Revert "Revert "Merge branch 'shiyun/skia' into dev_1.17.5""

This reverts commit 5434c2693ad93a46b777b150330e8e3f13db3735.

com.unity.uiwidgets/Runtime/animation/animation_controller.cs

         public AnimationController(
             float? value = null,
             TimeSpan? duration = null,
+            TimeSpan? reverseDuration = null,
             string debugLabel = null,
             float lowerBound = 0.0f,
             float upperBound = 1.0f,
             _direction = _AnimationDirection.forward;
 
             this.duration = duration;
+            this.reverseDuration = reverseDuration;
             this.debugLabel = debugLabel;
             this.lowerBound = lowerBound;
             this.upperBound = upperBound;
 
         public TimeSpan? duration;
 
+        public TimeSpan? reverseDuration;
+        
         Ticker _ticker;
 
         public void resync(TickerProvider vsync) {

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

             bool checkerboardRasterCacheImages = false, 
             bool checkerboardOffscreenLayers = false,
             bool showSemanticsDebugger = false,
-            bool debugShowCheckedModeBanner = true
+            bool debugShowCheckedModeBanner = true,
-            //Dictionary<LogicalKeySet, Intent> shortcuts = null,
-            //Dictionary<LocalKey, ActionFactory> actions = null
+            Dictionary<LogicalKeySet, Intent> shortcuts = null,
+            Dictionary<LocalKey, ActionFactory> actions = null
-            //D.assert(routes != null);
-            //D.assert(navigatorObservers != null);
+            D.assert(routes != null);
+            D.assert(navigatorObservers != null);
             D.assert(title != null);
             D.assert(showPerformanceOverlay != null);
             D.assert(checkerboardRasterCacheImages != null);
             this.localeResolutionCallback = localeResolutionCallback;
             this.supportedLocales = supportedLocales;
             this.showPerformanceOverlay = showPerformanceOverlay;
+            this.shortcuts = shortcuts;
+            this.actions = actions;
         }
 
         public readonly GlobalKey<NavigatorState> navigatorKey;
         public readonly bool debugShowWidgetInspector;
         public readonly bool debugShowCheckedModeBanner;
         //TBC ????
-        //public readonly Dictionary<LogicalKeySet, Intent> shortcuts;
-        //public readonly Dictionary<LocalKey, ActionFactory> actions;
+        public readonly Dictionary<LogicalKeySet, Intent> shortcuts;
+        public readonly Dictionary<LocalKey, ActionFactory> actions;
 
         public override State createState() {
             return new _CupertinoAppState();
                                         padding: EdgeInsets.zero,
                                         onPressed: onPressed
                                       );
-                                    }//,
-                                    //shortcuts: widget.shortcuts,
-                                    //actions: widget.actions,
+                                    },
+                                    shortcuts: widget.shortcuts,
+                                 
+                                    actions: widget.actions
                                   );  
                             }
                         )

com.unity.uiwidgets/Runtime/foundation/assertions.cs

             }
         }
     }
+    class DiagnosticsStackTrace : DiagnosticsBlock {
+        public DiagnosticsStackTrace(
+            string name,
+            IterableFilter<string> stackFilter = null,
+            bool showSeparator = true
+            ) : base(
+            name: name,
+            properties: new List<DiagnosticsNode>(),
+            style: DiagnosticsTreeStyle.flat,
+            showSeparator: showSeparator,
+            allowTruncate: true
+        ) {
+        }
+
+        public DiagnosticsStackTrace(
+            string name,
+            string frame,
+            bool showSeparator = true
+        ) : base(
+            name: name,
+            properties: new List<DiagnosticsNode>() {_createStackFrame(frame)},
+            style: DiagnosticsTreeStyle.whitespace,
+            showSeparator: showSeparator
+        ) {
+            
+        }
+        public static DiagnosticsNode _createStackFrame(string frame) {
+            return DiagnosticsNode.message(frame, allowWrap: false);
+        }
+    }
 
 
     public class UIWidgetsError : Exception {

com.unity.uiwidgets/Runtime/foundation/diagnostics.cs

             _maxDescendentsTruncatableNode = maxDescendentsTruncatableNode;
         }
 
+
         readonly int _wrapWidth;
         readonly int _wrapWidthProperties;
         readonly DiagnosticLevel _minLevel;
             return (foundation_._isSingleLine(childStyle) || childStyle == DiagnosticsTreeStyle.errorProperty)
                 ? textStyle
                 : child.textTreeConfiguration;
+          
+        public static DiagnosticsNode message(
+            string message,
+            DiagnosticsTreeStyle style = DiagnosticsTreeStyle.singleLine,
+            DiagnosticLevel level = DiagnosticLevel.info,
+            bool allowWrap = true
+        ) {
+            D.assert(style != null);
+            D.assert(level != null);
+            return new DiagnosticsProperty<object>(
+                "",
+                null,
+                description: message,
+                style: style,
+                showName: false,
+                level: level
+            );
         }
 
         public string render(
             return new List<DiagnosticsNode>();
         }
     }
-    
-    public class DiagnosticableNode<T> : DiagnosticsNode where T : Diagnosticable {
+
+    public class DiagnosticableNode<T> : DiagnosticsNode where T : IDiagnosticable {
-            T value = null,
+            T value = default,
             DiagnosticsTreeStyle? style = null
         ) : base(name: name, style: style) {
             D.assert(value != null);
         public override void debugFillProperties(DiagnosticPropertiesBuilder properties) {
         }
     }
-    
-    public abstract class Diagnosticable {
+
+    public interface IDiagnosticable {
+        string toStringShort();
+
+        string toString(DiagnosticLevel minLevel = DiagnosticLevel.debug);
+
+        DiagnosticsNode toDiagnosticsNode(
+            string name = null,
+            DiagnosticsTreeStyle style = DiagnosticsTreeStyle.sparse);
+
+        void debugFillProperties(DiagnosticPropertiesBuilder properties);
+    }
+
+    public abstract class Diagnosticable : IDiagnosticable {
+
         protected Diagnosticable() {
         }
 
 
         public virtual DiagnosticsNode toDiagnosticsNode(
             string name = null,
-            DiagnosticsTreeStyle style = DiagnosticsTreeStyle.sparse) {
+            DiagnosticsTreeStyle style = DiagnosticsTreeStyle.sparse ) {
             return new DiagnosticableNode<Diagnosticable>(
                 name: name, value: this, style: style
             );
 
         public override DiagnosticsNode toDiagnosticsNode(
             string name = null,
+
             DiagnosticsTreeStyle style = DiagnosticsTreeStyle.sparse) {
             return new DiagnosticableTreeNode(
                 name: name,

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

         public AlignmentGeometry() {
         }
 
-        float _x { get; }
+        protected float _x { get; }
-        float _start { get; }
+        protected float _start { get; }
-        float _y { get; }
+        protected float _y { get; }
 
         // public static AlignmentGeometry add(AlignmentGeometry other) {
         //   return new _MixedAlignment(
         // int get hashCode => hashValues(_x, _start, _y);
     }
 
-    public class Alignment : IEquatable<Alignment> {
+    public class Alignment : AlignmentGeometry, IEquatable<Alignment> {
         public Alignment(float x, float y) {
             this.x = x;
             this.y = y;
             }
 
             return $"Alignment({x:F1}, {y:F1})";
+        }
+
+        public override Alignment resolve(TextDirection? direction) {
+            D.assert(direction != null);
+            switch (direction) {
+                case TextDirection.rtl:
+                    return new Alignment(_x - _start, _y);
+                case TextDirection.ltr:
+                    return new Alignment(_x + _start, _y);
+            }
+            return null;
         }
     }
 }

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

 
     public abstract class InlineSpan : DiagnosticableTree, IEquatable<InlineSpan> {
         public InlineSpan(
-            TextStyle style , HoverRecognizer hoverRecognizer
+            TextStyle style = null 
-            this.hoverRecognizer = hoverRecognizer;
+            
-        
-        public readonly HoverRecognizer hoverRecognizer;
-
-        public bool hasHoverRecognizer {
-            get {
-                bool need = false;
-                visitChildren((text) => {
-                    if (text.hoverRecognizer != null) {
-                        need = true;
-                        return false;
-                    }
-
-                    return true;
-                });
-                return need;
-            }
-        }
-
+        
         public abstract void build(ParagraphBuilder builder,
             float textScaleFactor = 1, List<PlaceholderDimensions> dimensions = null
         );
-        public InlineSpan getSpanForPosition(TextPosition position) {
+        public virtual InlineSpan getSpanForPosition(TextPosition position) {
             D.assert(debugAssertIsValid());
             Accumulator offset = new Accumulator();
             InlineSpan result = null;
 
         protected abstract InlineSpan getSpanForPositionVisitor(TextPosition position, Accumulator offset);
 
-        public string toPlainText(
-            bool includeSemanticsLabels = true, bool includePlaceholders = true) {
+        public virtual string toPlainText(
+            bool includeSemanticsLabels = true,
+            bool includePlaceholders = true) 
+        {
             StringBuilder buffer = new StringBuilder();
             computeToPlainText(buffer, includeSemanticsLabels: includeSemanticsLabels,
                 includePlaceholders: includePlaceholders);
 
         public abstract void computeSemanticsInformation(List<InlineSpanSemanticsInformation> collector);
 
-        public abstract void computeToPlainText(StringBuilder buffer,
-            bool includeSemanticsLabels = true, bool includePlaceholders = true);
+        public abstract void computeToPlainText(
+            StringBuilder buffer,
+            bool includeSemanticsLabels = true, 
+            bool includePlaceholders = true);
 
         public int? codeUnitAt(int index) {
             if (index < 0)
 
         protected abstract int? codeUnitAtVisitor(int index, Accumulator offset);
 
-        public bool debugAssertIsValid() => true;
+        public virtual bool debugAssertIsValid() => true;
         public abstract RenderComparison compareTo(InlineSpan other);
 
         void debugFillProperties(DiagnosticPropertiesBuilder properties) {

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

 using System.Collections.Generic;
 using System.Text;
+using JetBrains.Annotations;
 using Unity.UIWidgets.foundation;
 using Unity.UIWidgets.gestures;
 using Unity.UIWidgets.ui;
         public PlaceholderSpan(
-            TextBaseline baseline,
-            TextStyle style,
-            PlaceholderAlignment alignment = PlaceholderAlignment.bottom,
-            HoverRecognizer hoverRecognizer = null
-        ) : base(style: style, hoverRecognizer: hoverRecognizer) {
+            TextBaseline? baseline = null,
+            TextStyle style = null,
+            PlaceholderAlignment alignment = PlaceholderAlignment.bottom
+            
+        ) : base(style: style) {
             this.baseline = baseline;
             this.alignment = alignment;
         }
-        public TextBaseline baseline;
+        public TextBaseline? baseline;
 
         public override void computeToPlainText(
             StringBuilder buffer,
             base.debugFillProperties(properties);
 
             properties.add(new EnumProperty<PlaceholderAlignment>("alignment", alignment, defaultValue: null));
-            properties.add(new EnumProperty<TextBaseline>("baseline", baseline, defaultValue: null));
+            properties.add(new EnumProperty<TextBaseline>("baseline", (TextBaseline)baseline, defaultValue: null));
         }
     }
 }

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

         public readonly string semanticsLabel;
 
         public TextSpan(
-            string text = "",
+            string text = null,
-            HoverRecognizer hoverRecognizer = null,
-            string semanticsLabel = null) : base(style: style, hoverRecognizer: hoverRecognizer) {
+            string semanticsLabel = null
+            ) : base(style: style) {
             this.text = text;
             this.children = children;
             this.recognizer = recognizer;
-        public override void build(ParagraphBuilder builder, float textScaleFactor = 1.0f,
-            List<PlaceholderDimensions> dimensions = null) {
+        public override void build(
+            ParagraphBuilder builder,
+            float textScaleFactor = 1.0f,
+            List<PlaceholderDimensions> dimensions = null
+            ) {
             D.assert(debugAssertIsValid());
             var hasStyle = style != null;
 
-
             if (text != null)
                 builder.addText(text);
             if (children != null) {
             return null;
         }
 
-        public override void computeToPlainText(StringBuilder buffer, bool includeSemanticsLabels = true,
-            bool includePlaceholders = true) {
+        public override void computeToPlainText(
+            StringBuilder buffer, 
+            bool includeSemanticsLabels = true,
+            bool includePlaceholders = true
+            ) {
             D.assert(debugAssertIsValid());
             if (semanticsLabel != null && includeSemanticsLabels) {
                 buffer.Append(semanticsLabel);
             return null;
         }
 
-        bool debugAssertIsValid() {
+        public override bool debugAssertIsValid() {
             D.assert(() => {
                 if (children != null) {
                     foreach (InlineSpan child in children) {
             return result;
         }
 
-        public override bool Equals(object obj) {
-            if (ReferenceEquals(null, obj)) {
-                return false;
-            }
-
-            if (ReferenceEquals(this, obj)) {
-                return true;
-            }
-
-            if (obj.GetType() != GetType()) {
-                return false;
-            }
-
-            return Equals((TextSpan) obj);
-        }
-
-            unchecked {
+            unchecked
+            {
                 var hashCode = base.GetHashCode();
                 hashCode = (hashCode * 397) ^ (text != null ? text.GetHashCode() : 0);
                 hashCode = (hashCode * 397) ^ (children != null ? children.GetHashCode() : 0);
             }
         }
-
-        public bool Equals(InlineSpan otherInline) {
-            if (ReferenceEquals(null, otherInline)) {
-                return false;
-            }
-
-            if (ReferenceEquals(this, otherInline)) {
-                return true;
-            }
-
-            TextSpan other = otherInline as TextSpan;
-
-            return Equals(style, other.style) && string.Equals(text, other.text) &&
-                   childEquals(children, other.children) && recognizer == other.recognizer;
-        }
-
         public static bool operator ==(TextSpan left, TextSpan right) {
             return Equals(left, right);
         }
         }
 
-        int childHash() {
-            unchecked {
-                var hashCode = 0;
-                if (children != null) {
-                    foreach (var child in children) {
-                        hashCode = (hashCode * 397) ^ (child != null ? child.GetHashCode() : 0);
-                    }
-                }
-
-                return hashCode;
-            }
-        }
-
         static bool childEquals(List<InlineSpan> left, List<InlineSpan> right) {
             if (ReferenceEquals(left, right)) {
                 return true;
             return left.SequenceEqual(right);
         }
 
+        public override string toStringShort() {
+            return GetType().ToString();
+        }
+
-            properties.defaultDiagnosticsTreeStyle = DiagnosticsTreeStyle.whitespace;
-            // Properties on style are added as if they were properties directly on
-            // this TextSpan.
-            if (style != null) {
-                style.debugFillProperties(properties);
-            }
+            properties.add(
+                new StringProperty(
+                    "text",
+                    text,
+                    showName: false,
+                    defaultValue: null
+                )
+            );
+            if (style == null && text == null && children == null)
+                properties.add(DiagnosticsNode.message("(empty)"));
-                description: recognizer == null ? "" : recognizer.GetType().FullName,
-                defaultValue: foundation_.kNullDefaultValue
+                description: recognizer?.GetType()?.ToString(),
+                defaultValue: null
-            properties.add(new StringProperty("text", text, showName: false,
-                defaultValue: foundation_.kNullDefaultValue));
-            if (style == null && text == null && children == null) {
-                properties.add(DiagnosticsNode.message("(empty)"));
+            if (semanticsLabel != null) {
+                properties.add(new StringProperty("semanticsLabel", semanticsLabel));
             }
         }
 
             }).ToList();
         }
 
-        public bool Equals(TextSpan other) {
+
+        public bool Equals(TextSpan other)
+        {
             if (ReferenceEquals(null, other)) {
                 return false;
             }
             }
 
-            return base.Equals(other) && text == other.text && Equals(children, other.children) &&
-                   Equals(recognizer, other.recognizer) && semanticsLabel == other.semanticsLabel;
+            return base.Equals(other) && text == other.text && Equals(children, other.children) && Equals(recognizer, other.recognizer) && semanticsLabel == other.semanticsLabel;
+        }
+
+        public override bool Equals(object obj)
+        {
+            if (ReferenceEquals(null, obj)) {
+                return false;
+            }
+
+            if (ReferenceEquals(this, obj)) {
+                return true;
+            }
+
+            if (obj.GetType() != GetType()) {
+                return false;
+            }
+
+            return Equals((TextSpan) obj);
         }
     }
 }

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

         public RenderAnimatedSize(
             TickerProvider vsync = null,
             TimeSpan? duration = null,
+            TimeSpan? reverseDuration = null,
             Curve curve = null,
             Alignment alignment = null,
             RenderBox child = null
             _vsync = vsync;
             _controller = new AnimationController(
                 vsync: this.vsync,
-                duration: duration);
+                duration: duration,
+                reverseDuration: reverseDuration);
             _controller.addListener(() => {
                 if (_controller.value != _lastValue) {
                     markNeedsLayout();
             }
         }
 
+        /// The duration of the animation when running in reverse.
+        public TimeSpan? reverseDuration {
+            get { return _controller.reverseDuration; }
+            set {
+                if (value == _controller.reverseDuration) {
+                    return;
+                }
+ 
+                _controller.reverseDuration = value;
+            }
+        }
+        
         public Curve curve {
             get { return _animation.curve; }
             set {
         protected override void performLayout() {
             _lastValue = _controller.value;
             _hasVisualOverflow = false;
-
+            BoxConstraints constraints = this.constraints;
             if (child == null || constraints.isTight) {
                 _controller.stop();
                 size = _sizeTween.begin = _sizeTween.end = constraints.smallest;

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

             });
             return scene;
         }
-        Future<ui.Image> toImage(Rect bounds, float pixelRatio = 1.0f)// async
+
+        public Future<ui.Image> toImage(Rect bounds, float pixelRatio = 1.0f)// async
         {
             D.assert(bounds != null);
             D.assert(pixelRatio != null);

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

     public delegate void PaintingContextCallback(PaintingContext context, Offset offset);
 
     public class PaintingContext : ClipContext {
-        PaintingContext(
+        public PaintingContext(
             ContainerLayer containerLayer = null,
             Rect estimatedBounds = null
         ) {
             });
         }
 
-        public void paintChild(RenderObject child, Offset offset) {
+        public virtual void paintChild(RenderObject child, Offset offset) {
             if (child.isRepaintBoundary) {
                 stopRecordingIfNeeded();
                 _compositeChild(child, offset);
             childContext.stopRecordingIfNeeded();
         }
 
-        protected PaintingContext createChildContext(ContainerLayer childLayer, Rect bounds) {
+        public virtual PaintingContext createChildContext(ContainerLayer childLayer, Rect bounds) {
             return new PaintingContext(childLayer, bounds);
         }
 
 
         public void pushOpacity(Offset offset, int alpha, PaintingContextCallback painter) {
             pushLayer(new OpacityLayer(alpha: alpha), painter, offset);
+        }
+        public OpacityLayer pushOpacity(Offset offset, int alpha, PaintingContextCallback painter,  OpacityLayer oldLayer = null) {
+            OpacityLayer layer = oldLayer ?? new OpacityLayer();
+            layer.alpha = alpha;
+            layer.offset = offset;
+            pushLayer(layer, painter, Offset.zero);
+            return layer;
         }
 
         public override string ToString() {
             D.assert(node._relayoutBoundary == node);
             return true;
         }
+        // TODO
+        /*void markNeedsSemanticsUpdate() { 
+            D.assert(!attached || !owner._debugDoingSemantics);
+            if (!attached || owner._semanticsOwner == null) {
+              _cachedSemanticsConfiguration = null;
+              return;
+            }
+
+            bool wasSemanticsBoundary = _semantics != null && _cachedSemanticsConfiguration?.isSemanticBoundary == true;
+            _cachedSemanticsConfiguration = null;
+            bool isEffectiveSemanticsBoundary = _semanticsConfiguration.isSemanticBoundary && wasSemanticsBoundary;
+            RenderObject node = this;
+
+            while (!isEffectiveSemanticsBoundary && node.parent is RenderObject) {
+                if (node != this && node._needsSemanticsUpdate)
+                    break;
+                node._needsSemanticsUpdate = true;
+                node = node.parent as RenderObject;
+                isEffectiveSemanticsBoundary = node._semanticsConfiguration.isSemanticBoundary;
+                if (isEffectiveSemanticsBoundary && node._semantics == null) {
+                    return;
+                }
+            }
+            if (node != this && _semantics != null && _needsSemanticsUpdate) {
+
+                owner._nodesNeedingSemantics.remove(this);
+            }
+            if (!node._needsSemanticsUpdate) {
+                node._needsSemanticsUpdate = true;
+                if (owner != null) {
+                    D.assert(node._semanticsConfiguration.isSemanticBoundary || node.parent is! RenderObject);
+                    owner._nodesNeedingSemantics.add(node);
+                    owner.requestVisualUpdate();
+                }
+            }
+        }*/
         public virtual void markNeedsLayout() {
             D.assert(_debugCanPerformMutations);
             if (_needsLayout) {
         RenderObject child { get; set; }
     }
 
