOffset] = x;
-
-                float advance;
-                if (ch == '\t') {
-                    advance = tabStops.nextTab(initAdvance + offset) - initAdvance - offset;
-                }
-                else {
-                    advance = glyphInfo.advance;
-                }
-
-                x += advance;
-                advances[i + layoutOffset] += advance;
-
-                if (i + 1 == wordCount) {
-                    advances[i + layoutOffset] += letterSpaceHalfRight;
-                    x += letterSpaceHalfRight;
-                }
-            }
-
-            return x;
-        }
-
-        static float _layoutEmoji(string text, int start, int count, TextStyle style, Font font, float[] advances,
-            float[] positions, ref UnityEngine.Rect bounds) {
-            var metrics = FontMetrics.fromFont(font, style.UnityFontSize);
-            float x = 0;
-            for (int i = 0; i < count; i++) {
-                char c = text[start + i];
-                if (EmojiUtils.isSingleCharNonEmptyEmoji(c) || char.IsHighSurrogate(c)) {
-                    float letterSpace = style.letterSpacing;
-                    float letterSpaceHalfLeft = letterSpace * 0.5f;
-                    float letterSpaceHalfRight = letterSpace - letterSpaceHalfLeft;
-
-                    x += letterSpaceHalfLeft;
-                    advances[i] = letterSpaceHalfLeft;
-
-                    float advance = style.fontSize * EmojiUtils.advanceFactor;
-                    var minX = x;
-                    var maxX = advance + x;
-                    var minY = -style.fontSize * EmojiUtils.sizeFactor;
-                    var maxY = metrics.descent;
-                    _updateBounds(minX, maxX, minY, maxY, ref bounds);
-
-                    positions[i] = x;
-
-                    x += advance;
-
-                    advances[i] += advance;
-                    advances[i] += letterSpaceHalfRight;
-
-                    x += letterSpaceHalfRight;
-                }
-                else {
-                    advances[i] = 0;
-                    positions[i] = x;
-                }
-            }
-
-            return x;
-        }
-
-        static void _updateBounds(CharacterInfo glyphInfo, float x, ref UnityEngine.Rect bounds) {
-            var minX = glyphInfo.minX + x;
-            var maxX = glyphInfo.maxX + x;
-            var minY = -glyphInfo.maxY;
-            var maxY = -glyphInfo.minY;
-            _updateBounds(minX, maxX, minY, maxY, ref bounds);
-        }
-
-        static void _updateBounds(float minX, float maxX, float minY, float maxY, ref UnityEngine.Rect bounds) {
-            if (bounds.width <= 0 || bounds.height <= 0) {
-                bounds.Set(minX, minY, maxX - minX, maxY - minY);
-            }
-            else {
-                if (minX < bounds.x) {
-                    bounds.x = minX;
-                }
-
-                if (minY < bounds.y) {
-                    bounds.y = minY;
-                }
-
-                if (maxX > bounds.xMax) {
-                    bounds.xMax = maxX;
-                }
-
-                if (maxY > bounds.yMax) {
-                    bounds.yMax = maxY;
-                }
-            }
-        }
-    }
+using UnityEngine;
+
+namespace Unity.UIWidgets.ui {
+    static class Layout {
+        // Measure the length of the span of the text. Currently, this is only used to compute the length
+        // of ellipsis, assuming that the ellipsis does not contain any tab, tab is not considered for simplicity
+        public static float measureText(string text, TextStyle style) {
+            char startingChar = text[0];
+            float totalWidth = 0;
+            if (char.IsHighSurrogate(startingChar) || EmojiUtils.isSingleCharEmoji(startingChar)) {
+                float advance = style.fontSize * EmojiUtils.advanceFactor + style.letterSpacing;
+                for (int i = 0; i < text.Length; i++) {
+                    char ch = text[i];
+                    if (char.IsHighSurrogate(ch) || EmojiUtils.isSingleCharNonEmptyEmoji(ch)) {
+                        totalWidth += advance;
+                    }
+                }
+            }
+            else {
+                Font font = FontManager.instance.getOrCreate(style.fontFamily, style.fontWeight, style.fontStyle).font;
+                font.RequestCharactersInTextureSafe(text, style.UnityFontSize, style.UnityFontStyle);
+                for (int i = 0; i < text.Length; i++) {
+                    char ch = text[i];
+                    if (font.getGlyphInfo(ch, out var glyphInfo, style.UnityFontSize, style.UnityFontStyle)) {
+                        totalWidth += glyphInfo.advance + style.letterSpacing;
+                    }
+                    else {
+                        totalWidth += style.letterSpacing;
+                    }
+
+                    if (LayoutUtils.isWordSpace(ch)) {
+                        totalWidth += style.wordSpacing;
+                    }
+                }
+            }
+
+            return totalWidth;
+        }
+
+        public static int computeTruncateCount(float offset, string text, int start, int count, TextStyle style,
+            float advanceLimit, TabStops tabStops) {
+            char startingChar = text[start];
+            float currentAdvance = offset;
+            if (char.IsHighSurrogate(startingChar) || EmojiUtils.isSingleCharEmoji(startingChar)) {
+                float advance = style.fontSize * EmojiUtils.advanceFactor + style.letterSpacing;
+                for (int i = 0; i < count; i++) {
+                    char ch = text[start + i];
+                    if (char.IsHighSurrogate(ch) || EmojiUtils.isSingleCharNonEmptyEmoji(ch)) {
+                        currentAdvance += advance;
+                        if (currentAdvance > advanceLimit) {
+                            return count - i;
+                        }
+                    }
+                }
+            }
+            else {
+                Font font = FontManager.instance.getOrCreate(style.fontFamily, style.fontWeight, style.fontStyle).font;
+                for (int i = 0; i < count; i++) {
+                    char ch = text[start + i];
+                    if (ch == '\t') {
+                        currentAdvance = tabStops.nextTab(currentAdvance);
+                    }
+                    else if (font.getGlyphInfo(ch, out var glyphInfo, style.UnityFontSize, style.UnityFontStyle)) {
+                        currentAdvance += glyphInfo.advance + style.letterSpacing;
+                    }
+                    else {
+                        currentAdvance += style.letterSpacing;
+                    }
+
+                    if (LayoutUtils.isWordSpace(ch)) {
+                        currentAdvance += style.wordSpacing;
+                    }
+
+                    if (currentAdvance > advanceLimit) {
+                        return count - i;
+                    }
+                }
+            }
+
+            return 0;
+        }
+
+        public static float computeCharWidths(float offset, string text, int start, int count, TextStyle style,
+            float[] advances, int advanceOffset, TabStops tabStops) {
+            char startingChar = text[start];
+            float totalWidths = 0;
+            if (char.IsHighSurrogate(startingChar) || EmojiUtils.isSingleCharEmoji(startingChar)) {
+                float advance = style.fontSize * EmojiUtils.advanceFactor + style.letterSpacing;
+                for (int i = 0; i < count; i++) {
+                    char ch = text[start + i];
+                    if (char.IsHighSurrogate(ch) || EmojiUtils.isSingleCharNonEmptyEmoji(ch)) {
+                        advances[i + advanceOffset] = advance;
+                        totalWidths += advance;
+                    }
+                    else {
+                        advances[i + advanceOffset] = 0;
+                    }
+                }
+            }
+            else {
+                Font font = FontManager.instance.getOrCreate(style.fontFamily, style.fontWeight, style.fontStyle).font;
+                // TODO: it is kind of a waste to require the entire string for this style, but SubString causes alloc
+                font.RequestCharactersInTextureSafe(text, style.UnityFontSize, style.UnityFontStyle);
+                for (int i = 0; i < count; i++) {
+                    char ch = text[start + i];
+                    if (ch == '\t') {
+                        advances[i + advanceOffset] = tabStops.nextTab(offset + totalWidths) - (offset + totalWidths);
+                    }
+                    else if (font.getGlyphInfo(ch, out var glyphInfo, style.UnityFontSize, style.UnityFontStyle)) {
+                        advances[i + advanceOffset] = glyphInfo.advance + style.letterSpacing;
+                    }
+                    else {
+                        advances[i + advanceOffset] = style.letterSpacing;
+                    }
+
+                    if (LayoutUtils.isWordSpace(ch)) {
+                        advances[i + advanceOffset] += style.wordSpacing;
+                    }
+
+                    totalWidths += advances[i + advanceOffset];
+                }
+            }
+
+            return totalWidths;
+        }
+
+        public static float doLayout(float offset, string text, int start, int count, TextStyle style,
+            float[] advances, float[] positions, TabStops tabStops, out UnityEngine.Rect bounds) {
+            float advance = 0;
+            Font font = FontManager.instance.getOrCreate(style.fontFamily, style.fontWeight, style.fontStyle).font;
+
+            char startingChar = text[start];
+            bounds = new UnityEngine.Rect();
+            if (char.IsHighSurrogate(startingChar) || EmojiUtils.isSingleCharEmoji(startingChar)) {
+                advance = _layoutEmoji(text, start, count, style, font, advances, positions, ref bounds);
+            }
+            else {
+                // According to the logic of Paragraph.layout, it is assured that all the characters are requested
+                // in the texture before (in computing line breaks), so skip it here for optimization.
+                // The only exception is the ellipsis, which did not appear in line breaking. It is taken care of
+                // only when needed.
+
+                // font.RequestCharactersInTextureSafe(buff.text, style.UnityFontSize, style.UnityFontStyle);
+
+//                int wordstart = start == buff.size
+//                    ? start
+//                    : LayoutUtils.getPrevWordBreakForCache(buff, start + 1);
+                int wordend;
+                for (int iter = start; iter < start + count; iter = wordend) {
+                    wordend = LayoutUtils.getNextWordBreak(text, iter, start + count);
+                    advance = _layoutWord(offset, iter - start, text, iter,
+                        wordend - iter, style, font, advances, positions, advance,
+                        tabStops, ref bounds);
+                }
+            }
+
+            // bounds relative to first character
+            bounds.x -= positions[0];
+            return advance;
+        }
+
+        static float _layoutWord(float offset, int layoutOffset,
+            string text, int start, int wordCount, TextStyle style, Font font, float[] advances,
+            float[] positions, float initAdvance, TabStops tabStops, ref UnityEngine.Rect bounds) {
+            float wordSpacing =
+                wordCount == 1 && LayoutUtils.isWordSpace(text[start]) ? style.wordSpacing : 0;
+
+            float x = initAdvance;
+            float letterSpace = style.letterSpacing;
+            float letterSpaceHalfLeft = letterSpace * 0.5f;
+            float letterSpaceHalfRight = letterSpace - letterSpaceHalfLeft;
+
+            for (int i = 0; i < wordCount; i++) {
+                initAdvance = x;
+                var ch = text[start + i];
+                if (i == 0) {
+                    x += letterSpaceHalfLeft + wordSpacing;
+                    advances[i + layoutOffset] = letterSpaceHalfLeft + wordSpacing;
+                }
+                else {
+                    advances[i - 1 + layoutOffset] += letterSpaceHalfRight;
+                    advances[i + layoutOffset] = letterSpaceHalfLeft;
+
+                    x += letterSpace;
+                }
+
+                if (font.getGlyphInfo(ch, out var glyphInfo, style.UnityFontSize, style.UnityFontStyle)) {
+                    _updateBounds(glyphInfo, x, ref bounds);
+                }
+
+                positions[i + layoutOffset] = x;
+
+                float advance;
+                if (ch == '\t') {
+                    advance = tabStops.nextTab(initAdvance + offset) - initAdvance - offset;
+                }
+                else {
+                    advance = glyphInfo.advance;
+                }
+
+                x += advance;
+                advances[i + layoutOffset] += advance;
+
+                if (i + 1 == wordCount) {
+                    advances[i + layoutOffset] += letterSpaceHalfRight;
+                    x += letterSpaceHalfRight;
+                }
+            }
+
+            return x;
+        }
+
+        static float _layoutEmoji(string text, int start, int count, TextStyle style, Font font, float[] advances,
+            float[] positions, ref UnityEngine.Rect bounds) {
+            var metrics = FontMetrics.fromFont(font, style.UnityFontSize);
+            float x = 0;
+            for (int i = 0; i < count; i++) {
+                char c = text[start + i];
+                if (EmojiUtils.isSingleCharNonEmptyEmoji(c) || char.IsHighSurrogate(c)) {
+                    float letterSpace = style.letterSpacing;
+                    float letterSpaceHalfLeft = letterSpace * 0.5f;
+                    float letterSpaceHalfRight = letterSpace - letterSpaceHalfLeft;
+
+                    x += letterSpaceHalfLeft;
+                    advances[i] = letterSpaceHalfLeft;
+
+                    float advance = style.fontSize * EmojiUtils.advanceFactor;
+                    var minX = x;
+                    var maxX = advance + x;
+                    var minY = -style.fontSize * EmojiUtils.sizeFactor;
+                    var maxY = metrics.descent;
+                    _updateBounds(minX, maxX, minY, maxY, ref bounds);
+
+                    positions[i] = x;
+
+                    x += advance;
+
+                    advances[i] += advance;
+                    advances[i] += letterSpaceHalfRight;
+
+                    x += letterSpaceHalfRight;
+                }
+                else {
+                    advances[i] = 0;
+                    positions[i] = x;
+                }
+            }
+
+            return x;
+        }
+
+        static void _updateBounds(CharacterInfo glyphInfo, float x, ref UnityEngine.Rect bounds) {
+            var minX = glyphInfo.minX + x;
+            var maxX = glyphInfo.maxX + x;
+            var minY = -glyphInfo.maxY;
+            var maxY = -glyphInfo.minY;
+            _updateBounds(minX, maxX, minY, maxY, ref bounds);
+        }
+
+        static void _updateBounds(float minX, float maxX, float minY, float maxY, ref UnityEngine.Rect bounds) {
+            if (bounds.width <= 0 || bounds.height <= 0) {
+                bounds.Set(minX, minY, maxX - minX, maxY - minY);
+            }
+            else {
+                if (minX < bounds.x) {
+                    bounds.x = minX;
+                }
+
+                if (minY < bounds.y) {
+                    bounds.y = minY;
+                }
+
+                if (maxX > bounds.xMax) {
+                    bounds.xMax = maxX;
+                }
+
+                if (maxY > bounds.yMax) {
+                    bounds.yMax = maxY;
+                }
+            }
+        }
+    }
 }

