Add support for line-height in TextStyle.

sky/sdk/lib/painting/text_style.dart

 // Copyright 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 import 'dart:sky';
 
-enum FontWeight {
-  w100,
-  w200,
-  w300,
-  w400,
-  w500,
-  w600,
-  w700,
-  w800,
-  w900
-}
-
+enum FontWeight { w100, w200, w300, w400, w500, w600, w700, w800, w900 }
 const thin = FontWeight.w100;
 const extraLight = FontWeight.w200;
 const light = FontWeight.w300;
 const normal = FontWeight.w400;
 const medium = FontWeight.w500;
 const semiBold = FontWeight.w600;
 const bold = FontWeight.w700;
 const extraBold = FontWeight.w800;
 const black = FontWeight.w900;
 
-enum TextAlign {
-  left,
-  right,
-  center
-}
+enum TextAlign { left, right, center }
 
-enum TextDecoration {
-  none,
-  underline,
-  overline,
-  lineThrough
-}
-
+enum TextDecoration { none, underline, overline, lineThrough }
 const underline = const <TextDecoration>[TextDecoration.underline];
 const overline = const <TextDecoration>[TextDecoration.overline];
 const lineThrough = const <TextDecoration>[TextDecoration.lineThrough];
 
-enum TextDecorationStyle {
-  solid,
-  double,
-  dotted,
-  dashed,
-  wavy
-}
+enum TextDecorationStyle { solid, double, dotted, dashed, wavy }
 
 class TextStyle {
   const TextStyle({
     this.color,
     this.fontFamily,
     this.fontSize,
     this.fontWeight,
     this.textAlign,
+    this.height,
     this.decoration,
     this.decorationColor,
     this.decorationStyle
   });
 
   final Color color;
   final String fontFamily;
   final double fontSize; // in pixels
   final FontWeight fontWeight;
   final TextAlign textAlign;
+  final double height; // multiple of fontSize
   final List<TextDecoration> decoration; // TODO(ianh): Switch this to a Set<> once Dart supports constant Sets
   final Color decorationColor;
   final TextDecorationStyle decorationStyle;
 
   TextStyle copyWith({
     Color color,
     String fontFamily,
     double fontSize,
     FontWeight fontWeight,
     TextAlign textAlign,
+    double height,
     List<TextDecoration> decoration,
     Color decorationColor,
     TextDecorationStyle decorationStyle
   }) {
     return new TextStyle(
       color: color != null ? color : this.color,
       fontFamily: fontFamily != null ? fontFamily : this.fontFamily,
       fontSize: fontSize != null ? fontSize : this.fontSize,
       fontWeight: fontWeight != null ? fontWeight : this.fontWeight,
       textAlign: textAlign != null ? textAlign : this.textAlign,
+      height: height != null ? height : this.height,
       decoration: decoration != null ? decoration : this.decoration,
       decorationColor: decorationColor != null ? decorationColor : this.decorationColor,
       decorationStyle: decorationStyle != null ? decorationStyle : this.decorationStyle
     );
   }
 
-  static String _colorToCSSString(Color color) {
-    return 'rgba(${color.red}, ${color.green}, ${color.blue}, ${color.alpha / 255.0})';
-  }
-
   TextStyle merge(TextStyle other) {
     return copyWith(
       color: other.color,
       fontFamily: other.fontFamily,
       fontSize: other.fontSize,
       fontWeight: other.fontWeight,
       textAlign: other.textAlign,
+      height: other.height,
       decoration: other.decoration,
       decorationColor: other.decorationColor,
       decorationStyle: other.decorationStyle
     );
   }
 
+  static String _colorToCSSString(Color color) {
+    return 'rgba(${color.red}, ${color.green}, ${color.blue}, ${color.alpha / 255.0})';
+  }
+
   static String _fontFamilyToCSSString(String fontFamily) {
     // TODO(hansmuller): escape the fontFamily string.
     return fontFamily;
   }
 
   static String _decorationToCSSString(List<TextDecoration> decoration) {
     assert(decoration != null);
     const toCSS = const <TextDecoration, String>{
       TextDecoration.none: 'none',
       TextDecoration.underline: 'underline',
@@ skipping 16 matching lines @@
   }
 
   void applyToCSSStyle(CSSStyleDeclaration cssStyle) {
     if (color != null) {
       cssStyle['color'] = _colorToCSSString(color);
     }
     if (fontFamily != null) {
       cssStyle['font-family'] = _fontFamilyToCSSString(fontFamily);
     }
     if (fontSize != null) {
-      cssStyle['font-size'] = "${fontSize}px";
+      cssStyle['font-size'] = '${fontSize}px';
     }
     if (fontWeight != null) {
       cssStyle['font-weight'] = const {
         FontWeight.w100: '100',
         FontWeight.w200: '200',
         FontWeight.w300: '300',
         FontWeight.w400: '400',
         FontWeight.w500: '500',
         FontWeight.w600: '600',
         FontWeight.w700: '700',
         FontWeight.w800: '800',
         FontWeight.w900: '900'
       }[fontWeight];
     }
     if (textAlign != null) {
       cssStyle['text-align'] = const {
         TextAlign.left: 'left',
         TextAlign.right: 'right',
         TextAlign.center: 'center',
       }[textAlign];
     }
+    if (height != null) {
+      cssStyle['line-height'] = '${height}';
+    }
     if (decoration != null) {
       cssStyle['text-decoration'] = _decorationToCSSString(decoration);
       if (decorationColor != null)
         cssStyle['text-decoration-color'] = _colorToCSSString(decorationColor);
       if (decorationStyle != null)
         cssStyle['text-decoration-style'] = _decorationStyleToCSSString(decorationStyle);
     }
   }
 
   bool operator ==(other) {
@@ skipping 41 matching lines @@
       result.add('${prefix}decoration: $decoration');
     if (decorationColor != null)
       result.add('${prefix}decorationColor: $decorationColor');
     if (decorationStyle != null)
       result.add('${prefix}decorationStyle: $decorationStyle');
     if (result.isEmpty)
       return '${prefix}<no style specified>';
     return result.join('\n');
   }
 }