-    public interface RenderObjectWithChildMixin<ChildType> : RenderObjectWithChildMixin
-        where ChildType : RenderObject {
-        new ChildType child { get; set; }
+    public interface RenderObjectWithChildMixin<ChildType> : RenderObjectWithChildMixin where ChildType : RenderObject {
+        ChildType child { get; set; }
     }
 
     public interface ContainerParentDataMixin<ChildType> where ChildType : RenderObject {
 
         public readonly RenderObject renderObject;
     }
-
+    
-        public DiagnosticsDebugCreator(object value) :
-            base(
+        public DiagnosticsDebugCreator(object value)
+            : base(
                 "debugCreator",
                 value,
                 level: DiagnosticLevel.hidden

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

 
     
     public class RenderParagraph : RenderBox{
+        // ContainerRenderObjectMixin<RenderBox, TextParentData>,
+        //RenderBoxContainerDefaultsMixin<RenderBox, TextParentData>,
+        //RelayoutWhenSystemFontsChangeMixin
         static readonly string _kEllipsis = "\u2026";
 
         bool _softWrap;
             _pointerHoverInside = true;
         }
 
-        void _onPointerExit(PointerEvent evt) {
+        /*void _onPointerExit(PointerEvent evt) {
-        }
+        }*/
-        void _onPointerHover(PointerEvent evt) {
+        /*void _onPointerHover(PointerEvent evt) {
             _layoutTextWithConstraints(constraints);
             Offset offset = globalToLocal(evt.position);
             TextPosition position = _textPainter.getPositionForOffset(offset);
                 (span as TextSpan)?.hoverRecognizer?.OnPointerEnter?.Invoke((PointerHoverEvent) evt);
                 _previousHoverSpan = span;
             }
-        }
+        }*/
 
         public override void handleEvent(PointerEvent evt, HitTestEntry entry) {
             D.assert(debugHandleEvent(evt, entry));

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

         }
 
         protected CustomClipper<T> _clipper;
-
+        
         public override void attach(object owner) {
             base.attach(owner);
             _clipper?._reclip?.addListener(_markNeedsClip);
         protected abstract T _defaultClip { get; }
         protected T _clip;
 
-        public readonly Clip clipBehavior;
+        protected Clip _clipBehavior;
+        
+        public Clip clipBehavior {
+            get { return _clipBehavior; }
+            set {
+                if (_clipBehavior == value) {
+                    return;
+                }
+
+                _clipBehavior = value;
+            }
+        }
+        
         protected override void performLayout() {
             Size oldSize = hasSize ? size : null;
             base.performLayout();

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

                 _geometry = value;
             }
         }
-
         SliverGeometry _geometry;
 
         public override Rect paintBounds {
             get { return 0.0f; }
         }
 
-        public bool hitTest(SliverHitTestResult result, float mainAxisPosition = 0, float crossAxisPosition = 0) {
+        public virtual bool hitTest(SliverHitTestResult result, float mainAxisPosition = 0, float crossAxisPosition = 0) {
             if (mainAxisPosition >= 0.0f && mainAxisPosition < geometry.hitTestExtent &&
                 crossAxisPosition >= 0.0f && crossAxisPosition < constraints.crossAxisExtent) {
                 if (hitTestChildren(result, mainAxisPosition: mainAxisPosition,

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

 using Rect = Unity.UIWidgets.ui.Rect;
 
 namespace Unity.UIWidgets.rendering {
+    public enum CacheExtentStyle {
+        /// Treat the [Viewport.cacheExtent] as logical pixels.
+        pixel,
+        /// Treat the [Viewport.cacheExtent] as a multiplier of the main axis extent.
+        viewport,
+    }
     public interface RenderAbstractViewport {
         RevealedOffset getOffsetToReveal(RenderObject target, float alignment, Rect rect = null);
         RenderObject parent { get; }
             AxisDirection axisDirection = AxisDirection.down,
             AxisDirection crossAxisDirection = AxisDirection.right,
             ViewportOffset offset = null,
-            float cacheExtent = RenderViewportUtils.defaultCacheExtent
+            float cacheExtent = RenderViewportUtils.defaultCacheExtent,
+            CacheExtentStyle cacheExtentStyle = CacheExtentStyle.pixel
-
+            D.assert(axisDirection != null);
+            D.assert(crossAxisDirection != null);
+            D.assert(cacheExtentStyle != null);
+            D.assert(cacheExtent != null || cacheExtentStyle == CacheExtentStyle.pixel);
+            _cacheExtentStyle = cacheExtentStyle;
         }
 
         public new RenderObject parent {
                 markNeedsLayout();
             }
         }
-
-
+        public float _calculatedCacheExtent;
+        public CacheExtentStyle cacheExtentStyle {
+            get {
+                return _cacheExtentStyle;
+            }
+            set {
+                D.assert(value != null);
+                if (value == _cacheExtentStyle) {
+                    return;
+                }
+                _cacheExtentStyle = value;
+                markNeedsLayout();
+            }
+        }
+        CacheExtentStyle _cacheExtentStyle;
+       
         public override void attach(object owner) {
             base.attach(owner);
             _offset.addListener(markNeedsLayout);
             float anchor = 0.0f,
             List<RenderSliver> children = null,
             RenderSliver center = null,
-            float cacheExtent = RenderViewportUtils.defaultCacheExtent
-        ) : base(axisDirection, crossAxisDirection, offset, cacheExtent) {
+            float cacheExtent = RenderViewportUtils.defaultCacheExtent,
+            CacheExtentStyle cacheExtentStyle = CacheExtentStyle.pixel
+        ) : base(axisDirection, crossAxisDirection, offset, cacheExtent,cacheExtentStyle) {
+            D.assert(anchor != null);
+            D.assert(cacheExtentStyle != CacheExtentStyle.viewport || cacheExtent != null);
-
-
             if (center == null && firstChild != null) {
                 _center = firstChild;
             }
             float reverseDirectionRemainingPaintExtent = centerOffset.clamp(0.0f, mainAxisExtent);
             float forwardDirectionRemainingPaintExtent = (mainAxisExtent - centerOffset).clamp(0.0f, mainAxisExtent);
 
-            float fullCacheExtent = mainAxisExtent + 2 * cacheExtent;
-            float centerCacheOffset = centerOffset + cacheExtent;
+            switch (cacheExtentStyle) {
+                case CacheExtentStyle.pixel:
+                    _calculatedCacheExtent = cacheExtent;
+                    break;
+                case CacheExtentStyle.viewport:
+                    _calculatedCacheExtent = mainAxisExtent * cacheExtent;
+                    break;
+            }
+
+            
+            float fullCacheExtent = mainAxisExtent + 2 * _calculatedCacheExtent;
+            float centerCacheOffset = centerOffset + _calculatedCacheExtent;
             float reverseDirectionRemainingCacheExtent = centerCacheOffset.clamp(0.0f, fullCacheExtent);
             float forwardDirectionRemainingCacheExtent =
                 (fullCacheExtent - centerCacheOffset).clamp(0.0f, fullCacheExtent);
                     growthDirection: GrowthDirection.reverse,
                     advance: childBefore,
                     remainingCacheExtent: reverseDirectionRemainingCacheExtent,
-                    cacheOrigin: (mainAxisExtent - centerOffset).clamp(-cacheExtent, 0.0f)
+                    cacheOrigin: (mainAxisExtent - centerOffset).clamp(-_calculatedCacheExtent, 0.0f)
                 );
                 if (result != 0.0f) {
                     return -result;
                 growthDirection: GrowthDirection.forward,
                 advance: childAfter,
                 remainingCacheExtent: forwardDirectionRemainingCacheExtent,
-                cacheOrigin: centerOffset.clamp(-cacheExtent, 0.0f)
+                cacheOrigin: centerOffset.clamp(-_calculatedCacheExtent, 0.0f)
             );
         }
 

com.unity.uiwidgets/Runtime/scheduler2/binding.cs

                 _ensureEventLoopCallback();
             return entry.completer.future;
         }
+        
 
         protected override void unlocked() {
             base.unlocked();
                         context: new ErrorDescription("during a task callback"),
                         informationCollector: callbackStack == null
                             ? (InformationCollector) null
-                            : infoCollector
+                            : (StringBuilder sb) => {
+                                sb.AppendLine("\nThis exception was thrown in the context of a scheduler callback. " +
+                                              "When the scheduler callback was _registered_ (as opposed to when the " +
+                                              "exception was thrown), this was the stack: " + callbackStack);
+                            }
                     ));
                 }
 
                     context: new ErrorDescription("during a scheduler callback"),
                     informationCollector: callbackStack == null
                         ? (InformationCollector) null
-                        : infoCollector
+                        : (StringBuilder information) => {
+                            information.AppendLine(
+                                "\nThis exception was thrown in the context of a scheduler callback. " +
+                                "When the scheduler callback was _registered_ (as opposed to when the " +
+                                "exception was thrown), this was the stack:"
+                            );
+                            foreach (var line in UIWidgetsError.defaultStackFilter(
+                                callbackStack.TrimEnd().Split('\n'))) {
+                                information.AppendLine(line);
+                            }
+                        }
                 ));
             }
 

com.unity.uiwidgets/Runtime/service/raw_keyboard.cs

 using System.Collections.Generic;
 using Unity.UIWidgets.foundation;
+using Unity.UIWidgets.services;
 using UnityEngine;
 
 namespace Unity.UIWidgets.service {
+        
+        public static readonly Dictionary<PhysicalKeyboardKey, LogicalKeyboardKey> _keysPressed = new Dictionary<PhysicalKeyboardKey, LogicalKeyboardKey>();
+        
+        public HashSet<LogicalKeyboardKey> keysPressed 
+        {
+            get {
+                HashSet<LogicalKeyboardKey> keyboardKeys = new HashSet<LogicalKeyboardKey>();
+                foreach (var value in _keysPressed.Values) {
+                    keyboardKeys.Add(value);
+                }
+                return keyboardKeys;
+            }
+        }
 
         RawKeyboard() {
             

com.unity.uiwidgets/Runtime/service/system_chrome.cs

+using System;
+using Unity.UIWidgets.async2;
+using Unity.UIWidgets.foundation;
 using Unity.UIWidgets.ui;
 
 namespace Unity.UIWidgets.service {
             return !Equals(left, right);
         }
     }
+    public class SystemChrome {
+        /*public static Future setPreferredOrientations(List<DeviceOrientation> orientations)  {
+            return SystemChannels.platform.invokeMethod(
+              "SystemChrome.setPreferredOrientations",
+              _stringify(orientations)
+            );
+        }
+
+        public static Future setApplicationSwitcherDescription(ApplicationSwitcherDescription description){
+          return SystemChannels.platform.invokeMethod(
+                "SystemChrome.setApplicationSwitcherDescription",
+                new Dictionary<string, object>{
+                  {"label",description.label},
+                  {"primaryColor", description.primaryColor},
+                }
+            );
+        }
+
+        static Future setEnabledSystemUIOverlays(List<SystemUiOverlay> overlays) {
+          return SystemChannels.platform.invokeMethod(
+                "SystemChrome.setEnabledSystemUIOverlays",
+                _stringify(overlays)
+            );
+        }
+        public static Future restoreSystemUIOverlays()  {
+          return SystemChannels.platform.invokeMethod(
+            "SystemChrome.restoreSystemUIOverlays",
+            null
+            );
+        }
+
+        public static void setSystemUIOverlayStyle(SystemUiOverlayStyle style) {
+            D.assert(style != null);
+            if (_pendingStyle != null) {
+                _pendingStyle = style;
+                return;
+            } 
+            if (style == _latestStyle) {
+                return;
+            } 
+            _pendingStyle = style;
+            scheduleMicrotask(()=> { 
+                D.assert(_pendingStyle != null); 
+                if (_pendingStyle != _latestStyle) {
+                  return SystemChannels.platform.invokeMethod(
+                        "SystemChrome.setSystemUIOverlayStyle",
+                        _pendingStyle._toMap()
+                    );
+                    _latestStyle = _pendingStyle;
+                }
+                _pendingStyle = null;
+            });
+        }*/
+        public static SystemUiOverlayStyle _pendingStyle; 
+        public static SystemUiOverlayStyle latestStyle {
+            get {
+                return _latestStyle;
+            }
+        }
+        static SystemUiOverlayStyle _latestStyle;
+    }
+
 }

com.unity.uiwidgets/Runtime/ui2/painting.cs

             }
         }
 
-        static int getAlphaFromOpacity(float opacity) {
+        public static int getAlphaFromOpacity(float opacity) {
             return (opacity.clamp(0.0f, 1.0f) * 255).round();
         }
 

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

             bool enabled = true,
             FocusNode focusNode = null,
             bool autofocus = false,
-            //Dictionary<LogicalKeySet, Intent> shortcuts = null,
+            Dictionary<LogicalKeySet, Intent> shortcuts = null,
             Dictionary<LocalKey, ActionFactory> actions = null,
             ValueChanged<bool> onShowFocusHighlight = null,
             ValueChanged<bool> onShowHoverHighlight = null,
             this.enabled = enabled;
             this.focusNode = focusNode;
             this.autofocus = autofocus;
-            //this.shortcuts = shortcuts;
+            this.shortcuts = shortcuts;
             this.actions = actions;
             this.onShowFocusHighlight = onShowFocusHighlight;
             this.onShowHoverHighlight = onShowHoverHighlight;
         public readonly Dictionary<LocalKey, ActionFactory> actions;
 
 
-        //public readonly Dictionary<LogicalKeySet, Intent> shortcuts;
+        public readonly Dictionary<LogicalKeySet, Intent> shortcuts;
 
 
         public readonly ValueChanged<bool> onShowFocusHighlight;
                
                 child = new Actions(actions: widget.actions, child: child);
             }
-            /*if (widget.enabled && widget.shortcuts != null && widget.shortcuts.isNotEmpty()) {
+            if (widget.enabled && widget.shortcuts != null && widget.shortcuts.isNotEmpty()) {
-            }*/
+            }
             return child;
         }
     }

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

             Alignment alignment = null,
             CrossFadeState? crossFadeState = null,
             TimeSpan? duration = null,
+            TimeSpan? reverseDuration = null,
             AnimatedCrossFadeBuilder layoutBuilder = null
         ) : base(key: key) {
             D.assert(firstChild != null);
             this.sizeCurve = sizeCurve ?? Curves.linear;
             this.alignment = alignment ?? Alignment.topCenter;
             this.crossFadeState = crossFadeState ?? CrossFadeState.showFirst;
-            this.duration = duration ?? TimeSpan.Zero;
+            this.duration = duration;
+            this.reverseDuration = reverseDuration;
             this.layoutBuilder = layoutBuilder ?? defaultLayoutBuilder;
         }
 
 
         public readonly CrossFadeState crossFadeState;
 
-        public readonly TimeSpan duration;
+        public readonly TimeSpan? duration;
+        public readonly TimeSpan? reverseDuration;
+        
         public readonly Curve firstCurve;
 
         public readonly Curve secondCurve;
             properties.add(new EnumProperty<CrossFadeState>("crossFadeState", crossFadeState));
             properties.add(new DiagnosticsProperty<Alignment>("alignment", alignment,
                 defaultValue: Alignment.topCenter));
+            properties.add(new IntProperty("duration", duration?.Milliseconds, unit: "ms"));
+            properties.add(new IntProperty("reverseDuration", reverseDuration?.Milliseconds, unit: "ms", defaultValue: null));
         }
     }
 
 
         public override void initState() {
             base.initState();
-            _controller = new AnimationController(duration: widget.duration, vsync: this);
+            _controller = new AnimationController(
+                duration: widget.duration, 
+                reverseDuration: widget.reverseDuration,
+                vsync: this);
             if (widget.crossFadeState == CrossFadeState.showSecond) {
                 _controller.setValue(1.0f);
             }
                 _controller.duration = widget.duration;
             }
 
+            if (widget.reverseDuration != _oldWidget.reverseDuration)
+                _controller.reverseDuration = widget.reverseDuration;
+            
             if (widget.firstCurve != _oldWidget.firstCurve) {
                 _firstAnimation = _initAnimation(widget.firstCurve, true);
             }
                 child: new AnimatedSize(
                     alignment: widget.alignment,
                     duration: widget.duration,
+                    reverseDuration: widget.reverseDuration,
                     curve: widget.sizeCurve,
                     vsync: this,
                     child: widget.layoutBuilder(topChild, topKey, bottomChild, bottomKey)

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

             Alignment alignment = null,
             Curve curve = null,
             TimeSpan? duration = null,
+            TimeSpan? reverseDuration = null,
+            D.assert(reverseDuration != null);
-            this.duration = duration ?? TimeSpan.Zero;
+            this.duration = duration;
+            this.reverseDuration = reverseDuration;
             this.vsync = vsync;
         }
 
 
-        public readonly TimeSpan duration;
+        public readonly TimeSpan? duration;
+        public readonly TimeSpan? reverseDuration;
+        
         public readonly TickerProvider vsync;
 
         public override RenderObject createRenderObject(BuildContext context) {
+                reverseDuration: reverseDuration,
                 curve: curve,
                 vsync: vsync);
         }
             _renderObject.alignment = alignment;
             _renderObject.duration = duration;
+            _renderObject.reverseDuration = reverseDuration;
+        }
+        
+        public override void debugFillProperties(DiagnosticPropertiesBuilder properties) {
+            base.debugFillProperties(properties);
+
+            properties.add(new DiagnosticsProperty<AlignmentGeometry>("alignment", alignment, defaultValue: Alignment.topCenter));
+            
+            properties.add(new IntProperty("duration", duration?.Milliseconds, unit: "ms"));
+            properties.add(new IntProperty("reverseDuration", reverseDuration?.Milliseconds, unit: "ms", defaultValue: null));
         }
     }
 }

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

             Key key = null,
             Widget child = null,
             TimeSpan? duration = null,
+            TimeSpan? reverseDuration = null,
             Curve switchInCurve = null,
             Curve switchOutCurve = null,
             AnimatedSwitcherTransitionBuilder transitionBuilder = null,
             this.layoutBuilder = layoutBuilder ?? defaultLayoutBuilder;
             this.child = child;
             this.duration = duration;
+            this.reverseDuration = reverseDuration;
+        
+        public readonly TimeSpan? reverseDuration;
 
         public readonly Curve switchInCurve;
 
                 children: children,
                 alignment: Alignment.center
             );
+        }
+        
+        public override void debugFillProperties(DiagnosticPropertiesBuilder properties) {
+            base.debugFillProperties(properties);
+            properties.add(new IntProperty("duration", duration?.Milliseconds, unit: "ms"));
+            properties.add(new IntProperty("reverseDuration", reverseDuration?.Milliseconds, unit: "ms", defaultValue: null));
         }
     }
 
 
             AnimationController controller = new AnimationController(
                 duration: widget.duration,
+                reverseDuration:widget.reverseDuration,
                 vsync: this
             );
             Animation<float> animation = new CurvedAnimation(