com.unity.uiwidgets/Runtime/ui/txt/linebreaker.cs

-using System.Collections.Generic;
-using UnityEngine;
-
-namespace Unity.UIWidgets.ui {
-    class TabStops {
-        int _tabWidth = int.MaxValue;
-
-        Font _font;
-
-        int _fontSize;
-
-        int _spaceAdvance;
-
-        const int kTabSpaceCount = 4;
-
-        public void setFont(Font font, int size) {
-            if (this._font != font || this._fontSize != size) {
-                this._tabWidth = int.MaxValue;
-            }
-
-            this._font = font;
-            // Recompute the advance of space (' ') if font size changes
-            if (this._fontSize != size) {
-                this._fontSize = size;
-                this._font.RequestCharactersInTextureSafe(" ", this._fontSize);
-                this._font.getGlyphInfo(' ', out var glyphInfo, this._fontSize, UnityEngine.FontStyle.Normal);
-                this._spaceAdvance = glyphInfo.advance;
-            }
-        }
-
-        public float nextTab(float widthSoFar) {
-            if (this._tabWidth == int.MaxValue) {
-                if (this._fontSize > 0) {
-                    this._tabWidth = this._spaceAdvance * kTabSpaceCount;
-                }
-            }
-
-            if (this._tabWidth == 0) {
-                return widthSoFar;
-            }
-
-            return (Mathf.Floor(widthSoFar / this._tabWidth + 1) * this._tabWidth);
-        }
-    }
-
-    struct Candidate {
-        public int offset;
-        public int pre;
-        public float preBreak;
-        public float penalty;
-
-        public float postBreak;
-        public int preSpaceCount;
-        public int postSpaceCount;
-    }
-
-    class LineBreaker {
-        const float ScoreInfty = float.MaxValue;
-        const float ScoreDesperate = 1e10f;
-
-        int _lineLimit = 0;
-
-        // Limit number of lines, 0 means no limit
-        public int lineLimit {
-            get { return this._lineLimit; }
-            set { this._lineLimit = value; }
-        }
-
-        public static LineBreaker instance {
-            get {
-                if (_instance == null) {
-                    _instance = new LineBreaker();
-                }
-
-                return _instance;
-            }
-        }
-
-        static LineBreaker _instance;
-
-        public static int[] newLinePositions(string text, out int count) {
-            count = 0;
-            for (var i = 0; i < text.Length; i++) {
-                if (text[i] == '\n') {
-                    count++;
-                }
-            }
-
-            count++;
-
-            if (_newLinePositions == null || _newLinePositions.Length < count) {
-                _newLinePositions = new int[count];
-            }
-
-            count = 0;
-            for (var i = 0; i < text.Length; i++) {
-                if (text[i] == '\n') {
-                    _newLinePositions[count++] = i;
-                }
-            }
-
-            _newLinePositions[count++] = text.Length;
-
-            return _newLinePositions;
-        }
-
-        static int[] _newLinePositions;
-
-        TextBuff _textBuf;
-        float[] _charWidths;
-        List<int> _breaks = new List<int>();
-        int _breaksCount = 0;
-        List<float> _widths = new List<float>();
-        int _widthsCount = 0;
-        WordBreaker _wordBreaker = new WordBreaker();
-        float _width = 0.0f;
-        float _preBreak;
-        float _lineWidth;
-        int _lastBreak;
-        int _bestBreak;
-        float _bestScore;
-        int _spaceCount;
-        TabStops _tabStops;
-        int mFirstTabIndex;
-        List<Candidate> _candidates = new List<Candidate>();
-        int _candidatesCount = 0;
-
-        public int computeBreaks() {
-            int nCand = this._candidatesCount;
-            if (nCand > 0 && (nCand == 1 || this._lastBreak != nCand - 1)) {
-                var cand = this._candidates[this._candidatesCount - 1];
-                this._pushBreak(cand.offset, (cand.postBreak - this._preBreak));
-            }
-
-            return this._breaksCount;
-        }
-
-        public int getBreaksCount() {
-            return this._breaksCount;
-        }
-
-        public int getBreak(int i) {
-            return this._breaks[i];
-        }
-
-        public float getWidth(int i) {
-            return this._widths[i];
-        }
-
-        public void resize(int size) {
-            if (this._charWidths == null || this._charWidths.Length < size) {
-                this._charWidths = new float[LayoutUtils.minPowerOfTwo(size)];
-            }
-        }
-
-        public void setText(string text, int textOffset, int textLength) {
-            this._textBuf = new TextBuff(text, textOffset, textLength);
-            this._wordBreaker.setText(this._textBuf);
-            this._wordBreaker.next();
-            this._candidatesCount = 0;
-            Candidate can = new Candidate {
-                offset = 0, postBreak = 0, preBreak = 0, postSpaceCount = 0, preSpaceCount = 0, pre = 0
-            };
-            this._addCandidateToList(can);
-            this._lastBreak = 0;
-            this._bestBreak = 0;
-            this._bestScore = ScoreInfty;
-            this._preBreak = 0;
-            this.mFirstTabIndex = int.MaxValue;
-            this._spaceCount = 0;
-        }
-
-        public void setLineWidth(float lineWidth) {
-            this._lineWidth = lineWidth;
-        }
-
-        public float addStyleRun(TextStyle style, int start, int end) {
-            float width = 0;
-            if (style != null) {
-//                Layout.measureText(this._width - this._preBreak, this._textBuf,
-//                    start, end - start, style,
-//                    this._charWidths, start, this._tabStops);
-                width = Layout.computeCharWidths(this._width - this._preBreak, this._textBuf.text,
-                    this._textBuf.offset + start, end - start, style,
-                    this._charWidths, start, this._tabStops);
-            }
-
-            int current = this._wordBreaker.current();
-            float postBreak = this._width;
-            int postSpaceCount = this._spaceCount;
-
-            for (int i = start; i < end; i++) {
-                char c = this._textBuf.charAt(i);
-                if (c == '\t') {
-                    this._width = this._preBreak + this._tabStops.nextTab(this._width - this._preBreak);
-                    if (this.mFirstTabIndex == int.MaxValue) {
-                        this.mFirstTabIndex = i;
-                    }
-                }
-                else {
-                    if (LayoutUtils.isWordSpace(c)) {
-                        this._spaceCount += 1;
-                    }
-
-                    this._width += this._charWidths[i];
-                    if (!LayoutUtils.isLineEndSpace(c)) {
-                        postBreak = this._width;
-                        postSpaceCount = this._spaceCount;
-                    }
-                }
-
-                if (i + 1 == current) {
-                    if (style != null || current == end || this._charWidths[current] > 0) {
-                        this._addWordBreak(current, this._width, postBreak, this._spaceCount, postSpaceCount, 0);
-                    }
-
-                    current = this._wordBreaker.next();
-                }
-            }
-
-            return width;
-        }
-
-        public void finish() {
-            this._wordBreaker.finish();
-            this._width = 0;
-            this._candidatesCount = 0;
-            this._breaksCount = 0;
-            this._widthsCount = 0;
-            this._textBuf = default;
-        }
-
-        public int getWidthsCount() {
-            return this._widthsCount;
-        }
-
-        public void setTabStops(TabStops tabStops) {
-            this._tabStops = tabStops;
-        }
-
-        void _addWordBreak(int offset, float preBreak, float postBreak, int preSpaceCount, int postSpaceCount,
-            float penalty) {
-            float width = this._candidates[this._candidatesCount - 1].preBreak;
-            if (postBreak - width > this._lineWidth) {
-                this._addCandidatesInsideWord(width, offset, postSpaceCount);
-            }
-
-            this._addCandidate(new Candidate {
-                offset = offset,
-                preBreak = preBreak,
-                postBreak = postBreak,
-                preSpaceCount = preSpaceCount,
-                postSpaceCount = postSpaceCount,
-                penalty = penalty
-            });
-        }
-
-        void _addCandidatesInsideWord(float width, int offset, int postSpaceCount) {
-            int i = this._candidates[this._candidatesCount - 1].offset;
-            width += this._charWidths[i++];
-            for (; i < offset; i++) {
-                float w = this._charWidths[i];
-                if (w > 0) {
-                    this._addCandidate(new Candidate {
-                        offset = i,
-                        preBreak = width,
-                        postBreak = width,
-                        preSpaceCount = postSpaceCount,
-                        postSpaceCount = postSpaceCount,
-                        penalty = ScoreDesperate,
-                    });
-                    width += w;
-                }
-            }
-        }
-
-        void _addCandidateToList(Candidate cand) {
-            if (this._candidates.Count == this._candidatesCount) {
-                this._candidates.Add(cand);
-                this._candidatesCount++;
-            }
-            else {
-                this._candidates[this._candidatesCount++] = cand;
-            }
-        }
-
-        void _addCandidate(Candidate cand) {
-            int candIndex = this._candidatesCount;
-            this._addCandidateToList(cand);
-            if (cand.postBreak - this._preBreak > this._lineWidth) {
-                if (this._bestBreak == this._lastBreak) {
-                    this._bestBreak = candIndex;
-                }
-
-                this._pushGreedyBreak();
-            }
-
-            while (this._lastBreak != candIndex && cand.postBreak - this._preBreak > this._lineWidth) {
-                for (int i = this._lastBreak + 1; i < candIndex; i++) {
-                    float penalty = this._candidates[i].penalty;
-                    if (penalty <= this._bestScore) {
-                        this._bestBreak = i;
-                        this._bestScore = penalty;
-                    }
-                }
-
-                if (this._bestBreak == this._lastBreak) {
-                    this._bestBreak = candIndex;
-                }
-
-                this._pushGreedyBreak();
-            }
-
-            if (cand.penalty <= this._bestScore) {
-                this._bestBreak = candIndex;
-                this._bestScore = cand.penalty;
-            }
-        }
-
-        void _pushGreedyBreak() {
-            var bestCandidate = this._candidates[this._bestBreak];
-            this._pushBreak(bestCandidate.offset, bestCandidate.postBreak - this._preBreak);
-            this._bestScore = ScoreInfty;
-            this._lastBreak = this._bestBreak;
-            this._preBreak = bestCandidate.preBreak;
-        }
-
-        void _pushBreak(int offset, float width) {
-            if (this.lineLimit == 0 || this._breaksCount < this.lineLimit) {
-                if (this._breaks.Count == this._breaksCount) {
-                    this._breaks.Add(offset);
-                    this._breaksCount++;
-                }
-                else {
-                    this._breaks[this._breaksCount++] = offset;
-                }
-
-                if (this._widths.Count == this._widthsCount) {
-                    this._widths.Add(width);
-                    this._widthsCount++;
-                }
-                else {
-                    this._widths[this._widthsCount++] = width;
-                }
-            }
-        }
-    }
+using System.Collections.Generic;
+using UnityEngine;
+
+namespace Unity.UIWidgets.ui {
+    class TabStops {
+        int _tabWidth = int.MaxValue;
+
+        Font _font;
+
+        int _fontSize;
+
+        int _spaceAdvance;
+
+        const int kTabSpaceCount = 4;
+
+        public void setFont(Font font, int size) {
+            if (this._font != font || this._fontSize != size) {
+                this._tabWidth = int.MaxValue;
+            }
+
+            this._font = font;
+            // Recompute the advance of space (' ') if font size changes
+            if (this._fontSize != size) {
+                this._fontSize = size;
+                this._font.RequestCharactersInTextureSafe(" ", this._fontSize);
+                this._font.getGlyphInfo(' ', out var glyphInfo, this._fontSize, UnityEngine.FontStyle.Normal);
+                this._spaceAdvance = glyphInfo.advance;
+            }
+        }
+
+        public float nextTab(float widthSoFar) {
+            if (this._tabWidth == int.MaxValue) {
+                if (this._fontSize > 0) {
+                    this._tabWidth = this._spaceAdvance * kTabSpaceCount;
+                }
+            }
+
+            if (this._tabWidth == 0) {
+                return widthSoFar;
+            }
+
+            return (Mathf.Floor(widthSoFar / this._tabWidth + 1) * this._tabWidth);
+        }
+    }
+
+    struct Candidate {
+        public int offset;
+        public int pre;
+        public float preBreak;
+        public float penalty;
+
+        public float postBreak;
+        public int preSpaceCount;
+        public int postSpaceCount;
+    }
+
+    class LineBreaker {
+        const float ScoreInfty = float.MaxValue;
+        const float ScoreDesperate = 1e10f;
+
+        int _lineLimit = 0;
+
+        // Limit number of lines, 0 means no limit
+        public int lineLimit {
+            get { return this._lineLimit; }
+            set { this._lineLimit = value; }
+        }
+
+        public static LineBreaker instance {
+            get {
+                if (_instance == null) {
+                    _instance = new LineBreaker();
+                }
+
+                return _instance;
+            }
+        }
+
+        static LineBreaker _instance;
+
+        public static int[] newLinePositions(string text, out int count) {
+            count = 0;
+            for (var i = 0; i < text.Length; i++) {
+                if (text[i] == '\n') {
+                    count++;
+                }
+            }
+
+            count++;
+
+            if (_newLinePositions == null || _newLinePositions.Length < count) {
+                _newLinePositions = new int[count];
+            }
+
+            count = 0;
+            for (var i = 0; i < text.Length; i++) {
+                if (text[i] == '\n') {
+                    _newLinePositions[count++] = i;
+                }
+            }
+
+            _newLinePositions[count++] = text.Length;
+
+            return _newLinePositions;
+        }
+
+        static int[] _newLinePositions;
+
+        TextBuff _textBuf;
+        float[] _charWidths;
+        List<int> _breaks = new List<int>();
+        int _breaksCount = 0;
+        List<float> _widths = new List<float>();
+        int _widthsCount = 0;
+        WordBreaker _wordBreaker = new WordBreaker();
+        float _width = 0.0f;
+        float _preBreak;
+        float _lineWidth;
+        int _lastBreak;
+        int _bestBreak;
+        float _bestScore;
+        int _spaceCount;
+        TabStops _tabStops;
+        int mFirstTabIndex;
+        List<Candidate> _candidates = new List<Candidate>();
+        int _candidatesCount = 0;
+
+        public int computeBreaks() {
+            int nCand = this._candidatesCount;
+            if (nCand > 0 && (nCand == 1 || this._lastBreak != nCand - 1)) {
+                var cand = this._candidates[this._candidatesCount - 1];
+                this._pushBreak(cand.offset, (cand.postBreak - this._preBreak));
+            }
+
+            return this._breaksCount;
+        }
+
+        public int getBreaksCount() {
+            return this._breaksCount;
+        }
+
+        public int getBreak(int i) {
+            return this._breaks[i];
+        }
+
+        public float getWidth(int i) {
+            return this._widths[i];
+        }
+
+        public void resize(int size) {
+            if (this._charWidths == null || this._charWidths.Length < size) {
+                this._charWidths = new float[LayoutUtils.minPowerOfTwo(size)];
+            }
+        }
+
+        public void setText(string text, int textOffset, int textLength) {
+            this._textBuf = new TextBuff(text, textOffset, textLength);
+            this._wordBreaker.setText(this._textBuf);
+            this._wordBreaker.next();
+            this._candidatesCount = 0;
+            Candidate can = new Candidate {
+                offset = 0, postBreak = 0, preBreak = 0, postSpaceCount = 0, preSpaceCount = 0, pre = 0
+            };
+            this._addCandidateToList(can);
+            this._lastBreak = 0;
+            this._bestBreak = 0;
+            this._bestScore = ScoreInfty;
+            this._preBreak = 0;
+            this.mFirstTabIndex = int.MaxValue;
+            this._spaceCount = 0;
+        }
+
+        public void setLineWidth(float lineWidth) {
+            this._lineWidth = lineWidth;
+        }
+
+        public float addStyleRun(TextStyle style, int start, int end) {
+            float width = 0;
+            if (style != null) {
+//                Layout.measureText(this._width - this._preBreak, this._textBuf,
+//                    start, end - start, style,
+//                    this._charWidths, start, this._tabStops);
+                width = Layout.computeCharWidths(this._width - this._preBreak, this._textBuf.text,
+                    this._textBuf.offset + start, end - start, style,
+                    this._charWidths, start, this._tabStops);
+            }
+
+            int current = this._wordBreaker.current();
+            float postBreak = this._width;
+            int postSpaceCount = this._spaceCount;
+
+            for (int i = start; i < end; i++) {
+                char c = this._textBuf.charAt(i);
+                if (c == '\t') {
+                    this._width = this._preBreak + this._tabStops.nextTab(this._width - this._preBreak);
+                    if (this.mFirstTabIndex == int.MaxValue) {
+                        this.mFirstTabIndex = i;
+                    }
+                }
+                else {
+                    if (LayoutUtils.isWordSpace(c)) {
+                        this._spaceCount += 1;
+                    }
+
+                    this._width += this._charWidths[i];
+                    if (!LayoutUtils.isLineEndSpace(c)) {
+                        postBreak = this._width;
+                        postSpaceCount = this._spaceCount;
+                    }
+                }
+
+                if (i + 1 == current) {
+                    if (style != null || current == end || this._charWidths[current] > 0) {
+                        this._addWordBreak(current, this._width, postBreak, this._spaceCount, postSpaceCount, 0);
+                    }
+
+                    current = this._wordBreaker.next();
+                }
+            }
+
+            return width;
+        }
+
+        public void finish() {
+            this._wordBreaker.finish();
+            this._width = 0;
+            this._candidatesCount = 0;
+            this._breaksCount = 0;
+            this._widthsCount = 0;
+            this._textBuf = default;
+        }
+
+        public int getWidthsCount() {
+            return this._widthsCount;
+        }
+
+        public void setTabStops(TabStops tabStops) {
+            this._tabStops = tabStops;
+        }
+
+        void _addWordBreak(int offset, float preBreak, float postBreak, int preSpaceCount, int postSpaceCount,
+            float penalty) {
+            float width = this._candidates[this._candidatesCount - 1].preBreak;
+            if (postBreak - width > this._lineWidth) {
+                this._addCandidatesInsideWord(width, offset, postSpaceCount);
+            }
+
+            this._addCandidate(new Candidate {
+                offset = offset,
+                preBreak = preBreak,
+                postBreak = postBreak,
+                preSpaceCount = preSpaceCount,
+                postSpaceCount = postSpaceCount,
+                penalty = penalty
+            });
+        }
+
+        void _addCandidatesInsideWord(float width, int offset, int postSpaceCount) {
+            int i = this._candidates[this._candidatesCount - 1].offset;
+            width += this._charWidths[i++];
+            for (; i < offset; i++) {
+                float w = this._charWidths[i];
+                if (w > 0) {
+                    this._addCandidate(new Candidate {
+                        offset = i,
+                        preBreak = width,
+                        postBreak = width,
+                        preSpaceCount = postSpaceCount,
+                        postSpaceCount = postSpaceCount,
+                        penalty = ScoreDesperate,
+                    });
+                    width += w;
+                }
+            }
+        }
+
+        void _addCandidateToList(Candidate cand) {
+            if (this._candidates.Count == this._candidatesCount) {
+                this._candidates.Add(cand);
+                this._candidatesCount++;
+            }
+            else {
+                this._candidates[this._candidatesCount++] = cand;
+            }
+        }
+
+        void _addCandidate(Candidate cand) {
+            int candIndex = this._candidatesCount;
+            this._addCandidateToList(cand);
+            if (cand.postBreak - this._preBreak > this._lineWidth) {
+                if (this._bestBreak == this._lastBreak) {
+                    this._bestBreak = candIndex;
+                }
+
+                this._pushGreedyBreak();
+            }
+
+            while (this._lastBreak != candIndex && cand.postBreak - this._preBreak > this._lineWidth) {
+                for (int i = this._lastBreak + 1; i < candIndex; i++) {
+                    float penalty = this._candidates[i].penalty;
+                    if (penalty <= this._bestScore) {
+                        this._bestBreak = i;
+                        this._bestScore = penalty;
+                    }
+                }
+
+                if (this._bestBreak == this._lastBreak) {
+                    this._bestBreak = candIndex;
+                }
+
+                this._pushGreedyBreak();
+            }
+
+            if (cand.penalty <= this._bestScore) {
+                this._bestBreak = candIndex;
+                this._bestScore = cand.penalty;
+            }
+        }
+
+        void _pushGreedyBreak() {
+            var bestCandidate = this._candidates[this._bestBreak];
+            this._pushBreak(bestCandidate.offset, bestCandidate.postBreak - this._preBreak);
+            this._bestScore = ScoreInfty;
+            this._lastBreak = this._bestBreak;
+            this._preBreak = bestCandidate.preBreak;
+        }
+
+        void _pushBreak(int offset, float width) {
+            if (this.lineLimit == 0 || this._breaksCount < this.lineLimit) {
+                if (this._breaks.Count == this._breaksCount) {
+                    this._breaks.Add(offset);
+                    this._breaksCount++;
+                }
+                else {
+                    this._breaks[this._breaksCount++] = offset;
+                }
+
+                if (this._widths.Count == this._widthsCount) {
+                    this._widths.Add(width);
+                    this._widthsCount++;
+                }
+                else {
+                    this._widths[this._widthsCount++] = width;
+                }
+            }
+        }
+    }
 }

com.unity.uiwidgets/Runtime/ui/painting/image.cs.meta

-fileFormatVersion: 2
-guid: bfd6fdb0d13948d6acbc528589ebef33
+fileFormatVersion: 2
+guid: bfd6fdb0d13948d6acbc528589ebef33
 timeCreated: 1534821698

com.unity.uiwidgets/Runtime/ui/painting/txt/text_blob.cs

-namespace Unity.UIWidgets.ui {
-    public struct TextBlob {
-        internal TextBlob(string text, int textOffset, int textSize, float[] positionXs,
-            UnityEngine.Rect bounds, TextStyle style) {
-            this.instanceId = ++_nextInstanceId;
-            this._positionXs = positionXs;
-            this.text = text;
-            this.textOffset = textOffset;
-            this.textSize = textSize;
-            this.style = style;
-            this._bounds = bounds;
-            this._boundsInText = null;
-        }
-
-        public Rect boundsInText {
-            get {
-                if (this._boundsInText == null) {
-                    var pos = this.getPositionX(0);
-                    this._boundsInText = Rect.fromLTWH(this._bounds.xMin + pos, this._bounds.yMin,
-                        this._bounds.width, this._bounds.height);
-                }
-
-                return this._boundsInText;
-            }
-        }
-
-        public Rect shiftedBoundsInText(float dx, float dy) {
-            var pos = this.getPositionX(0);
-            return Rect.fromLTWH(this._bounds.xMin + pos + dx, this._bounds.yMin + dy,
-                this._bounds.width, this._bounds.height);
-        }
-
-        public float getPositionX(int i) {
-            return this._positionXs[this.textOffset + i];
-        }
-
-        static long _nextInstanceId;
-        internal readonly long instanceId;
-        internal readonly string text;
-        internal readonly int textOffset;
-        internal readonly int textSize;
-        internal readonly TextStyle style;
-        readonly UnityEngine.Rect _bounds; // bounds with positions[start] as origin       
-        readonly float[] _positionXs;
-
-        Rect _boundsInText;
-    }
-
-    public struct TextBlobBuilder {
-        TextStyle _style;
-        float[] _positionXs;
-        string _text;
-        int _textOffset;
-        int _size;
-        UnityEngine.Rect _bounds;
-
-        public void allocRunPos(painting.TextStyle style, string text, int offset, int size,
-            float textScaleFactor = 1.0f) {
-            this.allocRunPos(TextStyle.applyStyle(null, style, textScaleFactor), text, offset, size);
-        }
-
-        internal void allocRunPos(TextStyle style, string text, int offset, int size) {
-            this._style = style;
-            this._text = text;
-            this._textOffset = offset;
-            this._size = size;
-            // Allocate a single buffer for all text blobs that share this text, to save memory and GC.
-            // It is assumed that all of `text` is being used. This may cause great waste if a long text is passed
-            // but only a small part of it is to be rendered, which is not the case for now.
-            this.allocPos(text.Length);
-        }
-
-        internal void allocPos(int size) {
-            if (this._positionXs == null || this._positionXs.Length < size) {
-                this._positionXs = new float[size];
-            }
-        }
-
-        public void setPositionX(int i, float positionX) {
-            this._positionXs[this._textOffset + i] = positionX;
-        }
-
-        public void setPositionXs(float[] positionXs) {
-            this._positionXs = positionXs;
-        }
-
-        public void setBounds(UnityEngine.Rect bounds) {
-            this._bounds = bounds;
-        }
-
-        public TextBlob make() {
-            var result = new TextBlob(this._text, this._textOffset,
-                this._size, this._positionXs, this._bounds, this._style);
-            return result;
-        }
-    }
+namespace Unity.UIWidgets.ui {
+    public struct TextBlob {
+        internal TextBlob(string text, int textOffset, int textSize, float[] positionXs,
+            UnityEngine.Rect bounds, TextStyle style) {
+            this.instanceId = ++_nextInstanceId;
+            this._positionXs = positionXs;
+            this.text = text;
+            this.textOffset = textOffset;
+            this.textSize = textSize;
+            this.style = style;
+            this._bounds = bounds;
+            this._boundsInText = null;
+        }
+
+        public Rect boundsInText {
+            get {
+                if (this._boundsInText == null) {
+                    var pos = this.getPositionX(0);
+                    this._boundsInText = Rect.fromLTWH(this._bounds.xMin + pos, this._bounds.yMin,
+                        this._bounds.width, this._bounds.height);
+                }
+
+                return this._boundsInText;
+            }
+        }
+
+        public Rect shiftedBoundsInText(float dx, float dy) {
+            var pos = this.getPositionX(0);
+            return Rect.fromLTWH(this._bounds.xMin + pos + dx, this._bounds.yMin + dy,
+                this._bounds.width, this._bounds.height);
+        }
+
+        public float getPositionX(int i) {
+            return this._positionXs[this.textOffset + i];
+        }
+
+        static long _nextInstanceId;
+        internal readonly long instanceId;
+        internal readonly string text;
+        internal readonly int textOffset;
+        internal readonly int textSize;
+        internal readonly TextStyle style;
+        readonly UnityEngine.Rect _bounds; // bounds with positions[start] as origin       
+        readonly float[] _positionXs;
+
+        Rect _boundsInText;
+    }
+
+    public struct TextBlobBuilder {
+        TextStyle _style;
+        float[] _positionXs;
+        string _text;
+        int _textOffset;
+        int _size;
+        UnityEngine.Rect _bounds;
+
+        public void allocRunPos(painting.TextStyle style, string text, int offset, int size,
+            float textScaleFactor = 1.0f) {
+            this.allocRunPos(TextStyle.applyStyle(null, style, textScaleFactor), text, offset, size);
+        }
+
+        internal void allocRunPos(TextStyle style, string text, int offset, int size) {
+            this._style = style;
+            this._text = text;
+            this._textOffset = offset;
+            this._size = size;
+            // Allocate a single buffer for all text blobs that share this text, to save memory and GC.
+            // It is assumed that all of `text` is being used. This may cause great waste if a long text is passed
+            // but only a small part of it is to be rendered, which is not the case for now.
+            this.allocPos(text.Length);
+        }
+
+        internal void allocPos(int size) {
+            if (this._positionXs == null || this._positionXs.Length < size) {
+                this._positionXs = new float[size];
+            }
+        }
+
+        public void setPositionX(int i, float positionX) {
+            this._positionXs[this._textOffset + i] = positionX;
+        }
+
+        public void setPositionXs(float[] positionXs) {
+            this._positionXs = positionXs;
+        }
+
+        public void setBounds(UnityEngine.Rect bounds) {
+            this._bounds = bounds;
+        }
+
+        public TextBlob make() {
+            var result = new TextBlob(this._text, this._textOffset,
+                this._size, this._positionXs, this._bounds, this._style);
+            return result;
+        }
+    }
 }

