feat: Add support for styles propagating through the text node tree (#1915)

This PR continues the work for enabling rich text support within Flame.
Here I add support for different text fragments having different TextStyles, and allow those styles to be inheritable within the text node tree.

examples/lib/stories/rendering/rich_text_example.dart

@@ -11,7 +11,7 @@ class RichTextExample extends FlameGame {
 
   @override
   Future<void> onLoad() async {
-    add(MyTextComponent()..position = Vector2.all(100));
+    add(MyTextComponent()..position = Vector2(100, 50));
   }
 }
 
@@ -29,8 +29,7 @@ class MyTextComponent extends PositionComponent {
         borderColor: const Color(0xFF000000),
         borderWidth: 2.0,
       ),
-      paragraphStyle: BlockStyle(
-        margin: const EdgeInsets.symmetric(vertical: 6),
+      paragraph: BlockStyle(
         padding: const EdgeInsets.symmetric(vertical: 2, horizontal: 6),
         background: BackgroundStyle(
           color: const Color(0xFFFFF0CB),
@@ -39,6 +38,7 @@ class MyTextComponent extends PositionComponent {
       ),
     );
     final document = DocumentNode([
+      HeaderNode.simple('1984', level: 1),
       ParagraphNode.simple(
         'Anything could be true. The so-called laws of nature were nonsense.',
       ),
@@ -48,11 +48,16 @@ class MyTextComponent extends PositionComponent {
         'out. "If he thinks he floats off the floor, and I simultaneously '
         'think I can see him do it, then the thing happens."',
       ),
-      ParagraphNode.simple(
-        'Suddenly, like a lump of submerged wreckage breaking the surface of '
-        'water, the thought burst into his mind: "It doesn\'t really happen. '
-        'We imagine it. It is hallucination."',
-      ),
+      ParagraphNode.group([
+        PlainTextNode(
+            'Suddenly, like a lump of submerged wreckage breaking the surface '
+            'of water, the thought burst into his mind: '),
+        ItalicTextNode.group([
+          PlainTextNode('"It doesn\'t really happen. We imagine it. It is '),
+          BoldTextNode.simple('hallucination'),
+          PlainTextNode('."'),
+        ]),
+      ]),
       ParagraphNode.simple(
         'He pushed the thought under instantly. The fallacy was obvious. It '
         'presupposed that somewhere or other, outside oneself, there was a '

packages/flame/lib/src/components/text_component.dart

@@ -46,8 +46,8 @@ class TextComponent<T extends TextRenderer> extends PositionComponent {
     if (_textRenderer is FormatterTextRenderer) {
       _textElement =
           (_textRenderer as FormatterTextRenderer).formatter.format(_text);
-      final measurements = _textElement!.lastLine.metrics;
-      _textElement!.lastLine.translate(0, measurements.ascent);
+      final measurements = _textElement!.metrics;
+      _textElement!.translate(0, measurements.ascent);
       size.setValues(measurements.width, measurements.height);
     } else {
       final expectedSize = textRenderer.measureText(_text);

packages/flame/lib/src/text/common/line_metrics.dart

@@ -1,8 +1,6 @@
 import 'dart:ui';
 
-import 'package:flame/src/text/common/text_line.dart';
-
-/// The [LineMetrics] object contains measurements of a [TextLine].
+/// The [LineMetrics] object contains measurements of a text line.
 ///
 /// A line of text can be thought of as surrounded by a box (rect) that outlines
 /// the boundaries of the text, plus there is a [baseline] inside the box which

packages/flame/lib/src/text/common/text_line.dart

@@ -1,15 +0,0 @@
-import 'package:flame/src/text/common/line_metrics.dart';
-import 'package:flame/src/text/elements/text_element.dart';
-
-/// [TextLine] is an abstract class describing a single line (or a fragment of
-/// a line) of a laid-out text.
-///
-/// More specifically, after any [TextElement] has been laid out, its layout
-/// will be described by one or more [TextLine]s.
-abstract class TextLine {
-  /// The dimensions of this line.
-  LineMetrics get metrics;
-
-  /// Move the text within this [TextLine] by the specified offsets [dx], [dy].
-  void translate(double dx, double dy);
-}

packages/flame/lib/src/text/common/utils.dart

@@ -1,5 +1,10 @@
 import 'dart:math';
 
+import 'package:flame/src/text/elements/element.dart';
+import 'package:flame/src/text/elements/group_element.dart';
+import 'package:flame/src/text/elements/rect_element.dart';
+import 'package:flame/src/text/elements/rrect_element.dart';
+import 'package:flame/src/text/styles/background_style.dart';
 import 'package:meta/meta.dart';
 
 @internal
@@ -10,3 +15,51 @@ double collapseMargin(double margin1, double margin2) {
     return (margin2 < 0) ? min(margin1, margin2) : margin1 + margin2;
   }
 }
+
+@internal
+Element? makeBackground(BackgroundStyle? style, double width, double height) {
+  if (style == null) {
+    return null;
+  }
+  final out = <Element>[];
+  final backgroundPaint = style.backgroundPaint;
+  final borderPaint = style.borderPaint;
+  final borders = style.borderWidths;
+  final radius = style.borderRadius;
+
+  if (backgroundPaint != null) {
+    if (radius == 0) {
+      out.add(RectElement(width, height, backgroundPaint));
+    } else {
+      out.add(RRectElement(width, height, radius, backgroundPaint));
+    }
+  }
+  if (borderPaint != null) {
+    if (radius == 0) {
+      out.add(
+        RectElement(
+          width - borders.horizontal / 2,
+          height - borders.vertical / 2,
+          borderPaint,
+        )..translate(borders.left / 2, borders.top / 2),
+      );
+    } else {
+      out.add(
+        RRectElement(
+          width - borders.horizontal / 2,
+          height - borders.vertical / 2,
+          radius,
+          borderPaint,
+        )..translate(borders.left / 2, borders.top / 2),
+      );
+    }
+  }
+  if (out.isEmpty) {
+    return null;
+  }
+  if (out.length == 1) {
+    return out.first;
+  } else {
+    return GroupElement(width: width, height: height, children: out);
+  }
+}

packages/flame/lib/src/text/elements/block_element.dart

@@ -7,6 +7,7 @@ import 'package:flame/src/text/elements/element.dart';
 /// such as `<div>` or `<blockquote>`.
 abstract class BlockElement extends Element {
   BlockElement(this.width, this.height);
-  double width;
-  double height;
+
+  final double width;
+  final double height;
 }

packages/flame/lib/src/text/elements/debug_text_painter_text_element.dart

@@ -1,6 +1,6 @@
 import 'dart:ui';
 
