Merge pull request #2135 from abarth/improve_text_span

Improve TextSpan

examples/layers/rendering/flex_layout.dart

@@ -14,24 +14,24 @@ void main() {
 
   void addAlignmentRow(FlexAlignItems alignItems) {
     TextStyle style = const TextStyle(color: const Color(0xFF000000));
-    RenderParagraph paragraph = new RenderParagraph(new StyledTextSpan(style, <TextSpan>[new PlainTextSpan('$alignItems')]));
+    RenderParagraph paragraph = new RenderParagraph(new TextSpan(style: style, text: '$alignItems'));
     table.add(new RenderPadding(child: paragraph, padding: new EdgeDims.only(top: 20.0)));
     RenderFlex row = new RenderFlex(alignItems: alignItems, textBaseline: TextBaseline.alphabetic);
     style = new TextStyle(fontSize: 15.0, color: const Color(0xFF000000));
     row.add(new RenderDecoratedBox(
       decoration: new BoxDecoration(backgroundColor: const Color(0x7FFFCCCC)),
-      child: new RenderParagraph(new StyledTextSpan(style, <TextSpan>[new PlainTextSpan('foo foo foo')]))
+      child: new RenderParagraph(new TextSpan(style: style, text: 'foo foo foo'))
     ));
     style = new TextStyle(fontSize: 10.0, color: const Color(0xFF000000));
     row.add(new RenderDecoratedBox(
       decoration: new BoxDecoration(backgroundColor: const Color(0x7FCCFFCC)),
-      child: new RenderParagraph(new StyledTextSpan(style, <TextSpan>[new PlainTextSpan('foo foo foo')]))
+      child: new RenderParagraph(new TextSpan(style: style, text: 'foo foo foo'))
     ));
     RenderFlex subrow = new RenderFlex(alignItems: alignItems, textBaseline: TextBaseline.alphabetic);
     style = new TextStyle(fontSize: 25.0, color: const Color(0xFF000000));
     subrow.add(new RenderDecoratedBox(
       decoration: new BoxDecoration(backgroundColor: const Color(0x7FCCCCFF)),
-      child: new RenderParagraph(new StyledTextSpan(style, <TextSpan>[new PlainTextSpan('foo foo foo foo')]))
+      child: new RenderParagraph(new TextSpan(style: style, text: 'foo foo foo foo'))
     ));
     subrow.add(new RenderSolidColorBox(const Color(0x7FCCFFFF), desiredSize: new Size(30.0, 40.0)));
     row.add(subrow);
@@ -48,7 +48,7 @@ void main() {
 
   void addJustificationRow(FlexJustifyContent justify) {
     const TextStyle style = const TextStyle(color: const Color(0xFF000000));
-    RenderParagraph paragraph = new RenderParagraph(new StyledTextSpan(style, <TextSpan>[new PlainTextSpan('$justify')]));
+    RenderParagraph paragraph = new RenderParagraph(new TextSpan(style: style, text: '$justify'));
     table.add(new RenderPadding(child: paragraph, padding: new EdgeDims.only(top: 20.0)));
     RenderFlex row = new RenderFlex(direction: FlexDirection.horizontal);
     row.add(new RenderSolidColorBox(const Color(0xFFFFCCCC), desiredSize: new Size(80.0, 60.0)));

examples/layers/rendering/hello_world.dart

@@ -16,7 +16,7 @@ void main() {
       alignment: const FractionalOffset(0.5, 0.5),
       // We use a RenderParagraph to display the text 'Hello, world.' without
       // any explicit styling.
-      child: new RenderParagraph(new PlainTextSpan('Hello, world.'))
+      child: new RenderParagraph(new TextSpan(text: 'Hello, world.'))
     )
   );
 }

examples/layers/rendering/touch_input.dart

@@ -97,9 +97,9 @@ class RenderDots extends RenderBox {
 void main() {
   // Create some styled text to tell the user to interact with the app.
   RenderParagraph paragraph = new RenderParagraph(
-    new StyledTextSpan(
-      new TextStyle(color: Colors.black87),
-      <TextSpan>[ new PlainTextSpan("Touch me!") ]
+    new TextSpan(
+      style: new TextStyle(color: Colors.black87),
+      text: "Touch me!"
     )
   );
   // A stack is a render object that layers its children on top of each other.