com.unity.uiwidgets/Runtime/rendering/debug.cs

-namespace Unity.UIWidgets.rendering {
-    public static class RenderingDebugUtils {
-        public static bool debugCheckElevationsEnabled = false;
-    }
+namespace Unity.UIWidgets.rendering {
+    public static class RenderingDebugUtils {
+        public static bool debugCheckElevationsEnabled = false;
+    }
 }

com.unity.uiwidgets/Runtime/rendering/error.cs.meta

-fileFormatVersion: 2
-guid: 64dfb38ea47d49c7b9f3d0debeee4409
+fileFormatVersion: 2
+guid: 64dfb38ea47d49c7b9f3d0debeee4409
 timeCreated: 1536819405

com.unity.uiwidgets/Runtime/rendering/image.cs.meta

-fileFormatVersion: 2
-guid: d0413272d07e4c958f45f9c7597fe2b7
+fileFormatVersion: 2
+guid: d0413272d07e4c958f45f9c7597fe2b7
 timeCreated: 1534820838

com.unity.uiwidgets/Runtime/rendering/rotated_box.cs.meta

-fileFormatVersion: 2
-guid: 057a0f3b94794fce9f9f3aa7bb624256
+fileFormatVersion: 2
+guid: 057a0f3b94794fce9f9f3aa7bb624256
 timeCreated: 1557210363

com.unity.uiwidgets/Runtime/rendering/sliver_persistent_header.cs.meta

-fileFormatVersion: 2
-guid: 8bf4842a43ca4b13ae8d333813e166c9
+fileFormatVersion: 2
+guid: 8bf4842a43ca4b13ae8d333813e166c9
 timeCreated: 1553064435

com.unity.uiwidgets/Runtime/rendering/wrap.cs.meta

-fileFormatVersion: 2
-guid: bf63171d5e9d4f9fb93cf8cf7a0534bb
+fileFormatVersion: 2
+guid: bf63171d5e9d4f9fb93cf8cf7a0534bb
 timeCreated: 1552011675

com.unity.uiwidgets/Runtime/promise/EnumerableExt.cs.meta

-fileFormatVersion: 2
-guid: bb9a3c5b387541cb800b11c84121f7f3
+fileFormatVersion: 2
+guid: bb9a3c5b387541cb800b11c84121f7f3
 timeCreated: 1534828260

com.unity.uiwidgets/Runtime/promise/Promise.cs.meta

-fileFormatVersion: 2
-guid: ffdd174fa01b47d99dae6b8b38945413
+fileFormatVersion: 2
+guid: ffdd174fa01b47d99dae6b8b38945413
 timeCreated: 1534828022

com.unity.uiwidgets/Runtime/promise/PromiseException.cs.meta

-fileFormatVersion: 2
-guid: ef24fa8abd794ec9ad904f149ade425b
+fileFormatVersion: 2
+guid: ef24fa8abd794ec9ad904f149ade425b
 timeCreated: 1534828173

com.unity.uiwidgets/Runtime/promise/PromiseHelpers.cs.meta

-fileFormatVersion: 2
-guid: 07f0b3c08d53427992f828dd9c4f0f15
+fileFormatVersion: 2
+guid: 07f0b3c08d53427992f828dd9c4f0f15
 timeCreated: 1534828078

com.unity.uiwidgets/Runtime/promise/PromiseStateException.cs.meta

-fileFormatVersion: 2
-guid: d922956f02bc4ff2a82f9404787380b0
+fileFormatVersion: 2
+guid: d922956f02bc4ff2a82f9404787380b0
 timeCreated: 1534828191

com.unity.uiwidgets/Runtime/promise/PromiseTimer.cs.meta

-fileFormatVersion: 2
-guid: e47ddf579a9a45f48fd9203faf93b52f
+fileFormatVersion: 2
+guid: e47ddf579a9a45f48fd9203faf93b52f
 timeCreated: 1534828095

com.unity.uiwidgets/Runtime/promise/Promise_NonGeneric.cs.meta

-fileFormatVersion: 2
-guid: fad6eb2d15b84c7cb92f115245ac09f8
+fileFormatVersion: 2
+guid: fad6eb2d15b84c7cb92f115245ac09f8
 timeCreated: 1534828106

com.unity.uiwidgets/Runtime/promise/Tuple.cs.meta

-fileFormatVersion: 2
-guid: 2e1ff13e974447a080559101999e17d9
+fileFormatVersion: 2
+guid: 2e1ff13e974447a080559101999e17d9
 timeCreated: 1534828127

com.unity.uiwidgets/Runtime/painting/box_fit.cs.meta

-fileFormatVersion: 2
-guid: 4d75ec15a75b4a7baca1968978b1eec9
+fileFormatVersion: 2
+guid: 4d75ec15a75b4a7baca1968978b1eec9
 timeCreated: 1534820694

com.unity.uiwidgets/Runtime/painting/image_cache.cs.meta

-fileFormatVersion: 2
-guid: 80732e4248ce48ec92e1463ddc59451d
+fileFormatVersion: 2
+guid: 80732e4248ce48ec92e1463ddc59451d
 timeCreated: 1534833891

com.unity.uiwidgets/Runtime/painting/image_provider.cs.meta

-fileFormatVersion: 2
-guid: 858587f8fb5d435e8a07a0ff46e5bc95
+fileFormatVersion: 2
+guid: 858587f8fb5d435e8a07a0ff46e5bc95
 timeCreated: 1534820746

com.unity.uiwidgets/Runtime/painting/image_stream.cs.meta

-fileFormatVersion: 2
-guid: 462d84cff25d484895d1a81e7ebd2a24
+fileFormatVersion: 2
+guid: 462d84cff25d484895d1a81e7ebd2a24
 timeCreated: 1534820764

com.unity.uiwidgets/Runtime/painting/notched_shapes.cs.meta

-fileFormatVersion: 2
-guid: c89c524fa7c242aa91900b63841be8b3
+fileFormatVersion: 2
+guid: c89c524fa7c242aa91900b63841be8b3
 timeCreated: 1553153571

com.unity.uiwidgets/Runtime/painting/strut_style.cs

-using System.Collections.Generic;
-using System.Linq;
-using Unity.UIWidgets.foundation;
-using Unity.UIWidgets.ui;
-
-namespace Unity.UIWidgets.painting {
-    public class StrutStyle : Diagnosticable {
-        public StrutStyle(
-            string fontFamily = null,
-            List<string> fontFamilyFallback = null,
-            float? fontSize = null,
-            float? height = null,
-            float? leading = null,
-            FontWeight fontWeight = null,
-            FontStyle? fontStyle = null,
-            bool forceStrutHeight = false,
-            string debugLabel = null
-        ) {
-            D.assert(fontSize == null || fontSize > 0);
-            D.assert(leading == null || leading >= 0);
-            this.fontFamily = fontFamily;
-            this._fontFamilyFallback = fontFamilyFallback;
-            this.fontSize = fontSize;
-            this.height = height;
-            this.fontWeight = fontWeight;
-            this.fontStyle = fontStyle;
-            this.leading = leading;
-            this.forceStrutHeight = forceStrutHeight;
-            this.debugLabel = debugLabel;
-        }
-
-        public static StrutStyle fromTextStyle(
-            TextStyle textStyle,
-            string fontFamily = null,
-            List<string> fontFamilyFallback = null,
-            float? fontSize = null,
-            float? height = null,
-            float? leading = null,
-            FontWeight fontWeight = null,
-            FontStyle? fontStyle = null,
-            bool forceStrutHeight = false,
-            string debugLabel = null
-        ) {
-            D.assert(textStyle != null);
-            D.assert(fontSize == null || fontSize > 0);
-            D.assert(leading == null || leading >= 0);
-            return new StrutStyle(
-                fontFamily: fontFamily ?? textStyle.fontFamily,
-                fontFamilyFallback: fontFamilyFallback ?? textStyle.fontFamilyFallback,
-                height: height ?? textStyle.height,
-                fontSize: fontSize ?? textStyle.fontSize,
-                fontWeight: fontWeight ?? textStyle.fontWeight,
-                fontStyle: fontStyle ?? textStyle.fontStyle,
-                debugLabel: debugLabel ?? textStyle.debugLabel
-            );
-        }
-
-        public static readonly StrutStyle disabled = new StrutStyle(
-            height: 0.0f,
-            leading: 0.0f
-        );
-
-        public readonly string fontFamily;
-
-        public List<string> fontFamilyFallback {
-            get { return this._fontFamilyFallback; }
-        }
-
-        readonly List<string> _fontFamilyFallback;
-
-        public readonly float? fontSize;
-        public readonly float? height;
-        public readonly FontWeight fontWeight;
-        public readonly FontStyle? fontStyle;
-        public readonly float? leading;
-        public readonly bool forceStrutHeight;
-        public readonly string debugLabel;
-
-        public RenderComparison compareTo(StrutStyle other) {
-            if (ReferenceEquals(this, other)) {
-                return RenderComparison.identical;
-            }
-
-            if (other == null) {
-                return RenderComparison.layout;
-            }
-
-            if (this.fontFamily != other.fontFamily ||
-                this.fontSize != other.fontSize ||
-                this.fontWeight != other.fontWeight ||
-                this.fontStyle != other.fontStyle ||
-                this.height != other.height ||
-                this.leading != other.leading ||
-                this.forceStrutHeight != other.forceStrutHeight ||
-                !CollectionUtils.equalsList(this.fontFamilyFallback, other.fontFamilyFallback)) {
-                return RenderComparison.layout;
-            }
-
-            return RenderComparison.identical;
-        }
-
-        public StrutStyle inheritFromTextStyle(TextStyle other) {
-            if (other == null) {
-                return this;
-            }
-
-            return new StrutStyle(
-                fontFamily: this.fontFamily ?? other.fontFamily,
-                fontFamilyFallback: this.fontFamilyFallback ?? other.fontFamilyFallback,
-                height: this.height ?? other.height,
-                leading: this.leading,
-                fontSize: this.fontSize ?? other.fontSize,
-                fontWeight: this.fontWeight ?? other.fontWeight,
-                fontStyle: this.fontStyle ?? other.fontStyle,
-                forceStrutHeight: this.forceStrutHeight,
-                debugLabel: this.debugLabel ?? other.debugLabel
-            );
-        }
-
-        public bool Equals(StrutStyle other) {
-            if (ReferenceEquals(null, other)) {
-                return false;
-            }
-
-            if (ReferenceEquals(this, other)) {
-                return true;
-            }
-
-            return this.fontFamily == other.fontFamily &&
-                   this.fontSize == other.fontSize &&
-                   this.fontWeight == other.fontWeight &&
-                   this.fontStyle == other.fontStyle &&
-                   this.height == other.height &&
-                   this.leading == other.leading &&
-                   this.forceStrutHeight == other.forceStrutHeight;
-        }
-
-        public override bool Equals(object obj) {
-            if (ReferenceEquals(null, obj)) {
-                return false;
-            }
-
-            if (ReferenceEquals(this, obj)) {
-                return true;
-            }
-
-            if (obj.GetType() != this.GetType()) {
-                return false;
-            }
-
-            return this.Equals((StrutStyle) obj);
-        }
-
-        public static bool operator ==(StrutStyle left, StrutStyle right) {
-            return Equals(left, right);
-        }
-
-        public static bool operator !=(StrutStyle left, StrutStyle right) {
-            return !Equals(left, right);
-        }
-
-        public override int GetHashCode() {
-            unchecked {
-                var hashCode = this.fontFamily?.GetHashCode() ?? 0;
-                hashCode = (hashCode * 397) ^ (this.fontSize?.GetHashCode() ?? 0);
-                hashCode = (hashCode * 397) ^ (this.fontWeight?.GetHashCode() ?? 0);
-                hashCode = (hashCode * 397) ^ (this.fontStyle?.GetHashCode() ?? 0);
-                hashCode = (hashCode * 397) ^ (this.height?.GetHashCode() ?? 0);
-                hashCode = (hashCode * 397) ^ (this.leading?.GetHashCode() ?? 0);
-                hashCode = (hashCode * 397) ^ this.forceStrutHeight.GetHashCode();
-                return hashCode;
-            }
-        }
-
-        public override string toStringShort() {
-            return $"{this.GetType()}";
-        }
-
-        public override void debugFillProperties(DiagnosticPropertiesBuilder properties) {
-            base.debugFillProperties(properties);
-            if (this.debugLabel != null) {
-                properties.add(new MessageProperty("debugLabel", this.debugLabel));
-            }
-
-            List<DiagnosticsNode> styles = new List<DiagnosticsNode>();
-            styles.Add(new StringProperty("family", this.fontFamily, defaultValue: Diagnostics.kNullDefaultValue,
-                quoted: false));
-            styles.Add(new EnumerableProperty<string>("familyFallback", this.fontFamilyFallback));
-            styles.Add(new DiagnosticsProperty<float?>("size", this.fontSize,
-                defaultValue: Diagnostics.kNullDefaultValue));
-            string weightDescription = "";
-            if (this.fontWeight != null) {
-                weightDescription = this.fontWeight.weightValue.ToString();
-            }
-
-            styles.Add(new DiagnosticsProperty<FontWeight>(
-                "weight", this.fontWeight,
-                description: weightDescription,
-                defaultValue: Diagnostics.kNullDefaultValue
-            ));
-            styles.Add(new EnumProperty<FontStyle?>("style", this.fontStyle,
-                defaultValue: Diagnostics.kNullDefaultValue));
-            styles.Add(new DiagnosticsProperty<float?>("height", this.height,
-                defaultValue: Diagnostics.kNullDefaultValue));
-            styles.Add(new FlagProperty("forceStrutHeight", value: this.forceStrutHeight,
-                defaultValue: Diagnostics.kNullDefaultValue));
-
-            bool styleSpecified = styles.Any((DiagnosticsNode n) => !n.isFiltered(DiagnosticLevel.info));
-            foreach (var style in styles) {
-                properties.add(style);
-            }
-
-            if (!styleSpecified) {
-                properties.add(new FlagProperty("forceStrutHeight", value: this.forceStrutHeight,
-                    ifTrue: "<strut height forced>",
-                    ifFalse: "<strut height normal>"));
-            }
-        }
-    }
+using System.Collections.Generic;
+using System.Linq;
+using Unity.UIWidgets.foundation;
+using Unity.UIWidgets.ui;
+
+namespace Unity.UIWidgets.painting {
+    public class StrutStyle : Diagnosticable {
+        public StrutStyle(
+            string fontFamily = null,
+            List<string> fontFamilyFallback = null,
+            float? fontSize = null,
+            float? height = null,
+            float? leading = null,
+            FontWeight fontWeight = null,
+            FontStyle? fontStyle = null,
+            bool forceStrutHeight = false,
+            string debugLabel = null
+        ) {
+            D.assert(fontSize == null || fontSize > 0);
+            D.assert(leading == null || leading >= 0);
+            this.fontFamily = fontFamily;
+            this._fontFamilyFallback = fontFamilyFallback;
+            this.fontSize = fontSize;
+            this.height = height;
+            this.fontWeight = fontWeight;
+            this.fontStyle = fontStyle;
+            this.leading = leading;
+            this.forceStrutHeight = forceStrutHeight;
+            this.debugLabel = debugLabel;
+        }
+
+        public static StrutStyle fromTextStyle(
+            TextStyle textStyle,
+            string fontFamily = null,
+            List<string> fontFamilyFallback = null,
+            float? fontSize = null,
+            float? height = null,
+            float? leading = null,
+            FontWeight fontWeight = null,
+            FontStyle? fontStyle = null,
+            bool forceStrutHeight = false,
+            string debugLabel = null
+        ) {
+            D.assert(textStyle != null);
+            D.assert(fontSize == null || fontSize > 0);
+            D.assert(leading == null || leading >= 0);
+            return new StrutStyle(
+                fontFamily: fontFamily ?? textStyle.fontFamily,
+                fontFamilyFallback: fontFamilyFallback ?? textStyle.fontFamilyFallback,
+                height: height ?? textStyle.height,
+                fontSize: fontSize ?? textStyle.fontSize,
+                fontWeight: fontWeight ?? textStyle.fontWeight,
+                fontStyle: fontStyle ?? textStyle.fontStyle,
+                debugLabel: debugLabel ?? textStyle.debugLabel
+            );
+        }
+
+        public static readonly StrutStyle disabled = new StrutStyle(
+            height: 0.0f,
+            leading: 0.0f
+        );
+
+        public readonly string fontFamily;
+
+        public List<string> fontFamilyFallback {
+            get { return this._fontFamilyFallback; }
+        }
+
+        readonly List<string> _fontFamilyFallback;
+
+        public readonly float? fontSize;
+        public readonly float? height;
+        public readonly FontWeight fontWeight;
+        public readonly FontStyle? fontStyle;
+        public readonly float? leading;
+        public readonly bool forceStrutHeight;
+        public readonly string debugLabel;
+
+        public RenderComparison compareTo(StrutStyle other) {
+            if (ReferenceEquals(this, other)) {
+                return RenderComparison.identical;
+            }
+
+            if (other == null) {
+                return RenderComparison.layout;
+            }
+
+            if (this.fontFamily != other.fontFamily ||
+                this.fontSize != other.fontSize ||
+                this.fontWeight != other.fontWeight ||
+                this.fontStyle != other.fontStyle ||
+                this.height != other.height ||
+                this.leading != other.leading ||
+                this.forceStrutHeight != other.forceStrutHeight ||
+                !CollectionUtils.equalsList(this.fontFamilyFallback, other.fontFamilyFallback)) {
+                return RenderComparison.layout;
+            }
+
+            return RenderComparison.identical;
+        }
+
+        public StrutStyle inheritFromTextStyle(TextStyle other) {
+            if (other == null) {
+                return this;
+            }
+
+            return new StrutStyle(
+                fontFamily: this.fontFamily ?? other.fontFamily,
+                fontFamilyFallback: this.fontFamilyFallback ?? other.fontFamilyFallback,
+                height: this.height ?? other.height,
+                leading: this.leading,
+                fontSize: this.fontSize ?? other.fontSize,
+                fontWeight: this.fontWeight ?? other.fontWeight,
+                fontStyle: this.fontStyle ?? other.fontStyle,
+                forceStrutHeight: this.forceStrutHeight,
+                debugLabel: this.debugLabel ?? other.debugLabel
+            );
+        }
+
+        public bool Equals(StrutStyle other) {
+            if (ReferenceEquals(null, other)) {
+                return false;
+            }
+
+            if (ReferenceEquals(this, other)) {
+                return true;
+            }
+
+            return this.fontFamily == other.fontFamily &&
+                   this.fontSize == other.fontSize &&
+                   this.fontWeight == other.fontWeight &&
+                   this.fontStyle == other.fontStyle &&
+                   this.height == other.height &&
+                   this.leading == other.leading &&
+                   this.forceStrutHeight == other.forceStrutHeight;
+        }
+
+        public override bool Equals(object obj) {
+            if (ReferenceEquals(null, obj)) {
+                return false;
+            }
+
+            if (ReferenceEquals(this, obj)) {
+                return true;
+            }
+
+            if (obj.GetType() != this.GetType()) {
+                return false;
+            }
+
+            return this.Equals((StrutStyle) obj);
+        }
+
+        public static bool operator ==(StrutStyle left, StrutStyle right) {
+            return Equals(left, right);
+        }
+
+        public static bool operator !=(StrutStyle left, StrutStyle right) {
+            return !Equals(left, right);
+        }
+
+        public override int GetHashCode() {
+            unchecked {
+                var hashCode = this.fontFamily?.GetHashCode() ?? 0;
+                hashCode = (hashCode * 397) ^ (this.fontSize?.GetHashCode() ?? 0);
+                hashCode = (hashCode * 397) ^ (this.fontWeight?.GetHashCode() ?? 0);
+                hashCode = (hashCode * 397) ^ (this.fontStyle?.GetHashCode() ?? 0);
+                hashCode = (hashCode * 397) ^ (this.height?.GetHashCode() ?? 0);
+                hashCode = (hashCode * 397) ^ (this.leading?.GetHashCode() ?? 0);
+                hashCode = (hashCode * 397) ^ this.forceStrutHeight.GetHashCode();
+                return hashCode;
+            }
+        }
+
+        public override string toStringShort() {
+            return $"{this.GetType()}";
+        }
+
+        public override void debugFillProperties(DiagnosticPropertiesBuilder properties) {
+            base.debugFillProperties(properties);
+            if (this.debugLabel != null) {
+                properties.add(new MessageProperty("debugLabel", this.debugLabel));
+            }
+
+            List<DiagnosticsNode> styles = new List<DiagnosticsNode>();
+            styles.Add(new StringProperty("family", this.fontFamily, defaultValue: Diagnostics.kNullDefaultValue,
+                quoted: false));
+            styles.Add(new EnumerableProperty<string>("familyFallback", this.fontFamilyFallback));
+            styles.Add(new DiagnosticsProperty<float?>("size", this.fontSize,
+                defaultValue: Diagnostics.kNullDefaultValue));
+            string weightDescription = "";
+            if (this.fontWeight != null) {
+                weightDescription = this.fontWeight.weightValue.ToString();
+            }
+
+            styles.Add(new DiagnosticsProperty<FontWeight>(
+                "weight", this.fontWeight,
+                description: weightDescription,
+                defaultValue: Diagnostics.kNullDefaultValue
+            ));
+            styles.Add(new EnumProperty<FontStyle?>("style", this.fontStyle,
+                defaultValue: Diagnostics.kNullDefaultValue));
+            styles.Add(new DiagnosticsProperty<float?>("height", this.height,
+                defaultValue: Diagnostics.kNullDefaultValue));
+            styles.Add(new FlagProperty("forceStrutHeight", value: this.forceStrutHeight,
+                defaultValue: Diagnostics.kNullDefaultValue));
+
+            bool styleSpecified = styles.Any((DiagnosticsNode n) => !n.isFiltered(DiagnosticLevel.info));
+            foreach (var style in styles) {
+                properties.add(style);
+            }
+
+            if (!styleSpecified) {
+                properties.add(new FlagProperty("forceStrutHeight", value: this.forceStrutHeight,
+                    ifTrue: "<strut height forced>",
+                    ifFalse: "<strut height normal>"));
+            }
+        }
+    }
 }