-import 'package:flame/src/text/inline/text_painter_text_element.dart';
+import 'package:flame/src/text/elements/text_painter_text_element.dart';
 
 /// Replacement class for [TextPainterTextElement] which draws solid rectangles
 /// instead of regular text.

packages/flame/lib/src/text/elements/element.dart

@@ -1,15 +1,17 @@
 import 'dart:ui';
+import 'package:flame/src/text/styles/style.dart';
 
-/// An [Element] is a basic building block of a rich-text document.
+/// An [Element] is a basic rendering block of a rich-text document.
 ///
 /// Elements are concrete and "physical": they are objects that are ready to be
 /// rendered on a canvas. This property distinguishes them from Nodes (which are
-/// structured pieces of text), and from Styles (which are descriptors for how
+/// structured pieces of text), and from [Style]s (which are descriptors for how
 /// arbitrary pieces of text ought to be rendered).
 ///
 /// Elements are at the final stage of the text rendering pipeline, they are
 /// created during the layout step.
 abstract class Element {
+  /// Moves the element by ([dx], [dy]) relative to its current location.
   void translate(double dx, double dy);
 
   /// Renders the element on the [canvas], at coordinates determined during the
@@ -17,6 +19,6 @@ abstract class Element {
   ///
   /// In order to render the element at a different location, consider either
   /// calling the [translate] method, or applying a translation transform to the
-  /// canvas beforehand.
+  /// canvas itself.
   void render(Canvas canvas);
 }

packages/flame/lib/src/text/elements/group_element.dart

@@ -1,10 +1,13 @@
-import 'dart:ui';
-
 import 'package:flame/src/text/elements/block_element.dart';
 import 'package:flame/src/text/elements/element.dart';
+import 'package:flutter/rendering.dart' hide TextStyle;
 
 class GroupElement extends BlockElement {
-  GroupElement(super.width, super.height, this.children);
+  GroupElement({
+    required double width,
+    required double height,
+    required this.children,
+  }) : super(width, height);
 
   final List<Element> children;
 

packages/flame/lib/src/text/elements/group_text_element.dart

@@ -0,0 +1,48 @@
+import 'dart:math';
+import 'dart:ui';
+
+import 'package:flame/src/text/common/line_metrics.dart';
+import 'package:flame/src/text/elements/text_element.dart';
+
+class GroupTextElement extends TextElement {
+  GroupTextElement(List<TextElement> children)
+      : assert(children.isNotEmpty, 'The children list cannot be empty'),
+        _children = children,
+        _metrics = _computeMetrics(children);
+
+  final List<TextElement> _children;
+  final LineMetrics _metrics;
+
+  @override
+  LineMetrics get metrics => _metrics;
+
+  @override
+  void render(Canvas canvas) {
+    for (final child in _children) {
+      child.render(canvas);
+    }
+  }
+
+  @override
+  void translate(double dx, double dy) {
+    _metrics.translate(dx, dy);
+    for (final child in _children) {
+      child.translate(dx, dy);
+    }
+  }
+
+  static LineMetrics _computeMetrics(List<TextElement> elements) {
+    var width = 0.0;
+    var ascent = 0.0;
+    var descent = 0.0;
+    for (final element in elements) {
+      final metrics = element.metrics;
+      assert(metrics.left == width);
+      assert(metrics.baseline == 0);
+      width += metrics.width;
+      ascent = max(ascent, metrics.ascent);
+      descent = max(descent, metrics.descent);
+    }
+    return LineMetrics(width: width, ascent: ascent, descent: descent);
+  }
+}

packages/flame/lib/src/text/elements/sprite_font_text_element.dart

@@ -2,10 +2,9 @@ import 'dart:typed_data';
 import 'dart:ui';
 
 import 'package:flame/src/text/common/line_metrics.dart';
-import 'package:flame/src/text/common/text_line.dart';
 import 'package:flame/src/text/elements/text_element.dart';
 
-class SpriteFontTextElement extends TextElement implements TextLine {
+class SpriteFontTextElement extends TextElement {
   SpriteFontTextElement({
     required this.source,
     required this.transforms,
@@ -20,9 +19,6 @@ class SpriteFontTextElement extends TextElement implements TextLine {
   final Paint paint;
   final LineMetrics _box;
 
-  @override
-  TextLine get lastLine => this;
-
   @override
   LineMetrics get metrics => _box;
 

packages/flame/lib/src/text/elements/text_element.dart

@@ -1,12 +1,9 @@
-import 'package:flame/src/text/common/text_line.dart';
+import 'package:flame/src/text/common/line_metrics.dart';
 import 'package:flame/src/text/elements/element.dart';
 
-/// [TextElement] is the base class describing a span of text that has *inline*
-/// placement rules.
-///
-/// Concrete implementations of this class must know how to perform own layout
-/// (i.e. determine the exact placement and size of each internal piece), and
-/// then render on a canvas afterwards.
+/// [TextElement] is the base class that represents a single line of text, laid
+/// out and prepared for rendering.
 abstract class TextElement extends Element {
-  TextLine get lastLine;
+  /// The dimensions of this line.
+  LineMetrics get metrics;
 }

packages/flame/lib/src/text/elements/text_painter_text_element.dart

@@ -1,29 +1,25 @@
 import 'dart:ui';
 
 import 'package:flame/src/text/common/line_metrics.dart';
-import 'package:flame/src/text/common/text_line.dart';
-import 'package:flame/src/text/elements/element.dart';
 import 'package:flame/src/text/elements/text_element.dart';
-import 'package:flutter/rendering.dart' show TextBaseline, TextPainter;
+import 'package:flutter/rendering.dart' as flutter;
 