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

 using System;
 using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using Unity.UIWidgets.services;
+using Unity.UIWidgets.widgets;
 using UnityEngine;
 using Color = Unity.UIWidgets.ui.Color;
 using TextStyle = Unity.UIWidgets.painting.TextStyle;
     public delegate string GenerateAppTitle(BuildContext context);
 
     public delegate PageRoute PageRouteFactory(RouteSettings settings, WidgetBuilder builder);
-    
     public delegate List<Route> InitialRouteListFactory(string initialRoute);
 
     public class WidgetsApp : StatefulWidget {
         public readonly bool checkerboardOffscreenLayers;
         public readonly bool showSemanticsDebugger;
         public readonly bool debugShowWidgetInspector;
-
+        public readonly Dictionary<LogicalKeySet, Intent> shortcuts;
+        public readonly  Dictionary<LocalKey, ActionFactory> actions;
+        
         public WidgetsApp(
             Key key = null,
             GlobalKey<NavigatorState> navigatorKey = null,
             bool showSemanticsDebugger = false,
             bool debugShowWidgetInspector = false,
             bool debugShowCheckedModeBanner = true,
-            InspectorSelectButtonBuilder inspectorSelectButtonBuilder = null
-            //shortcuts
-            //actions
+            InspectorSelectButtonBuilder inspectorSelectButtonBuilder = null,
+            Dictionary<LogicalKeySet, Intent> shortcuts = null,
+            Dictionary<LocalKey, ActionFactory> actions = null
         ) : base(key) {
             
             routes = routes ?? new Dictionary<string, WidgetBuilder>();
-            //D.assert(routes != null);
+            D.assert(routes != null);
             this.home = home;
             this.navigatorKey = navigatorKey;
             this.onGenerateRoute = onGenerateRoute;
             this.title = title;
             this.color = color;
             this.inspectorSelectButtonBuilder = inspectorSelectButtonBuilder;
+            this.shortcuts = shortcuts;
+            this.actions = actions;
             
             D.assert(
                 home == null ||
             );
         }
 
+        /*public static readonly Dictionary<LogicalKeySet, Intent> _defaultShortcuts = new Dictionary<LogicalKeySet, Intent>(){
+    // Activation
+    {new LogicalKeySet(LogicalKeyboardKey.enter), new Intent(ActivateAction.key)},
+    {new widgets.LogicalKeySet(LogicalKeyboardKey.space), new Intent(ActivateAction.key)},
+    {new widgets.LogicalKeySet(LogicalKeyboardKey.gameButtonA), new Intent(ActivateAction.key)},
+
+    // Keyboard traversal.
+    {new widgets.LogicalKeySet(LogicalKeyboardKey.tab), new Intent(NextFocusAction.key)},
+    {new widgets.LogicalKeySet(LogicalKeyboardKey.shift, LogicalKeyboardKey.tab), new Intent(PreviousFocusAction.key)},
+    {new widgets.LogicalKeySet(LogicalKeyboardKey.arrowLeft), new DirectionalFocusIntent(TraversalDirection.left)},
+    {new widgets.LogicalKeySet(LogicalKeyboardKey.arrowRight), new DirectionalFocusIntent(TraversalDirection.right)},
+    {new widgets.LogicalKeySet(LogicalKeyboardKey.arrowDown), new DirectionalFocusIntent(TraversalDirection.down)},
+    {new widgets.LogicalKeySet(LogicalKeyboardKey.arrowUp), new DirectionalFocusIntent(TraversalDirection.up)},
+
+    // Scrolling
+    {new widgets.LogicalKeySet(LogicalKeyboardKey.control, LogicalKeyboardKey.arrowUp), new ScrollIntent(direction: AxisDirection.up)},
+    {new widgets.LogicalKeySet(LogicalKeyboardKey.control, LogicalKeyboardKey.arrowDown), new ScrollIntent(direction: AxisDirection.down)},
+    {new widgets.LogicalKeySet(LogicalKeyboardKey.control, LogicalKeyboardKey.arrowLeft), new ScrollIntent(direction: AxisDirection.left)},
+    {new widgets.LogicalKeySet(LogicalKeyboardKey.control, LogicalKeyboardKey.arrowRight), new ScrollIntent(direction: AxisDirection.right)},
+    {new widgets.LogicalKeySet(LogicalKeyboardKey.pageUp), new ScrollIntent(direction: AxisDirection.up, type: ScrollIncrementType.page)},
+    {new widgets.LogicalKeySet(LogicalKeyboardKey.pageDown), new ScrollIntent(direction: AxisDirection.down, type: ScrollIncrementType.page)},
+  };
+
+  // Default shortcuts for the web platform.
+  public static readonly Dictionary<LogicalKeySet, Intent> _defaultWebShortcuts = new Dictionary<LogicalKeySet, Intent>(){
+    // Activation
+    {new widgets.LogicalKeySet(LogicalKeyboardKey.space), new Intent(ActivateAction.key)},
+
+    // Keyboard traversal.
+    {new widgets.LogicalKeySet(LogicalKeyboardKey.tab), new Intent(NextFocusAction.key)},
+    {new widgets.LogicalKeySet(LogicalKeyboardKey.shift, LogicalKeyboardKey.tab),new Intent(PreviousFocusAction.key)},
+
+    // Scrolling
+    {new widgets.LogicalKeySet(LogicalKeyboardKey.arrowUp), new ScrollIntent(direction: AxisDirection.up)},
+    {new widgets.LogicalKeySet(LogicalKeyboardKey.arrowDown), new ScrollIntent(direction: AxisDirection.down)},
+    {new widgets.LogicalKeySet(LogicalKeyboardKey.arrowLeft), new ScrollIntent(direction: AxisDirection.left)},
+    {new widgets.LogicalKeySet(LogicalKeyboardKey.arrowRight), new ScrollIntent(direction: AxisDirection.right)},
+    {new widgets.LogicalKeySet(LogicalKeyboardKey.pageUp), new ScrollIntent(direction: AxisDirection.up, type: ScrollIncrementType.page)},
+    {new widgets.LogicalKeySet(LogicalKeyboardKey.pageDown), new ScrollIntent(direction: AxisDirection.down, type: ScrollIncrementType.page)},
+  };
+
+  // Default shortcuts for the macOS platform.
+  public static readonly Dictionary<LogicalKeySet, Intent> _defaultMacOsShortcuts = new Dictionary<LogicalKeySet, Intent>(){
+    // Activation
+    new LogicalKeySet(LogicalKeyboardKey.enter), new Intent(ActivateAction.key),
+    new LogicalKeySet(LogicalKeyboardKey.space), new Intent(ActivateAction.key),
+
+    // Keyboard traversal
+    {new LogicalKeySet(LogicalKeyboardKey.tab), new Intent(NextFocusAction.key)},
+    {new LogicalKeySet(LogicalKeyboardKey.shift, LogicalKeyboardKey.tab), new Intent(PreviousFocusAction.key)},
+    {new LogicalKeySet(LogicalKeyboardKey.arrowLeft), new DirectionalFocusIntent(TraversalDirection.left)},
+    {new LogicalKeySet(LogicalKeyboardKey.arrowRight), new DirectionalFocusIntent(TraversalDirection.right)},
+    {new LogicalKeySet(LogicalKeyboardKey.arrowDown), new DirectionalFocusIntent(TraversalDirection.down)},
+    {new LogicalKeySet(LogicalKeyboardKey.arrowUp), new DirectionalFocusIntent(TraversalDirection.up)},
+
+    // Scrolling
+    {new LogicalKeySet(LogicalKeyboardKey.meta, LogicalKeyboardKey.arrowUp), new  ScrollIntent(direction: AxisDirection.up)},
+    {new LogicalKeySet(LogicalKeyboardKey.meta, LogicalKeyboardKey.arrowDown), new ScrollIntent(direction: AxisDirection.down)},
+    {new LogicalKeySet(LogicalKeyboardKey.meta, LogicalKeyboardKey.arrowLeft), new ScrollIntent(direction: AxisDirection.left)},
+    {new LogicalKeySet(LogicalKeyboardKey.meta, LogicalKeyboardKey.arrowRight), new ScrollIntent(direction: AxisDirection.right)},
+    {new LogicalKeySet(LogicalKeyboardKey.pageUp), new ScrollIntent(direction: AxisDirection.up, type: ScrollIncrementType.page)},
+    {new LogicalKeySet(LogicalKeyboardKey.pageDown), new ScrollIntent(direction: AxisDirection.down, type: ScrollIncrementType.page)},
+  };
+
+  /// Generates the default shortcut key bindings based on the
+  /// [defaultTargetPlatform].
+  ///
+  /// Used by [WidgetsApp] to assign a default value to [WidgetsApp.shortcuts].
+  public static Dictionary<LogicalKeySet, Intent> defaultShortcuts {
+      get {
+          if (kIsWeb) {
+              return _defaultWebShortcuts;
+          }
+          switch (defaultTargetPlatform) {
+              case TargetPlatform.android:
+              case TargetPlatform.fuchsia:
+              case TargetPlatform.linux:
+              case TargetPlatform.windows:
+                  return _defaultShortcuts;
+              case TargetPlatform.macOS:
+                  return _defaultMacOsShortcuts;
+              case TargetPlatform.iOS:
+                  // No keyboard support on iOS yet.
+                  break;
+          }
+          return new Dictionary<LogicalKeySet, Intent>();
+      }
+  }
+
+  /// The default value of [WidgetsApp.actions].
+  public static readonly Dictionary<LocalKey, ActionFactory> defaultActions = new Dictionary<LocalKey, ActionFactory>(){
+      {DoNothingAction.key, () => new  DoNothingAction()},
+      {RequestFocusAction.key, () => new RequestFocusAction()},
+      {NextFocusAction.key, () => new NextFocusAction()},
+      {PreviousFocusAction.key, () => new PreviousFocusAction()},
+      {DirectionalFocusAction.key, () => new DirectionalFocusAction()},
+      {ScrollAction.key, () => new ScrollAction()},
+  };*/
+        
         public override State createState() {
             return new _WidgetsAppState();
         }
         
 
         /*bool _debugCheckLocalizations(Locale appLocale) {
-            D.assert(() =>{
-                HashSet<Type> unsupportedTypes =
-                    _localizationsDelegates.map<Type>((LocalizationsDelegate delegate) => delegate.type).toSet();
-                foreach ( LocalizationsDelegate<dynamic> delegate in _localizationsDelegates) {
-                    if (!unsupportedTypes.contains(delegate.type))
+            D.assert(() => {
+                HashSet<Type> unsupportedTypes = new HashSet<Type>();
+                foreach (var _delegate in _localizationsDelegates) {
+                    unsupportedTypes.Add(_delegate.type);
+                }
+                foreach ( LocalizationsDelegate<dynamic> _delegate in _localizationsDelegates) {
+                    if (!unsupportedTypes.Contains(_delegate.type))
-                    if (delegate.isSupported(appLocale))
-                        unsupportedTypes.remove(delegate.type);
+                    if (_delegate.isSupported(appLocale))
+                        unsupportedTypes.Remove(_delegate.type);
+                    return true;
+                List<string> list = new List<string> {"CupertinoLocalizations"};
+                List<string> unsupportedTypesList = new List<string>();
+                foreach (var type in unsupportedTypes) {
+                    unsupportedTypesList.Add(type.ToString());
+                }
+                if (unsupportedTypesList.SequenceEqual(list))
-                if (listEquals(unsupportedTypes.map((Type type) => type.toString()).toList(), <String>['CupertinoLocalizations']))
-                return true;
-
-                    "Warning: This application's locale, $appLocale, is not supported by all of its\n"
-                'localization delegates.'
+                    "Warning: This application's locale, $appLocale, is not supported by all of its\n" +
+                "localization delegates."
-                    if (unsupportedType.toString() == 'CupertinoLocalizations')
+                    if (unsupportedType.ToString() == "CupertinoLocalizations")
-                        '> A $unsupportedType delegate that supports the $appLocale locale was not found.'
+                        "> A "+ unsupportedType + " delegate that supports the " + appLocale + "locale was not found."
-                    'See https://flutter.dev/tutorials/internationalization/ for more\n'
-                "information about configuring an app's locale, supportedLocales,\n"
-                'and localizationsDelegates parameters.'
+                    "See https://flutter.dev/tutorials/internationalization/ for more\n" +
+                "information about configuring an app's locale, supportedLocales,\n" +
+                "and localizationsDelegates parameters."
-                debugPrint(message.toString());
+                //Debug.Log(message.toString());
                 return true;
             });
             return true;
                 );
             }*/
             D.assert(() => {
-                if (WidgetInspectorService.instance.debugShowInspector) {
-                    result = new WidgetInspector(null, result, _InspectorSelectButtonBuilder);
+                if (widget.debugShowWidgetInspector || WidgetsApp.debugShowWidgetInspectorOverride) {
+                    result = new WidgetInspector(
+                        child: result,
+                        selectButtonBuilder: widget.inspectorSelectButtonBuilder
+                    );
+                if (widget.debugShowCheckedModeBanner && WidgetsApp.debugAllowBannerOverride) {
+                    result = new CheckedModeBanner(
+                        child: result
+                    );
+                }
+                return true;
 
                 /*if (widget.debugShowWidgetInspector || WidgetsApp.debugShowWidgetInspectorOverride) {
                     result = new WidgetInspector(
         }
     }
 
-    /*public class _MediaQueryFromWindow : StatefulWidget {
+    public class _MediaQueryFromWindow : StatefulWidget {
         public _MediaQueryFromWindow(Key key = null, Widget child = null) : base(key: key) {
         }
         public readonly Widget child;
             base.dispose();
         }
     }
-*/
+    
     class _InspectorSelectButton : StatelessWidget {
         public readonly GestureTapCallback onPressed;
 

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

         public readonly TextDirection textDirection;
 
         public static TextDirection of(BuildContext context) {
-            Directionality widget = context.inheritFromWidgetOfExactType(typeof(Directionality)) as Directionality;
-            return widget == null ? TextDirection.ltr : widget.textDirection;
+            Directionality widget = context.dependOnInheritedWidgetOfExactType<Directionality>();
+            return widget?.textDirection ?? TextDirection.ltr;
         }
 
         public override bool updateShouldNotify(InheritedWidget oldWidget) {
             bool willChange = false,
             Widget child = null
         ) : base(key: key, child: child) {
+            D.assert(painter != null || foregroundPainter != null || (!isComplex && !willChange));
             size = size ?? Size.zero;
             this.size = size;
             this.painter = painter;
             Clip clipBehavior = Clip.hardEdge,
             Widget child = null
         ) : base(key: key, child: child) {
+            D.assert(clipBehavior != null);
             this.clipper = clipper;
             this.clipBehavior = clipBehavior;
         }
         public readonly Clip clipBehavior;
 
         public override RenderObject createRenderObject(BuildContext context) {
+            D.assert(clipBehavior != Clip.none);
             return new RenderClipRect(
                 clipper: clipper,
                 clipBehavior: clipBehavior);
+            D.assert(clipBehavior != Clip.none);
+            _renderObject.clipBehavior = clipBehavior;
         }
 
         public override void didUnmountRenderObject(RenderObject renderObject) {
     public class ClipRRect : SingleChildRenderObjectWidget {
         public ClipRRect(
             Key key = null,
-            BorderRadius borderRadius = null,
+            BorderRadius borderRadius = null,//[!!!]borderRadius = BorderRadius.zero
             CustomClipper<RRect> clipper = null,
             Clip clipBehavior = Clip.antiAlias,
             Widget child = null
         public readonly Clip clipBehavior;
 
         public override RenderObject createRenderObject(BuildContext context) {
+            D.assert(clipBehavior != Clip.none);
+            D.assert(clipBehavior != Clip.none);
+            _renderObject.clipBehavior = clipBehavior;
         }
 
         public override void debugFillProperties(DiagnosticPropertiesBuilder properties) {
             Clip clipBehavior = Clip.antiAlias,
             Widget child = null) : base(key: key, child: child
         ) {
+            D.assert(clipBehavior != null);
             this.clipper = clipper;
             this.clipBehavior = clipBehavior;
         }
         public readonly Clip clipBehavior;
 
         public override RenderObject createRenderObject(BuildContext context) {
+            D.assert(clipBehavior != Clip.none);
+            D.assert(clipBehavior != Clip.none);
+            renderObject.clipBehavior = clipBehavior;
         }
 
         public override void didUnmountRenderObject(RenderObject _renderObject) {
             Clip clipBehavior = Clip.antiAlias,
             Widget child = null
         ) : base(key: key, child: child) {
+            D.assert(clipBehavior != null);
             this.clipper = clipper;
             this.clipBehavior = clipBehavior;
         }
             Widget child = null
         ) {
             D.assert(shape != null);
+            D.assert(clipBehavior != null);
+            D.assert(clipBehavior != Clip.none);
             return new Builder(
                 key: key,
                 builder: (BuildContext context) => {
 
 
         public override RenderObject createRenderObject(BuildContext context) {
+            D.assert(clipBehavior != Clip.none);
+            D.assert(clipBehavior != Clip.none);
+            _renderObject.clipBehavior = clipBehavior;
         }
 
 
               listeners.Add("exit");
             if (onHover != null)
               listeners.Add("hover");
-            //properties.add(IterableProperty<string>("listeners", listeners, ifEmpty: "<none>"));
+            properties.add(new EnumerableProperty<string>("listeners", listeners, ifEmpty: "<none>"));
-      }
+        }
-        void handleExit(PointerExitEvent Event) {
+        void handleExit(PointerExitEvent _event) {
-                widget.onExit(Event);
+                widget.onExit(_event);
-            if (widget.onExit == null) {
-                return handleExit;
-            }
-            else {
-                return null;
-            }
+            return widget.onExit == null ? null : handleExit;
         } 
         public override Widget build(BuildContext context) {
             return new _RawMouseRegion(this);
             renderObject.opaque = widget.opaque;
         }
     }
-
-    
-    
-    
-
     class _OffstageElement : SingleChildRenderObjectElement {
         internal _OffstageElement(Offstage widget) : base(widget) {
         }
             }
         }
 
-        public override Type debugTypicalAncestorWidgetClass { get => typeof(Stack); }
+        public override Type debugTypicalAncestorWidgetClass {
+            get { return typeof(Stack); }
+        }
 
         public override void debugFillProperties(DiagnosticPropertiesBuilder properties) {
             base.debugFillProperties(properties);
             }
         }
 