com.unity.uiwidgets/Runtime/material/app_bar_theme.cs.meta

-fileFormatVersion: 2
-guid: 0c0ee979ef6b4f32a092532c3bdae31e
+fileFormatVersion: 2
+guid: 0c0ee979ef6b4f32a092532c3bdae31e
 timeCreated: 1556178331

com.unity.uiwidgets/Runtime/material/bottom_app_bar.cs.meta

-fileFormatVersion: 2
-guid: aa89369405044a62a19225b2c20815f6
+fileFormatVersion: 2
+guid: aa89369405044a62a19225b2c20815f6
 timeCreated: 1553156127

com.unity.uiwidgets/Runtime/material/bottom_app_bar_theme.cs.meta

-fileFormatVersion: 2
-guid: 9c88d19dd1254f4eb6c0c998084832ea
+fileFormatVersion: 2
+guid: 9c88d19dd1254f4eb6c0c998084832ea
 timeCreated: 1556185402

com.unity.uiwidgets/Runtime/material/bottom_navigation_bar.cs.meta

-fileFormatVersion: 2
-guid: 6b8f793d1b8d4004b2c19c1c085752c3
+fileFormatVersion: 2
+guid: 6b8f793d1b8d4004b2c19c1c085752c3
 timeCreated: 1553161698

com.unity.uiwidgets/Runtime/material/card_theme.cs.meta

-fileFormatVersion: 2
-guid: d74c4f94f0994a3880425c80ec3d9ba3
+fileFormatVersion: 2
+guid: d74c4f94f0994a3880425c80ec3d9ba3
 timeCreated: 1556187816

com.unity.uiwidgets/Runtime/material/chip.cs.meta

-fileFormatVersion: 2
-guid: d4ca6b86209d4615b9aba98d6d112673
+fileFormatVersion: 2
+guid: d4ca6b86209d4615b9aba98d6d112673
 timeCreated: 1555477997

com.unity.uiwidgets/Runtime/material/chip_theme.cs.meta

-fileFormatVersion: 2
-guid: 4d46bfb5d5bb492e92f07114849df905
+fileFormatVersion: 2
+guid: 4d46bfb5d5bb492e92f07114849df905
 timeCreated: 1556165564

com.unity.uiwidgets/Runtime/material/circle_avatar.cs.meta

-fileFormatVersion: 2
-guid: 32591e65e11049cab124c86bc8fe573c
+fileFormatVersion: 2
+guid: 32591e65e11049cab124c86bc8fe573c
 timeCreated: 1556169017

com.unity.uiwidgets/Runtime/material/dropdown.cs.meta

-fileFormatVersion: 2
-guid: 54d382ec712d4e87b802716ca97c1f3d
+fileFormatVersion: 2
+guid: 54d382ec712d4e87b802716ca97c1f3d
 timeCreated: 1552537966

com.unity.uiwidgets/Runtime/material/floatting_action_button_theme.cs

-using Unity.UIWidgets.foundation;
-using Unity.UIWidgets.painting;
-using Unity.UIWidgets.ui;
-
-namespace Unity.UIWidgets.material {
-    public class FloatingActionButtonThemeData : Diagnosticable {
-        public FloatingActionButtonThemeData(
-            Color backgroundColor = null,
-            Color foregroundColor = null,
-            float? elevation = null,
-            float? disabledElevation = null,
-            float? highlightElevation = null,
-            ShapeBorder shape = null
-        ) {
-            this.backgroundColor = backgroundColor;
-            this.foregroundColor = foregroundColor;
-            this.elevation = elevation;
-            this.disabledElevation = disabledElevation;
-            this.highlightElevation = highlightElevation;
-            this.shape = shape;
-        }
-
-        public readonly Color backgroundColor;
-
-        public readonly Color foregroundColor;
-
-        public readonly float? elevation;
-
-        public readonly float? disabledElevation;
-
-        public readonly float? highlightElevation;
-
-        public readonly ShapeBorder shape;
-
-        public FloatingActionButtonThemeData copyWith(
-            Color backgroundColor,
-            Color foregroundColor,
-            float? elevation,
-            float? disabledElevation,
-            float? highlightElevation,
-            ShapeBorder shape
-        ) {
-            return new FloatingActionButtonThemeData(
-                backgroundColor: backgroundColor ?? this.backgroundColor,
-                foregroundColor: foregroundColor ?? this.foregroundColor,
-                elevation: elevation ?? this.elevation,
-                disabledElevation: disabledElevation ?? this.disabledElevation,
-                highlightElevation: highlightElevation ?? this.highlightElevation,
-                shape: shape ?? this.shape
-            );
-        }
-
-        public static FloatingActionButtonThemeData lerp(FloatingActionButtonThemeData a, FloatingActionButtonThemeData b,
-            float t) {
-            if (a == null && b == null) {
-                return null;
-            }
-
-            return new FloatingActionButtonThemeData(
-                backgroundColor: Color.lerp(a?.backgroundColor, b?.backgroundColor, t),
-                foregroundColor: Color.lerp(a?.foregroundColor, b?.foregroundColor, t),
-                elevation: MathUtils.lerpFloat(a?.elevation ?? 0, b?.elevation ?? 0, t),
-                disabledElevation: MathUtils.lerpFloat(a?.disabledElevation ?? 0, b?.disabledElevation ?? 0, t),
-                highlightElevation: MathUtils.lerpFloat(a?.highlightElevation ?? 0, b?.highlightElevation ?? 0, t),
-                shape: ShapeBorder.lerp(a?.shape, b?.shape, t)
-            );
-        }
-
-        public override int GetHashCode() {
-            var hashCode = this.backgroundColor?.GetHashCode() ?? 0;
-            hashCode = (hashCode * 397) ^ this.foregroundColor?.GetHashCode() ?? 0;
-            hashCode = (hashCode * 397) ^ this.elevation?.GetHashCode() ?? 0;
-            hashCode = (hashCode * 397) ^ this.disabledElevation?.GetHashCode() ?? 0;
-            hashCode = (hashCode * 397) ^ this.highlightElevation?.GetHashCode() ?? 0;
-            hashCode = (hashCode * 397) ^ this.shape?.GetHashCode() ?? 0;
-            return hashCode;
-        }
-
-        public bool Equals(FloatingActionButtonThemeData other) {
-            if (ReferenceEquals(null, other)) {
-                return false;
-            }
-
-            if (ReferenceEquals(this, other)) {
-                return true;
-            }
-
-            return Equals(this.backgroundColor, other.backgroundColor)
-                   && Equals(this.elevation, other.elevation)
-                   && Equals(this.shape, other.shape)
-                   && Equals(this.foregroundColor, other.foregroundColor)
-                   && Equals(this.disabledElevation, other.disabledElevation)
-                   && Equals(this.highlightElevation, other.highlightElevation);
-        }
-
-        public override bool Equals(object obj) {
-            if (ReferenceEquals(null, obj)) {
-                return false;
-            }
-
-            if (ReferenceEquals(this, obj)) {
-                return true;
-            }
-
-            if (obj.GetType() != this.GetType()) {
-                return false;
-            }
-
-            return this.Equals((FloatingActionButtonThemeData) obj);
-        }
-
-        public override void debugFillProperties(DiagnosticPropertiesBuilder properties) {
-            base.debugFillProperties(properties);
-            FloatingActionButtonThemeData defaultData = new FloatingActionButtonThemeData();
-
-            properties.add(new DiagnosticsProperty<Color>("backgroundColor", this.backgroundColor,
-                defaultValue: defaultData.backgroundColor));
-            properties.add(new DiagnosticsProperty<Color>("foregroundColor", this.foregroundColor,
-                defaultValue: defaultData.foregroundColor));
-            properties.add(new DiagnosticsProperty<float?>("elevation", this.elevation,
-                defaultValue: defaultData.elevation));
-            properties.add(new DiagnosticsProperty<float?>("disabledElevation", this.disabledElevation,
-                defaultValue: defaultData.disabledElevation));
-            properties.add(new DiagnosticsProperty<float?>("highlightElevation", this.highlightElevation,
-                defaultValue: defaultData.highlightElevation));
-            properties.add(new DiagnosticsProperty<ShapeBorder>("shape", this.shape, defaultValue: defaultData.shape));
-        }
-    }
+using Unity.UIWidgets.foundation;
+using Unity.UIWidgets.painting;
+using Unity.UIWidgets.ui;
+
+namespace Unity.UIWidgets.material {
+    public class FloatingActionButtonThemeData : Diagnosticable {
+        public FloatingActionButtonThemeData(
+            Color backgroundColor = null,
+            Color foregroundColor = null,
+            float? elevation = null,
+            float? disabledElevation = null,
+            float? highlightElevation = null,
+            ShapeBorder shape = null
+        ) {
+            this.backgroundColor = backgroundColor;
+            this.foregroundColor = foregroundColor;
+            this.elevation = elevation;
+            this.disabledElevation = disabledElevation;
+            this.highlightElevation = highlightElevation;
+            this.shape = shape;
+        }
+
+        public readonly Color backgroundColor;
+
+        public readonly Color foregroundColor;
+
+        public readonly float? elevation;
+
+        public readonly float? disabledElevation;
+
+        public readonly float? highlightElevation;
+
+        public readonly ShapeBorder shape;
+
+        public FloatingActionButtonThemeData copyWith(
+            Color backgroundColor,
+            Color foregroundColor,
+            float? elevation,
+            float? disabledElevation,
+            float? highlightElevation,
+            ShapeBorder shape
+        ) {
+            return new FloatingActionButtonThemeData(
+                backgroundColor: backgroundColor ?? this.backgroundColor,
+                foregroundColor: foregroundColor ?? this.foregroundColor,
+                elevation: elevation ?? this.elevation,
+                disabledElevation: disabledElevation ?? this.disabledElevation,
+                highlightElevation: highlightElevation ?? this.highlightElevation,
+                shape: shape ?? this.shape
+            );
+        }
+
+        public static FloatingActionButtonThemeData lerp(FloatingActionButtonThemeData a, FloatingActionButtonThemeData b,
+            float t) {
+            if (a == null && b == null) {
+                return null;
+            }
+
+            return new FloatingActionButtonThemeData(
+                backgroundColor: Color.lerp(a?.backgroundColor, b?.backgroundColor, t),
+                foregroundColor: Color.lerp(a?.foregroundColor, b?.foregroundColor, t),
+                elevation: MathUtils.lerpFloat(a?.elevation ?? 0, b?.elevation ?? 0, t),
+                disabledElevation: MathUtils.lerpFloat(a?.disabledElevation ?? 0, b?.disabledElevation ?? 0, t),
+                highlightElevation: MathUtils.lerpFloat(a?.highlightElevation ?? 0, b?.highlightElevation ?? 0, t),
+                shape: ShapeBorder.lerp(a?.shape, b?.shape, t)
+            );
+        }
+
+        public override int GetHashCode() {
+            var hashCode = this.backgroundColor?.GetHashCode() ?? 0;
+            hashCode = (hashCode * 397) ^ this.foregroundColor?.GetHashCode() ?? 0;
+            hashCode = (hashCode * 397) ^ this.elevation?.GetHashCode() ?? 0;
+            hashCode = (hashCode * 397) ^ this.disabledElevation?.GetHashCode() ?? 0;
+            hashCode = (hashCode * 397) ^ this.highlightElevation?.GetHashCode() ?? 0;
+            hashCode = (hashCode * 397) ^ this.shape?.GetHashCode() ?? 0;
+            return hashCode;
+        }
+
+        public bool Equals(FloatingActionButtonThemeData other) {
+            if (ReferenceEquals(null, other)) {
+                return false;
+            }
+
+            if (ReferenceEquals(this, other)) {
+                return true;
+            }
+
+            return Equals(this.backgroundColor, other.backgroundColor)
+                   && Equals(this.elevation, other.elevation)
+                   && Equals(this.shape, other.shape)
+                   && Equals(this.foregroundColor, other.foregroundColor)
+                   && Equals(this.disabledElevation, other.disabledElevation)
+                   && Equals(this.highlightElevation, other.highlightElevation);
+        }
+
+        public override bool Equals(object obj) {
+            if (ReferenceEquals(null, obj)) {
+                return false;
+            }
+
+            if (ReferenceEquals(this, obj)) {
+                return true;
+            }
+
+            if (obj.GetType() != this.GetType()) {
+                return false;
+            }
+
+            return this.Equals((FloatingActionButtonThemeData) obj);
+        }
+
+        public override void debugFillProperties(DiagnosticPropertiesBuilder properties) {
+            base.debugFillProperties(properties);
+            FloatingActionButtonThemeData defaultData = new FloatingActionButtonThemeData();
+
+            properties.add(new DiagnosticsProperty<Color>("backgroundColor", this.backgroundColor,
+                defaultValue: defaultData.backgroundColor));
+            properties.add(new DiagnosticsProperty<Color>("foregroundColor", this.foregroundColor,
+                defaultValue: defaultData.foregroundColor));
+            properties.add(new DiagnosticsProperty<float?>("elevation", this.elevation,
+                defaultValue: defaultData.elevation));
+            properties.add(new DiagnosticsProperty<float?>("disabledElevation", this.disabledElevation,
+                defaultValue: defaultData.disabledElevation));
+            properties.add(new DiagnosticsProperty<float?>("highlightElevation", this.highlightElevation,
+                defaultValue: defaultData.highlightElevation));
+            properties.add(new DiagnosticsProperty<ShapeBorder>("shape", this.shape, defaultValue: defaultData.shape));
+        }
+    }
 }

com.unity.uiwidgets/Runtime/material/input_border.cs.meta

-fileFormatVersion: 2
-guid: 6431f8efd0b444ea9982ff6d0a0e74f4
+fileFormatVersion: 2
+guid: 6431f8efd0b444ea9982ff6d0a0e74f4
 timeCreated: 1552619063

com.unity.uiwidgets/Runtime/material/input_decorator.cs.meta

-fileFormatVersion: 2
-guid: 2106361ab28b4560a12fdbae0f1b1c8f
+fileFormatVersion: 2
+guid: 2106361ab28b4560a12fdbae0f1b1c8f
 timeCreated: 1552548801

com.unity.uiwidgets/Runtime/material/outline_button.cs.meta

-fileFormatVersion: 2
-guid: 5c535b1d86054795b33e7f0f358d957a
+fileFormatVersion: 2
+guid: 5c535b1d86054795b33e7f0f358d957a
 timeCreated: 1552641292

com.unity.uiwidgets/Runtime/material/progress_indicator.cs.meta

-fileFormatVersion: 2
-guid: 42b0b0b180624c38b2dec573a232bd8a
+fileFormatVersion: 2
+guid: 42b0b0b180624c38b2dec573a232bd8a
 timeCreated: 1552530632

com.unity.uiwidgets/Runtime/material/radio.cs.meta

-fileFormatVersion: 2
-guid: 1328fb437a4047c49b51dfe3a2c3d106
+fileFormatVersion: 2
+guid: 1328fb437a4047c49b51dfe3a2c3d106
 timeCreated: 1553154501

com.unity.uiwidgets/Runtime/material/refresh_indicator.cs.meta

-fileFormatVersion: 2
-guid: 74dd879101fe4541a5b42619cf4f309c
+fileFormatVersion: 2
+guid: 74dd879101fe4541a5b42619cf4f309c
 timeCreated: 1554344854

com.unity.uiwidgets/Runtime/material/text_form_field.cs.meta

-fileFormatVersion: 2
-guid: 0a9f1467be1c4653b3dbf8a1c7209f70
+fileFormatVersion: 2
+guid: 0a9f1467be1c4653b3dbf8a1c7209f70
 timeCreated: 1557304128

com.unity.uiwidgets/Runtime/material/user_accounts_drawer_header.cs.meta

-fileFormatVersion: 2
-guid: fb34d1a7ff484d05b8074a10730d51a5
+fileFormatVersion: 2
+guid: fb34d1a7ff484d05b8074a10730d51a5
 timeCreated: 1554352270

com.unity.uiwidgets/Runtime/material/animated_icons/animated_icons_data.cs.meta

-fileFormatVersion: 2
-guid: 439a75e2cc39472ba806029b41996e9b
+fileFormatVersion: 2
+guid: 439a75e2cc39472ba806029b41996e9b
 timeCreated: 1552892371

com.unity.uiwidgets/Runtime/material/animated_icons/data/arrow_menu.g.cs.meta

-fileFormatVersion: 2
-guid: f38795e53cc54f628c2125e5e50fea1c
+fileFormatVersion: 2
+guid: f38795e53cc54f628c2125e5e50fea1c
 timeCreated: 1552894502

com.unity.uiwidgets/Runtime/material/animated_icons/data/close_menu.g.cs.meta

-fileFormatVersion: 2
-guid: e3a716495016460c8599ef52f9bd690f
+fileFormatVersion: 2
+guid: e3a716495016460c8599ef52f9bd690f
 timeCreated: 1552894786

com.unity.uiwidgets/Runtime/foundation/constants.cs.meta

-fileFormatVersion: 2
-guid: 36d19e17f3d947f98c7accec2cd5771b
+fileFormatVersion: 2
+guid: 36d19e17f3d947f98c7accec2cd5771b
 timeCreated: 1556097117