-class TextPainterTextElement extends TextElement implements TextLine, Element {
+class TextPainterTextElement extends TextElement {
   TextPainterTextElement(this._textPainter)
       : _box = LineMetrics(
-          ascent: _textPainter
-              .computeDistanceToActualBaseline(TextBaseline.alphabetic),
+          ascent: _textPainter.computeDistanceToActualBaseline(
+            flutter.TextBaseline.alphabetic,
+          ),
           width: _textPainter.width,
           height: _textPainter.height,
         );
 
-  final TextPainter _textPainter;
+  final flutter.TextPainter _textPainter;
   final LineMetrics _box;
 
   @override
   LineMetrics get metrics => _box;
 
-  @override
-  TextLine get lastLine => this;
-
   @override
   void translate(double dx, double dy) => _box.translate(dx, dy);
 

packages/flame/lib/src/text/formatter_text_renderer.dart

@@ -12,7 +12,7 @@ class FormatterTextRenderer<T extends TextFormatter> extends TextRenderer {
 
   @override
   Vector2 measureText(String text) {
-    final box = formatter.format(text).lastLine.metrics;
+    final box = formatter.format(text).metrics;
     return Vector2(box.width, box.height);
   }
 
@@ -24,8 +24,8 @@ class FormatterTextRenderer<T extends TextFormatter> extends TextRenderer {
     Anchor anchor = Anchor.topLeft,
   }) {
     final txt = formatter.format(text);
-    final box = txt.lastLine.metrics;
-    txt.lastLine.translate(
+    final box = txt.metrics;
+    txt.translate(
       position.x - box.width * anchor.x,
       position.y - box.height * anchor.y - box.top,
     );

packages/flame/lib/src/text/formatters/sprite_font_text_formatter.dart

@@ -5,9 +5,9 @@ import 'package:flame/src/text/common/glyph.dart';
 import 'package:flame/src/text/common/glyph_data.dart';
 import 'package:flame/src/text/common/line_metrics.dart';
 import 'package:flame/src/text/common/sprite_font.dart';
+import 'package:flame/src/text/elements/sprite_font_text_element.dart';
 import 'package:flame/src/text/elements/text_element.dart';
 import 'package:flame/src/text/formatters/text_formatter.dart';
-import 'package:flame/src/text/inline/sprite_font_text_element.dart';
 
 class SpriteFontTextFormatter extends TextFormatter {
   @Deprecated('Use SpriteFontTextFormatter.fromFont() instead; this '

packages/flame/lib/src/text/formatters/text_painter_text_formatter.dart

@@ -1,6 +1,6 @@
+import 'package:flame/src/text/elements/debug_text_painter_text_element.dart';
+import 'package:flame/src/text/elements/text_painter_text_element.dart';
 import 'package:flame/src/text/formatters/text_formatter.dart';
-import 'package:flame/src/text/inline/debug_text_painter_text_element.dart';
-import 'package:flame/src/text/inline/text_painter_text_element.dart';
 import 'package:flutter/rendering.dart';
 
 /// [TextPainterTextFormatter] applies a Flutter [TextStyle] to a string of
@@ -16,7 +16,7 @@ class TextPainterTextFormatter extends TextFormatter {
         this.debugMode = false,
   });
 
-  final TextStyle style;
+  final TextStyle style; // NOTE: this is a Flutter TextStyle
   final TextDirection textDirection;
   @Deprecated('Use DebugTextFormatter instead. Will be removed in 1.5.0')
   final bool debugMode;

packages/flame/lib/src/text/nodes.dart

@@ -1,41 +0,0 @@
-import 'package:flame/src/text/nodes/block_node.dart';
-
-class GroupBlockNode extends BlockNode {
-  GroupBlockNode(this.children);
-
-  final List<BlockNode> children;
-}
-
-class BlockquoteNode extends GroupBlockNode {
-  BlockquoteNode(super.children);
-}
-
-abstract class TextNode {}
-
-class PlainTextNode extends TextNode {
-  PlainTextNode(this.text);
-
-  final String text;
-}
-
-class GroupTextNode extends TextNode {
-  GroupTextNode(this.children);
-
-  final List<TextNode> children;
-}
-
-class BoldTextNode extends GroupTextNode {
-  BoldTextNode(super.children);
-}
-
-class ItalicTextNode extends GroupTextNode {
-  ItalicTextNode(super.children);
-}
-
-class StrikethroughTextNode extends GroupTextNode {
-  StrikethroughTextNode(super.children);
-}
-
-class HighlightedTextNode extends GroupTextNode {
-  HighlightedTextNode(super.children);
-}

packages/flame/lib/src/text/nodes/block_node.dart

@@ -1,55 +1,20 @@
-import 'package:flame/src/text/elements/element.dart';
-import 'package:flame/src/text/elements/group_element.dart';
-import 'package:flame/src/text/elements/rect_element.dart';
-import 'package:flame/src/text/elements/rrect_element.dart';
-import 'package:flame/src/text/styles/background_style.dart';
+import 'package:flame/src/text/elements/block_element.dart';
+import 'package:flame/src/text/styles/block_style.dart';
+import 'package:flame/src/text/styles/document_style.dart';
+import 'package:flame/src/text/styles/flame_text_style.dart';
 
-/// An abstract base class for all entities with "block" placement rules.
+/// [BlockNode] is a base class for all nodes with "block" placement rules; it
+/// roughly corresponds to `<div/>` in HTML.
+///
+/// A block node should be able to find its style in the root stylesheet, via
+/// the method [fillStyles], and then based on that style build the
+/// corresponding element in the [format] method. Both of these methods must be
+/// implemented by subclasses.
 abstract class BlockNode {
-  Element? makeBackground(BackgroundStyle? style, double width, double height) {
-    if (style == null) {
-      return null;
-    }
-    final out = <Element>[];
-    final backgroundPaint = style.backgroundPaint;
-    final borderPaint = style.borderPaint;
-    final borders = style.borderWidths;
-    final radius = style.borderRadius;
+  /// The runtime style applied to this node, this will be set by [fillStyles].
+  late BlockStyle style;
 