examples/layers/widgets/styled_text.dart

@@ -34,9 +34,24 @@ final TextStyle _kUnderline = const TextStyle(
 
 Widget toStyledText(String name, String text) {
   TextStyle lineStyle = (name == "Dave") ? _kDaveStyle : _kHalStyle;
-  return new StyledText(
+  return new RichText(
     key: new Key(text),
-    elements: [lineStyle, [_kBold, [_kUnderline, name], ":"], text]
+    text: new TextSpan(
+      style: lineStyle,
+      children: <TextSpan>[
+        new TextSpan(
+          style: _kBold,
+          children: <TextSpan>[
+            new TextSpan(
+              style: _kUnderline,
+              text: name
+            ),
+            new TextSpan(text: ':')
+          ]
+        ),
+        new TextSpan(text: text)
+      ]
+    )
   );
 }
 

packages/flutter/lib/src/material/time_picker.dart

@@ -240,9 +240,7 @@ List<TextPainter> _initPainters(List<String> labels) {
   for (int i = 0; i < painters.length; ++i) {
     String label = labels[i];
     TextPainter painter = new TextPainter(
-      new StyledTextSpan(style, [
-        new PlainTextSpan(label)
-      ])
+      new TextSpan(style: style, text: label)
     );
     painter
       ..maxWidth = double.INFINITY

packages/flutter/lib/src/painting/text_painter.dart

@@ -9,92 +9,86 @@ import 'text_editing.dart';
 import 'text_style.dart';
 
 /// An immutable span of text.
-abstract class TextSpan {
-  // This class must be immutable, because we won't notice when it changes.
-  const TextSpan();
-  void build(ui.ParagraphBuilder builder);
-  ui.ParagraphStyle get paragraphStyle => null;
-  String toPlainText(); // for semantics
-  String toString([String prefix = '']); // for debugging
-}
-
-/// An immutable span of unstyled text.
-class PlainTextSpan extends TextSpan {
-  const PlainTextSpan(this.text);
+class TextSpan {
+  const TextSpan({
+    this.style,
+    this.text,
+    this.children
+  });
+
+  /// The style to apply to the text and the children.
+  final TextStyle style;
 
   /// The text contained in the span.
+  ///
+  /// If both text and children are non-null, the text will preceed the
+  /// children.
   final String text;
 
-  void build(ui.ParagraphBuilder builder) {
-    assert(text != null);
-    builder.addText(text);
-  }
-
-  bool operator ==(dynamic other) {
-    if (other is! PlainTextSpan)
-      return false;
-    final PlainTextSpan typedOther = other;
-    return text == typedOther.text;
-  }
-
-  int get hashCode => text.hashCode;
-
-  String toPlainText() => text;
-  String toString([String prefix = '']) => '$prefix$runtimeType: "$text"';
-}
-
-/// An immutable text span that applies a style to a list of children.
-class StyledTextSpan extends TextSpan {
-  const StyledTextSpan(this.style, this.children);
-
-  /// The style to apply to the children.
-  final TextStyle style;
-
-  /// The children to which the style is applied.
+  /// Additional spans to include as children.
+  ///
+  /// If both text and children are non-null, the text will preceed the
+  /// children.
   final List<TextSpan> children;
 
   void build(ui.ParagraphBuilder builder) {
-    assert(style != null);
-    assert(children != null);
+    final bool hasStyle = style != null;
+    if (hasStyle)
       builder.pushStyle(style.textStyle);
+    if (text != null)
+      builder.addText(text);
+    if (children != null) {
       for (TextSpan child in children) {
         assert(child != null);
         child.build(builder);
       }
+    }
+    if (hasStyle)
       builder.pop();
   }
 
-  ui.ParagraphStyle get paragraphStyle => style.paragraphStyle;
+  void writePlainText(StringBuffer result) {
+    if (text != null)
+      result.write(text);
+    if (children != null) {
+      for (TextSpan child in children)
+        child.writePlainText(result);
+    }
+  }
+
+  String toString([String prefix = '']) {
+    StringBuffer buffer = new StringBuffer();
+    buffer.writeln('$prefix$runtimeType:');
+    String indent = '$prefix  ';
+    buffer.writeln(style.toString(indent));
+    if (text != null)
+      buffer.writeln('$indent"$text"');
+    for (TextSpan child in children)
+      buffer.writeln(child.toString(indent));
+    return buffer.toString();
+  }
 
