Remove getTextStyle from _layout.

Runtime/ui/text.cs

     }
 
     class TextStyle : IEquatable<TextStyle> {
-        public readonly Color color = Color.fromARGB(255, 0, 0, 0);
-        public readonly float fontSize = 14.0f;
-        public readonly FontWeight fontWeight = FontWeight.w400;
-        public readonly FontStyle fontStyle = FontStyle.normal;
-        public readonly float letterSpacing = 0.0f;
-        public readonly float wordSpacing = 0.0f;
-        public readonly TextBaseline textBaseline = TextBaseline.alphabetic;
-        public readonly float height = 1.0f;
-        public readonly TextDecoration decoration = TextDecoration.none;
+        public static readonly Color kDefaultColor = Color.fromARGB(255, 0, 0, 0);
+        public const float kDefaultFontSize = 14.0f;
+        public static readonly FontWeight kDefaultFontWeight = FontWeight.w400;
+        public const FontStyle kDefaultfontStyle = FontStyle.normal;
+        public const float kDefaultLetterSpacing = 0.0f;
+        public const float kDefaultWordSpacing = 0.0f;
+        public const TextBaseline kDefaultTextBaseline = TextBaseline.alphabetic;
+        public const float kDefaultHeight = 1.0f;
+        public static readonly TextDecoration kDefaultDecoration = TextDecoration.none;
+        public const TextDecorationStyle kDefaultDecorationStyle = TextDecorationStyle.solid;
+        public const string kDefaultFontFamily = "Helvetica";
+
+        public readonly Color color = kDefaultColor;
+        public readonly float fontSize = kDefaultFontSize;
+        public readonly FontWeight fontWeight = kDefaultFontWeight;
+        public readonly FontStyle fontStyle = kDefaultfontStyle;
+        public readonly float letterSpacing = kDefaultLetterSpacing;
+        public readonly float wordSpacing = kDefaultWordSpacing;
+        public readonly TextBaseline textBaseline = kDefaultTextBaseline;
+        public readonly float height = kDefaultHeight;
+        public readonly TextDecoration decoration = kDefaultDecoration;
-        public readonly TextDecorationStyle decorationStyle = TextDecorationStyle.solid;
-        public readonly string fontFamily = "Helvetica";
+        public readonly TextDecorationStyle decorationStyle = kDefaultDecorationStyle;
+        public readonly string fontFamily = kDefaultFontFamily;
         public readonly Paint background;
 
         internal UnityEngine.Color UnityColor {

Runtime/ui/txt/paragraph.cs

             this.codeUnits = codeUnits;
         }
 
-        public GlyphPosition shift(float shift) {
-            return new GlyphPosition(this.xPos.start + shift, this.xPos.end - this.xPos.start, this.codeUnits);
-        }
-
         public void shiftSelf(float shift) {
             this.xPos = new Range<float>(this.xPos.start + shift, this.xPos.end + shift);
         }
                 return;
             }
 
-            var textStyle = this._paragraphStyle.getTextStyle();
-                FontManager.instance.getOrCreate(textStyle.fontFamily, textStyle.fontWeight, textStyle.fontStyle).font,
-                textStyle.UnityFontSize);
+                FontManager.instance.getOrCreate(
+                    this._paragraphStyle.fontFamily ?? TextStyle.kDefaultFontFamily,
+                    this._paragraphStyle.fontWeight ?? TextStyle.kDefaultFontWeight,
+                    this._paragraphStyle.fontStyle ?? TextStyle.kDefaultfontStyle).font,
+                (int) (this._paragraphStyle.fontSize ?? TextStyle.kDefaultFontSize));
 
             this._needsLayout = false;
             this._width = Mathf.Floor(constraints.width);
             ref float justifyXOffset,
             ref float maxWordWidth,
             Range<int>[] words,
-            GlyphPosition[] lineGlyphPositions,
+            GlyphPosition[] glyphPositions,
             ref int pLineGlyphPositions) {
             string text = this._text;
             int textStart = run.start;
                 textStart, textCount,
                 builder, layout,
                 words,
-                lineGlyphPositions,
+                glyphPositions,
                 run.start,
                 runXOffset,
                 wordGapWidth,
             float advance = layout.getAdvance();
             PaintRecord paintRecord = this._generatePaintRecord(run.style, textBlob, runXOffset, advance);
             runXOffset += advance;
-            this._codeUnitRuns.Add(this._generateCodeUnitRun(run, lineNumber, lineGlyphPositions, 
+            this._codeUnitRuns.Add(this._generateCodeUnitRun(run, lineNumber, glyphPositions, 
                 pLineGlyphPositions - textCount, textCount));
 
             return paintRecord;
         void _populateGlyphPositions(int textStart, int textCount,
             TextBlobBuilder builder, Layout layout,
             Range<int>[] words,
-            GlyphPosition[] lineGlyphPositions,
+            GlyphPosition[] glyphPositions,
             int runStart,
             float runXOffset,
             float wordGapWidth,
                 float glyphXOffset = layout.getX(glyphIndex) + justifyXOffset;
                 float glyphAdvance = layout.getCharAdvance(glyphIndex);
                 builder.positions[glyphIndex] = new Vector2d(glyphXOffset);
-                lineGlyphPositions[pLineGlyphPositions++] = new GlyphPosition(runXOffset + glyphXOffset, glyphAdvance,
-                    new Range<int>(textStart + glyphIndex, textStart + glyphIndex + 1));
+                glyphPositions[pLineGlyphPositions++] = new GlyphPosition(runXOffset + glyphXOffset,
+                    glyphAdvance, new Range<int>(textStart + glyphIndex, textStart + glyphIndex + 1));
                 if (words != null && wordIndex < words.Length) {
                     Range<int> word = words[wordIndex];
                     if (word.start == runStart + glyphIndex) {
 
                         wordIndex++;
                         if (!float.IsNaN(wordStartPosition)) {
-                            float wordWidth = lineGlyphPositions[pLineGlyphPositions-1].xPos.end - wordStartPosition;
+                            float wordWidth = glyphPositions[pLineGlyphPositions-1].xPos.end - wordStartPosition;
                             maxWordWidth = Mathf.Max(wordWidth, maxWordWidth);
                             wordStartPosition = float.NaN;
                         }
                 // TODO: the default values are filled in directly, to avoid the cost of creating a new TextStyle
                 //       However this may become inconsistent with the default values in TextStyle (text.cs)
                 //       A better way is to define some global constants used in both places.
-                var defaultFont = FontManager.instance.getOrCreate(this._paragraphStyle.fontFamily ?? "Helvetica",
-                    this._paragraphStyle.fontWeight ?? FontWeight.w400, this._paragraphStyle.fontStyle ?? FontStyle.normal).font;
-                var metrics = FontMetrics.fromFont(defaultFont, (int) (this._paragraphStyle.fontSize ?? 14.0f));
-                updateLineMetrics(metrics, this._paragraphStyle.lineHeight ?? 1.0f);
+                var defaultFont = FontManager.instance.getOrCreate(
+                    this._paragraphStyle.fontFamily ?? TextStyle.kDefaultFontFamily,
+                    this._paragraphStyle.fontWeight ?? TextStyle.kDefaultFontWeight,
+                    this._paragraphStyle.fontStyle ?? TextStyle.kDefaultfontStyle).font;
+                var metrics = FontMetrics.fromFont(defaultFont, (int) (this._paragraphStyle.fontSize ?? TextStyle.kDefaultFontSize));
+                updateLineMetrics(metrics, this._paragraphStyle.lineHeight ?? TextStyle.kDefaultHeight);
             }
 
             this._lineHeights.Add(