-    if (backgroundPaint != null) {
-      if (radius == 0) {
-        out.add(RectElement(width, height, backgroundPaint));
-      } else {
-        out.add(RRectElement(width, height, radius, backgroundPaint));
-      }
-    }
-    if (borderPaint != null) {
-      if (radius == 0) {
-        out.add(
-          RectElement(
-            width - borders.horizontal / 2,
-            height - borders.vertical / 2,
-            borderPaint,
-          )..translate(borders.left / 2, borders.top / 2),
-        );
-      } else {
-        out.add(
-          RRectElement(
-            width - borders.horizontal / 2,
-            height - borders.vertical / 2,
-            radius,
-            borderPaint,
-          )..translate(borders.left / 2, borders.top / 2),
-        );
-      }
-    }
-    if (out.isEmpty) {
-      return null;
-    }
-    if (out.length == 1) {
-      return out.first;
-    } else {
-      return GroupElement(width, height, out);
-    }
-  }
+  BlockElement format(double availableWidth);
+
+  void fillStyles(DocumentStyle stylesheet, FlameTextStyle parentTextStyle);
 }

packages/flame/lib/src/text/nodes/bold_text_node.dart

@@ -0,0 +1,29 @@
+import 'dart:ui';
+
+import 'package:flame/src/text/nodes/group_text_node.dart';
+import 'package:flame/src/text/nodes/plain_text_node.dart';
+import 'package:flame/src/text/nodes/text_node.dart';
+import 'package:flame/src/text/styles/document_style.dart';
+import 'package:flame/src/text/styles/flame_text_style.dart';
+import 'package:flame/src/text/styles/style.dart';
+
+class BoldTextNode extends TextNode {
+  BoldTextNode(this.child);
+
+  BoldTextNode.simple(String text) : child = PlainTextNode(text);
+
+  BoldTextNode.group(List<TextNode> children) : child = GroupTextNode(children);
+
+  final TextNode child;
+
+  static final defaultStyle = FlameTextStyle(fontWeight: FontWeight.bold);
+
+  @override
+  void fillStyles(DocumentStyle stylesheet, FlameTextStyle parentTextStyle) {
+    textStyle = Style.merge(parentTextStyle, stylesheet.boldText)!;
+    child.fillStyles(stylesheet, textStyle);
+  }
+
+  @override
+  TextNodeLayoutBuilder get layoutBuilder => child.layoutBuilder;
+}

packages/flame/lib/src/text/nodes/column_node.dart

@@ -0,0 +1,64 @@
+import 'package:flame/src/text/common/utils.dart';
+import 'package:flame/src/text/elements/block_element.dart';
+import 'package:flame/src/text/elements/element.dart';
+import 'package:flame/src/text/elements/group_element.dart';
+import 'package:flame/src/text/nodes/block_node.dart';
+import 'package:flame/src/text/styles/document_style.dart';
+import 'package:flame/src/text/styles/flame_text_style.dart';
+import 'package:meta/meta.dart';
+
+/// [ColumnNode] is a block node containing other block nodes arranged as a
+/// column.
+///
+/// During formatting, produces an element which is as wide as the available
+/// width, and tall enough to fit all the available children elements.
+abstract class ColumnNode extends BlockNode {
+  ColumnNode(this.children);
+
+  final List<BlockNode> children;
+
+  @override
+  BlockElement format(double availableWidth) {
+    final out = <Element>[];
+    final blockWidth = availableWidth;
+    final padding = style.padding;
+
+    var verticalOffset = 0.0;
+    var currentMargin = padding.top;
+    for (final node in children) {
+      final nodeMargins = node.style.margin;
+      final marginLeft = collapseMargin(padding.left, nodeMargins.left);
+      final marginRight = collapseMargin(padding.right, nodeMargins.right);
+      final nodeAvailableWidth = blockWidth - marginLeft - marginRight;
+      final nodeElement = node.format(nodeAvailableWidth);
+      out.add(nodeElement);
+
+      verticalOffset += collapseMargin(currentMargin, nodeMargins.top);
+      nodeElement.translate(marginLeft, verticalOffset);
+      verticalOffset += nodeElement.height;
+      currentMargin = nodeMargins.bottom;
+    }
+    // Do not collapse padding if there are no children.
+    final blockHeight = children.isEmpty
+        ? padding.vertical
+        : verticalOffset + collapseMargin(currentMargin, padding.bottom);
+    final background =
+        makeBackground(style.background, blockWidth, blockHeight);
+    if (background != null) {
+      out.insert(0, background);
+    }
+    return GroupElement(
+      width: blockWidth,
+      height: blockHeight,
+      children: out,
+    );
+  }
+
+  @mustCallSuper
+  @override
+  void fillStyles(DocumentStyle rootStyle, FlameTextStyle parentTextStyle) {
+    for (final node in children) {
+      node.fillStyles(rootStyle, parentTextStyle);
+    }
+  }
+}

packages/flame/lib/src/text/nodes/document_node.dart

@@ -3,13 +3,14 @@ import 'dart:math';
 import 'package:flame/src/text/common/utils.dart';
 import 'package:flame/src/text/elements/element.dart';
 import 'package:flame/src/text/elements/group_element.dart';
-import 'package:flame/src/text/nodes.dart';
-import 'package:flame/src/text/nodes/paragraph_node.dart';
+import 'package:flame/src/text/nodes/block_node.dart';
 import 'package:flame/src/text/styles/document_style.dart';
 import 'package:flutter/painting.dart';
 
-class DocumentNode extends GroupBlockNode {
-  DocumentNode(super.children);
+class DocumentNode {
+  DocumentNode(this.children);
+
+  final List<BlockNode> children;
 
   /// Applies [style] to this document, producing an object that can be rendered
   /// on a canvas. Parameters [width] and [height] serve as the fallback values
@@ -21,21 +22,19 @@ class DocumentNode extends GroupBlockNode {
       'Width must be either provided explicitly or set in the stylesheet',
     );
     final out = <Element>[];
-    final border = style.backgroundStyle?.borderWidths ?? EdgeInsets.zero;
+    final border = style.background?.borderWidths ?? EdgeInsets.zero;
     final padding = style.padding;
 