com.unity.uiwidgets/Runtime/cupertino/bottom_app_bar.cs

-using System.Collections.Generic;
-using Unity.UIWidgets.foundation;
-using Unity.UIWidgets.gestures;
-using Unity.UIWidgets.painting;
-using Unity.UIWidgets.rendering;
-using Unity.UIWidgets.ui;
-using Unity.UIWidgets.widgets;
-using TextStyle = Unity.UIWidgets.painting.TextStyle;
-
-namespace Unity.UIWidgets.cupertino {
-    class BottomAppBarUtils {
-        public const float _kTabBarHeight = 50.0f;
-        public static readonly Color _kDefaultTabBarBorderColor = new Color(0x4C000000);
-    }
-
-
-    public class CupertinoTabBar : StatelessWidget {
-        public CupertinoTabBar(
-            Key key = null,
-            List<BottomNavigationBarItem> items = null,
-            ValueChanged<int> onTap = null,
-            int currentIndex = 0,
-            Color backgroundColor = null,
-            Color activeColor = null,
-            Color inactiveColor = null,
-            float iconSize = 30.0f,
-            Border border = null
-        ) : base(key: key) {
-            D.assert(items != null);
-            D.assert(items.Count >= 2,
-                () => "Tabs need at least 2 items to conform to Apple's HIG"
-            );
-            D.assert(0 <= currentIndex && currentIndex < items.Count);
-            
-
-            this.items = items;
-            this.onTap = onTap;
-            this.currentIndex = currentIndex;
-
-            this.backgroundColor = backgroundColor;
-            this.activeColor = activeColor;
-            this.inactiveColor = inactiveColor ?? CupertinoColors.inactiveGray;
-            this.iconSize = iconSize;
-            this.border = border ?? new Border(
-                              top: new BorderSide(
-                                  color: BottomAppBarUtils._kDefaultTabBarBorderColor,
-                                  width: 0.0f, // One physical pixel.
-                                  style: BorderStyle.solid
-                              )
-                          );
-        }
-
-        public readonly List<BottomNavigationBarItem> items;
-
-        public readonly ValueChanged<int> onTap;
-
-        public readonly int currentIndex;
-
-        public readonly Color backgroundColor;
-
-        public readonly Color activeColor;
-
-        public readonly Color inactiveColor;
-
-        public readonly float iconSize;
-
-        public readonly Border border;
-
-        public Size preferredSize {
-            get { return Size.fromHeight(BottomAppBarUtils._kTabBarHeight); }
-        }
-
-        public bool opaque(BuildContext context) {
-            Color backgroundColor =
-                this.backgroundColor ?? CupertinoTheme.of(context).barBackgroundColor;
-            return backgroundColor.alpha == 0xFF;
-        }
-
-        public override Widget build(BuildContext context) {
-            float bottomPadding = MediaQuery.of(context).padding.bottom;
-
-            Widget result = new DecoratedBox(
-                decoration: new BoxDecoration(
-                    border: this.border,
-                    color: this.backgroundColor ?? CupertinoTheme.of(context).barBackgroundColor
-                ),
-                child: new SizedBox(
-                    height: BottomAppBarUtils._kTabBarHeight + bottomPadding,
-                    child: IconTheme.merge( // Default with the inactive state.
-                        data: new IconThemeData(
-                            color: this.inactiveColor,
-                            size: this.iconSize
-                        ),
-                        child: new DefaultTextStyle( // Default with the inactive state.
-                            style: CupertinoTheme.of(context).textTheme.tabLabelTextStyle
-                                .copyWith(color: this.inactiveColor),
-                            child: new Padding(
-                                padding: EdgeInsets.only(bottom: bottomPadding),
-                                child: new Row(
-                                    crossAxisAlignment: CrossAxisAlignment.end,
-                                    children: this._buildTabItems(context)
-                                )
-                            )
-                        )
-                    )
-                )
-            );
-
-            if (!this.opaque(context)) {
-                result = new ClipRect(
-                    child: new BackdropFilter(
-                        filter: ImageFilter.blur(sigmaX: 10.0f, sigmaY: 10.0f),
-                        child: result
-                    )
-                );
-            }
-
-            return result;
-        }
-
-        List<Widget> _buildTabItems(BuildContext context) {
-            List<Widget> result = new List<Widget> { };
-
-            for (int index = 0; index < this.items.Count; index += 1) {
-                bool active = index == this.currentIndex;
-                var tabIndex = index;
-                result.Add(
-                    this._wrapActiveItem(
-                        context,
-                        new Expanded(
-                            child: new GestureDetector(
-                                behavior: HitTestBehavior.opaque,
-                                onTap: this.onTap == null ? null : (GestureTapCallback) (() => { this.onTap(tabIndex); }),
-                                child: new Padding(
-                                    padding: EdgeInsets.only(bottom: 4.0f),
-                                    child: new Column(
-                                        mainAxisAlignment: MainAxisAlignment.end,
-                                        children: this._buildSingleTabItem(this.items[index], active)
-                                    )
-                                )
-                            )
-                        ),
-                        active: active
-                    )
-                );
-            }
-
-            return result;
-        }
-
-        List<Widget> _buildSingleTabItem(BottomNavigationBarItem item, bool active) {
-            List<Widget> components = new List<Widget> {
-                new Expanded(
-                    child: new Center(child: active ? item.activeIcon : item.icon)
-                )
-            };
-
-            if (item.title != null) {
-                components.Add(item.title);
-            }
-
-            return components;
-        }
-
-        Widget _wrapActiveItem(BuildContext context, Widget item, bool active) {
-            if (!active) {
-                return item;
-            }
-
-            Color activeColor = this.activeColor ?? CupertinoTheme.of(context).primaryColor;
-            return IconTheme.merge(
-                data: new IconThemeData(color: activeColor),
-                child: DefaultTextStyle.merge(
-                    style: new TextStyle(color: activeColor),
-                    child: item
-                )
-            );
-        }
-
-        public CupertinoTabBar copyWith(
-            Key key = null,
-            List<BottomNavigationBarItem> items = null,
-            Color backgroundColor = null,
-            Color activeColor = null,
-            Color inactiveColor = null,
-            float? iconSize = null,
-            Border border = null,
-            int? currentIndex = null,
-            ValueChanged<int> onTap = null
-        ) {
-            return new CupertinoTabBar(
-                key: key ?? this.key,
-                items: items ?? this.items,
-                backgroundColor: backgroundColor ?? this.backgroundColor,
-                activeColor: activeColor ?? this.activeColor,
-                inactiveColor: inactiveColor ?? this.inactiveColor,
-                iconSize: iconSize ?? this.iconSize,
-                border: border ?? this.border,
-                currentIndex: currentIndex ?? this.currentIndex,
-                onTap: onTap ?? this.onTap
-            );
-        }
-    }
+using System.Collections.Generic;
+using Unity.UIWidgets.foundation;
+using Unity.UIWidgets.gestures;
+using Unity.UIWidgets.painting;
+using Unity.UIWidgets.rendering;
+using Unity.UIWidgets.ui;
+using Unity.UIWidgets.widgets;
+using TextStyle = Unity.UIWidgets.painting.TextStyle;
+
+namespace Unity.UIWidgets.cupertino {
+    class BottomAppBarUtils {
+        public const float _kTabBarHeight = 50.0f;
+        public static readonly Color _kDefaultTabBarBorderColor = new Color(0x4C000000);
+    }
+
+
+    public class CupertinoTabBar : StatelessWidget {
+        public CupertinoTabBar(
+            Key key = null,
+            List<BottomNavigationBarItem> items = null,
+            ValueChanged<int> onTap = null,
+            int currentIndex = 0,
+            Color backgroundColor = null,
+            Color activeColor = null,
+            Color inactiveColor = null,
+            float iconSize = 30.0f,
+            Border border = null
+        ) : base(key: key) {
+            D.assert(items != null);
+            D.assert(items.Count >= 2,
+                () => "Tabs need at least 2 items to conform to Apple's HIG"
+            );
+            D.assert(0 <= currentIndex && currentIndex < items.Count);
+            
+
+            this.items = items;
+            this.onTap = onTap;
+            this.currentIndex = currentIndex;
+
+            this.backgroundColor = backgroundColor;
+            this.activeColor = activeColor;
+            this.inactiveColor = inactiveColor ?? CupertinoColors.inactiveGray;
+            this.iconSize = iconSize;
+            this.border = border ?? new Border(
+                              top: new BorderSide(
+                                  color: BottomAppBarUtils._kDefaultTabBarBorderColor,
+                                  width: 0.0f, // One physical pixel.
+                                  style: BorderStyle.solid
+                              )
+                          );
+        }
+
+        public readonly List<BottomNavigationBarItem> items;
+
+        public readonly ValueChanged<int> onTap;
+
+        public readonly int currentIndex;
+
+        public readonly Color backgroundColor;
+
+        public readonly Color activeColor;
+
+        public readonly Color inactiveColor;
+
+        public readonly float iconSize;
+
+        public readonly Border border;
+
+        public Size preferredSize {
+            get { return Size.fromHeight(BottomAppBarUtils._kTabBarHeight); }
+        }
+
+        public bool opaque(BuildContext context) {
+            Color backgroundColor =
+                this.backgroundColor ?? CupertinoTheme.of(context).barBackgroundColor;
+            return backgroundColor.alpha == 0xFF;
+        }
+
+        public override Widget build(BuildContext context) {
+            float bottomPadding = MediaQuery.of(context).padding.bottom;
+
+            Widget result = new DecoratedBox(
+                decoration: new BoxDecoration(
+                    border: this.border,
+                    color: this.backgroundColor ?? CupertinoTheme.of(context).barBackgroundColor
+                ),
+                child: new SizedBox(
+                    height: BottomAppBarUtils._kTabBarHeight + bottomPadding,
+                    child: IconTheme.merge( // Default with the inactive state.
+                        data: new IconThemeData(
+                            color: this.inactiveColor,
+                            size: this.iconSize
+                        ),
+                        child: new DefaultTextStyle( // Default with the inactive state.
+                            style: CupertinoTheme.of(context).textTheme.tabLabelTextStyle
+                                .copyWith(color: this.inactiveColor),
+                            child: new Padding(
+                                padding: EdgeInsets.only(bottom: bottomPadding),
+                                child: new Row(
+                                    crossAxisAlignment: CrossAxisAlignment.end,
+                                    children: this._buildTabItems(context)
+                                )
+                            )
+                        )
+                    )
+                )
+            );
+
+            if (!this.opaque(context)) {
+                result = new ClipRect(
+                    child: new BackdropFilter(
+                        filter: ImageFilter.blur(sigmaX: 10.0f, sigmaY: 10.0f),
+                        child: result
+                    )
+                );
+            }
+
+            return result;
+        }
+
+        List<Widget> _buildTabItems(BuildContext context) {
+            List<Widget> result = new List<Widget> { };
+
+            for (int index = 0; index < this.items.Count; index += 1) {
+                bool active = index == this.currentIndex;
+                var tabIndex = index;
+                result.Add(
+                    this._wrapActiveItem(
+                        context,
+                        new Expanded(
+                            child: new GestureDetector(
+                                behavior: HitTestBehavior.opaque,
+                                onTap: this.onTap == null ? null : (GestureTapCallback) (() => { this.onTap(tabIndex); }),
+                                child: new Padding(
+                                    padding: EdgeInsets.only(bottom: 4.0f),
+                                    child: new Column(
+                                        mainAxisAlignment: MainAxisAlignment.end,
+                                        children: this._buildSingleTabItem(this.items[index], active)
+                                    )
+                                )
+                            )
+                        ),
+                        active: active
+                    )
+                );
+            }
+
+            return result;
+        }
+
+        List<Widget> _buildSingleTabItem(BottomNavigationBarItem item, bool active) {
+            List<Widget> components = new List<Widget> {
+                new Expanded(
+                    child: new Center(child: active ? item.activeIcon : item.icon)
+                )
+            };
+
+            if (item.title != null) {
+                components.Add(item.title);
+            }
+
+            return components;
+        }
+
+        Widget _wrapActiveItem(BuildContext context, Widget item, bool active) {
+            if (!active) {
+                return item;
+            }
+
+            Color activeColor = this.activeColor ?? CupertinoTheme.of(context).primaryColor;
+            return IconTheme.merge(
+                data: new IconThemeData(color: activeColor),
+                child: DefaultTextStyle.merge(
+                    style: new TextStyle(color: activeColor),
+                    child: item
+                )
+            );
+        }
+
+        public CupertinoTabBar copyWith(
+            Key key = null,
+            List<BottomNavigationBarItem> items = null,
+            Color backgroundColor = null,
+            Color activeColor = null,
+            Color inactiveColor = null,
+            float? iconSize = null,
+            Border border = null,
+            int? currentIndex = null,
+            ValueChanged<int> onTap = null
+        ) {
+            return new CupertinoTabBar(
+                key: key ?? this.key,
+                items: items ?? this.items,
+                backgroundColor: backgroundColor ?? this.backgroundColor,
+                activeColor: activeColor ?? this.activeColor,
+                inactiveColor: inactiveColor ?? this.inactiveColor,
+                iconSize: iconSize ?? this.iconSize,
+                border: border ?? this.border,
+                currentIndex: currentIndex ?? this.currentIndex,
+                onTap: onTap ?? this.onTap
+            );
+        }
+    }
 }