   bool operator ==(dynamic other) {
     if (identical(this, other))
       return true;
-    if (other is! StyledTextSpan)
+    if (other is! TextSpan)
       return false;
-    final StyledTextSpan typedOther = other;
-    if (style != typedOther.style ||
-        children.length != typedOther.children.length)
+    final TextSpan typedOther = other;
+    if (typedOther.text != text)
       return false;
+    if (typedOther.style != style)
+      return false;
+    if ((typedOther.children == null) != (children == null))
+      return false;
+    if (children != null) {
       for (int i = 0; i < children.length; ++i) {
-      if (children[i] != typedOther.children[i])
+        if (typedOther.children[i] != children[i])
           return false;
       }
-    return true;
     }
-
-  int get hashCode => hashValues(style, hashList(children));
-
-  String toPlainText() => children.map((TextSpan child) => child.toPlainText()).join();
-
-  String toString([String prefix = '']) {
-    List<String> result = <String>[];
-    result.add('$prefix$runtimeType:');
-    var indent = '$prefix  ';
-    result.add('${style.toString(indent)}');
-    for (TextSpan child in children)
-      result.add(child.toString(indent));
-    return result.join('\n');
+    return true;
   }
+  int get hashCode => hashValues(style, text, hashList(children));
 }
 
 /// An object that paints a [TextSpan] into a canvas.
@@ -115,7 +109,7 @@ class TextPainter {
     _text = value;
     ui.ParagraphBuilder builder = new ui.ParagraphBuilder();
     _text.build(builder);
-    _paragraph = builder.build(_text.paragraphStyle ?? new ui.ParagraphStyle());
+    _paragraph = builder.build(_text.style?.paragraphStyle ?? new ui.ParagraphStyle());
     _needsLayout = true;
   }
 

packages/flutter/lib/src/rendering/editable_line.dart

@@ -19,7 +19,7 @@ final String _kZeroWidthSpace = new String.fromCharCode(0x200B);
 /// A single line of editable text.
 class RenderEditableLine extends RenderBox {
   RenderEditableLine({
-    StyledTextSpan text,
+    TextSpan text,
     Color cursorColor,
     bool showCursor: false,
     Color selectionColor,
@@ -49,12 +49,12 @@ class RenderEditableLine extends RenderBox {
   ValueChanged<TextSelection> onSelectionChanged;
 
   /// The text to display
-  StyledTextSpan get text => _textPainter.text;
+  TextSpan get text => _textPainter.text;
   final TextPainter _textPainter;
-  void set text(StyledTextSpan value) {
+  void set text(TextSpan value) {
     if (_textPainter.text == value)
       return;
-    StyledTextSpan oldStyledText = _textPainter.text;
+    TextSpan oldStyledText = _textPainter.text;
     if (oldStyledText.style != value.style)
       _layoutTemplate = null;
     _textPainter.text = value;

packages/flutter/lib/src/rendering/paragraph.dart

@@ -100,7 +100,9 @@ class RenderParagraph extends RenderBox {
 
   Iterable<SemanticAnnotator> getSemanticAnnotators() sync* {
     yield (SemanticsNode node) {
-      node.label = text.toPlainText();
+      StringBuffer buffer = new StringBuffer();
+      text.writePlainText(buffer);
+      node.label = buffer.toString();
     };
   }
 

packages/flutter/lib/src/widgets/basic.dart

@@ -1405,12 +1405,12 @@ class Flexible extends ParentDataWidget<Flex> {
   }
 }
 
-/// A raw paragraph of text.
+/// A paragraph of rich text.
 ///
 /// This class is rarely used directly. Instead, consider using [Text], which
 /// integrates with [DefaultTextStyle].
-class RawText extends LeafRenderObjectWidget {
-  RawText({ Key key, this.text }) : super(key: key) {
+class RichText extends LeafRenderObjectWidget {
+  RichText({ Key key, this.text }) : super(key: key) {
     assert(text != null);
   }
 
@@ -1418,45 +1418,11 @@ class RawText extends LeafRenderObjectWidget {
 
   RenderParagraph createRenderObject() => new RenderParagraph(text);
 
-  void updateRenderObject(RenderParagraph renderObject, RawText oldWidget) {
+  void updateRenderObject(RenderParagraph renderObject, RichText oldWidget) {
     renderObject.text = text;
   }
 }
 