     final pageWidth = style.width ?? width!;
-    final contentWidth = pageWidth - padding.horizontal - border.horizontal;
-    final horizontalOffset = padding.left + border.left;
+    final contentWidth = pageWidth - padding.horizontal;
+    final horizontalOffset = padding.left;
     var verticalOffset = border.top;
     var currentMargin = padding.top;
     for (final node in children) {
-      final blockStyle = style.styleFor(node);
+      node.fillStyles(style, style.text);
+      final blockStyle = node.style;
       verticalOffset += collapseMargin(currentMargin, blockStyle.margin.top);
-      final nodeElement = (node as ParagraphNode).format(
-        blockStyle,
-        parentWidth: contentWidth,
-      );
+      final nodeElement = node.format(contentWidth);
       nodeElement.translate(horizontalOffset, verticalOffset);
       out.add(nodeElement);
       currentMargin = blockStyle.margin.bottom;
@@ -48,13 +47,13 @@ class DocumentNode extends GroupBlockNode {
           border.bottom,
     );
     final background = makeBackground(
-      style.backgroundStyle,
+      style.background,
       pageWidth,
       pageHeight,
     );
     if (background != null) {
       out.insert(0, background);
     }
-    return GroupElement(pageWidth, pageHeight, out);
+    return GroupElement(width: pageWidth, height: pageHeight, children: out);
   }
 }

packages/flame/lib/src/text/nodes/group_text_node.dart

@@ -0,0 +1,66 @@
+import 'package:flame/src/text/elements/group_text_element.dart';
+import 'package:flame/src/text/elements/text_element.dart';
+import 'package:flame/src/text/nodes/text_node.dart';
+import 'package:flame/src/text/styles/document_style.dart';
+import 'package:flame/src/text/styles/flame_text_style.dart';
+
+class GroupTextNode extends TextNode {
+  GroupTextNode(this.children);
+
+  final List<TextNode> children;
+
+  @override
+  void fillStyles(DocumentStyle stylesheet, FlameTextStyle parentTextStyle) {
+    textStyle = parentTextStyle;
+    for (final node in children) {
+      node.fillStyles(stylesheet, textStyle);
+    }
+  }
+
+  @override
+  TextNodeLayoutBuilder get layoutBuilder => _GroupTextLayoutBuilder(this);
+}
+
+class _GroupTextLayoutBuilder extends TextNodeLayoutBuilder {
+  _GroupTextLayoutBuilder(this.node);
+
+  final GroupTextNode node;
+  int _currentChildIndex = 0;
+  TextNodeLayoutBuilder? _currentChildBuilder;
+
+  @override
+  bool get isDone => _currentChildIndex == node.children.length;
+
+  @override
+  TextElement? layOutNextLine(double availableWidth) {
+    assert(!isDone);
+    final out = <TextElement>[];
+    var usedWidth = 0.0;
+    while (true) {
+      if (_currentChildBuilder?.isDone ?? false) {
+        _currentChildBuilder = null;
+        _currentChildIndex += 1;
+        if (_currentChildIndex == node.children.length) {
+          break;
+        }
+      }
+      _currentChildBuilder ??= node.children[_currentChildIndex].layoutBuilder;
+
+      final maybeLine =
+          _currentChildBuilder!.layOutNextLine(availableWidth - usedWidth);
+      if (maybeLine == null) {
+        break;
+      } else {
+        assert(maybeLine.metrics.left == 0 && maybeLine.metrics.baseline == 0);
+        maybeLine.translate(usedWidth, 0);
+        out.add(maybeLine);
+        usedWidth += maybeLine.metrics.width;
+      }
+    }
+    if (out.isEmpty) {
+      return null;
+    } else {
+      return GroupTextElement(out);
+    }
+  }
+}

packages/flame/lib/src/text/nodes/header_node.dart

@@ -1,9 +1,56 @@
-import 'package:flame/src/text/nodes.dart';
-import 'package:flame/src/text/nodes/block_node.dart';
+import 'dart:ui';
 
-class HeaderNode extends BlockNode {
-  HeaderNode(this.child, {required this.level});
+import 'package:flame/src/text/nodes/plain_text_node.dart';
+import 'package:flame/src/text/nodes/text_block_node.dart';
+import 'package:flame/src/text/styles/block_style.dart';
+import 'package:flame/src/text/styles/document_style.dart';
+import 'package:flame/src/text/styles/flame_text_style.dart';
+import 'package:flame/src/text/styles/style.dart';
+import 'package:flutter/rendering.dart' show EdgeInsets;
+
+class HeaderNode extends TextBlockNode {
+  HeaderNode(super.child, {required this.level});
+
+  HeaderNode.simple(String text, {required this.level})
+      : super(PlainTextNode(text));
 
-  final GroupTextNode child;
   final int level;
+
+  static BlockStyle defaultStyleH1 = BlockStyle(
+    text: FlameTextStyle(fontScale: 2.0, fontWeight: FontWeight.bold),
+    margin: const EdgeInsets.fromLTRB(0, 24, 0, 12),
+  );
+  static BlockStyle defaultStyleH2 = BlockStyle(
+    text: FlameTextStyle(fontScale: 1.5, fontWeight: FontWeight.bold),
+    margin: const EdgeInsets.fromLTRB(0, 24, 0, 8),
+  );
+  static BlockStyle defaultStyleH3 = BlockStyle(
+    text: FlameTextStyle(fontScale: 1.25, fontWeight: FontWeight.bold),
+  );
+  static BlockStyle defaultStyleH4 = BlockStyle(
+    text: FlameTextStyle(fontScale: 1.0, fontWeight: FontWeight.bold),
+  );
+  static BlockStyle defaultStyleH5 = BlockStyle(
+    text: FlameTextStyle(fontScale: 0.875, fontWeight: FontWeight.bold),
+  );
+  static BlockStyle defaultStyleH6 = BlockStyle(
+    text: FlameTextStyle(fontScale: 0.85, fontWeight: FontWeight.bold),
+  );
+
+  @override
+  void fillStyles(DocumentStyle stylesheet, FlameTextStyle parentTextStyle) {
+    style = level == 1
+        ? stylesheet.header1
+        : level == 2
+            ? stylesheet.header2
+            : level == 3
+                ? stylesheet.header3
+                : level == 4
+                    ? stylesheet.header4
+                    : level == 5
+                        ? stylesheet.header5
+                        : stylesheet.header6;
+    final textStyle = Style.merge(parentTextStyle, style.text)!;
+    super.fillStyles(stylesheet, textStyle);
+  }
 }