com.unity.uiwidgets/Runtime/cupertino/slider.cs

-using System;
-using Unity.UIWidgets.animation;
-using Unity.UIWidgets.foundation;
-using Unity.UIWidgets.gestures;
-using Unity.UIWidgets.rendering;
-using Unity.UIWidgets.scheduler;
-using Unity.UIWidgets.ui;
-using Unity.UIWidgets.widgets;
-using UnityEngine;
-using Canvas = Unity.UIWidgets.ui.Canvas;
-using Color = Unity.UIWidgets.ui.Color;
-using Rect = Unity.UIWidgets.ui.Rect;
-
-namespace Unity.UIWidgets.cupertino {
-    class SliderUtils {
-        public const float _kPadding = 8.0f;
-        public static readonly Color _kTrackColor = new Color(0xFFB5B5B5);
-        public const float _kSliderHeight = 2.0f * (CupertinoThumbPainter.radius + _kPadding);
-        public const float _kSliderWidth = 176.0f; // Matches Material Design slider.
-        public static readonly TimeSpan _kDiscreteTransitionDuration = new TimeSpan(0, 0, 0, 0, 500);
-        public const float _kAdjustmentUnit = 0.1f; // Matches iOS implementation of material slider.
-    }
-
-    public class CupertinoSlider : StatefulWidget {
-        public CupertinoSlider(
-            Key key = null,
-            float? value = null,
-            ValueChanged<float> onChanged = null,
-            ValueChanged<float> onChangeStart = null,
-            ValueChanged<float> onChangeEnd = null,
-            float min = 0.0f,
-            float max = 1.0f,
-            int? divisions = null,
-            Color activeColor = null
-        ) : base(key: key) {
-            D.assert(value != null);
-            D.assert(onChanged != null);
-            D.assert(value >= min && value <= max);
-            D.assert(divisions == null || divisions > 0);
-            this.value = value.Value;
-            this.onChanged = onChanged;
-            this.onChangeStart = onChangeStart;
-            this.onChangeEnd = onChangeEnd;
-            this.min = min;
-            this.max = max;
-            this.divisions = divisions;
-            this.activeColor = activeColor;
-        }
-
-        public readonly float value;
-
-        public readonly ValueChanged<float> onChanged;
-
-        public readonly ValueChanged<float> onChangeStart;
-
-        public readonly ValueChanged<float> onChangeEnd;
-
-        public readonly float min;
-
-        public readonly float max;
-
-        public readonly int? divisions;
-
-        public readonly Color activeColor;
-
-        public override State createState() {
-            return new _CupertinoSliderState();
-        }
-
-        public override void debugFillProperties(DiagnosticPropertiesBuilder properties) {
-            base.debugFillProperties(properties);
-            properties.add(new FloatProperty("value", this.value));
-            properties.add(new FloatProperty("min", this.min));
-            properties.add(new FloatProperty("max", this.max));
-        }
-    }
-
-    class _CupertinoSliderState : TickerProviderStateMixin<CupertinoSlider> {
-        void _handleChanged(float value) {
-            D.assert(this.widget.onChanged != null);
-            float lerpValue = MathUtils.lerpFloat(this.widget.min, this.widget.max, value);
-            if (lerpValue != this.widget.value) {
-                this.widget.onChanged(lerpValue);
-            }
-        }
-
-        void _handleDragStart(float value) {
-            D.assert(this.widget.onChangeStart != null);
-            this.widget.onChangeStart(MathUtils.lerpFloat(this.widget.min, this.widget.max, value));
-        }
-
-        void _handleDragEnd(float value) {
-            D.assert(this.widget.onChangeEnd != null);
-            this.widget.onChangeEnd(MathUtils.lerpFloat(this.widget.min, this.widget.max, value));
-        }
-
-        public override Widget build(BuildContext context) {
-            return new _CupertinoSliderRenderObjectWidget(
-                value: (this.widget.value - this.widget.min) / (this.widget.max - this.widget.min),
-                divisions: this.widget.divisions,
-                activeColor: this.widget.activeColor ?? CupertinoTheme.of(context).primaryColor,
-                onChanged: this.widget.onChanged != null ? (ValueChanged<float>) this._handleChanged : null,
-                onChangeStart: this.widget.onChangeStart != null ? (ValueChanged<float>) this._handleDragStart : null,
-                onChangeEnd: this.widget.onChangeEnd != null ? (ValueChanged<float>) this._handleDragEnd : null,
-                vsync: this
-            );
-        }
-    }
-
-    class _CupertinoSliderRenderObjectWidget : LeafRenderObjectWidget {
-        public _CupertinoSliderRenderObjectWidget(
-            Key key = null,
-            float? value = null,
-            int? divisions = null,
-            Color activeColor = null,
-            ValueChanged<float> onChanged = null,
-            ValueChanged<float> onChangeStart = null,
-            ValueChanged<float> onChangeEnd = null,
-            TickerProvider vsync = null
-        ) : base(key: key) {
-            this.value = value;
-            this.divisions = divisions;
-            this.activeColor = activeColor;
-            this.onChanged = onChanged;
-            this.onChangeStart = onChangeStart;
-            this.onChangeEnd = onChangeEnd;
-            this.vsync = vsync;
-        }
-
-        public readonly float? value;
-        public readonly int? divisions;
-        public readonly Color activeColor;
-        public readonly ValueChanged<float> onChanged;
-        public readonly ValueChanged<float> onChangeStart;
-        public readonly ValueChanged<float> onChangeEnd;
-        public readonly TickerProvider vsync;
-
-        public override RenderObject createRenderObject(BuildContext context) {
-            return new _RenderCupertinoSlider(
-                value: this.value ?? 0.0f,
-                divisions: this.divisions,
-                activeColor: this.activeColor,
-                onChanged: this.onChanged,
-                onChangeStart: this.onChangeStart,
-                onChangeEnd: this.onChangeEnd,
-                vsync: this.vsync
-            );
-        }
-
-        public override void updateRenderObject(BuildContext context, RenderObject _renderObject) {
-            _RenderCupertinoSlider renderObject = _renderObject as _RenderCupertinoSlider;
-            renderObject.value = this.value ?? 0.0f;
-            renderObject.divisions = this.divisions;
-            renderObject.activeColor = this.activeColor;
-            renderObject.onChanged = this.onChanged;
-            renderObject.onChangeStart = this.onChangeStart;
-            renderObject.onChangeEnd = this.onChangeEnd;
-        }
-    }
-
-    class _RenderCupertinoSlider : RenderConstrainedBox {
-        public _RenderCupertinoSlider(
-            float value,
-            int? divisions = null,
-            Color activeColor = null,
-            ValueChanged<float> onChanged = null,
-            ValueChanged<float> onChangeStart = null,
-            ValueChanged<float> onChangeEnd = null,
-            TickerProvider vsync = null
-        ) : base(additionalConstraints: BoxConstraints.tightFor(width: SliderUtils._kSliderWidth,
-            height: SliderUtils._kSliderHeight)) {
-            D.assert(value >= 0.0f && value <= 1.0f);
-            this._value = value;
-            this._divisions = divisions;
-            this._activeColor = activeColor;
-            this._onChanged = onChanged;
-            this.onChangeStart = onChangeStart;
-            this.onChangeEnd = onChangeEnd;
-            this._drag = new HorizontalDragGestureRecognizer();
-            this._drag.onStart = this._handleDragStart;
-            this._drag.onUpdate = this._handleDragUpdate;
-            this._drag.onEnd = this._handleDragEnd;
-            this._position = new AnimationController(
-                value: value,
-                duration: SliderUtils._kDiscreteTransitionDuration,
-                vsync: vsync
-            );
-            this._position.addListener(this.markNeedsPaint);
-        }
-
-        public float value {
-            get { return this._value; }
-            set {
-                D.assert(value >= 0.0f && value <= 1.0f);
-                if (value == this._value) {
-                    return;
-                }
-
-                this._value = value;
-                if (this.divisions != null) {
-                    this._position.animateTo(value, curve: Curves.fastOutSlowIn);
-                }
-                else {
-                    this._position.setValue(value);
-                }
-            }
-        }
-
-        float _value;
-
-        public int? divisions {
-            get { return this._divisions; }
-            set {
-                if (value == this._divisions) {
-                    return;
-                }
-
-                this._divisions = value;
-                this.markNeedsPaint();
-            }
-        }
-
-        int? _divisions;
-
-        public Color activeColor {
-            get { return this._activeColor; }
-            set {
-                if (value == this._activeColor) {
-                    return;
-                }
-
-                this._activeColor = value;
-                this.markNeedsPaint();
-            }
-        }
-
-        Color _activeColor;
-
-        public ValueChanged<float> onChanged {
-            get { return this._onChanged; }
-            set {
-                if (value == this._onChanged) {
-                    return;
-                }
-
-                this._onChanged = value;
-            }
-        }
-
-        ValueChanged<float> _onChanged;
-
-        public ValueChanged<float> onChangeStart;
-        public ValueChanged<float> onChangeEnd;
-
-
-        AnimationController _position;
-
-        HorizontalDragGestureRecognizer _drag;
-        float _currentDragValue = 0.0f;
-
-        float _discretizedCurrentDragValue {
-            get {
-                float dragValue = this._currentDragValue.clamp(0.0f, 1.0f);
-                if (this.divisions != null) {
-                    dragValue = Mathf.Round(dragValue * this.divisions.Value) / this.divisions.Value;
-                }
-
-                return dragValue;
-            }
-        }
-
-        public float _trackLeft {
-            get { return SliderUtils._kPadding; }
-        }
-
-        public float _trackRight {
-            get { return this.size.width - SliderUtils._kPadding; }
-        }
-
-        float _thumbCenter {
-            get {
-                float visualPosition = this._value;
-
-                return MathUtils.lerpFloat(this._trackLeft + CupertinoThumbPainter.radius,
-                    this._trackRight - CupertinoThumbPainter.radius,
-                    visualPosition);
-            }
-        }
-
-        public bool isInteractive {
-            get { return this.onChanged != null; }
-        }
-
-        void _handleDragStart(DragStartDetails details) {
-            this._startInteraction(details.globalPosition);
-        }
-
-        void _handleDragUpdate(DragUpdateDetails details) {
-            if (this.isInteractive) {
-                float extent = Mathf.Max(SliderUtils._kPadding,
-                    this.size.width - 2.0f * (SliderUtils._kPadding + CupertinoThumbPainter.radius));
-                float? valueDelta = details.primaryDelta / extent;
-                this._currentDragValue += valueDelta ?? 0.0f;
-
-                this.onChanged(this._discretizedCurrentDragValue);
-            }
-        }
-
-        void _handleDragEnd(DragEndDetails details) {
-            this._endInteraction();
-        }
-
-        void _startInteraction(Offset globalPosition) {
-            if (this.isInteractive) {
-                if (this.onChangeStart != null) {
-                    this.onChangeStart(this._discretizedCurrentDragValue);
-                }
-
-                this._currentDragValue = this._value;
-                this.onChanged(this._discretizedCurrentDragValue);
-            }
-        }
-
-        void _endInteraction() {
-            if (this.onChangeEnd != null) {
-                this.onChangeEnd(this._discretizedCurrentDragValue);
-            }
-
-            this._currentDragValue = 0.0f;
-        }
-
-        protected override bool hitTestSelf(Offset position) {
-            return (position.dx - this._thumbCenter).abs() < CupertinoThumbPainter.radius + SliderUtils._kPadding;
-        }
-
-        public override void handleEvent(PointerEvent e, HitTestEntry entry) {
-            D.assert(this.debugHandleEvent(e, entry));
-            if (e is PointerDownEvent pointerDownEvent && this.isInteractive) {
-                this._drag.addPointer(pointerDownEvent);
-            }
-        }
-
-        CupertinoThumbPainter _thumbPainter = new CupertinoThumbPainter();
-
-        public override
-            void paint(PaintingContext context, Offset offset) {
-            float visualPosition;
-            Color leftColor;
-            Color rightColor;
-            visualPosition = this._position.value;
-            leftColor = SliderUtils._kTrackColor;
-            rightColor = this._activeColor;
-
-            float trackCenter = offset.dy + this.size.height / 2.0f;
-            float trackLeft = offset.dx + this._trackLeft;
-            float trackTop = trackCenter - 1.0f;
-            float trackBottom = trackCenter + 1.0f;
-            float trackRight = offset.dx + this._trackRight;
-            float trackActive = offset.dx + this._thumbCenter;
-
-            Canvas canvas = context.canvas;
-
-            if (visualPosition > 0.0f) {
-                Paint paint = new Paint();
-                paint.color = rightColor;
-                canvas.drawRRect(RRect.fromLTRBXY(trackLeft, trackTop, trackActive, trackBottom, 1.0f, 1.0f), paint);
-            }
-
-            if (visualPosition < 1.0f) {
-                Paint paint = new Paint();
-                paint.color = leftColor;
-                canvas.drawRRect(RRect.fromLTRBXY(trackActive, trackTop, trackRight, trackBottom, 1.0f, 1.0f), paint);
-            }
-
-            Offset thumbCenter = new Offset(trackActive, trackCenter);
-            this._thumbPainter.paint(canvas,
-                Rect.fromCircle(center: thumbCenter, radius: CupertinoThumbPainter.radius));
-        }
-    }
+using System;
+using Unity.UIWidgets.animation;
+using Unity.UIWidgets.foundation;
+using Unity.UIWidgets.gestures;
+using Unity.UIWidgets.rendering;
+using Unity.UIWidgets.scheduler;
+using Unity.UIWidgets.ui;
+using Unity.UIWidgets.widgets;
+using UnityEngine;
+using Canvas = Unity.UIWidgets.ui.Canvas;
+using Color = Unity.UIWidgets.ui.Color;
+using Rect = Unity.UIWidgets.ui.Rect;
+
+namespace Unity.UIWidgets.cupertino {
+    class SliderUtils {
+        public const float _kPadding = 8.0f;
+        public static readonly Color _kTrackColor = new Color(0xFFB5B5B5);
+        public const float _kSliderHeight = 2.0f * (CupertinoThumbPainter.radius + _kPadding);
+        public const float _kSliderWidth = 176.0f; // Matches Material Design slider.
+        public static readonly TimeSpan _kDiscreteTransitionDuration = new TimeSpan(0, 0, 0, 0, 500);
+        public const float _kAdjustmentUnit = 0.1f; // Matches iOS implementation of material slider.
+    }
+
+    public class CupertinoSlider : StatefulWidget {
+        public CupertinoSlider(
+            Key key = null,
+            float? value = null,
+            ValueChanged<float> onChanged = null,
+            ValueChanged<float> onChangeStart = null,
+            ValueChanged<float> onChangeEnd = null,
+            float min = 0.0f,
+            float max = 1.0f,
+            int? divisions = null,
+            Color activeColor = null
+        ) : base(key: key) {
+            D.assert(value != null);
+            D.assert(onChanged != null);
+            D.assert(value >= min && value <= max);
+            D.assert(divisions == null || divisions > 0);
+            this.value = value.Value;
+            this.onChanged = onChanged;
+            this.onChangeStart = onChangeStart;
+            this.onChangeEnd = onChangeEnd;
+            this.min = min;
+            this.max = max;
+            this.divisions = divisions;
+            this.activeColor = activeColor;
+        }
+
+        public readonly float value;
+
+        public readonly ValueChanged<float> onChanged;
+
+        public readonly ValueChanged<float> onChangeStart;
+
+        public readonly ValueChanged<float> onChangeEnd;
+
+        public readonly float min;
+
+        public readonly float max;
+
+        public readonly int? divisions;
+
+        public readonly Color activeColor;
+
+        public override State createState() {
+            return new _CupertinoSliderState();
+        }
+
+        public override void debugFillProperties(DiagnosticPropertiesBuilder properties) {
+            base.debugFillProperties(properties);
+            properties.add(new FloatProperty("value", this.value));
+            properties.add(new FloatProperty("min", this.min));
+            properties.add(new FloatProperty("max", this.max));
+        }
+    }
+
+    class _CupertinoSliderState : TickerProviderStateMixin<CupertinoSlider> {
+        void _handleChanged(float value) {
+            D.assert(this.widget.onChanged != null);
+            float lerpValue = MathUtils.lerpFloat(this.widget.min, this.widget.max, value);
+            if (lerpValue != this.widget.value) {
+                this.widget.onChanged(lerpValue);
+            }
+        }
+
+        void _handleDragStart(float value) {
+            D.assert(this.widget.onChangeStart != null);
+            this.widget.onChangeStart(MathUtils.lerpFloat(this.widget.min, this.widget.max, value));
+        }
+
+        void _handleDragEnd(float value) {
+            D.assert(this.widget.onChangeEnd != null);
+            this.widget.onChangeEnd(MathUtils.lerpFloat(this.widget.min, this.widget.max, value));
+        }
+
+        public override Widget build(BuildContext context) {
+            return new _CupertinoSliderRenderObjectWidget(
+                value: (this.widget.value - this.widget.min) / (this.widget.max - this.widget.min),
+                divisions: this.widget.divisions,
+                activeColor: this.widget.activeColor ?? CupertinoTheme.of(context).primaryColor,
+                onChanged: this.widget.onChanged != null ? (ValueChanged<float>) this._handleChanged : null,
+                onChangeStart: this.widget.onChangeStart != null ? (ValueChanged<float>) this._handleDragStart : null,
+                onChangeEnd: this.widget.onChangeEnd != null ? (ValueChanged<float>) this._handleDragEnd : null,
+                vsync: this
+            );
+        }
+    }
+
+    class _CupertinoSliderRenderObjectWidget : LeafRenderObjectWidget {
+        public _CupertinoSliderRenderObjectWidget(
+            Key key = null,
+            float? value = null,
+            int? divisions = null,
+            Color activeColor = null,
+            ValueChanged<float> onChanged = null,
+            ValueChanged<float> onChangeStart = null,
+            ValueChanged<float> onChangeEnd = null,
+            TickerProvider vsync = null
+        ) : base(key: key) {
+            this.value = value;
+            this.divisions = divisions;
+            this.activeColor = activeColor;
+            this.onChanged = onChanged;
+            this.onChangeStart = onChangeStart;
+            this.onChangeEnd = onChangeEnd;
+            this.vsync = vsync;
+        }
+
+        public readonly float? value;
+        public readonly int? divisions;
+        public readonly Color activeColor;
+        public readonly ValueChanged<float> onChanged;
+        public readonly ValueChanged<float> onChangeStart;
+        public readonly ValueChanged<float> onChangeEnd;
+        public readonly TickerProvider vsync;
+
+        public override RenderObject createRenderObject(BuildContext context) {
+            return new _RenderCupertinoSlider(
+                value: this.value ?? 0.0f,
+                divisions: this.divisions,
+                activeColor: this.activeColor,
+                onChanged: this.onChanged,
+                onChangeStart: this.onChangeStart,
+                onChangeEnd: this.onChangeEnd,
+                vsync: this.vsync
+            );
+        }
+
+        public override void updateRenderObject(BuildContext context, RenderObject _renderObject) {
+            _RenderCupertinoSlider renderObject = _renderObject as _RenderCupertinoSlider;
+            renderObject.value = this.value ?? 0.0f;
+            renderObject.divisions = this.divisions;
+            renderObject.activeColor = this.activeColor;
+            renderObject.onChanged = this.onChanged;
+            renderObject.onChangeStart = this.onChangeStart;
+            renderObject.onChangeEnd = this.onChangeEnd;
+        }
+    }
+
+    class _RenderCupertinoSlider : RenderConstrainedBox {
+        public _RenderCupertinoSlider(
+            float value,
+            int? divisions = null,
+            Color activeColor = null,
+            ValueChanged<float> onChanged = null,
+            ValueChanged<float> onChangeStart = null,
+            ValueChanged<float> onChangeEnd = null,
+            TickerProvider vsync = null
+        ) : base(additionalConstraints: BoxConstraints.tightFor(width: SliderUtils._kSliderWidth,
+            height: SliderUtils._kSliderHeight)) {
+            D.assert(value >= 0.0f && value <= 1.0f);
+            this._value = value;
+            this._divisions = divisions;
+            this._activeColor = activeColor;
+            this._onChanged = onChanged;
+            this.onChangeStart = onChangeStart;
+            this.onChangeEnd = onChangeEnd;
+            this._drag = new HorizontalDragGestureRecognizer();
+            this._drag.onStart = this._handleDragStart;
+            this._drag.onUpdate = this._handleDragUpdate;
+            this._drag.onEnd = this._handleDragEnd;
+            this._position = new AnimationController(
+                value: value,
+                duration: SliderUtils._kDiscreteTransitionDuration,
+                vsync: vsync
+            );
+            this._position.addListener(this.markNeedsPaint);
+        }
+
+        public float value {
+            get { return this._value; }
+            set {
+                D.assert(value >= 0.0f && value <= 1.0f);
+                if (value == this._value) {
+                    return;
+                }
+
+                this._value = value;
+                if (this.divisions != null) {
+                    this._position.animateTo(value, curve: Curves.fastOutSlowIn);
+                }
+                else {
+                    this._position.setValue(value);
+                }
+            }
+        }
+
+        float _value;
+
+        public int? divisions {
+            get { return this._divisions; }
+            set {
+                if (value == this._divisions) {
+                    return;
+                }
+
+                this._divisions = value;
+                this.markNeedsPaint();
+            }
+        }
+
+        int? _divisions;
+
+        public Color activeColor {
+            get { return this._activeColor; }
+            set {
+                if (value == this._activeColor) {
+                    return;
+                }
+
+                this._activeColor = value;
+                this.markNeedsPaint();
+            }
+        }
+
+        Color _activeColor;
+
+        public ValueChanged<float> onChanged {
+            get { return this._onChanged; }
+            set {
+                if (value == this._onChanged) {
+                    return;
+                }
+
+                this._onChanged = value;
+            }
+        }
+
+        ValueChanged<float> _onChanged;
+
+        public ValueChanged<float> onChangeStart;
+        public ValueChanged<float> onChangeEnd;
+
+
+        AnimationController _position;
+
+        HorizontalDragGestureRecognizer _drag;
+        float _currentDragValue = 0.0f;
+
+        float _discretizedCurrentDragValue {
+            get {
+                float dragValue = this._currentDragValue.clamp(0.0f, 1.0f);
+                if (this.divisions != null) {
+                    dragValue = Mathf.Round(dragValue * this.divisions.Value) / this.divisions.Value;
+                }
+
+                return dragValue;
+            }
+        }
+
+        public float _trackLeft {
+            get { return SliderUtils._kPadding; }
+        }
+
+        public float _trackRight {
+            get { return this.size.width - SliderUtils._kPadding; }
+        }
+
+        float _thumbCenter {
+            get {
+                float visualPosition = this._value;
+
+                return MathUtils.lerpFloat(this._trackLeft + CupertinoThumbPainter.radius,
+                    this._trackRight - CupertinoThumbPainter.radius,
+                    visualPosition);
+            }
+        }
+
+        public bool isInteractive {
+            get { return this.onChanged != null; }
+        }
+
+        void _handleDragStart(DragStartDetails details) {
+            this._startInteraction(details.globalPosition);
+        }
+
+        void _handleDragUpdate(DragUpdateDetails details) {
+            if (this.isInteractive) {
+                float extent = Mathf.Max(SliderUtils._kPadding,
+                    this.size.width - 2.0f * (SliderUtils._kPadding + CupertinoThumbPainter.radius));
+                float? valueDelta = details.primaryDelta / extent;
+                this._currentDragValue += valueDelta ?? 0.0f;
+
+                this.onChanged(this._discretizedCurrentDragValue);
+            }
+        }
+
+        void _handleDragEnd(DragEndDetails details) {
+            this._endInteraction();
+        }
+
+        void _startInteraction(Offset globalPosition) {
+            if (this.isInteractive) {
+                if (this.onChangeStart != null) {
+                    this.onChangeStart(this._discretizedCurrentDragValue);
+                }
+
+                this._currentDragValue = this._value;
+                this.onChanged(this._discretizedCurrentDragValue);
+            }
+        }
+
+        void _endInteraction() {
+            if (this.onChangeEnd != null) {
+                this.onChangeEnd(this._discretizedCurrentDragValue);
+            }
+
+            this._currentDragValue = 0.0f;
+        }
+
+        protected override bool hitTestSelf(Offset position) {
+            return (position.dx - this._thumbCenter).abs() < CupertinoThumbPainter.radius + SliderUtils._kPadding;
+        }
+
+        public override void handleEvent(PointerEvent e, HitTestEntry entry) {
+            D.assert(this.debugHandleEvent(e, entry));
+            if (e is PointerDownEvent pointerDownEvent && this.isInteractive) {
+                this._drag.addPointer(pointerDownEvent);
+            }
+        }
+
+        CupertinoThumbPainter _thumbPainter = new CupertinoThumbPainter();
+
+        public override
+            void paint(PaintingContext context, Offset offset) {
+            float visualPosition;
+            Color leftColor;
+            Color rightColor;
+            visualPosition = this._position.value;
+            leftColor = SliderUtils._kTrackColor;
+            rightColor = this._activeColor;
+
+            float trackCenter = offset.dy + this.size.height / 2.0f;
+            float trackLeft = offset.dx + this._trackLeft;
+            float trackTop = trackCenter - 1.0f;
+            float trackBottom = trackCenter + 1.0f;
+            float trackRight = offset.dx + this._trackRight;
+            float trackActive = offset.dx + this._thumbCenter;
+
+            Canvas canvas = context.canvas;
+
+            if (visualPosition > 0.0f) {
+                Paint paint = new Paint();
+                paint.color = rightColor;
+                canvas.drawRRect(RRect.fromLTRBXY(trackLeft, trackTop, trackActive, trackBottom, 1.0f, 1.0f), paint);
+            }
+
+            if (visualPosition < 1.0f) {
+                Paint paint = new Paint();
+                paint.color = leftColor;
+                canvas.drawRRect(RRect.fromLTRBXY(trackActive, trackTop, trackRight, trackBottom, 1.0f, 1.0f), paint);
+            }
+
+            Offset thumbCenter = new Offset(trackActive, trackCenter);
+            this._thumbPainter.paint(canvas,
+                Rect.fromCircle(center: thumbCenter, radius: CupertinoThumbPainter.radius));
+        }
+    }
 }