-        public override Type debugTypicalAncestorWidgetClass { get => typeof(Flex); }
+        public override Type debugTypicalAncestorWidgetClass {
+            get { return typeof(Flex); }
+        }
 
         public override void debugFillProperties(DiagnosticPropertiesBuilder properties) {
             base.debugFillProperties(properties);
             Widget child = null) : base(key: key, child: child) {
             D.assert(color != null);
             D.assert(elevation >= 0.0f);
-
+            D.assert(clipBehavior != null);
             this.shape = shape;
             this.clipBehavior = clipBehavior;
             this.borderRadius = borderRadius;
         public override void updateRenderObject(BuildContext context, RenderObject renderObject) {
             RenderPhysicalModel _renderObject = (RenderPhysicalModel) renderObject;
             _renderObject.shape = shape;
+            _renderObject.clipBehavior = clipBehavior;
             _renderObject.borderRadius = borderRadius;
             _renderObject.elevation = elevation;
             _renderObject.color = color;
             properties.add(new EnumProperty<BoxShape>("shape", shape));
             properties.add(new DiagnosticsProperty<BorderRadius>("borderRadius", borderRadius));
             properties.add(new FloatProperty("elevation", elevation));
-            properties.add(new DiagnosticsProperty<Color>("color", color));
-            properties.add(new DiagnosticsProperty<Color>("shadowColor", shadowColor));
+            properties.add(new ColorProperty("color", color));
+            properties.add(new ColorProperty("shadowColor", shadowColor));
         }
     }
 
             base.debugFillProperties(properties);
             properties.add(new DiagnosticsProperty<CustomClipper<Path>>("clipper", clipper));
             properties.add(new FloatProperty("elevation", elevation));
-            properties.add(new DiagnosticsProperty<Color>("color", color));
-            properties.add(new DiagnosticsProperty<Color>("shadowColor", shadowColor));
+            properties.add(new ColorProperty("color", color));
+            properties.add(new ColorProperty("shadowColor", shadowColor));
         }
     }
 
             properties.add(new DiagnosticsProperty<EdgeInsets>("padding", padding));
         }
     }
+    
+    /*public class Flow : MultiChildRenderObjectWidget {
+        /// Creates a flow layout.
+        ///
+        /// Wraps each of the given children in a [RepaintBoundary] to avoid
+        /// repainting the children when the flow repaints.
+        ///
+        /// The [delegate] argument must not be null.
+        public Flow(
+            Key key,
+            FlowDelegate _delegate,
+            List<Widget> children = null
+            ) 
+            : base(key: key, children: RepaintBoundary.wrapAll(children)) {
+                D.assert(_delegate != null);
+            }
+            // https://github.com/dart-lang/sdk/issues/29277
+
+            /// Creates a flow layout.
+            ///
+            /// Does not wrap the given children in repaint boundaries, unlike the default
+            /// constructor. Useful when the child is trivial to paint or already contains
+            /// a repaint boundary.
+            ///
+            /// The [delegate] argument must not be null.
+            Flow.unwrapped(
+                Key key,
+                FlowDelegate _delegate,
+                List<Widget> children = null
+            ) : 
+            base(key: key, children: children) {
+                    D.assert(_delegate != null);
+                }
+
+            /// The delegate that controls the transformation matrices of the children.
+            public readonly FlowDelegate _delegate;
+
+            
+            public override RenderFlow createRenderObject(BuildContext context) => RenderFlow(_delegate: _delegate);
+                
+            public override void updateRenderObject(BuildContext context, RenderFlow renderObject) {
+                renderObject._delegate = _delegate;
+            }
+    }*/
+    
+    
     public class RichText : MultiChildRenderObjectWidget {
         public RichText(
             Key key = null,
             properties.add(new FloatProperty("width", width, defaultValue: foundation_.kNullDefaultValue));
             properties.add(new FloatProperty("height", height, defaultValue: foundation_.kNullDefaultValue));
             properties.add(new FloatProperty("scale", scale, defaultValue: 1.0f));
-            properties.add(new DiagnosticsProperty<Color>("color", color,
+            properties.add(new ColorProperty("color", color,
                 defaultValue: foundation_.kNullDefaultValue));
             properties.add(new EnumProperty<BlendMode>("colorBlendMode", colorBlendMode,
                 defaultValue: foundation_.kNullDefaultValue));
 
         public static AssetBundle of(BuildContext context) {
             DefaultAssetBundle result =
-                (DefaultAssetBundle) context.inheritFromWidgetOfExactType(typeof(DefaultAssetBundle));
+                (DefaultAssetBundle) context.dependOnInheritedWidgetOfExactType<DefaultAssetBundle>();
             return result?.bundle;
         }
 
     }
 
-    public class Listener : SingleChildRenderObjectWidget {
+    public class Listener : StatelessWidget {
         public Listener(
             Key key = null,
             PointerDownEventListener onPointerDown = null,
             PointerDragFromEditorReleaseEventListener onPointerDragFromEditorRelease = null,
             HitTestBehavior behavior = HitTestBehavior.deferToChild,
             Widget child = null
-        ) : base(key: key, child: child) {
+        ) : base(key: key) {
+            _child = child;
             this.onPointerDown = onPointerDown;
             this.onPointerMove = onPointerMove;
             this.onPointerUp = onPointerUp;
             this.onPointerDragFromEditorRelease = onPointerDragFromEditorRelease;
         }
 
+
+
+
         public readonly PointerDownEventListener onPointerDown;
 
         public readonly PointerMoveEventListener onPointerMove;
         public readonly HitTestBehavior behavior;
 
         public readonly PointerDragFromEditorEnterEventListener onPointerDragFromEditorEnter;
-        
+
-        
+
-        
+
+        public readonly Widget _child;
+
+        public override Widget build(BuildContext context) {
+            Widget result = _child;
+            if (onPointerEnter != null ||
+                onPointerExit != null ||
+                onPointerHover != null) {
+                result = new MouseRegion(
+                    onEnter: onPointerEnter,
+                    onExit: onPointerExit,
+                    onHover: onPointerHover,
+                    opaque: false,
+                    child: result
+                );
+            }
+
+            result = new _PointerListener(
+                onPointerDown: onPointerDown,
+                onPointerUp: onPointerUp,
+                onPointerMove: onPointerMove,
+                onPointerCancel: onPointerCancel,
+                onPointerSignal: onPointerSignal,
+                behavior: behavior,
+                child: result
+            );
+            return result;
+        }
+    }
+    public class _PointerListener : SingleChildRenderObjectWidget {
+        public _PointerListener(
+            Key key = null,
+            PointerDownEventListener onPointerDown = null, 
+            PointerMoveEventListener onPointerMove = null,
+            PointerUpEventListener onPointerUp = null,
+            PointerCancelEventListener onPointerCancel = null,
+            PointerSignalEventListener onPointerSignal = null,
+            HitTestBehavior behavior = HitTestBehavior.deferToChild,
+            Widget child = null
+        ) :
+        base(key: key, child: child) {
+            D.assert(behavior != null);
+        }
+
+        public readonly PointerDownEventListener onPointerDown;
+        public readonly PointerMoveEventListener onPointerMove;
+        public readonly PointerUpEventListener onPointerUp;
+        public readonly PointerCancelEventListener onPointerCancel;
+        public readonly PointerSignalEventListener onPointerSignal;
+        public readonly HitTestBehavior behavior;
+
+
         public override RenderObject createRenderObject(BuildContext context) {
             return new RenderPointerListener(
                 onPointerDown: onPointerDown,
                 onPointerSignal: onPointerSignal,
-                /*onPointerEnter: onPointerEnter,
-                onPointerExit: onPointerExit,
-                onPointerHover: onPointerHover,
-                onPointerScroll: onPointerScroll,
-                onPointerDragFromEditorEnter: onPointerDragFromEditorEnter,
-                onPointerDragFromEditorHover: onPointerDragFromEditorHover,
-                onPointerDragFromEditorExit: onPointerDragFromEditorExit,
-                onPointerDragFromEditorRelease: onPointerDragFromEditorRelease,*/
                 behavior: behavior
             );
         }
             renderObject.onPointerUp = onPointerUp;
             renderObject.onPointerCancel = onPointerCancel;
             renderObject.onPointerSignal = onPointerSignal;
-            //renderObject.onPointerEnter = onPointerEnter;
-            //renderObject.onPointerHover = onPointerHover;
-            //renderObject.onPointerExit = onPointerExit;
-            //renderObject.onPointerScroll = onPointerScroll;
-
-/*#if UNITY_EDITOR
-            renderObject.onPointerDragFromEditorEnter = onPointerDragFromEditorEnter;
-            renderObject.onPointerDragFromEditorHover = onPointerDragFromEditorHover;
-            renderObject.onPointerDragFromEditorExit = onPointerDragFromEditorExit;
-            renderObject.onPointerDragFromEditorRelease = onPointerDragFromEditorRelease;
-#endif*/
+            
         }
 
         public override void debugFillProperties(DiagnosticPropertiesBuilder properties) {
                 listeners.Add("signal");
             }
 
-            if (onPointerEnter != null) {
-                listeners.Add("enter");
-            }
-
-            if (onPointerHover != null) {
-                listeners.Add("hover");
-            }
-
-            if (onPointerExit != null) {
-                listeners.Add("exit");
-            }
-
-            if (onPointerScroll != null) {
-                listeners.Add("scroll");
-            }
-
-#if UNITY_EDITOR
-            if (onPointerDragFromEditorEnter != null) {
-                listeners.Add("dragFromEditorEnter");
-            }
-
-            if (onPointerDragFromEditorHover != null) {
-                listeners.Add("dragFromEditorHover");
-            }
-
-            if (onPointerDragFromEditorExit != null) {
-                listeners.Add("dragFromEditorExit");
-            }
-
-            if (onPointerDragFromEditorRelease != null) {
-                listeners.Add("dragFromEditorRelease");
-            }
-#endif
-
             properties.add(new EnumerableProperty<string>("listeners", listeners, ifEmpty: "<none>"));
             properties.add(new EnumProperty<HitTestBehavior>("behavior", behavior));
         }
         }
 
         public readonly bool ignoring;
-
+ 
+        
         public override RenderObject createRenderObject(BuildContext context) {
             return new RenderIgnorePointer(
                 ignoring: ignoring
         }
     }
 
-    /*public class Semantics : SingleChildRenderObjectWidget { 
-        public Semantics(
-            Key key,
-            Widget child,
-            bool container = false,
-            bool explicitChildNodes = false,
-            bool excludeSemantics = false,
-            bool enabled,
-            bool checked,
-            bool selected,
-            bool toggled,
-            bool button,
-            bool link,
-            bool header,
-            bool textField,
-            bool readOnly,
-            bool focusable,
-            bool focused,
-            bool inMutuallyExclusiveGroup,
-            bool obscured,
-            bool multiline,
-            bool scopesRoute,
-            bool namesRoute,
-            bool hidden,
-            bool image,
-            bool liveRegion,
-            int maxValueLength,
-            int currentValueLength,
-            string label,
-            string value,
-            string increasedValue,
-            string decreasedValue,
-            string hint,
-            string onTapHint,
-            string onLongPressHint,
-            TextDirection textDirection,
-            SemanticsSortKey sortKey,
-            VoidCallback onTap,
-            VoidCallback onLongPress,
-            VoidCallback onScrollLeft,
-            VoidCallback onScrollRight,
-            VoidCallback onScrollUp,
-            VoidCallback onScrollDown,
-            VoidCallback onIncrease,
-            VoidCallback onDecrease,
-            VoidCallback onCopy,
-            VoidCallback onCut,
-            VoidCallback onPaste,
-            VoidCallback onDismiss,
-            MoveCursorHandler onMoveCursorForwardByCharacter,
-            MoveCursorHandler onMoveCursorBackwardByCharacter,
-            SetSelectionHandler onSetSelection,
-            VoidCallback onDidGainAccessibilityFocus,
-            VoidCallback onDidLoseAccessibilityFocus,
-            Dictionary<CustomSemanticsAction, VoidCallback> customSemanticsActions
-        ) : base(key: key, child: child) {
-            D.assert(container != null);
-            this.container = container;
-            this.explicitChildNodes = explicitChildNodes;
-            this.excludeSemantics = excludeSemantics;
-            properties = new SemanticsProperties(
-                enabled: enabled,
-                checked: checked,
-                toggled: toggled,
-                selected: selected,
-                button: button,
-                link: link,
-                header: header,
-                textField: textField,
-                readOnly: readOnly,
-                focusable: focusable,
-                focused: focused,
-                inMutuallyExclusiveGroup: inMutuallyExclusiveGroup,
-                obscured: obscured,
-                multiline: multiline,
-                scopesRoute: scopesRoute,
-                namesRoute: namesRoute,
-                hidden: hidden,
-                image: image,
-                liveRegion: liveRegion,
-                maxValueLength: maxValueLength,
-                currentValueLength: currentValueLength,
-                label: label,
-                value: value,
-                increasedValue: increasedValue,
-                decreasedValue: decreasedValue,
-                hint: hint,
-                textDirection: textDirection,
-                sortKey: sortKey,
-                onTap: onTap,
-                onLongPress: onLongPress,
-                onScrollLeft: onScrollLeft,
-                onScrollRight: onScrollRight,
-                onScrollUp: onScrollUp,
-                onScrollDown: onScrollDown,
-                onIncrease: onIncrease,
-                onDecrease: onDecrease,
-                onCopy: onCopy,
-                onCut: onCut,
-                onPaste: onPaste,
-                onMoveCursorForwardByCharacter: onMoveCursorForwardByCharacter,
-                onMoveCursorBackwardByCharacter: onMoveCursorBackwardByCharacter,
-                onDidGainAccessibilityFocus: onDidGainAccessibilityFocus,
-                onDidLoseAccessibilityFocus: onDidLoseAccessibilityFocus,
-                onDismiss: onDismiss,
-                onSetSelection: onSetSelection,
-                customSemanticsActions: customSemanticsActions,
-                hintOverrides: onTapHint != null || onLongPressHint != null ?
-                        new SemanticsHintOverrides(
-                            onTapHint: onTapHint,
-                            onLongPressHint: onLongPressHint
-                        ) : null
-                );
-            
-        }
-
-        
-
-
-    public readonly  SemanticsProperties properties;
-    public readonly  bool container;
-    public readonly  bool explicitChildNodes;
-    public readonly  bool excludeSemantics;
-
-  @override
-  RenderSemanticsAnnotations createRenderObject(BuildContext context) {
-    return RenderSemanticsAnnotations(
-      container: container,
-      explicitChildNodes: explicitChildNodes,
-      excludeSemantics: excludeSemantics,
-      enabled: properties.enabled,
-      checked: properties.checked,
-      toggled: properties.toggled,
-      selected: properties.selected,
-      button: properties.button,
-      link: properties.link,
-      header: properties.header,
-      textField: properties.textField,
-      readOnly: properties.readOnly,
-      focusable: properties.focusable,
-      focused: properties.focused,
-      liveRegion: properties.liveRegion,
-      maxValueLength: properties.maxValueLength,
-      currentValueLength: properties.currentValueLength,
-      inMutuallyExclusiveGroup: properties.inMutuallyExclusiveGroup,
-      obscured: properties.obscured,
-      multiline: properties.multiline,
-      scopesRoute: properties.scopesRoute,
-      namesRoute: properties.namesRoute,
-      hidden: properties.hidden,
-      image: properties.image,
-      label: properties.label,
-      value: properties.value,
-      increasedValue: properties.increasedValue,
-      decreasedValue: properties.decreasedValue,
-      hint: properties.hint,
-      hintOverrides: properties.hintOverrides,
-      textDirection: _getTextDirection(context),
-      sortKey: properties.sortKey,
-      onTap: properties.onTap,
-      onLongPress: properties.onLongPress,
-      onScrollLeft: properties.onScrollLeft,
-      onScrollRight: properties.onScrollRight,
-      onScrollUp: properties.onScrollUp,
-      onScrollDown: properties.onScrollDown,
-      onIncrease: properties.onIncrease,
-      onDecrease: properties.onDecrease,
-      onCopy: properties.onCopy,
-      onDismiss: properties.onDismiss,
-      onCut: properties.onCut,
-      onPaste: properties.onPaste,
-      onMoveCursorForwardByCharacter: properties.onMoveCursorForwardByCharacter,
-      onMoveCursorBackwardByCharacter: properties.onMoveCursorBackwardByCharacter,
-      onMoveCursorForwardByWord: properties.onMoveCursorForwardByWord,
-      onMoveCursorBackwardByWord: properties.onMoveCursorBackwardByWord,
-      onSetSelection: properties.onSetSelection,
-      onDidGainAccessibilityFocus: properties.onDidGainAccessibilityFocus,
-      onDidLoseAccessibilityFocus: properties.onDidLoseAccessibilityFocus,
-      customSemanticsActions: properties.customSemanticsActions,
-    );
-  }
-
-  TextDirection _getTextDirection(BuildContext context) {
-    if (properties.textDirection != null)
-      return properties.textDirection;
-
-    final bool containsText = properties.label != null || properties.value != null || properties.hint != null;
-
-    if (!containsText)
-      return null;
-
-    return Directionality.of(context);
-  }
-
-  @override
-  void updateRenderObject(BuildContext context, RenderSemanticsAnnotations renderObject) {
-    renderObject
-      ..container = container
-      ..explicitChildNodes = explicitChildNodes
-      ..excludeSemantics = excludeSemantics
-      ..scopesRoute = properties.scopesRoute
-      ..enabled = properties.enabled
-      ..checked = properties.checked
-      ..toggled = properties.toggled
-      ..selected = properties.selected
-      ..button = properties.button
-      ..link = properties.link
-      ..header = properties.header
-      ..textField = properties.textField
-      ..readOnly = properties.readOnly
-      ..focusable = properties.focusable
-      ..focused = properties.focused
-      ..inMutuallyExclusiveGroup = properties.inMutuallyExclusiveGroup
-      ..obscured = properties.obscured
-      ..multiline = properties.multiline
-      ..hidden = properties.hidden
-      ..image = properties.image
-      ..liveRegion = properties.liveRegion
-      ..maxValueLength = properties.maxValueLength
-      ..currentValueLength = properties.currentValueLength
-      ..label = properties.label
-      ..value = properties.value
-      ..increasedValue = properties.increasedValue
-      ..decreasedValue = properties.decreasedValue
-      ..hint = properties.hint
-      ..hintOverrides = properties.hintOverrides
-      ..namesRoute = properties.namesRoute
-      ..textDirection = _getTextDirection(context)
-      ..sortKey = properties.sortKey
-      ..onTap = properties.onTap
-      ..onLongPress = properties.onLongPress
-      ..onScrollLeft = properties.onScrollLeft
-      ..onScrollRight = properties.onScrollRight
-      ..onScrollUp = properties.onScrollUp
-      ..onScrollDown = properties.onScrollDown
-      ..onIncrease = properties.onIncrease
-      ..onDismiss = properties.onDismiss
-      ..onDecrease = properties.onDecrease
-      ..onCopy = properties.onCopy
-      ..onCut = properties.onCut
-      ..onPaste = properties.onPaste
-      ..onMoveCursorForwardByCharacter = properties.onMoveCursorForwardByCharacter
-      ..onMoveCursorBackwardByCharacter = properties.onMoveCursorForwardByCharacter
-      ..onMoveCursorForwardByWord = properties.onMoveCursorForwardByWord
-      ..onMoveCursorBackwardByWord = properties.onMoveCursorBackwardByWord
-      ..onSetSelection = properties.onSetSelection
-      ..onDidGainAccessibilityFocus = properties.onDidGainAccessibilityFocus
-      ..onDidLoseAccessibilityFocus = properties.onDidLoseAccessibilityFocus
-      ..customSemanticsActions = properties.customSemanticsActions;
-  }
-
-  @override
-  void debugFillProperties(DiagnosticPropertiesBuilder properties) {
-    super.debugFillProperties(properties);
-    properties.add(DiagnosticsProperty<bool>('container', container));
-    properties.add(DiagnosticsProperty<SemanticsProperties>('properties', this.properties));
-    this.properties.debugFillProperties(properties);
-  }
-}
-
-class MergeSemantics extends SingleChildRenderObjectWidget {
-  /// Creates a widget that merges the semantics of its descendants.
-  const MergeSemantics({ Key key, Widget child }) : super(key: key, child: child);
-
-  @override
-  RenderMergeSemantics createRenderObject(BuildContext context) => RenderMergeSemantics();
-}
-
-
-class BlockSemantics extends SingleChildRenderObjectWidget {
-  
-  const BlockSemantics({ Key key, this.blocking = true, Widget child }) : super(key: key, child: child);
-
-  /// Whether this widget is blocking semantics of all widget that were painted
-  /// before it in the same semantic container.
-  final bool blocking;
-
-  @override
-  RenderBlockSemantics createRenderObject(BuildContext context) => RenderBlockSemantics(blocking: blocking);
-
-  @override
-  void updateRenderObject(BuildContext context, RenderBlockSemantics renderObject) {
-    renderObject.blocking = blocking;
-  }
-
-  @override
-  void debugFillProperties(DiagnosticPropertiesBuilder properties) {
-    super.debugFillProperties(properties);
-    properties.add(DiagnosticsProperty<bool>('blocking', blocking));
-  }
-}
-
-class ExcludeSemantics extends SingleChildRenderObjectWidget {
-  /// Creates a widget that drops all the semantics of its descendants.
-  const ExcludeSemantics({
-    Key key,
-    this.excluding = true,
-    Widget child,
-  }) : assert(excluding != null),
-       super(key: key, child: child);
-
-  /// Whether this widget is excluded in the semantics tree.
-  final bool excluding;
-
-  @override
-  RenderExcludeSemantics createRenderObject(BuildContext context) => RenderExcludeSemantics(excluding: excluding);
-
-  @override
-  void updateRenderObject(BuildContext context, RenderExcludeSemantics renderObject) {
-    renderObject.excluding = excluding;
-  }
-
-  @override
-  void debugFillProperties(DiagnosticPropertiesBuilder properties) {
-    super.debugFillProperties(properties);
-    properties.add(DiagnosticsProperty<bool>('excluding', excluding));
-  }
-}
-
-
-class IndexedSemantics extends SingleChildRenderObjectWidget {
-  
-  const IndexedSemantics({
-    Key key,
-    @required this.index,
-    Widget child,
-  }) : assert(index != null),
-       super(key: key, child: child);
-
-  /// The index used to annotate the first child semantics node.
-  final int index;
-
-  @override
-  RenderIndexedSemantics createRenderObject(BuildContext context) => RenderIndexedSemantics(index: index);
-
-  @override
-  void updateRenderObject(BuildContext context, RenderIndexedSemantics renderObject) {
-    renderObject.index = index;
-  }
-  @override
-  void debugFillProperties(DiagnosticPropertiesBuilder properties) {
-    super.debugFillProperties(properties);
-    properties.add(DiagnosticsProperty<int>('index', index));
-  }
-}*/
-    
     public class KeyedSubtree : StatelessWidget {
         public KeyedSubtree(
             Key key,