packages/flame/lib/src/text/nodes/italic_text_node.dart

@@ -0,0 +1,30 @@
+import 'dart:ui';
+
+import 'package:flame/src/text/nodes/group_text_node.dart';
+import 'package:flame/src/text/nodes/plain_text_node.dart';
+import 'package:flame/src/text/nodes/text_node.dart';
+import 'package:flame/src/text/styles/document_style.dart';
+import 'package:flame/src/text/styles/flame_text_style.dart';
+import 'package:flame/src/text/styles/style.dart';
+
+class ItalicTextNode extends TextNode {
+  ItalicTextNode(this.child);
+
+  ItalicTextNode.simple(String text) : child = PlainTextNode(text);
+
+  ItalicTextNode.group(List<TextNode> children)
+      : child = GroupTextNode(children);
+
+  final TextNode child;
+
+  static final defaultStyle = FlameTextStyle(fontStyle: FontStyle.italic);
+
+  @override
+  void fillStyles(DocumentStyle stylesheet, FlameTextStyle parentTextStyle) {
+    textStyle = Style.merge(parentTextStyle, stylesheet.italicText)!;
+    child.fillStyles(stylesheet, textStyle);
+  }
+
+  @override
+  TextNodeLayoutBuilder get layoutBuilder => child.layoutBuilder;
+}

packages/flame/lib/src/text/nodes/paragraph_node.dart

@@ -1,59 +1,29 @@
-import 'package:flame/src/text/elements/block_element.dart';
-import 'package:flame/src/text/elements/group_element.dart';
-import 'package:flame/src/text/formatters/text_painter_text_formatter.dart';
-import 'package:flame/src/text/inline/text_painter_text_element.dart';
-import 'package:flame/src/text/nodes.dart';
-import 'package:flame/src/text/nodes/block_node.dart';
+import 'package:flame/src/text/nodes/group_text_node.dart';
+import 'package:flame/src/text/nodes/plain_text_node.dart';
+import 'package:flame/src/text/nodes/text_block_node.dart';
+import 'package:flame/src/text/nodes/text_node.dart';
 import 'package:flame/src/text/styles/block_style.dart';
-import 'package:flutter/painting.dart' as painting;
+import 'package:flame/src/text/styles/document_style.dart';
+import 'package:flame/src/text/styles/flame_text_style.dart';
+import 'package:flame/src/text/styles/style.dart';
+import 'package:flutter/rendering.dart' show EdgeInsets;
 
-class ParagraphNode extends BlockNode {
-  ParagraphNode.simple(String text)
-      : child = GroupTextNode([PlainTextNode(text)]);
+class ParagraphNode extends TextBlockNode {
+  ParagraphNode(super.child);
 
-  final GroupTextNode child;
+  ParagraphNode.simple(String text) : super(PlainTextNode(text));
 
-  BlockElement format(BlockStyle style, {required double parentWidth}) {
-    final text = (child.children.first as PlainTextNode).text;
-    final formatter = TextPainterTextFormatter(
-      style: const painting.TextStyle(fontSize: 16),
-    );
-    final contentWidth = parentWidth - style.padding.horizontal;
-    final horizontalOffset = style.padding.left;
+  ParagraphNode.group(List<TextNode> fragments)
+      : super(GroupTextNode(fragments));
 
-    final words = text.split(' ');
-    final lines = <TextPainterTextElement>[];
-    var verticalOffset = style.padding.top;
-    var i0 = 0;
-    var i1 = 1;
-    var startNewLine = true;
-    while (i1 <= words.length) {
-      final lineText = words.sublist(i0, i1).join(' ');
-      final formattedLine = formatter.format(lineText);
-      if (formattedLine.metrics.width <= contentWidth || i1 - i0 == 1) {
-        formattedLine.translate(
-          horizontalOffset,
-          verticalOffset + formattedLine.metrics.ascent,
-        );
-        if (startNewLine) {
-          lines.add(formattedLine);
-          startNewLine = false;
-        } else {
-          lines[lines.length - 1] = formattedLine;
-        }
-        i1++;
-      } else {
-        i0 = i1 - 1;
-        startNewLine = true;
-        verticalOffset += lines.last.metrics.height;
-      }
-    }
-    if (!startNewLine) {
-      verticalOffset += lines.last.metrics.height;
-    }
-    verticalOffset += style.padding.bottom;
-    final bg = makeBackground(style.background, parentWidth, verticalOffset);
-    final elements = bg == null ? lines : [bg, ...lines];
-    return GroupElement(parentWidth, verticalOffset, elements);
+  static const defaultStyle = BlockStyle(
+    margin: EdgeInsets.all(6),
+  );
+
+  @override
+  void fillStyles(DocumentStyle stylesheet, FlameTextStyle parentTextStyle) {
+    style = stylesheet.paragraph;
+    final textStyle = Style.merge(parentTextStyle, style.text)!;
+    super.fillStyles(stylesheet, textStyle);
   }
 }

packages/flame/lib/src/text/nodes/plain_text_node.dart

@@ -0,0 +1,58 @@
+import 'package:flame/src/text/elements/text_element.dart';
+import 'package:flame/src/text/formatters/text_formatter.dart';
+import 'package:flame/src/text/nodes/text_node.dart';
+import 'package:flame/src/text/styles/document_style.dart';
+import 'package:flame/src/text/styles/flame_text_style.dart';
+
+class PlainTextNode extends TextNode {
+  PlainTextNode(this.text);
+
+  final String text;
+
+  @override
+  void fillStyles(DocumentStyle stylesheet, FlameTextStyle parentTextStyle) {
+    textStyle = parentTextStyle;
+  }
+
+  @override
+  TextNodeLayoutBuilder get layoutBuilder => _PlainTextLayoutBuilder(this);
+}
+
+class _PlainTextLayoutBuilder extends TextNodeLayoutBuilder {
+  _PlainTextLayoutBuilder(this.node)
+      : formatter = node.textStyle.asTextFormatter(),
+        words = node.text.split(' ');
+
+  final PlainTextNode node;
+  final TextFormatter formatter;
+  final List<String> words;
+  int index0 = 0;
+  int index1 = 1;
+
+  @override
+  bool get isDone => index1 > words.length;
+
+  @override
+  TextElement? layOutNextLine(double availableWidth) {
+    TextElement? tentativeLine;
+    int? tentativeIndex0;
+    while (index1 <= words.length) {
+      final textPiece = words.sublist(index0, index1).join(' ');
+      final formattedPiece = formatter.format(textPiece);
+      if (formattedPiece.metrics.width > availableWidth) {
+        break;
+      } else {
+        tentativeLine = formattedPiece;
+        tentativeIndex0 = index1;
+        index1 += 1;
+      }
+    }
+    if (tentativeLine != null) {
+      assert(tentativeIndex0 != 0 && tentativeIndex0! > index0);
+      index0 = tentativeIndex0!;
+      return tentativeLine;
+    } else {
+      return null;
+    }
+  }
+}