com.unity.uiwidgets/Runtime/cupertino/tab_scaffold.cs

-using System.Collections.Generic;
-using System.Linq;
-using Unity.UIWidgets.foundation;
-using Unity.UIWidgets.painting;
-using Unity.UIWidgets.rendering;
-using Unity.UIWidgets.ui;
-using Unity.UIWidgets.widgets;
-
-namespace Unity.UIWidgets.cupertino {
-    public class CupertinoTabScaffold : StatefulWidget {
-        public CupertinoTabScaffold(
-            Key key = null,
-            CupertinoTabBar tabBar = null,
-            IndexedWidgetBuilder tabBuilder = null,
-            Color backgroundColor = null,
-            bool resizeToAvoidBottomInset = true
-        ) : base(key: key) {
-            D.assert(tabBar != null);
-            D.assert(tabBuilder != null);
-            this.tabBar = tabBar;
-            this.tabBuilder = tabBuilder;
-            this.backgroundColor = backgroundColor;
-            this.resizeToAvoidBottomInset = resizeToAvoidBottomInset;
-        }
-
-
-        public readonly CupertinoTabBar tabBar;
-
-        public readonly IndexedWidgetBuilder tabBuilder;
-
-        public readonly Color backgroundColor;
-
-        public readonly bool resizeToAvoidBottomInset;
-
-        public override State createState() {
-            return new _CupertinoTabScaffoldState();
-        }
-    }
-
-    class _CupertinoTabScaffoldState : State<CupertinoTabScaffold> {
-        int _currentPage;
-
-        public override void initState() {
-            base.initState();
-            this._currentPage = this.widget.tabBar.currentIndex;
-            
-        }
-
-        public override void didUpdateWidget(StatefulWidget _oldWidget) {
-            CupertinoTabScaffold oldWidget = _oldWidget as CupertinoTabScaffold;
-            base.didUpdateWidget(oldWidget);
-            if (this._currentPage >= this.widget.tabBar.items.Count) {
-                this._currentPage = this.widget.tabBar.items.Count - 1;
-                D.assert(this._currentPage >= 0,
-                    () => "CupertinoTabBar is expected to keep at least 2 tabs after updating"
-                );
-            }
-
-            if (this.widget.tabBar.currentIndex != oldWidget.tabBar.currentIndex) {
-                this._currentPage = this.widget.tabBar.currentIndex;
-            }
-        }
-
-        public override Widget build(BuildContext context) {
-            List<Widget> stacked = new List<Widget> { };
-
-            MediaQueryData existingMediaQuery = MediaQuery.of(context);
-            MediaQueryData newMediaQuery = MediaQuery.of(context);
-
-            Widget content = new _TabSwitchingView(
-                currentTabIndex: this._currentPage,
-                tabNumber: this.widget.tabBar.items.Count,
-                tabBuilder: this.widget.tabBuilder
-            );
-            EdgeInsets contentPadding = EdgeInsets.zero;
-
-            if (this.widget.resizeToAvoidBottomInset) {
-                newMediaQuery = newMediaQuery.removeViewInsets(removeBottom: true);
-                contentPadding = EdgeInsets.only(bottom: existingMediaQuery.viewInsets.bottom);
-            }
-
-            if (this.widget.tabBar != null &&
-                (!this.widget.resizeToAvoidBottomInset ||
-                 this.widget.tabBar.preferredSize.height > existingMediaQuery.viewInsets.bottom)) {
-                float bottomPadding = this.widget.tabBar.preferredSize.height + existingMediaQuery.padding.bottom;
-
-                if (this.widget.tabBar.opaque(context)) {
-                    contentPadding = EdgeInsets.only(bottom: bottomPadding);
-                }
-                else {
-                    newMediaQuery = newMediaQuery.copyWith(
-                        padding: newMediaQuery.padding.copyWith(
-                            bottom: bottomPadding
-                        )
-                    );
-                }
-            }
-
-            content = new MediaQuery(
-                data: newMediaQuery,
-                child: new Padding(
-                    padding: contentPadding,
-                    child: content
-                )
-            );
-
-            stacked.Add(content);
-
-            if (this.widget.tabBar != null) {
-                stacked.Add(new Align(
-                    alignment: Alignment.bottomCenter,
-                    child: this.widget.tabBar.copyWith(
-                        currentIndex: this._currentPage,
-                        onTap: (int newIndex) => {
-                            this.setState(() => { this._currentPage = newIndex; });
-                            if (this.widget.tabBar.onTap != null) {
-                                this.widget.tabBar.onTap(newIndex);
-                            }
-                        }
-                    )
-                ));
-            }
-
-            return new DecoratedBox(
-                decoration: new BoxDecoration(
-                    color: this.widget.backgroundColor ?? CupertinoTheme.of(context).scaffoldBackgroundColor
-                ),
-                child: new Stack(
-                    children: stacked
-                )
-            );
-        }
-    }
-
-    class _TabSwitchingView : StatefulWidget {
-        public _TabSwitchingView(
-            int currentTabIndex,
-            int tabNumber,
-            IndexedWidgetBuilder tabBuilder
-        ) {
-            D.assert(tabNumber > 0);
-            D.assert(tabBuilder != null);
-            this.currentTabIndex = currentTabIndex;
-            this.tabNumber = tabNumber;
-            this.tabBuilder = tabBuilder;
-        }
-
-        public readonly int currentTabIndex;
-        public readonly int tabNumber;
-        public readonly IndexedWidgetBuilder tabBuilder;
-
-        public override State createState() {
-            return new _TabSwitchingViewState();
-        }
-    }
-
-    class _TabSwitchingViewState : State<_TabSwitchingView> {
-        List<Widget> tabs;
-        List<FocusScopeNode> tabFocusNodes;
-
-        public override void initState() {
-            base.initState();
-            this.tabs = new List<Widget>(this.widget.tabNumber);
-            for (int i = 0; i < this.widget.tabNumber; i++) {
-                this.tabs.Add(null);
-            }
-            this.tabFocusNodes = Enumerable.Repeat(new FocusScopeNode(), this.widget.tabNumber).ToList();
-        }
-
-        public override void didChangeDependencies() {
-            base.didChangeDependencies();
-            this._focusActiveTab();
-        }
-
-        public override void didUpdateWidget(StatefulWidget _oldWidget) {
-            _TabSwitchingView oldWidget = _oldWidget as _TabSwitchingView;
-            base.didUpdateWidget(oldWidget);
-            this._focusActiveTab();
-        }
-
-        void _focusActiveTab() {
-            FocusScope.of(this.context).setFirstFocus(this.tabFocusNodes[this.widget.currentTabIndex]);
-        }
-
-        public override void dispose() {
-            foreach (FocusScopeNode focusScopeNode in this.tabFocusNodes) {
-                focusScopeNode.detach();
-            }
-
-            base.dispose();
-        }
-
-        public override Widget build(BuildContext context) {
-            List<Widget> children = new List<Widget>();
-            for (int index = 0; index < this.widget.tabNumber; index++) {
-                bool active = index == this.widget.currentTabIndex;
-
-                var tabIndex = index;
-                if (active || this.tabs[index] != null) {
-                    this.tabs[index] = this.widget.tabBuilder(context, tabIndex);
-                }
-
-                children.Add(new Offstage(
-                    offstage: !active,
-                    child: new TickerMode(
-                        enabled: active,
-                        child: new FocusScope(
-                            node: this.tabFocusNodes[index],
-                            child: this.tabs[index] ?? new Container()
-                        )
-                    )
-                ));
-            }
-
-            return new Stack(
-                fit: StackFit.expand,
-                children: children
-            );
-        }
-    }
+using System.Collections.Generic;
+using System.Linq;
+using Unity.UIWidgets.foundation;
+using Unity.UIWidgets.painting;
+using Unity.UIWidgets.rendering;
+using Unity.UIWidgets.ui;
+using Unity.UIWidgets.widgets;
+
+namespace Unity.UIWidgets.cupertino {
+    public class CupertinoTabScaffold : StatefulWidget {
+        public CupertinoTabScaffold(
+            Key key = null,
+            CupertinoTabBar tabBar = null,
+            IndexedWidgetBuilder tabBuilder = null,
+            Color backgroundColor = null,
+            bool resizeToAvoidBottomInset = true
+        ) : base(key: key) {
+            D.assert(tabBar != null);
+            D.assert(tabBuilder != null);
+            this.tabBar = tabBar;
+            this.tabBuilder = tabBuilder;
+            this.backgroundColor = backgroundColor;
+            this.resizeToAvoidBottomInset = resizeToAvoidBottomInset;
+        }
+
+
+        public readonly CupertinoTabBar tabBar;
+
+        public readonly IndexedWidgetBuilder tabBuilder;
+
+        public readonly Color backgroundColor;
+
+        public readonly bool resizeToAvoidBottomInset;
+
+        public override State createState() {
+            return new _CupertinoTabScaffoldState();
+        }
+    }
+
+    class _CupertinoTabScaffoldState : State<CupertinoTabScaffold> {
+        int _currentPage;
+
+        public override void initState() {
+            base.initState();
+            this._currentPage = this.widget.tabBar.currentIndex;
+            
+        }
+
+        public override void didUpdateWidget(StatefulWidget _oldWidget) {
+            CupertinoTabScaffold oldWidget = _oldWidget as CupertinoTabScaffold;
+            base.didUpdateWidget(oldWidget);
+            if (this._currentPage >= this.widget.tabBar.items.Count) {
+                this._currentPage = this.widget.tabBar.items.Count - 1;
+                D.assert(this._currentPage >= 0,
+                    () => "CupertinoTabBar is expected to keep at least 2 tabs after updating"
+                );
+            }
+
+            if (this.widget.tabBar.currentIndex != oldWidget.tabBar.currentIndex) {
+                this._currentPage = this.widget.tabBar.currentIndex;
+            }
+        }
+
+        public override Widget build(BuildContext context) {
+            List<Widget> stacked = new List<Widget> { };
+
+            MediaQueryData existingMediaQuery = MediaQuery.of(context);
+            MediaQueryData newMediaQuery = MediaQuery.of(context);
+
+            Widget content = new _TabSwitchingView(
+                currentTabIndex: this._currentPage,
+                tabNumber: this.widget.tabBar.items.Count,
+                tabBuilder: this.widget.tabBuilder
+            );
+            EdgeInsets contentPadding = EdgeInsets.zero;
+
+            if (this.widget.resizeToAvoidBottomInset) {
+                newMediaQuery = newMediaQuery.removeViewInsets(removeBottom: true);
+                contentPadding = EdgeInsets.only(bottom: existingMediaQuery.viewInsets.bottom);
+            }
+
+            if (this.widget.tabBar != null &&
+                (!this.widget.resizeToAvoidBottomInset ||
+                 this.widget.tabBar.preferredSize.height > existingMediaQuery.viewInsets.bottom)) {
+                float bottomPadding = this.widget.tabBar.preferredSize.height + existingMediaQuery.padding.bottom;
+
+                if (this.widget.tabBar.opaque(context)) {
+                    contentPadding = EdgeInsets.only(bottom: bottomPadding);
+                }
+                else {
+                    newMediaQuery = newMediaQuery.copyWith(
+                        padding: newMediaQuery.padding.copyWith(
+                            bottom: bottomPadding
+                        )
+                    );
+                }
+            }
+
+            content = new MediaQuery(
+                data: newMediaQuery,
+                child: new Padding(
+                    padding: contentPadding,
+                    child: content
+                )
+            );
+
+            stacked.Add(content);
+
+            if (this.widget.tabBar != null) {
+                stacked.Add(new Align(
+                    alignment: Alignment.bottomCenter,
+                    child: this.widget.tabBar.copyWith(
+                        currentIndex: this._currentPage,
+                        onTap: (int newIndex) => {
+                            this.setState(() => { this._currentPage = newIndex; });
+                            if (this.widget.tabBar.onTap != null) {
+                                this.widget.tabBar.onTap(newIndex);
+                            }
+                        }
+                    )
+                ));
+            }
+
+            return new DecoratedBox(
+                decoration: new BoxDecoration(
+                    color: this.widget.backgroundColor ?? CupertinoTheme.of(context).scaffoldBackgroundColor
+                ),
+                child: new Stack(
+                    children: stacked
+                )
+            );
+        }
+    }
+
+    class _TabSwitchingView : StatefulWidget {
+        public _TabSwitchingView(
+            int currentTabIndex,
+            int tabNumber,
+            IndexedWidgetBuilder tabBuilder
+        ) {
+            D.assert(tabNumber > 0);
+            D.assert(tabBuilder != null);
+            this.currentTabIndex = currentTabIndex;
+            this.tabNumber = tabNumber;
+            this.tabBuilder = tabBuilder;
+        }
+
+        public readonly int currentTabIndex;
+        public readonly int tabNumber;
+        public readonly IndexedWidgetBuilder tabBuilder;
+
+        public override State createState() {
+            return new _TabSwitchingViewState();
+        }
+    }
+
+    class _TabSwitchingViewState : State<_TabSwitchingView> {
+        List<Widget> tabs;
+        List<FocusScopeNode> tabFocusNodes;
+
+        public override void initState() {
+            base.initState();
+            this.tabs = new List<Widget>(this.widget.tabNumber);
+            for (int i = 0; i < this.widget.tabNumber; i++) {
+                this.tabs.Add(null);
+            }
+            this.tabFocusNodes = Enumerable.Repeat(new FocusScopeNode(), this.widget.tabNumber).ToList();
+        }
+
+        public override void didChangeDependencies() {
+            base.didChangeDependencies();
+            this._focusActiveTab();
+        }
+
+        public override void didUpdateWidget(StatefulWidget _oldWidget) {
+            _TabSwitchingView oldWidget = _oldWidget as _TabSwitchingView;
+            base.didUpdateWidget(oldWidget);
+            this._focusActiveTab();
+        }
+
+        void _focusActiveTab() {
+            FocusScope.of(this.context).setFirstFocus(this.tabFocusNodes[this.widget.currentTabIndex]);
+        }
+
+        public override void dispose() {
+            foreach (FocusScopeNode focusScopeNode in this.tabFocusNodes) {
+                focusScopeNode.detach();
+            }
+
+            base.dispose();
+        }
+
+        public override Widget build(BuildContext context) {
+            List<Widget> children = new List<Widget>();
+            for (int index = 0; index < this.widget.tabNumber; index++) {
+                bool active = index == this.widget.currentTabIndex;
+
+                var tabIndex = index;
+                if (active || this.tabs[index] != null) {
+                    this.tabs[index] = this.widget.tabBuilder(context, tabIndex);
+                }
+
+                children.Add(new Offstage(
+                    offstage: !active,
+                    child: new TickerMode(
+                        enabled: active,
+                        child: new FocusScope(
+                            node: this.tabFocusNodes[index],
+                            child: this.tabs[index] ?? new Container()
+                        )
+                    )
+                ));
+            }
+
+            return new Stack(
+                fit: StackFit.expand,
+                children: children
+            );
+        }
+    }
 }