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

             _buildOwner = new BuildOwner();
             buildOwner.onBuildScheduled = _handleBuildScheduled;
             window.onLocaleChanged += handleLocaleChanged;
-            widgetInspectorService = new WidgetInspectorService(this);
+            widgetInspectorService = new WidgetInspectorService();
 
             // window.onAccessibilityFeaturesChanged = handleAccessibilityFeaturesChanged;
             // SystemChannels.navigation.setMethodCallHandler(_handleNavigationInvocation);

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

         public ImplicitlyAnimatedWidget(
             Key key = null,
             Curve curve = null,
-            TimeSpan? duration = null
+            TimeSpan? duration = null,
+            VoidCallback onEnd = null
+            this.onEnd = onEnd;
+        
+        public readonly VoidCallback onEnd;
 
         public override void debugFillProperties(DiagnosticPropertiesBuilder properties) {
             base.debugFillProperties(properties);

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

 
         public abstract override RenderObject createRenderObject(BuildContext context);
     }
+    public class SliverIgnorePointer : SingleChildRenderObjectWidget {
+        public SliverIgnorePointer(
+            Key key = null,
+            bool ignoring = true,
+            bool? ignoringSemantics = null,
+            Widget sliver = null
+        ) : base(key: key, child: sliver) {
+            D.assert(ignoring != null);
+            this.ignoring = ignoring;
+            this.ignoringSemantics = ignoringSemantics;
+
+        }
+
+        public readonly bool ignoring;
+        public readonly bool? ignoringSemantics;
+
+        public override RenderObject  createRenderObject(BuildContext context) {
+            return new RenderSliverIgnorePointer(
+              ignoring: ignoring,
+              ignoringSemantics: ignoringSemantics
+            );
+        }
+        public override void updateRenderObject(BuildContext context, RenderObject renderObject) {
+            renderObject = (RenderSliverIgnorePointer) renderObject;
+            ((RenderSliverIgnorePointer)renderObject).ignoring = ignoring;
+            ((RenderSliverIgnorePointer)renderObject).ignoringSemantics = ignoringSemantics;
+        }
+        public override void debugFillProperties(DiagnosticPropertiesBuilder properties) {
+            base.debugFillProperties(properties);
+            properties.add(new DiagnosticsProperty<bool>("ignoring", ignoring));
+            properties.add(new DiagnosticsProperty<bool>("ignoringSemantics", (bool)ignoringSemantics, defaultValue: null));
+        }
+    }
+    public class SliverOffstage : SingleChildRenderObjectWidget {
+        public SliverOffstage(
+        Key key = null,
+        bool offstage = true,
+        Widget sliver = null) : base(key: key, child: sliver) {
+            D.assert(offstage != null);
+            this.offstage = offstage;
+        }
+
+
+        public readonly bool offstage;
+
+        public override RenderObject createRenderObject(BuildContext context) {
+            return new RenderSliverOffstage(offstage: offstage);
+        }
+
+        public override void updateRenderObject(BuildContext context, RenderObject renderObject) {
+            renderObject = (RenderSliverOffstage) renderObject;
+            ((RenderSliverOffstage)renderObject).offstage = offstage;
+        }
+        public override void debugFillProperties(DiagnosticPropertiesBuilder properties) {
+            base.debugFillProperties(properties);
+            properties.add(new DiagnosticsProperty<bool>("offstage", offstage));
+        }
+
+        public override Element createElement() {
+            return new _SliverOffstageElement(this);
+        }
+    }
+
 
     public abstract class SliverMultiBoxAdaptorWidget : SliverWithKeepAliveWidget {
         protected SliverMultiBoxAdaptorWidget(
         public override RenderObject createRenderObject(BuildContext context) {
             SliverMultiBoxAdaptorElement element = (SliverMultiBoxAdaptorElement) context;
             return new RenderSliverList(childManager: element);
+        }
+    }
+    public class SliverOpacity : SingleChildRenderObjectWidget {
+        public SliverOpacity(
+            Key key = null,
+            float opacity = 0f,
+            bool alwaysIncludeSemantics = false,
+            Widget sliver = null) : base(key: key, child: sliver) { 
+            D.assert(opacity != null && opacity >= 0.0 && opacity <= 1.0); 
+            D.assert(alwaysIncludeSemantics != null);
+            this.opacity = opacity;
+            this.alwaysIncludeSemantics = alwaysIncludeSemantics;
+        }
+
+        public readonly float opacity;
+        public readonly bool alwaysIncludeSemantics;
+        public override RenderObject createRenderObject(BuildContext context) {
+            return new RenderSliverOpacity(
+              opacity: opacity,
+              alwaysIncludeSemantics: alwaysIncludeSemantics
+            );
+        }
+        public override void updateRenderObject(BuildContext context, RenderObject renderObject) {
+            renderObject = (RenderSliverOpacity) renderObject;
+            ((RenderSliverOpacity) renderObject).opacity = opacity;
+            ((RenderSliverOpacity) renderObject).alwaysIncludeSemantics = alwaysIncludeSemantics;
+        }
+        public override void debugFillProperties(DiagnosticPropertiesBuilder properties) { 
+            base.debugFillProperties(properties);
+            properties.add(new DiagnosticsProperty<float>("opacity", opacity));
+            properties.add(new FlagProperty("alwaysIncludeSemantics", value: alwaysIncludeSemantics, ifTrue: "alwaysIncludeSemantics"));
+        }
+    }
+
+    
+    public class _SliverOffstageElement : SingleChildRenderObjectElement {
+        public _SliverOffstageElement(SliverOffstage widget) : base(widget) {
+        }
+
+        public SliverOffstage widget {
+            get { return base.widget as SliverOffstage; }
+        }
+
+        public override void debugVisitOnstageChildren(ElementVisitor visitor) {
+            if (!widget.offstage)
+                base.debugVisitOnstageChildren(visitor);
         }
     }
 

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

 
     public abstract class TextSelectionControls {
         public abstract Widget buildHandle(BuildContext context, TextSelectionHandleType type, float textLineHeight);
-
-        public abstract Widget buildToolbar(BuildContext context, Rect globalEditableRegion, Offset position,
-            TextSelectionDelegate selectionDelegate);
+        public abstract Offset getHandleAnchor(TextSelectionHandleType type, float textLineHeight);
+        public abstract Widget buildToolbar(
+            BuildContext context, 
+            Rect globalEditableRegion, 
+            float textLineHeight,
+            Offset position,
+            List<TextSelectionPoint> endpoints,
+            TextSelectionDelegate selectionDelegate
+            );
+        public abstract Size getHandleSize(float textLineHeight);
-        public virtual bool canCut(TextSelectionDelegate selectionDelegate) {
-            return !selectionDelegate.textEditingValue.selection.isCollapsed;
+        public virtual bool canCut(TextSelectionDelegate _delegate) {
+            return _delegate.cutEnabled && !_delegate.textEditingValue.selection.isCollapsed;
-        public virtual bool canCopy(TextSelectionDelegate selectionDelegate) {
-            return !selectionDelegate.textEditingValue.selection.isCollapsed;
+
+        bool canCopy(TextSelectionDelegate _delegate) {
+            return _delegate.copyEnabled && !_delegate.textEditingValue.selection.isCollapsed;
-        public virtual bool canPaste(TextSelectionDelegate selectionDelegate) {
-            // TODO in flutter: return false when clipboard is empty
-            return true;
+        bool canPaste(TextSelectionDelegate _delegate) {
+            // TODO(goderbauer): return false when clipboard is empty, https://github.com/flutter/flutter/issues/11254
+            return _delegate.pasteEnabled;
-        public virtual bool canSelectAll(TextSelectionDelegate selectionDelegate) {
-            return selectionDelegate.textEditingValue.text.isNotEmpty() &&
-                   selectionDelegate.textEditingValue.selection.isCollapsed;
+        bool canSelectAll(TextSelectionDelegate _delegate) {
+            return _delegate.selectAllEnabled 
+                   && _delegate.textEditingValue.text.isNotEmpty() 
+                   && _delegate.textEditingValue.selection.isCollapsed;
+
 
         public void handleCut(TextSelectionDelegate selectionDelegate) {
             TextEditingValue value = selectionDelegate.textEditingValue;
     }
 
     public class TextSelectionOverlay {
-        public TextSelectionOverlay(TextEditingValue value = null,
-            BuildContext context = null, Widget debugRequiredFor = null,
+        public TextSelectionOverlay(
+            TextEditingValue value = null,
+            BuildContext context = null, 
+            Widget debugRequiredFor = null,
             LayerLink layerLink = null,
             RenderEditable renderObject = null,
             TextSelectionControls selectionControls = null,

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

 using Unity.UIWidgets.scheduler2;
 
 namespace Unity.UIWidgets.widgets {
-    public class TickerMode : InheritedWidget {
+    public class TickerMode : StatelessWidget {
-            : base(key, child) {
+            : base(key:key) {
+            D.assert(enabled != null);
+            this.child = child;
-
+        public readonly Widget child;
-            var widget = (TickerMode) context.inheritFromWidgetOfExactType(typeof(TickerMode));
-            return widget != null ? widget.enabled : true;
+            _EffectiveTickerMode widget = context.dependOnInheritedWidgetOfExactType<_EffectiveTickerMode>();
+            return widget?.enabled ?? true;
-        public override bool updateShouldNotify(InheritedWidget oldWidget) {
-            return enabled != ((TickerMode) oldWidget).enabled;
+        public override Widget build(BuildContext context) {
+            return new _EffectiveTickerMode(
+                enabled: enabled && TickerMode.of(context),
+                child: child
+            );
+        }
+        public override void debugFillProperties(DiagnosticPropertiesBuilder properties) {
+            base.debugFillProperties(properties);
+            properties.add(new FlagProperty("requested mode", value: enabled, ifTrue: "enabled", ifFalse: "disabled", showName: true));
+        }
+    }
+    public class _EffectiveTickerMode : InheritedWidget { 
+        public _EffectiveTickerMode(
+            bool enabled,
+            Key key = null,
+            Widget child = null) : 
+            base(key: key, child: child) {
+            D.assert(enabled != null);
+            this.enabled = enabled;
+        public readonly bool enabled;
-            properties.add(new FlagProperty("mode", value: enabled, ifTrue: "enabled", ifFalse: "disabled",
-                showName: true));
+            properties.add(new FlagProperty("effective mode", value: enabled, ifTrue: "enabled", ifFalse: "disabled", showName: true));
+        }
+
+        public override bool updateShouldNotify(InheritedWidget oldWidget) {
+            oldWidget = (_EffectiveTickerMode) oldWidget;
+            return enabled != ((_EffectiveTickerMode) oldWidget).enabled;
+
 
     public abstract class SingleTickerProviderStateMixin<T> : State<T>, TickerProvider where T : StatefulWidget {
         Ticker _ticker;

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

 namespace Unity.UIWidgets.widgets {
     public abstract class AnimatedWidget : StatefulWidget {
         public readonly Listenable listenable;
-
-        protected AnimatedWidget(Key key = null, Listenable listenable = null) : base(key) {
+        protected AnimatedWidget(
+            Key key = null,
+            Listenable listenable = null
+            ) : base(key) {
             D.assert(listenable != null);
             this.listenable = listenable;
         }
     }
 
     public class SlideTransition : AnimatedWidget {
-        public SlideTransition(Key key = null,
+        public SlideTransition(
+            Key key = null,
-            Widget child = null) : base(key: key, listenable: position) {
+            Widget child = null
+            ) : base(key: key, listenable: position) {
             D.assert(position != null);
             this.transformHitTests = transformHitTests;
             this.textDirection = textDirection;
 
         protected internal override Widget build(BuildContext context) {
             float scaleValue = scale.value;
-            Matrix4 transform = Matrix4.diagonal3Values(scaleValue, scaleValue, 1);
+            Matrix4 transform = Matrix4.identity();
+            transform.scale(scaleValue, scaleValue, 1.0f);
             return new Transform(
                 transform: transform,
                 alignment: alignment,
             Key key = null,
             Animation<float> turns = null,
             Alignment alignment = null,
-            Widget child = null) : base(key: key, listenable: turns) {
+            Widget child = null) : 
+            base(key: key, listenable: turns) {
             D.assert(turns != null);
             this.alignment = alignment ?? Alignment.center;
             this.child = child;
             Axis axis = Axis.vertical,
             Animation<float> sizeFactor = null,
             float axisAlignment = 0.0f,
-            Widget child = null) : base(key: key, listenable: sizeFactor) {
+            Widget child = null) 
+            : base(key: key, listenable: sizeFactor) {
             D.assert(sizeFactor != null);
             this.axis = axis;
             this.axisAlignment = axisAlignment;
     }
 
     public class FadeTransition : SingleChildRenderObjectWidget {
-        public FadeTransition(Key key = null, Animation<float> opacity = null,
-            Widget child = null) : base(key: key, child: child) {
+        public FadeTransition(
+            Key key = null, 
+            Animation<float> opacity = null,
+            bool alwaysIncludeSemantics = false,
+            Widget child = null
+            ) : base(key: key, child: child) {
+            this.alwaysIncludeSemantics = alwaysIncludeSemantics;
-
+        public readonly bool alwaysIncludeSemantics;
+                //alwaysIncludeSemantics: alwaysIncludeSemantics
+            //((RenderAnimatedOpacity) renderObject).alwaysIncludeSemantics = alwaysIncludeSemantics;
+            properties.add(new FlagProperty("alwaysIncludeSemantics", value: alwaysIncludeSemantics, ifTrue: "alwaysIncludeSemantics"));
+    /*public class SliverFadeTransition : SingleChildRenderObjectWidget {
+        public SliverFadeTransition(
+            Animation<float> opacity ,
+            Key key = null,
+            bool alwaysIncludeSemantics = false,
+            Widget sliver = null
+        ) : base(key: key, child: sliver) {
+            D.assert(opacity != null);
+        }
+        public readonly Animation<float> opacity;
+        public readonly bool alwaysIncludeSemantics;
+        public override RenderObject createRenderObject(BuildContext context) {
+            return new RenderSliverAnimatedOpacity(
+                opacity: opacity,
+                alwaysIncludeSemantics: alwaysIncludeSemantics
+            );
+        }
+        public override void updateRenderObject(BuildContext context, RenderSliverAnimatedOpacity renderObject) {
+            renderObject = (RenderSliverAnimatedOpacity) renderObject;
+            ((RenderSliverAnimatedOpacity) renderObject).opacity = opacity;
+            ((RenderSliverAnimatedOpacity) renderObject).alwaysIncludeSemantics = alwaysIncludeSemantics;
+        
+        }
+        public override void debugFillProperties(DiagnosticPropertiesBuilder properties) {
+            base.debugFillProperties(properties);
+            properties.add(new DiagnosticsProperty<Animation<float>>("opacity", opacity));
+            properties.add(new FlagProperty("alwaysIncludeSemantics", value: alwaysIncludeSemantics, ifTrue: "alwaysIncludeSemantics"));
+        }
+    }*/
-        public RelativeRectTween(RelativeRect begin = null, RelativeRect end = null) : base(begin: begin, end: end) {
+        public RelativeRectTween(
+            RelativeRect begin = null, 
+            RelativeRect end = null) : base(begin: begin, end: end) {
         }
 
         public override RelativeRect lerp(float t) {
 
     public class PositionedTransition : AnimatedWidget {
         public PositionedTransition(
+            Animation<RelativeRect> rect ,
-            Animation<RelativeRect> rect = null,
-            D.assert(child != null);
             this.child = child;
         }
 
-
-
-
-
         protected internal override Widget build(BuildContext context) {
             return Positioned.fromRelativeRect(
                 rect: rect.value,
 
     public class RelativePositionedTransition : AnimatedWidget {
         public RelativePositionedTransition(
-            Key key = null,
-            Animation<Rect> rect = null,
-            Size size = null,
-            Widget child = null
+            Animation<Rect> rect,
+            Size size,
+            Widget child ,
+            Key key = null
         ) : base(key: key, listenable: rect) {
             D.assert(rect != null);
             D.assert(size != null);
 
     public class DecoratedBoxTransition : AnimatedWidget {
         public DecoratedBoxTransition(
-            Key key = null,
-            Animation<Decoration> decoration = null,
-            DecorationPosition position = DecorationPosition.background,
-            Widget child = null
+            Animation<Decoration> decoration ,
+            Widget child ,
+            Key key = null, 
+            DecorationPosition position = DecorationPosition.background
         ) : base(key: key, listenable: decoration) {
             D.assert(decoration != null);
             D.assert(child != null);
 
     public class AlignTransition : AnimatedWidget {
         public AlignTransition(
+            Animation<Alignment> alignment,
+            Widget child,
-            Animation<Alignment> alignment = null,
-            Widget child = null,
             float? widthFactor = null,
             float? heightFactor = null
         ) : base(key: key, listenable: alignment) {
 
     public class DefaultTextStyleTransition : AnimatedWidget {
         public DefaultTextStyleTransition(
+            Animation<TextStyle> style,
+            Widget child,
-            Animation<TextStyle> style = null,
-            Widget child = null,
             TextAlign? textAlign = null,
             bool softWrap = true,
             TextOverflow overflow = TextOverflow.clip,
 
     public class AnimatedBuilder : AnimatedWidget {
         public readonly TransitionBuilder builder;
-
-
-        public AnimatedBuilder(Key key = null, Listenable animation = null, TransitionBuilder builder = null,
-            Widget child = null) :
-            base(key, animation) {
+        public AnimatedBuilder(
+            Listenable animation, 
+            TransitionBuilder builder,
+            Key key = null, 
+            Widget child = null) : base(key, animation) {
             D.assert(builder != null);
             D.assert(animation != null);
             this.builder = builder;

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

 
     public class ValueListenableBuilder<T> : StatefulWidget {
         public ValueListenableBuilder(
-            ValueListenable<T> valueListenable,
-            ValueWidgetBuilder<T> builder,
+            ValueListenable<T> valueListenable ,
+            ValueWidgetBuilder<T> builder ,
+            Key key = null,
-        ) {
+        ) : base(key: key) {
             D.assert(valueListenable != null);
             D.assert(builder != null);
             this.valueListenable = valueListenable;