packages/flame/lib/src/text/nodes/text_block_node.dart

@@ -0,0 +1,58 @@
+import 'package:flame/src/text/common/utils.dart';
+import 'package:flame/src/text/elements/block_element.dart';
+import 'package:flame/src/text/elements/group_element.dart';
+import 'package:flame/src/text/elements/text_element.dart';
+import 'package:flame/src/text/nodes/block_node.dart';
+import 'package:flame/src/text/nodes/text_node.dart';
+import 'package:flame/src/text/styles/document_style.dart';
+import 'package:flame/src/text/styles/flame_text_style.dart';
+import 'package:meta/meta.dart';
+
+abstract class TextBlockNode extends BlockNode {
+  TextBlockNode(this.child);
+
+  final TextNode child;
+
+  @mustCallSuper
+  @override
+  void fillStyles(DocumentStyle stylesheet, FlameTextStyle parentTextStyle) {
+    child.fillStyles(stylesheet, parentTextStyle);
+  }
+
+  /// Converts this node into a [BlockElement].
+  ///
+  /// All late variables must be initialized prior to calling this method.
+  @override
+  BlockElement format(double availableWidth) {
+    final layoutBuilder = child.layoutBuilder;
+    final blockWidth = availableWidth;
+    final contentWidth = blockWidth - style.padding.horizontal;
+
+    final lines = <TextElement>[];
+    final horizontalOffset = style.padding.left;
+    var verticalOffset = style.padding.top;
+    while (!layoutBuilder.isDone) {
+      final element = layoutBuilder.layOutNextLine(contentWidth);
+      if (element == null) {
+        // Not enough horizontal space to lay out. For now we just stop the
+        // layout altogether cutting off the remainder of the content. But is
+        // there a better alternative?
+        break;
+      } else {
+        final metrics = element.metrics;
+        assert(metrics.left == 0 && metrics.baseline == 0);
+        element.translate(horizontalOffset, verticalOffset + metrics.ascent);
+        lines.add(element);
+        verticalOffset += metrics.height;
+      }
+    }
+    verticalOffset += style.padding.bottom;
+    final bg = makeBackground(style.background, blockWidth, verticalOffset);
+    final elements = bg == null ? lines : [bg, ...lines];
+    return GroupElement(
+      width: blockWidth,
+      height: verticalOffset,
+      children: elements,
+    );
+  }
+}

packages/flame/lib/src/text/nodes/text_node.dart

@@ -0,0 +1,16 @@
+import 'package:flame/src/text/elements/text_element.dart';
+import 'package:flame/src/text/styles/document_style.dart';
+import 'package:flame/src/text/styles/flame_text_style.dart';
+
+abstract class TextNode {
+  late FlameTextStyle textStyle;
+
+  void fillStyles(DocumentStyle stylesheet, FlameTextStyle parentTextStyle);
+
+  TextNodeLayoutBuilder get layoutBuilder;
+}
+
+abstract class TextNodeLayoutBuilder {
+  TextElement? layOutNextLine(double availableWidth);
+  bool get isDone;
+}

packages/flame/lib/src/text/styles/background_style.dart

@@ -1,6 +1,8 @@
 import 'package:flame/src/text/styles/style.dart';
 import 'package:flutter/rendering.dart';
+import 'package:meta/meta.dart';
 
+@immutable
 class BackgroundStyle extends Style {
   BackgroundStyle({
     Color? color,
@@ -13,45 +15,28 @@ class BackgroundStyle extends Style {
           'Parameters `paint` and `color` are exclusive',
         ),
         borderWidths = EdgeInsets.all(borderWidth ?? 0),
-        borderRadius = borderRadius ?? 0 {
-    if (paint != null) {
-      backgroundPaint = paint;
-    } else if (color != null) {
-      backgroundPaint = Paint()..color = color;
-    } else {
-      backgroundPaint = null;
-    }
-    if (borderColor != null) {
-      borderPaint = Paint()
-        ..color = borderColor
-        ..style = PaintingStyle.stroke
-        ..strokeWidth = borderWidth ?? 0;
-    } else {
-      borderPaint = null;
-    }
-  }
+        borderRadius = borderRadius ?? 0,
+        backgroundPaint =
+            paint ?? (color != null ? (Paint()..color = color) : null),
+        borderPaint = borderColor != null
+            ? (Paint()
+              ..color = borderColor
+              ..style = PaintingStyle.stroke
+              ..strokeWidth = borderWidth ?? 0)
+            : null;
 
-  late final Paint? backgroundPaint;
-  late final Paint? borderPaint;
+  final Paint? backgroundPaint;
+  final Paint? borderPaint;
   final double borderRadius;
   final EdgeInsets borderWidths;
 
   @override
-  BackgroundStyle clone() => copyWith();
-
-  BackgroundStyle copyWith({
-    Color? color,
-    Paint? paint,
-    Color? borderColor,
-    double? borderRadius,
-    double? borderWidth,
-  }) {
+  BackgroundStyle copyWith(BackgroundStyle other) {
     return BackgroundStyle(
-      color: color ?? (paint == null ? backgroundPaint?.color : null),
-      paint: paint ?? backgroundPaint,
-      borderColor: borderColor ?? borderPaint?.color,
-      borderRadius: borderRadius ?? this.borderRadius,
-      borderWidth: borderWidth ?? borderWidths.left,
+      paint: other.backgroundPaint ?? backgroundPaint,
+      borderColor: other.borderPaint?.color ?? borderPaint?.color,
+      borderRadius: other.borderRadius,
+      borderWidth: other.borderWidths.top,
     );
   }
 }

packages/flame/lib/src/text/styles/block_style.dart

@@ -1,30 +1,36 @@
 import 'package:flame/src/text/styles/background_style.dart';
+import 'package:flame/src/text/styles/flame_text_style.dart';
 import 'package:flame/src/text/styles/style.dart';
-import 'package:flutter/painting.dart';
+import 'package:flutter/painting.dart' hide TextStyle;
+import 'package:meta/meta.dart';
 