com.unity.uiwidgets/Runtime/Plugins/platform/ios/UIWidgetsTextInputPlugin.mm

+#include "UIWidgetsTextInputPlugin.h"
+#include "UIWidgetsMessageManager.h"
+#include <Foundation/Foundation.h>
+#include <UIKit/UIKit.h>
+
+static const char _kTextAffinityDownstream[] = "TextAffinity.downstream";
+static const char _kTextAffinityUpstream[] = "TextAffinity.upstream";
+
+static UIKeyboardType ToUIKeyboardType(NSDictionary* type) {
+    NSString* inputType = type[@"name"];
+    if ([inputType isEqualToString:@"TextInputType.text"])
+        return UIKeyboardTypeDefault;
+    if ([inputType isEqualToString:@"TextInputType.multiline"])
+        return UIKeyboardTypeDefault;
+    if ([inputType isEqualToString:@"TextInputType.number"]) {
+        if ([type[@"signed"] boolValue])
+            return UIKeyboardTypeNumbersAndPunctuation;
+        return UIKeyboardTypeDecimalPad;
+    }
+    if ([inputType isEqualToString:@"TextInputType.phone"])
+        return UIKeyboardTypePhonePad;
+    if ([inputType isEqualToString:@"TextInputType.emailAddress"])
+        return UIKeyboardTypeEmailAddress;
+    if ([inputType isEqualToString:@"TextInputType.url"])
+        return UIKeyboardTypeURL;
+    return UIKeyboardTypeDefault;
+}
+
+static UITextAutocapitalizationType ToUITextAutoCapitalizationType(NSDictionary* type) {
+    NSString* textCapitalization = type[@"textCapitalization"];
+    if ([textCapitalization isEqualToString:@"TextCapitalization.characters"]) {
+        return UITextAutocapitalizationTypeAllCharacters;
+    } else if ([textCapitalization isEqualToString:@"TextCapitalization.sentences"]) {
+        return UITextAutocapitalizationTypeSentences;
+    } else if ([textCapitalization isEqualToString:@"TextCapitalization.words"]) {
+        return UITextAutocapitalizationTypeWords;
+    }
+    return UITextAutocapitalizationTypeNone;
+}
+
+static UIReturnKeyType ToUIReturnKeyType(NSString* inputType) {
+    // Where did the term "unspecified" come from? iOS has a "default" and Android
+    // has "unspecified." These 2 terms seem to mean the same thing but we need
+    // to pick just one. "unspecified" was chosen because "default" is often a
+    // reserved word in languages with switch statements (dart, java, etc).
+    if ([inputType isEqualToString:@"TextInputAction.unspecified"])
+        return UIReturnKeyDefault;
+    
+    if ([inputType isEqualToString:@"TextInputAction.done"])
+        return UIReturnKeyDone;
+    
+    if ([inputType isEqualToString:@"TextInputAction.go"])
+        return UIReturnKeyGo;
+    
+    if ([inputType isEqualToString:@"TextInputAction.send"])
+        return UIReturnKeySend;
+    
+    if ([inputType isEqualToString:@"TextInputAction.search"])
+        return UIReturnKeySearch;
+    
+    if ([inputType isEqualToString:@"TextInputAction.next"])
+        return UIReturnKeyNext;
+    
+    if (@available(iOS 9.0, *))
+        if ([inputType isEqualToString:@"TextInputAction.continueAction"])
+            return UIReturnKeyContinue;
+    
+    if ([inputType isEqualToString:@"TextInputAction.join"])
+        return UIReturnKeyJoin;
+    
+    if ([inputType isEqualToString:@"TextInputAction.route"])
+        return UIReturnKeyRoute;
+    
+    if ([inputType isEqualToString:@"TextInputAction.emergencyCall"])
+        return UIReturnKeyEmergencyCall;
+    
+    if ([inputType isEqualToString:@"TextInputAction.newline"])
+        return UIReturnKeyDefault;
+    
+    // Present default key if bad input type is given.
+    return UIReturnKeyDefault;
+}
+
+#pragma mark - UIWidgetsTextPosition
+
+@implementation UIWidgetsTextPosition
+
++ (instancetype)positionWithIndex:(NSUInteger)index {
+    return [[[UIWidgetsTextPosition alloc] initWithIndex:index] autorelease];
+}
+
+- (instancetype)initWithIndex:(NSUInteger)index {
+    self = [super init];
+    if (self) {
+        _index = index;
+    }
+    return self;
+}
+
+@end
+
+#pragma mark - UIWidgetsTextRange
+
+@implementation UIWidgetsTextRange
+
++ (instancetype)rangeWithNSRange:(NSRange)range {
+    return [[[UIWidgetsTextRange alloc] initWithNSRange:range] autorelease];
+}
+
+- (instancetype)initWithNSRange:(NSRange)range {
+    self = [super init];
+    if (self) {
+        _range = range;
+    }
+    return self;
+}
+
+- (UITextPosition*)start {
+    return [UIWidgetsTextPosition positionWithIndex:self.range.location];
+}
+
+- (UITextPosition*)end {
+    return [UIWidgetsTextPosition positionWithIndex:self.range.location + self.range.length];
+}
+
+- (BOOL)isEmpty {
+    return self.range.length == 0;
+}
+
+- (id)copyWithZone:(NSZone*)zone {
+    return [[UIWidgetsTextRange allocWithZone:zone] initWithNSRange:self.range];
+}
+
+@end
+
+@interface UIWidgetsTextInputView : UIView <UITextInput>
+
+// UITextInput
+@property(nonatomic, readonly) NSMutableString* text;
+@property(nonatomic, readonly) NSMutableString* markedText;
+@property(readwrite, copy) UITextRange* selectedTextRange;
+@property(nonatomic, strong) UITextRange* markedTextRange;
+@property(nonatomic, copy) NSDictionary* markedTextStyle;
+@property(nonatomic, assign) id<UITextInputDelegate> inputDelegate;
+
+// UITextInputTraits
+@property(nonatomic) UITextAutocapitalizationType autocapitalizationType;
+@property(nonatomic) UITextAutocorrectionType autocorrectionType;
+@property(nonatomic) UITextSpellCheckingType spellCheckingType;
+@property(nonatomic) BOOL enablesReturnKeyAutomatically;
+@property(nonatomic) UIKeyboardAppearance keyboardAppearance;
+@property(nonatomic) UIKeyboardType keyboardType;
+@property(nonatomic) UIReturnKeyType returnKeyType;
+@property(nonatomic, getter=isSecureTextEntry) BOOL secureTextEntry;
+
+@property(nonatomic, assign) id<UIWidgetsTextInputDelegate> textInputDelegate;
+
+@end
+
+@implementation UIWidgetsTextInputView {
+    int _textInputClient;
+    const char* _selectionAffinity;
+    UIWidgetsTextRange* _selectedTextRange;
+}
+
+@synthesize tokenizer = _tokenizer;
+
+- (instancetype)init {
+    self = [super init];
+    
+    if (self) {
+        _textInputClient = 0;
+        _selectionAffinity = _kTextAffinityUpstream;
+        
+        // UITextInput
+        _text = [[NSMutableString alloc] init];
+        _markedText = [[NSMutableString alloc] init];
+        _selectedTextRange = [[UIWidgetsTextRange alloc] initWithNSRange:NSMakeRange(0, 0)];
+        
+        // UITextInputTraits
+        _autocapitalizationType = UITextAutocapitalizationTypeSentences;
+        _autocorrectionType = UITextAutocorrectionTypeDefault;
+        _spellCheckingType = UITextSpellCheckingTypeDefault;
+        _enablesReturnKeyAutomatically = NO;
+        _keyboardAppearance = UIKeyboardAppearanceDefault;
+        _keyboardType = UIKeyboardTypeDefault;
+        _returnKeyType = UIReturnKeyDone;
+        _secureTextEntry = NO;
+    }
+    
+    return self;
+}
+
+- (void)dealloc {
+    [_text release];
+    [_markedText release];
+    [_markedTextRange release];
+    [_selectedTextRange release];
+    [_tokenizer release];
+    [super dealloc];
+}
+
+- (void)setTextInputClient:(int)client {
+    _textInputClient = client;
+}
+
+- (void)setTextInputState:(NSDictionary*)state {
+    NSString* newText = state[@"text"];
+    BOOL textChanged = ![self.text isEqualToString:newText];
+    if (textChanged) {
+        [self.inputDelegate textWillChange:self];
+        [self.text setString:newText];
+    }
+
+    NSInteger composingBase = [state[@"composingBase"] intValue];
+    NSInteger composingExtent = [state[@"composingExtent"] intValue];
+    NSRange composingRange = [self clampSelection:NSMakeRange(MIN(composingBase, composingExtent), ABS(composingBase - composingExtent)) forText:self.text];
+    self.markedTextRange = composingRange.length > 0 ? [UIWidgetsTextRange rangeWithNSRange:composingRange] : nil;
+    
+    NSInteger selectionBase = [state[@"selectionBase"] intValue];
+    NSInteger selectionExtent = [state[@"selectionExtent"] intValue];
+    NSRange selectedRange = [self clampSelection:NSMakeRange(MIN(selectionBase, selectionExtent),
+                                                             ABS(selectionBase - selectionExtent))
+                                         forText:self.text];
+    NSRange oldSelectedRange = [(UIWidgetsTextRange*)self.selectedTextRange range];
+    if (selectedRange.location != oldSelectedRange.location ||
+        selectedRange.length != oldSelectedRange.length) {
+        [self.inputDelegate selectionWillChange:self];
+        [self setSelectedTextRange:[UIWidgetsTextRange rangeWithNSRange:selectedRange]
+                updateEditingState:NO];
+        _selectionAffinity = _kTextAffinityDownstream;
+        if ([state[@"selectionAffinity"] isEqualToString:@(_kTextAffinityUpstream)])
+            _selectionAffinity = _kTextAffinityUpstream;
+        [self.inputDelegate selectionDidChange:self];
+    }
+    
+    if (textChanged) {
+        [self.inputDelegate textDidChange:self];
+        
+        // For consistency with Android behavior, send an update to the framework.
+        [self updateEditingState];
+    }
+}
+
+- (NSRange)clampSelection:(NSRange)range forText:(NSString*)text {
+    int start = MIN(MAX(range.location, 0), text.length);
+    int length = MIN(range.length, text.length - start);
+    return NSMakeRange(start, length);
+}
+
+#pragma mark - UIResponder Overrides
+
+- (BOOL)canBecomeFirstResponder {
+    return YES;
+}
+
+#pragma mark - UITextInput Overrides
+
+- (id<UITextInputTokenizer>)tokenizer {
+    if (_tokenizer == nil) {
+        _tokenizer = [[UITextInputStringTokenizer alloc] initWithTextInput:self];
+    }
+    return _tokenizer;
+}
+
+- (UITextRange*)selectedTextRange {
+    return [[_selectedTextRange copy] autorelease];
+}
+
+- (void)setSelectedTextRange:(UITextRange*)selectedTextRange {
+    [self setSelectedTextRange:selectedTextRange updateEditingState:YES];
+}
+
+- (void)setSelectedTextRange:(UITextRange*)selectedTextRange updateEditingState:(BOOL)update {
+    if (_selectedTextRange != selectedTextRange) {
+        UITextRange* oldSelectedRange = _selectedTextRange;
+        _selectedTextRange = [selectedTextRange copy];
+        [oldSelectedRange release];
+        
+        if (update)
+            [self updateEditingState];
+    }
+}
+
+- (id)insertDictationResultPlaceholder {
+    return @"";
+}
+
+- (void)removeDictationResultPlaceholder:(id)placeholder willInsertResult:(BOOL)willInsertResult {
+}
+
+- (NSString*)textInRange:(UITextRange*)range {
+    NSRange textRange = ((UIWidgetsTextRange*)range).range;
+    return [self.text substringWithRange:textRange];
+}
+
+- (void)replaceRange:(UITextRange*)range withText:(NSString*)text {
+    NSRange replaceRange = ((UIWidgetsTextRange*)range).range;
+    NSRange selectedRange = _selectedTextRange.range;
+    // Adjust the text selection:
+    // * reduce the length by the intersection length
+    // * adjust the location by newLength - oldLength + intersectionLength
+    NSRange intersectionRange = NSIntersectionRange(replaceRange, selectedRange);
+    if (replaceRange.location <= selectedRange.location)
+        selectedRange.location += text.length - replaceRange.length;
+    if (intersectionRange.location != NSNotFound) {
+        selectedRange.location += intersectionRange.length;
+        selectedRange.length -= intersectionRange.length;
+    }
+    
+    [self.text replaceCharactersInRange:[self clampSelection:replaceRange forText:self.text]
+                             withString:text];
+    [self setSelectedTextRange:[UIWidgetsTextRange rangeWithNSRange:[self clampSelection:selectedRange
+                                                                                 forText:self.text]]
+            updateEditingState:NO];
+    
+    [self updateEditingState];
+}
+
+- (BOOL)shouldChangeTextInRange:(UITextRange*)range replacementText:(NSString*)text {
+    if (self.returnKeyType == UIReturnKeyDefault && [text isEqualToString:@"\n"]) {
+        [_textInputDelegate performAction:UIWidgetsTextInputActionNewline withClient:_textInputClient];
+        return YES;
+    }
+    
+    if ([text isEqualToString:@"\n"]) {
+        UIWidgetsTextInputAction action;
+        switch (self.returnKeyType) {
+            case UIReturnKeyDefault:
+                action = UIWidgetsTextInputActionUnspecified;
+                break;
+            case UIReturnKeyDone:
+                action = UIWidgetsTextInputActionDone;
+                break;
+            case UIReturnKeyGo:
+                action = UIWidgetsTextInputActionGo;
+                break;
+            case UIReturnKeySend:
+                action = UIWidgetsTextInputActionSend;
+                break;
+            case UIReturnKeySearch:
+            case UIReturnKeyGoogle:
+            case UIReturnKeyYahoo:
+                action = UIWidgetsTextInputActionSearch;
+                break;
+            case UIReturnKeyNext:
+                action = UIWidgetsTextInputActionNext;
+                break;
+            case UIReturnKeyContinue:
+                action = UIWidgetsTextInputActionContinue;
+                break;
+            case UIReturnKeyJoin:
+                action = UIWidgetsTextInputActionJoin;
+                break;
+            case UIReturnKeyRoute:
+                action = UIWidgetsTextInputActionRoute;
+                break;
+            case UIReturnKeyEmergencyCall:
+                action = UIWidgetsTextInputActionEmergencyCall;
+                break;
+        }
+        
+        [_textInputDelegate performAction:action withClient:_textInputClient];
+        return NO;
+    }
+    
+    return YES;
+}
+
+- (void)setMarkedText:(NSString*)markedText selectedRange:(NSRange)markedSelectedRange {
+    NSRange selectedRange = _selectedTextRange.range;
+    NSRange markedTextRange = ((UIWidgetsTextRange*)self.markedTextRange).range;
+    
+    if (markedText == nil)
+        markedText = @"";
+    
+    if (markedTextRange.length > 0) {
+        // Replace text in the marked range with the new text.
+        [self replaceRange:self.markedTextRange withText:markedText];
+        markedTextRange.length = markedText.length;
+    } else {
+        // Replace text in the selected range with the new text.
+        [self replaceRange:_selectedTextRange withText:markedText];
+        markedTextRange = NSMakeRange(selectedRange.location, markedText.length);
+    }
+    
+    self.markedTextRange =
+    markedTextRange.length > 0 ? [UIWidgetsTextRange rangeWithNSRange:markedTextRange] : nil;
+    
+    NSUInteger selectionLocation = markedSelectedRange.location + markedTextRange.location;
+    selectedRange = NSMakeRange(selectionLocation, markedSelectedRange.length);
+    [self setSelectedTextRange:[UIWidgetsTextRange rangeWithNSRange:[self clampSelection:selectedRange
+                                                                                 forText:self.text]]
+            updateEditingState:YES];
+}
+
+- (void)unmarkText {
+    self.markedTextRange = nil;
+    [self updateEditingState];
+}
+
+- (UITextRange*)textRangeFromPosition:(UITextPosition*)fromPosition
+                           toPosition:(UITextPosition*)toPosition {
+    NSUInteger fromIndex = ((UIWidgetsTextPosition*)fromPosition).index;
+    NSUInteger toIndex = ((UIWidgetsTextPosition*)toPosition).index;
+    return [UIWidgetsTextRange rangeWithNSRange:NSMakeRange(fromIndex, toIndex - fromIndex)];
+}
+
+/** Returns the range of the character sequence at the specified index in the
+ * text. */
+- (NSRange)rangeForCharacterAtIndex:(NSUInteger)index {
+    if (index < self.text.length)
+        return [self.text rangeOfComposedCharacterSequenceAtIndex:index];
+    return NSMakeRange(index, 0);
+}
+
+- (NSUInteger)decrementOffsetPosition:(NSUInteger)position {
+    return [self rangeForCharacterAtIndex:MAX(0, position - 1)].location;
+}
+
+- (NSUInteger)incrementOffsetPosition:(NSUInteger)position {
+    NSRange charRange = [self rangeForCharacterAtIndex:position];
+    return MIN(position + charRange.length, self.text.length);
+}
+
+- (UITextPosition*)positionFromPosition:(UITextPosition*)position offset:(NSInteger)offset {
+    NSUInteger offsetPosition = ((UIWidgetsTextPosition*)position).index;
+    NSInteger newLocation = (NSInteger)offsetPosition + offset;
+    if (newLocation < 0 || newLocation > (NSInteger)self.text.length) {
+      return nil;
+    }
+    if (offset >= 0) {
+        for (NSInteger i = 0; i < offset && offsetPosition < self.text.length; ++i)
+            offsetPosition = [self incrementOffsetPosition:offsetPosition];
+    } else {
+        for (NSInteger i = 0; i < ABS(offset) && offsetPosition > 0; ++i)
+            offsetPosition = [self decrementOffsetPosition:offsetPosition];
+    }
+    return [UIWidgetsTextPosition positionWithIndex:offsetPosition];
+}
+
+- (UITextPosition*)positionFromPosition:(UITextPosition*)position
+                            inDirection:(UITextLayoutDirection)direction
+                                 offset:(NSInteger)offset {
+    // TODO(cbracken) Add RTL handling.
+    switch (direction) {
+        case UITextLayoutDirectionLeft:
+        case UITextLayoutDirectionUp:
+            return [self positionFromPosition:position offset:offset * -1];
+        case UITextLayoutDirectionRight:
+        case UITextLayoutDirectionDown:
+            return [self positionFromPosition:position offset:1];
+    }
+}
+
+- (UITextPosition*)beginningOfDocument {
+    return [UIWidgetsTextPosition positionWithIndex:0];
+}
+
+- (UITextPosition*)endOfDocument {
+    return [UIWidgetsTextPosition positionWithIndex:self.text.length];
+}
+
+- (NSComparisonResult)comparePosition:(UITextPosition*)position toPosition:(UITextPosition*)other {
+    NSUInteger positionIndex = ((UIWidgetsTextPosition*)position).index;
+    NSUInteger otherIndex = ((UIWidgetsTextPosition*)other).index;
+    if (positionIndex < otherIndex)
+        return NSOrderedAscending;
+    if (positionIndex > otherIndex)
+        return NSOrderedDescending;
+    return NSOrderedSame;
+}
+
+- (NSInteger)offsetFromPosition:(UITextPosition*)from toPosition:(UITextPosition*)toPosition {
+    return ((UIWidgetsTextPosition*)toPosition).index - ((UIWidgetsTextPosition*)from).index;
+}
+
+- (UITextPosition*)positionWithinRange:(UITextRange*)range
+                   farthestInDirection:(UITextLayoutDirection)direction {
+    NSUInteger index;
+    switch (direction) {
+        case UITextLayoutDirectionLeft:
+        case UITextLayoutDirectionUp:
+            index = ((UIWidgetsTextPosition*)range.start).index;
+            break;
+        case UITextLayoutDirectionRight:
+        case UITextLayoutDirectionDown:
+            index = ((UIWidgetsTextPosition*)range.end).index;
+            break;
+    }
+    return [UIWidgetsTextPosition positionWithIndex:index];
+}
+
+- (UITextRange*)characterRangeByExtendingPosition:(UITextPosition*)position
+                                      inDirection:(UITextLayoutDirection)direction {
+    NSUInteger positionIndex = ((UIWidgetsTextPosition*)position).index;
+    NSUInteger startIndex;
+    NSUInteger endIndex;
+    switch (direction) {
+        case UITextLayoutDirectionLeft:
+        case UITextLayoutDirectionUp:
+            startIndex = [self decrementOffsetPosition:positionIndex];
+            endIndex = positionIndex;
+            break;
+        case UITextLayoutDirectionRight:
+        case UITextLayoutDirectionDown:
+            startIndex = positionIndex;
+            endIndex = [self incrementOffsetPosition:positionIndex];
+            break;
+    }
+    return [UIWidgetsTextRange rangeWithNSRange:NSMakeRange(startIndex, endIndex - startIndex)];
+}
+
+#pragma mark - UITextInput text direction handling
+
+- (UITextWritingDirection)baseWritingDirectionForPosition:(UITextPosition*)position
+                                              inDirection:(UITextStorageDirection)direction {
+    return UITextWritingDirectionNatural;
+}
+
+- (void)setBaseWritingDirection:(UITextWritingDirection)writingDirection
+                       forRange:(UITextRange*)range {
+}
+
+#pragma mark - UITextInput cursor, selection rect handling
+
+- (CGRect)firstRectForRange:(UITextRange*)range {
+    return CGRectZero;
+}
+
+- (CGRect)caretRectForPosition:(UITextPosition*)position {
+    return CGRectZero;
+}
+
+- (UITextPosition*)closestPositionToPoint:(CGPoint)point {
+    NSUInteger currentIndex = ((UIWidgetsTextPosition*)_selectedTextRange.start).index;
+    return [UIWidgetsTextPosition positionWithIndex:currentIndex];
+}
+
+- (NSArray*)selectionRectsForRange:(UITextRange*)range {
+    return @[];
+}
+
+- (UITextPosition*)closestPositionToPoint:(CGPoint)point withinRange:(UITextRange*)range {
+    return range.start;
+}
+
+- (UITextRange*)characterRangeAtPoint:(CGPoint)point {
+    NSUInteger currentIndex = ((UIWidgetsTextPosition*)_selectedTextRange.start).index;
+    return [UIWidgetsTextRange rangeWithNSRange:[self rangeForCharacterAtIndex:currentIndex]];
+}
+
+#pragma mark - UIKeyInput Overrides
+
+- (void)updateEditingState {
+    NSUInteger selectionBase = ((UIWidgetsTextPosition*)_selectedTextRange.start).index;
+    NSUInteger selectionExtent = ((UIWidgetsTextPosition*)_selectedTextRange.end).index;
+    
+    NSUInteger composingBase = 0;
+    NSUInteger composingExtent = 0;
+    if (self.markedTextRange != nil) {
+        composingBase = ((UIWidgetsTextPosition*)self.markedTextRange.start).index;
+        composingExtent = ((UIWidgetsTextPosition*)self.markedTextRange.end).index;
+    }
+    [_textInputDelegate updateEditingClient:_textInputClient
+                                  withState:@{
+                                              @"selectionBase" : @(selectionBase),
+                                              @"selectionExtent" : @(selectionExtent),
+                                              @"selectionAffinity" : @(_selectionAffinity),
+                                              @"selectionIsDirectional" : @(false),
+                                              @"composingBase" : @(composingBase),
+                                              @"composingExtent" : @(composingExtent),
+                                              @"text" : [NSString stringWithString:self.text],
+                                              }];
+}
+
+- (BOOL)hasText {
+    return self.text.length > 0;
+}
+
+- (void)insertText:(NSString*)text {
+    _selectionAffinity = _kTextAffinityDownstream;
+    [self replaceRange:_selectedTextRange withText:text];
+}
+
+- (void)deleteBackward {
+    _selectionAffinity = _kTextAffinityDownstream;
+    if (!_selectedTextRange.isEmpty)
+        [self replaceRange:_selectedTextRange withText:@""];
+}
+
+@end
+
+/**
+ * Hides `UIWidgetsTextInputView` from iOS accessibility system so it
+ * does not show up twice, once where it is in the `UIView` hierarchy,
+ * and a second time as part of the `SemanticsObject` hierarchy.
+ */
+@interface UIWidgetsTextInputViewAccessibilityHider : UIView {
+}
+
+@end
+
+@implementation UIWidgetsTextInputViewAccessibilityHider {
+}
+
+- (BOOL)accessibilityElementsHidden {
+    return YES;
+}
+
+@end
+
+@implementation UIWidgetsTextInputPlugin {
+    UIWidgetsTextInputView* _view;
+    UIWidgetsTextInputViewAccessibilityHider* _inputHider;
+}
+
+@synthesize textInputDelegate = _textInputDelegate;
+
+- (instancetype)init {
+    self = [super init];
+    
+    if (self) {
+        _view = [[UIWidgetsTextInputView alloc] init];
+        _inputHider = [[UIWidgetsTextInputViewAccessibilityHider alloc] init];
+    }
+    
+    return self;
+}
+
+- (void)dealloc {
+    [self hideTextInput];
+    [_view release];
+    [_inputHider release];
+    
+    [super dealloc];
+}
+
+- (UIView<UITextInput>*)textInputView {
+    return _view;
+}
+
+- (void)showTextInput {
+    NSAssert([UIApplication sharedApplication].keyWindow != nullptr,
+             @"The application must have a key window since the keyboard client "
+             @"must be part of the responder chain to function");
+    _view.textInputDelegate = _textInputDelegate;
+    [_inputHider addSubview:_view];
+    [[UIApplication sharedApplication].keyWindow addSubview:_inputHider];
+    [_view becomeFirstResponder];
+}
+
+- (void)hideTextInput {
+    [_view resignFirstResponder];
+    [_view removeFromSuperview];
+    [_inputHider removeFromSuperview];
+}
+
+- (void)setTextInputClient:(int)client withConfiguration:(NSDictionary*)configuration {
+    NSDictionary* inputType = configuration[@"inputType"];
+    NSString* keyboardAppearance = configuration[@"keyboardAppearance"];
+    _view.keyboardType = ToUIKeyboardType(inputType);
+    _view.returnKeyType = ToUIReturnKeyType(configuration[@"inputAction"]);
+    _view.autocapitalizationType = ToUITextAutoCapitalizationType(configuration);
+    if ([keyboardAppearance isEqualToString:@"Brightness.dark"]) {
+        _view.keyboardAppearance = UIKeyboardAppearanceDark;
+    } else if ([keyboardAppearance isEqualToString:@"Brightness.light"]) {
+        _view.keyboardAppearance = UIKeyboardAppearanceLight;
+    } else {
+        _view.keyboardAppearance = UIKeyboardAppearanceDefault;
+    }
+    _view.secureTextEntry = [configuration[@"obscureText"] boolValue];
+    NSString* autocorrect = configuration[@"autocorrect"];
+    _view.autocorrectionType = autocorrect && ![autocorrect boolValue]
+    ? UITextAutocorrectionTypeNo
+    : UITextAutocorrectionTypeDefault;
+    [_view setTextInputClient:client];
+    [_view reloadInputViews];
+}
+
+- (void)setTextInputEditingState:(NSDictionary*)state {
+    [_view setTextInputState:state];
+}
+
+- (void)clearTextInputClient {
+    [_view setTextInputClient:0];
+}
+
++ (instancetype)sharedInstance {
+    static UIWidgetsTextInputPlugin *sharedInstance = nil;
+    static dispatch_once_t onceToken;
+    
+    dispatch_once(&onceToken, ^{
+        sharedInstance = [[UIWidgetsTextInputPlugin alloc] init];
+        sharedInstance.textInputDelegate = [[DefaultUIWidgetsTextInputDelegate alloc] init];
+    });
+    return sharedInstance;
+}
+@end
+
+
+@implementation DefaultUIWidgetsTextInputDelegate
+
+- (void)updateEditingClient:(int)client withState:(NSDictionary*)state {
+    UIWidgetsMethodMessage(@"TextInput", @"TextInputClient.updateEditingState", @[@(client), state]);
+}
+
+- (void)performAction:(UIWidgetsTextInputAction)action withClient:(int)client {
+    NSString* actionString;
+    switch (action) {
+        case UIWidgetsTextInputActionUnspecified:
+            // Where did the term "unspecified" come from? iOS has a "default" and Android
+            // has "unspecified." These 2 terms seem to mean the same thing but we need
+            // to pick just one. "unspecified" was chosen because "default" is often a
+            // reserved word in languages with switch statements (dart, java, etc).
+            actionString = @"TextInputAction.unspecified";
+            break;
+        case UIWidgetsTextInputActionDone:
+            actionString = @"TextInputAction.done";
+            break;
+        case UIWidgetsTextInputActionGo:
+            actionString = @"TextInputAction.go";
+            break;
+        case UIWidgetsTextInputActionSend:
+            actionString = @"TextInputAction.send";
+            break;
+        case UIWidgetsTextInputActionSearch:
+            actionString = @"TextInputAction.search";
+            break;
+        case UIWidgetsTextInputActionNext:
+            actionString = @"TextInputAction.next";
+            break;
+        case UIWidgetsTextInputActionContinue:
+            actionString = @"TextInputAction.continue";
+            break;
+        case UIWidgetsTextInputActionJoin:
+            actionString = @"TextInputAction.join";
+            break;
+        case UIWidgetsTextInputActionRoute:
+            actionString = @"TextInputAction.route";
+            break;
+        case UIWidgetsTextInputActionEmergencyCall:
+            actionString = @"TextInputAction.emergencyCall";
+            break;
+        case UIWidgetsTextInputActionNewline:
+            actionString = @"TextInputAction.newline";
+            break;
+    }
+    
+    UIWidgetsMethodMessage(@"TextInput", @"TextInputClient.performAction", @[@(client), actionString]);
+}
+@end
+
+extern "C" {
+    
+    void UIWidgetsTextInputShow() {
+        [[UIWidgetsTextInputPlugin sharedInstance] showTextInput];
+    }
+    
+    void UIWidgetsTextInputHide() {
+        [[UIWidgetsTextInputPlugin sharedInstance] hideTextInput];
+    }
+    
+    void UIWidgetsTextInputSetClient(int client, const char* configurationJson) {
+        NSError *jsonError = nil;
+        NSString *nsJsonString=[NSString stringWithUTF8String:configurationJson];
+        NSData *objectData = [nsJsonString dataUsingEncoding:NSUTF8StringEncoding];
+        NSDictionary *json = [NSJSONSerialization JSONObjectWithData:objectData
+                                                             options:NSJSONReadingMutableContainers
+                                                               error:&jsonError];
+        
+        [[UIWidgetsTextInputPlugin sharedInstance] setTextInputClient:client withConfiguration:json];
+    }
+    
+    void UIWidgetsTextInputSetTextInputEditingState(const char* jsonText) {
+        NSError *jsonError;
+        NSString *nsJsonString=[NSString stringWithUTF8String:jsonText];
+        NSData *objectData = [nsJsonString dataUsingEncoding:NSUTF8StringEncoding];
+        NSDictionary *args = [NSJSONSerialization JSONObjectWithData:objectData
+                                                             options:NSJSONReadingMutableContainers
+                                                               error:&jsonError];
+        [[UIWidgetsTextInputPlugin sharedInstance] setTextInputEditingState:args];
+    }
+    
+    void UIWidgetsTextInputClearTextInputClient() {
+        [[UIWidgetsTextInputPlugin sharedInstance] clearTextInputClient];
+    }
+}
+