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

             ViewportOffset offset = null,
             Key center = null,
             float? cacheExtent = null,
+            CacheExtentStyle cacheExtentStyle = CacheExtentStyle.pixel,
-            D.assert(center == null || children.Count(child => child.key == center) == 1);
-
+            D.assert(slivers != null);
+            D.assert(center == null || slivers.Where((Widget child) => child.key == center).Count() == 1);
+            D.assert(cacheExtentStyle != null);
+            D.assert(cacheExtentStyle != CacheExtentStyle.viewport || cacheExtent != null);
             this.axisDirection = axisDirection;
             this.crossAxisDirection = crossAxisDirection;
             this.anchor = anchor;
+            this.cacheExtentStyle = cacheExtentStyle;
         }
 
         public readonly AxisDirection axisDirection;
         public readonly Key center;
 
         public readonly float? cacheExtent;
+        
+        public readonly CacheExtentStyle cacheExtentStyle;
 
         public static AxisDirection getDefaultCrossAxisDirection(BuildContext context, AxisDirection axisDirection) {
             switch (axisDirection) {
         public override RenderObject createRenderObject(BuildContext context) {
             return new RenderViewport(
                 axisDirection: axisDirection,
-                crossAxisDirection: crossAxisDirection ??
-                                    getDefaultCrossAxisDirection(context, axisDirection),
+                crossAxisDirection: crossAxisDirection ?? getDefaultCrossAxisDirection(context, axisDirection),
-                cacheExtent: cacheExtent ?? RenderViewportUtils.defaultCacheExtent
-            );
+                cacheExtent: cacheExtent ?? RenderViewportUtils.defaultCacheExtent,
+                cacheExtentStyle: cacheExtentStyle);
-            renderObject.crossAxisDirection = crossAxisDirection ??
-                                              getDefaultCrossAxisDirection(context, axisDirection);
+            renderObject.crossAxisDirection = crossAxisDirection ?? getDefaultCrossAxisDirection(context, axisDirection);
+            renderObject.cacheExtentStyle = cacheExtentStyle;
         }
 
         public override Element createElement() {
             else if (children.isNotEmpty() && children.First().key != null) {
                 properties.add(new DiagnosticsProperty<Key>("center", children.First().key, tooltip: "implicit"));
             }
+            properties.add(new DiagnosticsProperty<float>("cacheExtent", (float)cacheExtent));
+            properties.add(new DiagnosticsProperty<CacheExtentStyle>("cacheExtentStyle", cacheExtentStyle));
         }
     }
 
             ViewportOffset offset = null,
             List<Widget> slivers = null
         ) : base(key: key, children: slivers) {
+            slivers = slivers ?? new List<Widget>();
-
             this.axisDirection = axisDirection;
             this.crossAxisDirection = crossAxisDirection;
             this.offset = offset;

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

             bool maintainState = false,
             bool maintainAnimation = false,
             bool maintainSize = false,
+            bool maintainSemantics = false,
+            D.assert(replacement != null);
+            D.assert(visible != null);
+            D.assert(maintainState != null);
+            D.assert(maintainAnimation != null);
+            D.assert(maintainSize != null);
+            D.assert(
+                maintainSize == true || maintainSemantics == false,
+                ()=>"Cannot maintain semantics if size is not maintained."
+            );
             D.assert(maintainSize == true || maintainInteractivity == false,
                 () => "Cannot maintain interactivity if size is not maintained.");
             this.replacement = replacement ?? SizedBox.shrink();
             this.maintainAnimation = maintainAnimation;
             this.maintainSize = maintainSize;
+            this.maintainSemantics = maintainSemantics;
             this.maintainInteractivity = maintainInteractivity;
         }
 
 
         public readonly bool maintainSize;
 
+        public readonly bool maintainSemantics;
+
         public readonly bool maintainInteractivity;
 
         public override Widget build(BuildContext context) {
                     result = new IgnorePointer(
                         child: child,
                         ignoring: !visible
+                        //todo : ignoringSemantics: !visible && !maintainSemantics, 
+                    //alwaysIncludeSemantics: maintainSemantics,
+            D.assert(!maintainSemantics);
+            
             if (maintainState) {
                 Widget result = child;
                 if (!maintainAnimation) {
                     offstage: !visible
                 );
             }
-
             D.assert(!maintainAnimation);
             D.assert(!maintainState);
             return visible ? child : replacement;
             properties.add(new FlagProperty("maintainAnimation", value: maintainAnimation,
                 ifFalse: "maintainAnimation"));
             properties.add(new FlagProperty("maintainSize", value: maintainSize, ifFalse: "maintainSize"));
+            properties.add(new FlagProperty("maintainSemantics", value: maintainSemantics, ifFalse: "maintainSemantics"));
+    public class SliverVisibility : StatelessWidget {
+        public SliverVisibility(
+            Widget sliver,
+            Widget replacementSliver ,
+            Key key = null,
+            bool visible = true,
+            bool maintainState = false,
+            bool maintainAnimation = false,
+            bool maintainSize = false,
+            bool maintainSemantics = false,
+            bool maintainInteractivity = false) : base (key: key) {
+            replacementSliver = replacementSliver ?? new SliverToBoxAdapter();
+            D.assert(sliver != null);
+            D.assert(replacementSliver != null);
+            D.assert(visible != null);
+            D.assert(maintainState != null);
+            D.assert(maintainAnimation != null);
+            D.assert(maintainSize != null);
+            D.assert(maintainSemantics != null);
+            D.assert(maintainInteractivity != null);
+            D.assert(
+                maintainState == true || maintainAnimation == false,
+                ()=>"Cannot maintain animations if the state is not also maintained."
+            );
+            D.assert(
+                maintainAnimation == true || maintainSize == false,
+                ()=> "Cannot maintain size if animations are not maintained."
+            );
+            D.assert(
+                maintainSize == true || maintainSemantics == false,
+                ()=> "Cannot maintain semantics if size is not maintained."
+            );
+            D.assert(
+                maintainSize == true || maintainInteractivity == false,
+                ()=> "Cannot maintain interactivity if size is not maintained."
+            );
+        }
+
+
+        public readonly Widget sliver;
+
+        public readonly Widget replacementSliver;
+        public readonly bool visible;
+        public readonly bool maintainState;
+        public readonly bool maintainAnimation; 
+        public readonly bool maintainSize;
+        public readonly bool maintainSemantics;
+        public readonly bool maintainInteractivity;
+        public override Widget build(BuildContext context) { 
+            if (maintainSize) { 
+                Widget result = sliver; 
+                if (!maintainInteractivity) { 
+                    result = new SliverIgnorePointer(
+                        sliver: sliver,
+                        ignoring: !visible,
+                        ignoringSemantics: !visible && !maintainSemantics
+                    );
+                } 
+                return new SliverOpacity(
+                    opacity: visible ? 1.0f : 0.0f,
+                    alwaysIncludeSemantics: maintainSemantics,
+                    sliver: result
+                );
+            }
+            D.assert(!maintainInteractivity);
+            D.assert(!maintainSemantics);
+            D.assert(!maintainSize);
+            if (maintainState) { 
+                Widget result = sliver; 
+                if (!maintainAnimation)
+                    result = new TickerMode(child: sliver, enabled: visible); 
+                return new SliverOffstage(
+                    sliver: result,
+                    offstage: !visible
+                );
+            }
+            D.assert(!maintainAnimation);
+            D.assert(!maintainState);
+            return visible ? sliver : replacementSliver;
+        }
+        public override void debugFillProperties(DiagnosticPropertiesBuilder properties) {
+            base.debugFillProperties(properties);
+            properties.add( new FlagProperty("visible", value: visible, ifFalse: "hidden", ifTrue: "visible"));
+            properties.add( new FlagProperty("maintainState", value: maintainState, ifFalse: "maintainState"));
+            properties.add( new FlagProperty("maintainAnimation", value: maintainAnimation, ifFalse: "maintainAnimation"));
+            properties.add( new FlagProperty("maintainSize", value: maintainSize, ifFalse: "maintainSize"));
+            properties.add( new FlagProperty("maintainSemantics", value: maintainSemantics, ifFalse: "maintainSemantics"));
+            properties.add( new FlagProperty("maintainInteractivity", value: maintainInteractivity, ifFalse: "maintainInteractivity"));
+        }
+    }
+
+    
 }

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

+using System;
 using System.Collections.Generic;
 using Unity.UIWidgets.foundation;
 using Unity.UIWidgets.painting;
 namespace Unity.UIWidgets.widgets {
-    class WidgetSpan : PlaceholderSpan {
+    class WidgetSpan : PlaceholderSpan,IEquatable<WidgetSpan> {
-            Widget child,
-            TextBaseline baseline,
-            TextStyle style,
+            Widget child ,
+            TextBaseline? baseline = null,
+            TextStyle style = null,
             PlaceholderAlignment alignment = PlaceholderAlignment.bottom
         ) : base(
             alignment: alignment,
         public override RenderComparison compareTo(InlineSpan other) {
             if (this == other)
                 return RenderComparison.identical;
+            if (style.GetType() == GetType())
+                return RenderComparison.layout;
-            if (child.Equals(typedOther.child) || alignment != typedOther.alignment) {
+            if (!child.Equals(typedOther.child) || alignment != typedOther.alignment) {
                 return RenderComparison.layout;
             }
 
         }
 
         public override int GetHashCode() {
-            int hashCode = base.GetHashCode();
-            hashCode = (hashCode * 397) ^ (child.GetHashCode());
-            hashCode = (hashCode * 397) ^ (alignment.GetHashCode());
-            hashCode = (hashCode * 397) ^ (baseline.GetHashCode());
-            return hashCode;
+            unchecked
+            {
+                return (base.GetHashCode() * 397) ^ (child != null ? child.GetHashCode() : 0);
+            }
+            return true;
+        }
+
+        public bool Equals(WidgetSpan other)
+        {
+            if (ReferenceEquals(null, other)) {
+                return false;
+            }
+
+            if (ReferenceEquals(this, other)) {
+                return true;
+            }
+
+            return base.Equals(other) && Equals(child, other.child);
+        }
+
+        public override bool Equals(object obj)
+        {
+            if (ReferenceEquals(null, obj)) {
+                return false;
+            }
+
+            if (ReferenceEquals(this, obj)) {
+                return true;
+            }
+
+            if (obj.GetType() != GetType()) {
+                return false;
+            }
+
+            return Equals((WidgetSpan) obj);
+        }
+        public static bool operator ==(WidgetSpan left, WidgetSpan right) {
+            return Equals(left, right);
+        }
+
+        public static bool operator !=(WidgetSpan left, WidgetSpan right) {
+            return !Equals(left, right);
+        }
+        public override bool debugAssertIsValid() {
             return true;
         }
     }

com.unity.uiwidgets/Runtime/foundation/diagnosticable.mixin.gen.cs

+namespace Unity.UIWidgets.foundation {
+    public class DiagnosticableMixinChangeNotifier : ChangeNotifier, IDiagnosticable {
+        protected DiagnosticableMixinChangeNotifier() {
+        }
+
+        public virtual string toStringShort() {
+            return foundation_.describeIdentity(this);
+        }
+
+        public override string ToString() {
+            return toString();
+        }
+
+        public virtual string toString(DiagnosticLevel minLevel = DiagnosticLevel.debug) {
+            string fullString = null;
+            D.assert(() => {
+                fullString = toDiagnosticsNode(style: DiagnosticsTreeStyle.singleLine)
+                    .toString(minLevel: minLevel);
+                return true;
+            });
+            return fullString ?? toStringShort();
+        }
+
+        public virtual DiagnosticsNode toDiagnosticsNode(
+            string name = null,
+            DiagnosticsTreeStyle style = DiagnosticsTreeStyle.sparse) {
+            return new DiagnosticableNode<DiagnosticableMixinChangeNotifier>(
+                name: name, value: this, style: style
+            );
+        }
+
+        public virtual void debugFillProperties(DiagnosticPropertiesBuilder properties) {
+        }
+    }
+
+}
+

com.unity.uiwidgets/Runtime/foundation/diagnosticable.mixin.njk

+namespace Unity.UIWidgets.foundation {
+{% macro DiagnosticableMixin(with) %}
+    {% set className = 'DiagnosticableMixin' + with %}
+    public class {{className}} : {{with}}, IDiagnosticable {
+        protected {{className}}() {
+        }
+
+        public virtual string toStringShort() {
+            return foundation_.describeIdentity(this);
+        }
+
+        public override string ToString() {
+            return toString();
+        }
+
+        public virtual string toString(DiagnosticLevel minLevel = DiagnosticLevel.debug) {
+            string fullString = null;
+            D.assert(() => {
+                fullString = toDiagnosticsNode(style: DiagnosticsTreeStyle.singleLine)
+                    .toString(minLevel: minLevel);
+                return true;
+            });
+            return fullString ?? toStringShort();
+        }
+
+        public virtual DiagnosticsNode toDiagnosticsNode(
+            string name = null,
+            DiagnosticsTreeStyle style = DiagnosticsTreeStyle.sparse) {
+            return new DiagnosticableNode<{{className}}>(
+                name: name, value: this, style: style
+            );
+        }
+
+        public virtual void debugFillProperties(DiagnosticPropertiesBuilder properties) {
+        }
+    }
+{% endmacro %}
+{{ DiagnosticableMixin('ChangeNotifier') }}
+}
+

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

+using System;
+using System.Collections.Generic;
+using Unity.UIWidgets.animation;
+using Unity.UIWidgets.foundation;
+using Unity.UIWidgets.gestures;
+using Unity.UIWidgets.painting;
+using Unity.UIWidgets.ui;
+
+namespace Unity.UIWidgets.rendering {
+    public abstract class RenderProxySliver : RenderSliver , RenderObjectWithChildMixin<RenderSliver> {
+        public RenderProxySliver(RenderSliver child = null) {
+            this.child = child;
+        }
+       
+        RenderSliver _child; 
+        public RenderSliver child {
+            get { return _child; }
+            set {
+                if (_child != null)
+                    dropChild(_child);
+                _child = value;
+                if (_child != null)
+                    adoptChild(_child);
+            }
+        }
+        public override void setupParentData(RenderObject child) {
+            if (!(child.parentData is SliverPhysicalParentData))
+                child.parentData = new SliverPhysicalParentData();
+        }
+
+        protected override void performLayout() {
+            D.assert(child != null);
+            child.layout(constraints, parentUsesSize: true);
+            geometry = child.geometry;
+        }
+        public override void paint(PaintingContext context, Offset offset) {
+            if (child != null)
+                context.paintChild(child, offset);
+        }
+
+        protected override bool hitTestChildren(SliverHitTestResult result, float mainAxisPosition = 0, float crossAxisPosition = 0) { 
+            return child != null 
+                   && child.geometry.hitTestExtent > 0
+                   && child.hitTest(
+                       result,
+                       mainAxisPosition: mainAxisPosition,
+                       crossAxisPosition: crossAxisPosition);
+        }
+        public override float childMainAxisPosition(RenderObject  child) {
+            child = (RenderSliver)child;
+            D.assert(child != null); 
+            D.assert(child == this.child);
+            return 0.0f;
+        }
+        public override void applyPaintTransform(RenderObject child, Matrix4 transform) { 
+            D.assert(child != null); 
+            SliverPhysicalParentData childParentData = child.parentData as SliverPhysicalParentData;
+            childParentData.applyPaintTransform(transform);
+        }
+
+        public bool debugValidateChild(RenderObject child) {
+            D.assert(() => {
+                if (!(child is RenderSliver)) {
+                    string result = "";
+                    result += new ErrorDescription(
+                        $"A {GetType()} expected a child of type $ChildType but received a " +
+                        $"child of type {child.GetType()}.");
+                    result += new ErrorDescription(
+                        "RenderObjects expect specific types of children because they " +
+                        "coordinate with their children during layout and paint. For " +
+                        "example, a RenderSliver cannot be the child of a RenderBox because " +
+                        "a RenderSliver does not understand the RenderBox layout protocol."
+                    );
+                    result += new ErrorSpacer();
+                    result += new DiagnosticsProperty<dynamic>(
+                        $"The {GetType()} that expected a $ChildType child was created by",
+                        debugCreator,
+                        style: DiagnosticsTreeStyle.errorProperty
+                    );
+                    result += new ErrorSpacer();
+                    result += new DiagnosticsProperty<dynamic>(
+                        $"The {child.GetType()} that did not match the expected child type " +
+                        "was created by",
+                        child.debugCreator,
+                        style: DiagnosticsTreeStyle.errorProperty
+                    );
+                    throw new UIWidgetsError(result);
+                }
+
+                return true;
+            });
+            return true;
+
+        }
+
+        RenderObject RenderObjectWithChildMixin.child {
+            get { return child; }
+            set { child = (RenderSliver) value; }
+        }
+    }
+    public class RenderSliverOpacity : RenderProxySliver {
+        public RenderSliverOpacity(
+            RenderSliver sliver = null,
+            float opacity = 1.0f, 
+            bool alwaysIncludeSemantics = false
+        ) : base( child:sliver) {
+            D.assert(opacity != null && opacity >= 0.0 && opacity <= 1.0);
+            D.assert(alwaysIncludeSemantics != null);
+            _opacity = opacity;
+            _alwaysIncludeSemantics = alwaysIncludeSemantics;
+            _alpha = ui.Color.getAlphaFromOpacity(opacity);
+            child = sliver;
+        }
+
+
+        bool alwaysNeedsCompositing {
+            get { return child != null && (_alpha != 0 && _alpha != 255);}
+        }
+        int _alpha;
+
+        public float opacity {
+            get { return _opacity; }
+            set { 
+                D.assert(value != null);
+                D.assert(value >= 0.0 && value <= 1.0);
+                if (_opacity == value) 
+                    return;
+                bool didNeedCompositing = alwaysNeedsCompositing;
+                bool wasVisible = _alpha != 0;
+                _opacity = value;
+                _alpha = ui.Color.getAlphaFromOpacity(_opacity);
+                if (didNeedCompositing != alwaysNeedsCompositing) 
+                    markNeedsCompositingBitsUpdate();
+                markNeedsPaint(); 
+                //if (wasVisible != (_alpha != 0) && !alwaysIncludeSemantics) 
+                //    markNeedsSemanticsUpdate();
+            }
+        }
+        float _opacity;
+
+        public bool alwaysIncludeSemantics {
+            get { return _alwaysIncludeSemantics;}
+            set { 
+                if (value == _alwaysIncludeSemantics)
+                    return;
+                _alwaysIncludeSemantics = value;
+               // markNeedsSemanticsUpdate(); 
+            }
+        }
+        bool _alwaysIncludeSemantics;
+        public override void paint(PaintingContext context, Offset offset) {
+            if (child != null && child.geometry.visible) {
+                if (_alpha == 0) {
+                    setLayer(null);
+                    return;
+                } 
+                if (_alpha == 255) {
+                    setLayer(null);
+                    context.paintChild(child, offset);
+                    return;
+                }
+                D.assert(needsCompositing);
+                var opacity = context.pushOpacity(
+                    offset,
+                    _alpha,
+                    base.paint,
+                    oldLayer: layer as OpacityLayer
+                );
+                setLayer(opacity);
+            }
+        }
+        /*public override void visitChildrenForSemantics(RenderObject visitor) {
+            visitor = (RenderObjectVisitor)visitor;
+            if (child != null && (_alpha != 0 || alwaysIncludeSemantics))
+              visitor(child);
+        }*/
+        public override void debugFillProperties(DiagnosticPropertiesBuilder properties) { 
+            base.debugFillProperties(properties);
+            properties.add(new FloatProperty("opacity", opacity));
+            properties.add(new FlagProperty("alwaysIncludeSemantics", value: alwaysIncludeSemantics, ifTrue: "alwaysIncludeSemantics"));
+        }
+    }
+
+    public class RenderSliverIgnorePointer : RenderProxySliver {
+        public RenderSliverIgnorePointer(
+            RenderSliver sliver = null,
+            bool ignoring = true,
+            bool? ignoringSemantics = null
+            ):base(child:sliver){
+                child = sliver;
+                D.assert(ignoring != null);
+                _ignoring = ignoring;
+                _ignoringSemantics = ignoringSemantics;
+        }
+
+
+        public bool ignoring {
+            get { return _ignoring; }
+            set {
+                D.assert(value != null);
+                if (value == _ignoring)
+                    return;
+                _ignoring = value;
+                //if (_ignoringSemantics == null || !_ignoringSemantics)
+                //    markNeedsSemanticsUpdate();
+            }
+        }
+        bool _ignoring;
+
+
+        public bool? ignoringSemantics {
+            get { return _ignoringSemantics; }
+            set {
+                if (value == _ignoringSemantics)
+                    return ;
+                bool oldEffectiveValue = _effectiveIgnoringSemantics;
+                _ignoringSemantics = value;
+                //if (oldEffectiveValue != _effectiveIgnoringSemantics)
+                //    markNeedsSemanticsUpdate();
+                
+            }
+        }
+        bool? _ignoringSemantics;
+
+
+        bool _effectiveIgnoringSemantics {
+            get { return ignoringSemantics ?? ignoring; }
+        }
+
+        public override bool hitTest(SliverHitTestResult result, float mainAxisPosition = 0, float crossAxisPosition = 0) { 
+            return !ignoring && base.hitTest(
+                result,
+                mainAxisPosition: mainAxisPosition,
+                crossAxisPosition: crossAxisPosition
+              );
+        }
+        /*public override void visitChildrenForSemantics(RenderObjectVisitor visitor) {
+            if (child != null && !_effectiveIgnoringSemantics)
+            visitor(child);
+         }*/
+        public override void debugFillProperties(DiagnosticPropertiesBuilder properties) {
+            base.debugFillProperties(properties);
+            properties.add(new DiagnosticsProperty<bool>("ignoring", ignoring));
+            properties.add(new DiagnosticsProperty<bool>("ignoringSemantics", _effectiveIgnoringSemantics, description: ignoringSemantics == null ? $"implicitly {_effectiveIgnoringSemantics}" : null));
+        }
+    }
+    public class RenderSliverOffstage : RenderProxySliver {
+        public RenderSliverOffstage(
+            RenderSliver sliver = null,
+            bool offstage = true): base(child:sliver)  {
+              D.assert(offstage != null);
+              _offstage = offstage;
+              child = sliver;
+        }
+
+        public bool offstage {
+            get { return _offstage; }
+            set {
+                D.assert(value != null);
+                if (value == _offstage)
+                    return;
+                _offstage = value;
+                markNeedsLayoutForSizedByParentChange();
+            }
+        }
+        bool _offstage;
+
+        protected override void performLayout() {
+            D.assert(child != null);
+            child.layout(constraints, parentUsesSize: true);
+            if (!offstage)
+                geometry = child.geometry;
+            else
+                geometry = new SliverGeometry(
+                scrollExtent: 0.0f,
+                visible: false,
+                maxPaintExtent: 0.0f);
+        }
+        public override bool hitTest(SliverHitTestResult result, float mainAxisPosition = 0, float crossAxisPosition = 0) {
+            return !offstage && base.hitTest(result, mainAxisPosition: mainAxisPosition, crossAxisPosition: crossAxisPosition);
+    }
+        protected override bool hitTestChildren(SliverHitTestResult result, float mainAxisPosition = 0, float crossAxisPosition = 0) {
+            return !offstage
+              && child != null
+              && child.geometry.hitTestExtent > 0
+              && child.hitTest(
+                result,
+                mainAxisPosition: mainAxisPosition,
+                crossAxisPosition: crossAxisPosition
+              );
+        }
+        public override void paint(PaintingContext context, Offset offset) {
+            if (offstage)
+                return;
+            context.paintChild(child, offset);
+        }
+
+        /*public override void visitChildrenForSemantics(RenderObjectVisitor visitor) {
+            if (offstage)
+              return;
+            base.visitChildrenForSemantics(visitor);
+          }*/ 
+        public override void debugFillProperties(DiagnosticPropertiesBuilder properties) {
+            base.debugFillProperties(properties);
+            properties.add(new DiagnosticsProperty<bool>("offstage", offstage));
+        }
+        public override List<DiagnosticsNode> debugDescribeChildren() { 
+            if (child == null) 
+                return new List<DiagnosticsNode>();
+            return new List<DiagnosticsNode>{
+              child.toDiagnosticsNode(
+                name: "child",
+                style: offstage ? DiagnosticsTreeStyle.offstage : DiagnosticsTreeStyle.sparse
+              ),
+            };
+        }
+    }
+    /*public class RenderSliverAnimatedOpacity : RenderProxySliver ,RenderAnimatedOpacityMixin<RenderSliver>{
+        public RenderSliverAnimatedOpacity(
+        Animation<double> opacity = null,
+        bool alwaysIncludeSemantics = false,
+            RenderSliver sliver = null
+        ):base(sliver) {
+            D.assert(opacity != null);
+            D.assert(alwaysIncludeSemantics != null);
+            this.opacity = opacity;
+            this.alwaysIncludeSemantics = alwaysIncludeSemantics;
+            child = sliver;
+        }
+    }*/
+
+    
+}