-/// A convience widget for paragraphs of text with heterogeneous style.
-///
-/// The elements parameter is a recursive list of lists that matches the
-/// following grammar:
-///
-///   `elements ::= "string" | [<text-style> <elements>*]``
-///
-/// Where "string" is text to display and text-style is an instance of
-/// TextStyle. The text-style applies to all of the elements that follow.
-class StyledText extends StatelessComponent {
-  StyledText({ this.elements, Key key }) : super(key: key) {
-    assert(_toSpan(elements) != null);
-  }
-
-  /// The recursive list of lists that describes the text and style to paint.
-  final dynamic elements;
-
-  TextSpan _toSpan(dynamic element) {
-    if (element is String)
-      return new PlainTextSpan(element);
-    if (element is Iterable) {
-      dynamic first = element.first;
-      if (first is! TextStyle)
-        throw new ArgumentError("First element of Iterable is a ${first.runtimeType} not a TextStyle");
-      return new StyledTextSpan(first, element.skip(1).map(_toSpan).toList());
-    }
-    throw new ArgumentError("Element is ${element.runtimeType} not a String or an Iterable");
-  }
-
-  Widget build(BuildContext context) {
-    return new RawText(text: _toSpan(elements));
-  }
-}
-
 /// The text style to apply to descendant [Text] widgets without explicit style.
 class DefaultTextStyle extends InheritedWidget {
   DefaultTextStyle({
@@ -1504,17 +1470,20 @@ class Text extends StatelessComponent {
   /// replace the closest enclosing [DefaultTextStyle].
   final TextStyle style;
 
+  TextStyle _getEffectiveStyle(BuildContext context) {
+    if (style == null || style.inherit)
+      return DefaultTextStyle.of(context)?.merge(style) ?? style;
+    else
+      return style;
+  }
+
   Widget build(BuildContext context) {
-    TextSpan text = new PlainTextSpan(data);
-    TextStyle combinedStyle;
-    if (style == null || style.inherit) {
-      combinedStyle = DefaultTextStyle.of(context)?.merge(style) ?? style;
-    } else {
-      combinedStyle = style;
-    }
-    if (combinedStyle != null)
-      text = new StyledTextSpan(combinedStyle, <TextSpan>[text]);
-    return new RawText(text: text);
+    return new RichText(
+      text: new TextSpan(
+        style: _getEffectiveStyle(context),
+        text: data
+      )
+    );
   }
 
   void debugFillDescription(List<String> description) {

packages/flutter/lib/src/widgets/checked_mode_banner.dart

@@ -25,7 +25,7 @@ class _CheckedModeBannerPainter extends CustomPainter {
   );
 
   static final TextPainter textPainter = new TextPainter()
-    ..text = new StyledTextSpan(kTextStyles, <TextSpan>[new PlainTextSpan('SLOW MODE')])
+    ..text = new TextSpan(style: kTextStyles, text: 'SLOW MODE')
     ..maxWidth = kOffset * 2.0
     ..maxHeight = kHeight
     ..layout();

packages/flutter/lib/src/widgets/editable.dart

@@ -394,24 +394,27 @@ class _EditableLineWidget extends LeafRenderObjectWidget {
       ..paintOffset = paintOffset;
   }
 
-  StyledTextSpan get _styledTextSpan {
+  TextSpan get _styledTextSpan {
     if (!hideText && value.composing.isValid) {
       TextStyle composingStyle = style.merge(
         const TextStyle(decoration: TextDecoration.underline)
       );
 
-      return new StyledTextSpan(style, <TextSpan>[
-        new PlainTextSpan(value.composing.textBefore(value.text)),
-        new StyledTextSpan(composingStyle, <TextSpan>[
-          new PlainTextSpan(value.composing.textInside(value.text))
-        ]),
-        new PlainTextSpan(value.composing.textAfter(value.text))
+      return new TextSpan(
+        style: style,
+        children: <TextSpan>[
+          new TextSpan(text: value.composing.textBefore(value.text)),
+          new TextSpan(
+            style: composingStyle,
+            text: value.composing.textInside(value.text)
+          ),
+          new TextSpan(text: value.composing.textAfter(value.text))
       ]);
     }
 