com.unity.uiwidgets/Runtime/services/keyboard_key.cs

+
+
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using Unity.UIWidgets.foundation;
+
+namespace Unity.UIWidgets.services 
+{
+    public abstract class KeyboardKey : Diagnosticable
+    {
+        protected KeyboardKey() { }
+    }
+    
+    public class LogicalKeyboardKey : KeyboardKey, IEquatable<LogicalKeyboardKey> 
+    {
+        public bool Equals(LogicalKeyboardKey other)
+        {
+            if (ReferenceEquals(null, other)) {
+                return false;
+            }
+
+            if (ReferenceEquals(this, other)) {
+                return true;
+            }
+
+            return keyId == other.keyId;
+        }
+
+        public override bool Equals(object obj)
+        {
+            if (ReferenceEquals(null, obj)) {
+                return false;
+            }
+
+            if (ReferenceEquals(this, obj)) {
+                return true;
+            }
+
+            if (obj.GetType() != GetType()) {
+                return false;
+            }
+
+            return Equals((LogicalKeyboardKey) obj);
+        }
+
+        public override int GetHashCode()
+        {
+            unchecked
+            {
+                int hashCode = (int)keyId;
+                hashCode = (hashCode * 397) ^ (debugName != null ? debugName.GetHashCode() : 0);
+                hashCode = (hashCode * 397) ^ (keyLabel != null ? keyLabel.GetHashCode() : 0);
+                return hashCode;
+            }
+        }
+
+        protected LogicalKeyboardKey(long keyId, string debugName = null, string keyLabel = null) : base()
+        {
+            D.assert(keyId != null);
+            this.keyId = keyId;
+            this.debugName = debugName;
+            this.keyLabel = keyLabel;
+        }
+        
+        public readonly long keyId;
+          
+        public readonly string debugName;
+
+        public readonly string keyLabel;
+
+        public static LogicalKeyboardKey findKeyByKeyId(int keyId) => _knownLogicalKeys[keyId];
+
+        public static bool isControlCharacter(string label) 
+        {
+            if (label.Length > 1) 
+            {
+              return false;
+            }
+            int codeUnit = label[0];
+            return (codeUnit <= 0x1f && codeUnit >= 0x00) || (codeUnit >= 0x7f && codeUnit <= 0x9f);
+        }
+          
+        public bool  isAutogenerated 
+        {
+            get 
+            {
+                return (keyId & autogeneratedMask) != 0;
+            }
+        }
+
+        public HashSet<LogicalKeyboardKey> synonyms 
+        {
+            get {
+                HashSet<LogicalKeyboardKey> result = new HashSet<LogicalKeyboardKey>();
+                LogicalKeyboardKey item = _synonyms[this];
+                if (item == null) {
+                    return result;
+                }
+                result.Add(item: item);
+                return result;
+            }
+        }
+        
+        public static HashSet<LogicalKeyboardKey> collapseSynonyms(HashSet<LogicalKeyboardKey> input) 
+        { 
+            HashSet<LogicalKeyboardKey> result = new HashSet<LogicalKeyboardKey>();
+            foreach (LogicalKeyboardKey key in input) 
+            {
+                LogicalKeyboardKey synonym = _synonyms[key];
+                result.Add(synonym ?? key);
+            }
+            return result;
+        }
+
+      
+      public override void debugFillProperties(DiagnosticPropertiesBuilder properties) {
+        base.debugFillProperties(properties);
+        properties.add(new StringProperty("keyId", keyId.ToString().PadLeft(8,'\0'), showName: true));
+        properties.add(new StringProperty("keyLabel", keyLabel, showName: true));
+        properties.add(new StringProperty("debugName", debugName, showName: true, defaultValue: null));
+      }
+      
+      /// Mask for the 32-bit value portion of the key code.
+      ///
+      /// This is used by platform-specific code to generate Flutter key codes.
+      public static readonly long valueMask = 0x000FFFFFFFF;
+      
+      /// Mask for the platform prefix portion of the key code.
+      ///
+      /// This is used by platform-specific code to generate Flutter key codes.
+      public static readonly long platformMask = 0x0FF00000000;
+
+      /// Mask for the auto-generated bit portion of the key code.
+      ///
+      /// This is used by platform-specific code to generate new Flutter key codes
+      /// for keys which are not recognized.
+      public static readonly long autogeneratedMask = 0x10000000000;
+      
+      /// Mask for the synonym pseudo-keys generated for keys which appear in more
+      /// than one place on the keyboard.
+      ///
+      /// IDs in this range are used to represent keys which appear in multiple
+      /// places on the keyboard, such as the SHIFT, ALT, CTRL, and numeric keypad
+      /// keys. These key codes will never be generated by the key event system, but
+      /// may be used in key maps to represent the union of all the keys of each
+      /// type in order to match them.
+      ///
+      /// To look up the synonyms that are defined, look in the [synonyms] map.
+      public static readonly long synonymMask = 0x20000000000;
+
+      /// The code prefix for keys which have a Unicode representation.
+      ///
+      /// This is used by platform-specific code to generate Flutter key codes.
+      public static readonly long unicodePlane = 0x00000000000;
+
+      /// The code prefix for keys which do not have a Unicode representation.
+      ///
+      /// This is used by platform-specific code to generate Flutter key codes using
+      /// HID Usage codes.
+      public static readonly long hidPlane = 0x00100000000;
+
+      /// Represents the logical "None" key on the keyboard.
+      ///
+      /// See the function [RawKeyEvent.logicalKey] for more information.
+      public static readonly LogicalKeyboardKey none = new LogicalKeyboardKey(0x00100000000, debugName: foundation_.kReleaseMode ? null : "None");
+
+        /// Represents the logical "Control Left" key on the keyboard.
+      ///
+      /// See the function [RawKeyEvent.logicalKey] for more information.
+      public static readonly LogicalKeyboardKey controlLeft = new LogicalKeyboardKey(0x001000700e0, debugName: foundation_.kReleaseMode ? null : "Control Left");
+
+      /// Represents the logical "Shift Left" key on the keyboard.
+      ///
+      /// See the function [RawKeyEvent.logicalKey] for more information.
+      public static readonly LogicalKeyboardKey shiftLeft = new LogicalKeyboardKey(0x001000700e1, debugName: foundation_.kReleaseMode ? null : "Shift Left");
+
+      /// Represents the logical "Alt Left" key on the keyboard.
+      ///
+      /// See the function [RawKeyEvent.logicalKey] for more information.
+      public static readonly LogicalKeyboardKey altLeft = new LogicalKeyboardKey(0x001000700e2, debugName: foundation_.kReleaseMode ? null : "Alt Left");
+
+      /// Represents the logical "Meta Left" key on the keyboard.
+      ///
+      /// See the function [RawKeyEvent.logicalKey] for more information.
+      public static readonly LogicalKeyboardKey metaLeft = new LogicalKeyboardKey(0x001000700e3, debugName: foundation_.kReleaseMode ? null : "Meta Left");
+
+      /// Represents the logical "Control Right" key on the keyboard.
+      ///
+      /// See the function [RawKeyEvent.logicalKey] for more information.
+      public static readonly LogicalKeyboardKey controlRight = new LogicalKeyboardKey(0x001000700e4, debugName: foundation_.kReleaseMode ? null : "Control Right");
+
+      /// Represents the logical "Shift Right" key on the keyboard.
+      ///
+      /// See the function [RawKeyEvent.logicalKey] for more information.
+      public static readonly LogicalKeyboardKey shiftRight = new LogicalKeyboardKey(0x001000700e5, debugName: foundation_.kReleaseMode ? null : "Shift Right");
+
+      /// Represents the logical "Alt Right" key on the keyboard.
+      ///
+      /// See the function [RawKeyEvent.logicalKey] for more information.
+      public static readonly LogicalKeyboardKey altRight = new LogicalKeyboardKey(0x001000700e6, debugName: foundation_.kReleaseMode ? null : "Alt Right");
+
+      /// Represents the logical "Meta Right" key on the keyboard.
+      ///
+      /// See the function [RawKeyEvent.logicalKey] for more information.
+      public static readonly LogicalKeyboardKey metaRight = new LogicalKeyboardKey(0x001000700e7, debugName: foundation_.kReleaseMode ? null : "Meta Right");
+
+      /// Represents the logical "Shift" key on the keyboard.
+      ///
+      /// This key represents the union of the keys {shiftLeft, shiftRight} when
+      /// comparing keys. This key will never be generated directly, its main use is
+      /// in defining key maps.
+      public static readonly LogicalKeyboardKey shift = new LogicalKeyboardKey(0x201000700e1, debugName: foundation_.kReleaseMode ? null : "Shift");
+
+      /// Represents the logical "Meta" key on the keyboard.
+      ///
+      /// This key represents the union of the keys {metaLeft, metaRight} when
+      /// comparing keys. This key will never be generated directly, its main use is
+      /// in defining key maps.
+      public static readonly LogicalKeyboardKey meta = new LogicalKeyboardKey(0x201000700e3, debugName: foundation_.kReleaseMode ? null : "Meta");
+
+      /// Represents the logical "Alt" key on the keyboard.
+      ///
+      /// This key represents the union of the keys {altLeft, altRight} when
+      /// comparing keys. This key will never be generated directly, its main use is
+      /// in defining key maps.
+      public static readonly LogicalKeyboardKey alt = new LogicalKeyboardKey(0x201000700e2, debugName: foundation_.kReleaseMode ? null : "Alt");
+
+      /// Represents the logical "Control" key on the keyboard.
+      ///
+      /// This key represents the union of the keys {controlLeft, controlRight} when
+      /// comparing keys. This key will never be generated directly, its main use is
+      /// in defining key maps.
+      public static readonly LogicalKeyboardKey control = new LogicalKeyboardKey(0x201000700e0, debugName: foundation_.kReleaseMode ? null : "Control");
+
+      // A list of all predefined constant LogicalKeyboardKeys so they can be
+      // searched.
+      public static readonly Dictionary<long, LogicalKeyboardKey> _knownLogicalKeys = new Dictionary<long, LogicalKeyboardKey>{
+          {0x0100000000, none},
+          {0x201000700e1, shift},
+          {0x201000700e3, meta},
+          {0x201000700e2, alt},
+          {0x201000700e0, control},
+      };
+
+      // A map of keys to the pseudo-key synonym for that key. Used by getSynonyms.
+      public static readonly Dictionary<LogicalKeyboardKey, LogicalKeyboardKey> _synonyms = new Dictionary<LogicalKeyboardKey, LogicalKeyboardKey>{
+          {shiftLeft, shift},
+          {shiftRight, shift},
+          {metaLeft, meta},
+          {metaRight, meta},
+          {altLeft, alt},
+          {altRight, alt},
+          {controlLeft, control},
+          {controlRight, control},
+      };
+    }
+    
+    public class PhysicalKeyboardKey : KeyboardKey, IEquatable<PhysicalKeyboardKey>  
+    {
+
+        protected PhysicalKeyboardKey(int usbHidUsage, string debugName = null) 
+        {
+            D.assert(usbHidUsage != null);
+            this.usbHidUsage = usbHidUsage;
+            this.debugName = debugName;
+        }
+        
+
+        /// The unique USB HID usage ID of this physical key on the keyboard.
+        ///
+        /// Due to the variations in platform APIs, this may not be the actual HID
+        /// usage code from the hardware, but a value derived from available
+        /// information on the platform.
+        ///
+        /// See <https://www.usb.org/sites/default/files/documents/hut1_12v2.pdf>
+        /// for the HID usage values and their meanings.
+        public readonly int usbHidUsage;
+
+        /// The debug string to print for this keyboard key, which will be null in
+        /// release mode.
+        public readonly string debugName;
+
+        /// Finds a known [PhysicalKeyboardKey] that matches the given USB HID usage
+        /// code.
+        public static PhysicalKeyboardKey findKeyByCode(int usageCode) => _knownPhysicalKeys[usageCode];
+        
+        public override void debugFillProperties(DiagnosticPropertiesBuilder properties) {
+            base.debugFillProperties(properties);
+            properties.add(new StringProperty("usbHidUsage", usbHidUsage.ToString().PadLeft(8,'0'), showName: true));
+            properties.add(new StringProperty("debugName", debugName, showName: true, defaultValue: null));
+        }
+
+        public bool Equals(PhysicalKeyboardKey other)
+        {
+            if (ReferenceEquals(null, other)) {
+                return false;
+            }
+
+            if (ReferenceEquals(this, other)) {
+                return true;
+            }
+
+            return usbHidUsage == other.usbHidUsage;
+        }
+
+        public override bool Equals(object obj)
+        {
+            if (ReferenceEquals(null, obj)) {
+                return false;
+            }
+
+            if (ReferenceEquals(this, obj)) {
+                return true;
+            }
+
+            if (obj.GetType() != GetType()) {
+                return false;
+            }
+
+            return Equals((PhysicalKeyboardKey) obj);
+        }
+
+        public override int GetHashCode()
+        {
+            unchecked
+            {
+                return (usbHidUsage * 397) ^ (debugName != null ? debugName.GetHashCode() : 0);
+            }
+        }
+        // Key constants for all keyboard keys in the USB HID specification at the
+        // time Flutter was built.
+
+        /// Represents the location of the "None" key on a generalized keyboard.
+        ///
+        /// See the function [RawKeyEvent.physicalKey] for more information.
+        public static readonly PhysicalKeyboardKey none = new PhysicalKeyboardKey(0x00000000, debugName: foundation_.kReleaseMode ? null : "None");
+
+        /// Represents the location of the "Control Left" key on a generalized
+        /// keyboard.
+        ///
+        /// See the function [RawKeyEvent.physicalKey] for more information.
+        public static readonly PhysicalKeyboardKey controlLeft = new PhysicalKeyboardKey(0x000700e0, debugName: foundation_.kReleaseMode ? null : "Control Left");
+
+        /// Represents the location of the "Shift Left" key on a generalized keyboard.
+        ///
+        /// See the function [RawKeyEvent.physicalKey] for more information.
+        public static readonly PhysicalKeyboardKey shiftLeft = new PhysicalKeyboardKey(0x000700e1, debugName: foundation_.kReleaseMode ? null : "Shift Left");
+
+        /// Represents the location of the "Alt Left" key on a generalized keyboard.
+        ///
+        /// See the function [RawKeyEvent.physicalKey] for more information.
+        public static readonly PhysicalKeyboardKey altLeft = new PhysicalKeyboardKey(0x000700e2, debugName: foundation_.kReleaseMode ? null : "Alt Left");
+
+        /// Represents the location of the "Meta Left" key on a generalized keyboard.
+        ///
+        /// See the function [RawKeyEvent.physicalKey] for more information.
+        public static readonly PhysicalKeyboardKey metaLeft = new PhysicalKeyboardKey(0x000700e3, debugName: foundation_.kReleaseMode ? null : "Meta Left");
+
+        /// Represents the location of the "Control Right" key on a generalized
+        /// keyboard.
+        ///
+        /// See the function [RawKeyEvent.physicalKey] for more information.
+        public static readonly PhysicalKeyboardKey controlRight = new PhysicalKeyboardKey(0x000700e4, debugName: foundation_.kReleaseMode ? null : "Control Right");
+
+        /// Represents the location of the "Shift Right" key on a generalized
+        /// keyboard.
+        ///
+        /// See the function [RawKeyEvent.physicalKey] for more information.
+        public static readonly PhysicalKeyboardKey shiftRight = new PhysicalKeyboardKey(0x000700e5, debugName: foundation_.kReleaseMode ? null : "Shift Right");
+
+        /// Represents the location of the "Alt Right" key on a generalized keyboard.
+        ///
+        /// See the function [RawKeyEvent.physicalKey] for more information.
+        public static readonly PhysicalKeyboardKey altRight = new PhysicalKeyboardKey(0x000700e6, debugName: foundation_.kReleaseMode ? null : "Alt Right");
+
+        /// Represents the location of the "Meta Right" key on a generalized keyboard.
+        ///
+        /// See the function [RawKeyEvent.physicalKey] for more information.
+        public static readonly PhysicalKeyboardKey metaRight = new PhysicalKeyboardKey(0x000700e7, debugName: foundation_.kReleaseMode ? null : "Meta Right");
+
+        
+        public static readonly Dictionary<int, PhysicalKeyboardKey> _knownPhysicalKeys =
+            new Dictionary<int, PhysicalKeyboardKey>() {
+                {0x00000000, none},
+                {0x000700e0, controlLeft},
+                {0x000700e1, shiftLeft},
+                {0x000700e2, altLeft},
+                {0x000700e3, metaLeft},
+                {0x000700e4, controlRight},
+                {0x000700e5, shiftRight},
+                {0x000700e6, altRight},
+                {0x000700e7, metaRight},
+            };
+    }
+
+
+}

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

+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Runtime.CompilerServices;
+using Unity.UIWidgets.foundation;
+using Unity.UIWidgets.service;
+using Unity.UIWidgets.services;
+
+namespace Unity.UIWidgets.widgets {
+
+    public class KeySet<T> : KeyboardKey, IEquatable<KeySet<T>> 
+    {  
+        public KeySet(
+            T key1,
+            T key2 = default(T),
+            T key3 = default(T),
+            T key4 = default(T)
+        ) {
+            D.assert(key1 != null);
+            _keys = new HashSet<T>();
+            _keys.Add(key1);
+            int count = 1;
+            if (key2 != null) {
+                _keys.Add(key2);
+                D.assert(() => {
+                    count++;
+                    return true;
+                });
+            }
+
+            if (key3 != null) {
+                _keys.Add(key3);
+                D.assert(() => {
+                    count++;
+                    return true;
+                });
+            }
+
+            if (key4 != null) {
+                _keys.Add(key4);
+                D.assert(() => {
+                    count++;
+                    return true;
+                });
+            }
+
+            D.assert(_keys.Count == count,
+                () => "Two or more provided keys are identical. Each key must appear only once.");
+        }
+
+        public KeySet(HashSet<T> keys) 
+        {
+            D.assert(keys != null);
+            D.assert(keys.isNotEmpty);
+            D.assert(!keys.Contains(default(T)));
+            foreach (var key in keys) {
+                _keys.Add(key);
+            }
+        }
+
+        public HashSet<T> keys 
+        {
+            get { return new HashSet<T>(_keys); }
+        }
+
+        public readonly HashSet<T> _keys;
+        
+        
+        public static readonly List<int> _tempHashStore3 = new List<int>() {0, 0, 0}; // used to sort exactly 3 keys
+        public static readonly List<int> _tempHashStore4 = new List<int>() {0, 0, 0, 0}; // used to sort exactly 4 keys
+        
+        public int _hashCode;
+
+        public bool Equals(KeySet<T> other)
+        {
+            if (ReferenceEquals(null, other)) {
+                return false;
+            }
+
+            if (ReferenceEquals(this, other)) {
+                return true;
+            }
+
+            return Equals(_keys, other._keys) && _hashCode == other._hashCode;
+        }
+
+        public override bool Equals(object obj)
+        {
+            if (ReferenceEquals(null, obj)) {
+                return false;
+            }
+
+            if (ReferenceEquals(this, obj)) {
+                return true;
+            }
+
+            if (obj.GetType() != GetType()) {
+                return false;
+            }
+
+            return Equals((KeySet<T>) obj);
+        }
+
+        public override int GetHashCode()
+        {
+            unchecked
+            {
+                if (_hashCode != 0) {
+                    return _hashCode;
+                }
+
+                int length = _keys.Count;
+                IEnumerator<T> iterator = _keys.GetEnumerator();
+
+                // There's always at least one key. Just extract it.
+                iterator.MoveNext();
+                int h1 = iterator.GetHashCode();
+
+                if (length == 1) {
+                    // Don't do anything fancy if there's exactly one key.
+                    return _hashCode = h1;
+                }
+
+                iterator.MoveNext();
+                int h2 = iterator.GetHashCode();
+                if (length == 2) {
+                    // No need to sort if there's two keys, just compare them.
+                    return _hashCode = h1 < h2
+                        ? ((h1 != null ? h1.GetHashCode() : 0) * 397) ^ h2.GetHashCode()
+                        : ((h2 != null ? h2.GetHashCode() : 0) * 397) ^ h1.GetHashCode();
+                }
+
+                // Sort key hash codes and feed to hashList to ensure the aggregate
+                // hash code does not depend on the key order.
+                List<int> sortedHashes = length == 3
+                    ? _tempHashStore3
+                    : _tempHashStore4;
+                sortedHashes[0] = h1;
+                sortedHashes[1] = h2;
+                iterator.MoveNext();
+                sortedHashes[2] = iterator.GetHashCode();
+                if (length == 4) {
+                    iterator.MoveNext();
+                    sortedHashes[3] = iterator.GetHashCode();
+                }
+                sortedHashes.Sort();
+                return _hashCode  = (_hashCode * 397) ^ (sortedHashes != null ? sortedHashes.GetHashCode() : 0);;
+            }
+        }
+    }
+    
+    public class LogicalKeySet : KeySet<LogicalKeyboardKey> {
+
+        public LogicalKeySet(
+            LogicalKeyboardKey key1,
+            LogicalKeyboardKey key2 = default(LogicalKeyboardKey),
+            LogicalKeyboardKey key3 = default(LogicalKeyboardKey),
+            LogicalKeyboardKey key4 = default(LogicalKeyboardKey)
+        ) : base(key1: key1, key2: key2, key3: key3, key4: key4){ }
+        
+        public LogicalKeySet(HashSet<LogicalKeyboardKey> keys) : base(keys) { }
+
+        public static readonly HashSet<LogicalKeyboardKey> _modifiers = new HashSet<LogicalKeyboardKey>(){
+            LogicalKeyboardKey.alt,
+            LogicalKeyboardKey.control,
+            LogicalKeyboardKey.meta,
+            LogicalKeyboardKey.shift,
+        };
+
+      /// Returns a description of the key set that is short and readable.
+      ///
+      /// Intended to be used in debug mode for logging purposes.
+      public string debugDescribeKeys() {
+          List<LogicalKeyboardKey> sortedKeys = keys.ToList();
+             sortedKeys.Sort(
+             (LogicalKeyboardKey a, LogicalKeyboardKey b) => { 
+                 bool aIsModifier = a.synonyms.isNotEmpty() || _modifiers.Contains(a);
+                 bool bIsModifier = b.synonyms.isNotEmpty() || _modifiers.Contains(b);
+                 if (aIsModifier && !bIsModifier) {
+                     return -1;
+                 } else if (bIsModifier && !aIsModifier) {
+                     return 1;
+                 }
+                 return a.debugName.CompareTo(b.debugName);
+             }
+        ); 
+          List<string> result = new List<string>();
+          foreach (var key in sortedKeys) {
+              result.Add(key.debugName);
+          }
+          return string.Join(" + ", result.ToArray());
+      }
+      
+      
+      public override void debugFillProperties(DiagnosticPropertiesBuilder properties) {
+        base.debugFillProperties(properties);
+        properties.add(new DiagnosticsProperty<HashSet<LogicalKeyboardKey>>("keys", _keys, description: debugDescribeKeys()));
+      }
+    }
+    
+    public class ShortcutMapProperty : DiagnosticsProperty<Dictionary<LogicalKeySet, Intent>> {
+
+        public ShortcutMapProperty(
+            string name,
+            Dictionary<LogicalKeySet, Intent> value,
+            bool showName = true,
+            Object defaultValue =  null,//foundation_.kNoDefaultValue
+            DiagnosticLevel level = DiagnosticLevel.info,
+            string description = null
+        ) : base(
+                name: name,
+                value: value,
+                showName: showName,
+                defaultValue: defaultValue,
+                level: level,
+                description: description
+            ) 
+            {
+                D.assert(showName != null);
+                D.assert(level != null);
+            }
+
+    
+        protected override string valueToString( TextTreeConfiguration parentConfiguration = null) {
+            List<string> res = new List<string>();
+            foreach (var key in value.Keys) {
+                string temp = "{" + key.debugDescribeKeys() + "}:" + value[key];
+                res.Add(temp);
+            }
+            return string.Join(", ", res);
+        }
+    }
+    
+    public class ShortcutManager : DiagnosticableMixinChangeNotifier {
+
+      public ShortcutManager(
+        Dictionary<LogicalKeySet, Intent> shortcuts = null,
+        bool modal = false
+      ) {
+          shortcuts = shortcuts ?? new Dictionary<LogicalKeySet, Intent>();
+          D.assert(shortcuts != null);
+          this.modal = modal;
+          this.shortcuts = shortcuts;
+        } 
+
+      /// True if the [ShortcutManager] should not pass on keys that it doesn't
+      /// handle to any key-handling widgets that are ancestors to this one.
+      ///
+      /// Setting [modal] to true is the equivalent of always handling any key given
+      /// to it, even if that key doesn't appear in the [shortcuts] map. Keys that
+      /// don't appear in the map will be dropped.
+      public readonly bool modal;
+
+
+      Dictionary<LogicalKeySet, Intent> _shortcuts;
+    
+      public Dictionary<LogicalKeySet, Intent>  shortcuts {
+          get { return _shortcuts; }
+          set {
+              _shortcuts = value;
+              notifyListeners();
+          }
+      }
+
+      /// Handles a key pressed `event` in the given `context`.
+      ///
+      /// The optional `keysPressed` argument provides an override to keys that the
+      /// [RawKeyboard] reports. If not specified, uses [RawKeyboard.keysPressed]
+      /// instead.
+      public bool handleKeypress(
+        BuildContext context,
+        RawKeyEvent rawKeyEvent,
+        LogicalKeySet keysPressed = null
+      ) {
+        if (!(rawKeyEvent is RawKeyDownEvent)) {
+          return false;
+        }
+        D.assert(context != null);
+        LogicalKeySet keySet = keysPressed ?? new LogicalKeySet(RawKeyboard.instance.keysPressed);
+        Intent matchedIntent = _shortcuts[keySet];
+        if (matchedIntent == null) {
+          // If there's not a more specific match, We also look for any keys that
+          // have synonyms in the map.  This is for things like left and right shift
+          // keys mapping to just the "shift" pseudo-key.
+          HashSet<LogicalKeyboardKey> pseudoKeys = new HashSet<LogicalKeyboardKey>{};
+          foreach (LogicalKeyboardKey setKey in keySet.keys) {
+            HashSet<LogicalKeyboardKey> synonyms = setKey.synonyms;
+            if (synonyms.isNotEmpty()) {
+              // There currently aren't any synonyms that match more than one key.
+              pseudoKeys.Add(synonyms.First());
+            } else {
+              pseudoKeys.Add(setKey);
+            }
+          }
+          matchedIntent = _shortcuts[new LogicalKeySet(pseudoKeys)];
+        }
+        if (matchedIntent != null) {
+          BuildContext primaryContext = FocusManagerUtils.primaryFocus?.context;
+          if (primaryContext == null) {
+            return false;
+          }
+          return Actions.invoke(primaryContext, matchedIntent, nullOk: true);
+        }
+        return false;
+      }
+
+      public override void debugFillProperties(DiagnosticPropertiesBuilder properties) {
+          base.debugFillProperties(properties: properties);
+          properties.add(new DiagnosticsProperty<Dictionary<LogicalKeySet, Intent>>("shortcuts", _shortcuts));
+          properties.add(new FlagProperty("modal", value: modal, ifTrue: "modal", defaultValue: false));
+      }
+    }
+      
+    public class Shortcuts : StatefulWidget {
+      /// Creates a ActionManager object.
+      ///
+      /// The [child] argument must not be null.
+      public Shortcuts(
+        Key key = null,
+        ShortcutManager manager = null,
+        Dictionary<LogicalKeySet, Intent> shortcuts = null,
+        Widget child = null,
+        string debugLabel = null
+      ) : base(key: key) {
+          this.manager = manager;
+          this.shortcuts = shortcuts;
+          this.child = child;
+          this.debugLabel = debugLabel;
+      }
+      
+      public readonly ShortcutManager manager;
+      
+      public readonly Dictionary<LogicalKeySet, Intent> shortcuts;
+      
+      public readonly Widget child;
+      
+      public readonly string debugLabel;
+
+      public static ShortcutManager of(BuildContext context, bool nullOk = false) {
+        D.assert(context != null);
+        _ShortcutsMarker inherited = context.dependOnInheritedWidgetOfExactType<_ShortcutsMarker>();
+        D.assert(() => {
+          if (nullOk) {
+            return true;
+          }
+          if (inherited == null) {
+            throw new UIWidgetsError($"Unable to find a {typeof(Shortcuts)} widget in the context.\n" +
+                $"{typeof(Shortcuts)}.of()was called with a context that does not contain a " +
+                $"{typeof(Shortcuts)} widget.\n" +
+                $"No {typeof(Shortcuts)} ancestor could be found starting from the context that was " +
+                $"passed to {typeof(Shortcuts)}.of().\n" +
+                "The context used was:\n" +
+                $"  {context}");
+          }
+          return true;
+        });
+        return inherited?.notifier;
+      }
+
+      
+      public override State createState() {
+          return new _ShortcutsState();
+      }
+
+
+      public override void debugFillProperties(DiagnosticPropertiesBuilder properties) {
+        base.debugFillProperties(properties);
+        properties.add(new DiagnosticsProperty<ShortcutManager>("manager", manager, defaultValue: null));
+        properties.add(new ShortcutMapProperty("shortcuts", shortcuts, description: debugLabel?.isNotEmpty() ?? false ? debugLabel : null));
+      }
+    }
+
+    public class _ShortcutsState : State<Shortcuts> {
+        
+      private ShortcutManager _internalManager;
+      public ShortcutManager manager {
+          get { return widget.manager ?? _internalManager; }
+      }
+
+      
+      public override void dispose() {
+        _internalManager?.dispose();
+        base.dispose();
+      }
+
+      
+      public override void initState() {
+        base.initState();
+        if (widget.manager == null) {
+          _internalManager = new ShortcutManager();
+        }
+        manager.shortcuts = widget.shortcuts;
+      }
+
+      
+      public override void didUpdateWidget(StatefulWidget oldWidget) {
+        base.didUpdateWidget((Shortcuts)oldWidget);
+        if (widget.manager != ((Shortcuts)oldWidget).manager) {
+          if (widget.manager != null) {
+            _internalManager?.dispose();
+            _internalManager = null;
+          } else {
+            _internalManager = _internalManager?? new ShortcutManager();
+          }
+        }
+        manager.shortcuts = widget.shortcuts;
+      }
+
+      public bool _handleOnKey(FocusNode node, RawKeyEvent _event)
+      {
+        if (node.context == null) {
+          return false;
+        }
+        return manager.handleKeypress(node.context, _event) || manager.modal;
+      }
+      
+      public override Widget build(BuildContext context) {
+        return new Focus(
+          debugLabel: typeof(Shortcuts).ToString(),
+          canRequestFocus: false,
+          onKey: _handleOnKey,
+          child: new _ShortcutsMarker(
+            manager: manager,
+            child: widget.child
+          )
+        );
+      }
+    }
+
+    public class _ShortcutsMarker : InheritedNotifier<ShortcutManager> {
+        public _ShortcutsMarker(
+            ShortcutManager manager = null,
+            Widget child = null
+        ) : base(notifier: manager, child: child) {
+            D.assert(manager != null);
+            D.assert(child != null);
+        }
+    }
+    
+}

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

+using System;
+using System.Collections.Generic;
+using Unity.UIWidgets.foundation;
+using Unity.UIWidgets.scheduler2;
+using Unity.UIWidgets.ui;
+using Unity.UIWidgets.service;
+namespace Unity.UIWidgets.widgets {
+    class Title : StatelessWidget {
+        public Title(
+            Color color,
+            Key key = null,
+            string title = "",
+            Widget child = null
+        ) : base(key: key) {
+            D.assert(title != null);
+            D.assert(color != null && color.alpha == 0xFF);
+        }
+
+        public readonly String title;
+        public readonly Color color;
+        public readonly Widget child;
+        public override Widget build(BuildContext context) {
+            /*SystemChrome.setApplicationSwitcherDescription(
+                new ApplicationSwitcherDescription(
+                    label: title,
+                    primaryColor: (int)color.value
+                )
+            );*/
+            return child;
+        }
+        public override void debugFillProperties(DiagnosticPropertiesBuilder properties) {
+            base.debugFillProperties(properties);
+            properties.add(new StringProperty("title", title, defaultValue: ""));
+            //properties.add(new ColorProperty("color", color, defaultValue: null));
+        }
+    }
+
+}

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

+using System;
+using Unity.UIWidgets.animation;
+using Unity.UIWidgets.foundation;
+using Unity.UIWidgets.ui;
+
+namespace Unity.UIWidgets.widgets {
+    public class TweenAnimationBuilder<T> : ImplicitlyAnimatedWidget {
+        public TweenAnimationBuilder(
+            Key key = null,
+            Tween<T> tween = null,
+            TimeSpan? duration = null,
+            Curve curve = null,
+            ValueWidgetBuilder<T> builder = null,
+            VoidCallback onEnd = null,
+            Widget child = null
+        ) : base(key: key, duration: duration, curve: curve, onEnd: onEnd) {
+            curve = curve ?? Curves.linear;
+            D.assert(tween != null);
+            D.assert(curve != null);
+            D.assert(builder != null);
+        }
+
+
+        public readonly Tween<T> tween;
+        public readonly ValueWidgetBuilder<T> builder;
+        public readonly Widget child;
+        public override State createState() {
+            return new _TweenAnimationBuilderState<T>();
+        }
+    }
+    public class _TweenAnimationBuilderState<T> : AnimatedWidgetBaseState<TweenAnimationBuilder<T>> { 
+        Tween<T> _currentTween;
+
+        public override void initState() {
+            _currentTween = widget.tween;
+            if (_currentTween.begin == null) {
+                _currentTween.begin = _currentTween.end;
+            }
+
+            
+            base.initState();
+            if (_currentTween.begin.Equals( _currentTween.end)) {
+                controller.forward();
+            }
+        }
+
+        protected override void forEachTween(TweenVisitor visitor) { 
+            D.assert(
+                widget.tween.end != null,()=> 
+                    "Tween provided to TweenAnimationBuilder must have non-null Tween.end value.");
+            _currentTween = visitor.visit(
+                this,
+                _currentTween, 
+                widget.tween.end, 
+                (value) =>{
+                    D.assert(false);
+                    return null; }) as Tween<T>;
+        }
+
+        public override Widget build(BuildContext context) {
+            return widget.builder(context, _currentTween.evaluate(animation), widget.child);
+        }
+    }
+
+}

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

+using Unity.UIWidgets.foundation;
+
+namespace Unity.UIWidgets.widgets {
+    public abstract class UniqueWidget<T> :StatefulWidget where T: State<StatefulWidget> {
+        
+        public UniqueWidget(
+            GlobalKey<T> key
+        ) : base(key: key) {
+            D.assert(key != null);
+        }
+        public abstract override State createState();
+        
+        T currentState {
+            get {
+                GlobalKey<T> globalKey = key as GlobalKey<T>;
+                return globalKey.currentState;
+            }
+        }
+    }
+
+}