     String text = value.text;
     if (hideText)
       text = new String.fromCharCodes(new List<int>.filled(text.length, 0x2022));
-    return new StyledTextSpan(style, <TextSpan>[ new PlainTextSpan(text) ]);
+    return new TextSpan(style: style, text: text);
   }
 }

packages/flutter/lib/src/widgets/semantics_debugger.dart

@@ -172,7 +172,7 @@ class _SemanticsDebuggerEntry {
     message = message.trim();
     if (message != '') {
       textPainter ??= new TextPainter();
-      textPainter.text = new StyledTextSpan(textStyles, <TextSpan>[new PlainTextSpan(message)]);
+      textPainter.text = new TextSpan(style: textStyles, text: message);
       textPainter.maxWidth = rect.width;
       textPainter.maxHeight = rect.height;
       textPainter.layout();

packages/flutter/test/rendering/block_test.dart

@@ -15,11 +15,9 @@ class TestBlockPainter extends Painter {
 void main() {
   test('block intrinsics', () {
     RenderParagraph paragraph = new RenderParagraph(
-      new StyledTextSpan(
-        new TextStyle(
-          height: 1.0
-        ),
-        <TextSpan>[new PlainTextSpan('Hello World')]
+      new TextSpan(
+        style: new TextStyle(height: 1.0),
+        text: 'Hello World'
       )
     );
     const BoxConstraints unconstrained = const BoxConstraints();

packages/flutter/test/rendering/overflow_test.dart

@@ -15,7 +15,7 @@ void main() {
 
     root = new RenderPositionedBox(
       child: new RenderCustomPaint(
-        child: child = text = new RenderParagraph(new PlainTextSpan('Hello World')),
+        child: child = text = new RenderParagraph(new TextSpan(text: 'Hello World')),
         painter: new TestCallbackPainter(
           onPaint: () {
             baseline1 = child.getDistanceToBaseline(TextBaseline.alphabetic);
@@ -29,7 +29,7 @@ void main() {
     root = new RenderPositionedBox(
       child: new RenderCustomPaint(
         child: child = new RenderOverflowBox(
-          child: text = new RenderParagraph(new PlainTextSpan('Hello World')),
+          child: text = new RenderParagraph(new TextSpan(text: 'Hello World')),
           maxHeight: height1 / 2.0,
           alignment: const FractionalOffset(0.0, 0.0)
         ),

packages/flutter_sprites/lib/src/label.dart

@@ -35,9 +35,7 @@ class Label extends Node {
 
   void paint(Canvas canvas) {
     if (_painter == null) {
-      PlainTextSpan textSpan = new PlainTextSpan(_text);
-      StyledTextSpan styledTextSpan = new StyledTextSpan(_textStyle, <TextSpan>[textSpan]);
-      _painter = new TextPainter(styledTextSpan);
+      _painter = new TextPainter(new TextSpan(style: _textStyle, text: _text));
 
       _painter.maxWidth = double.INFINITY;
       _painter.minWidth = 0.0;

packages/playfair/lib/src/base.dart

@@ -166,9 +166,9 @@ class ChartPainter {
         ..value = _roundToPlaces(data.startY + stepSize * i, data.roundToPlaces);
       if (gridline.value < data.startY || gridline.value > data.endY)
         continue;  // TODO(jackson): Align things so this doesn't ever happen
-      TextSpan text = new StyledTextSpan(
-        _textTheme.body1,
-        [new PlainTextSpan("${gridline.value}")]
+      TextSpan text = new TextSpan(
+        style: _textTheme.body1,
+        text: '${gridline.value}'
       );
       gridline.labelPainter = new TextPainter(text)
         ..maxWidth = _rect.width
@@ -213,9 +213,9 @@ class ChartPainter {
         ..start = _convertPointToRectSpace(new Point(data.startX, data.indicatorLine), markerRect)
         ..end = _convertPointToRectSpace(new Point(data.endX, data.indicatorLine), markerRect);
       if (data.indicatorText != null) {
-        TextSpan text = new StyledTextSpan(
-          _textTheme.body1,
-          <TextSpan>[new PlainTextSpan("${data.indicatorText}")]
+        TextSpan text = new TextSpan(
+          style: _textTheme.body1,
+          text: '${data.indicatorText}'
         );
         _indicator.labelPainter = new TextPainter(text)
           ..maxWidth = markerRect.width