+/// [BlockStyle] is a generic descriptor for a visual appearance of a block-
+/// level element.
+@immutable
 class BlockStyle extends Style {
-  BlockStyle({
-    this.margin = EdgeInsets.zero,
-    this.padding = EdgeInsets.zero,
-    this.background,
-  });
-
-  EdgeInsets margin;
-  EdgeInsets padding;
-  BackgroundStyle? background;
-
-  @override
-  BlockStyle clone() => copyWith();
-
-  BlockStyle copyWith({
+  const BlockStyle({
     EdgeInsets? margin,
     EdgeInsets? padding,
-    BackgroundStyle? background,
-  }) {
+    this.background,
+    this.text,
+  })  : _margin = margin,
+        _padding = padding;
+
+  final EdgeInsets? _margin;
+  final EdgeInsets? _padding;
+  final BackgroundStyle? background;
+  final FlameTextStyle? text;
+
+  EdgeInsets get margin => _margin ?? EdgeInsets.zero;
+  EdgeInsets get padding => _padding ?? EdgeInsets.zero;
+
+  @override
+  BlockStyle copyWith(BlockStyle other) {
     return BlockStyle(
-      margin: margin ?? this.margin,
-      padding: padding ?? this.padding,
-      background: background ?? this.background,
+      margin: other._margin ?? _margin,
+      padding: other._padding ?? _padding,
+      background: other.background ?? background,
+      text: Style.merge(text, other.text),
     );
   }
 }

packages/flame/lib/src/text/styles/document_style.dart

@@ -1,12 +1,13 @@
-import 'package:flame/src/text/nodes/block_node.dart';
+import 'package:flame/src/text/nodes/bold_text_node.dart';
 import 'package:flame/src/text/nodes/header_node.dart';
+import 'package:flame/src/text/nodes/italic_text_node.dart';
 import 'package:flame/src/text/nodes/paragraph_node.dart';
 import 'package:flame/src/text/styles/background_style.dart';
 import 'package:flame/src/text/styles/block_style.dart';
+import 'package:flame/src/text/styles/flame_text_style.dart';
 import 'package:flame/src/text/styles/overflow.dart';
 import 'package:flame/src/text/styles/style.dart';
 import 'package:flutter/painting.dart' show EdgeInsets;
-import 'package:meta/meta.dart';
 
 /// [DocumentStyle] is a user-facing description of how to render an entire
 /// body of text; it roughly corresponds to a stylesheet in HTML.
@@ -21,25 +22,39 @@ class DocumentStyle extends Style {
   DocumentStyle({
     this.width,
     this.height,
-    EdgeInsets? padding,
-    BackgroundStyle? background,
-    BlockStyle? paragraphStyle,
-    BlockStyle? header1Style,
-    BlockStyle? header2Style,
-    BlockStyle? header3Style,
-    BlockStyle? header4Style,
-    BlockStyle? header5Style,
-    BlockStyle? header6Style,
-  }) : padding = padding ?? EdgeInsets.zero {
-    backgroundStyle = acquire(background);
-    this.paragraphStyle = acquire(paragraphStyle ?? defaultParagraphStyle)!;
-    this.header1Style = acquire(header1Style ?? defaultHeader1Style)!;
-    this.header2Style = acquire(header2Style ?? defaultHeader2Style)!;
-    this.header3Style = acquire(header3Style ?? defaultHeader3Style)!;
-    this.header4Style = acquire(header4Style ?? defaultHeader4Style)!;
-    this.header5Style = acquire(header5Style ?? defaultHeader5Style)!;
-    this.header6Style = acquire(header6Style ?? defaultHeader6Style)!;
-  }
+    this.padding = EdgeInsets.zero,
+    this.background,
+    FlameTextStyle? text,
+    FlameTextStyle? boldText,
+    FlameTextStyle? italicText,
+    BlockStyle? paragraph,
+    BlockStyle? header1,
+    BlockStyle? header2,
+    BlockStyle? header3,
+    BlockStyle? header4,
+    BlockStyle? header5,
+    BlockStyle? header6,
+  })  : _text = Style.merge(text, DocumentStyle.defaultTextStyle),
+        _boldText = Style.merge(boldText, BoldTextNode.defaultStyle),
+        _italicText = Style.merge(italicText, ItalicTextNode.defaultStyle),
+        _paragraph = Style.merge(paragraph, ParagraphNode.defaultStyle),
+        _header1 = Style.merge(header1, HeaderNode.defaultStyleH1),
+        _header2 = Style.merge(header2, HeaderNode.defaultStyleH2),
+        _header3 = Style.merge(header3, HeaderNode.defaultStyleH3),
+        _header4 = Style.merge(header4, HeaderNode.defaultStyleH4),
+        _header5 = Style.merge(header5, HeaderNode.defaultStyleH5),
+        _header6 = Style.merge(header6, HeaderNode.defaultStyleH6);
+
+  final FlameTextStyle? _text;
+  final FlameTextStyle? _boldText;
+  final FlameTextStyle? _italicText;
+  final BlockStyle? _paragraph;
+  final BlockStyle? _header1;
+  final BlockStyle? _header2;
+  final BlockStyle? _header3;
+  final BlockStyle? _header4;
+  final BlockStyle? _header5;
+  final BlockStyle? _header6;
 
   /// Outer width of the document page.
   ///
@@ -65,7 +80,7 @@ class DocumentStyle extends Style {
   /// Behavior of the document when the amount of content that needs to be laid
   /// out exceeds the provided [height]. See the [Overflow] enum description for
   /// more details.
-  final Overflow overflow = Overflow.expand;
+  Overflow get overflow => Overflow.expand;
 
   /// The distance from the outer edges of the page to the inner content box of
   /// the document.
@@ -79,89 +94,51 @@ class DocumentStyle extends Style {
 
   /// If present, describes what kind of background and borders to draw for the
   /// document page(s).
-  late final BackgroundStyle? backgroundStyle;
+  final BackgroundStyle? background;
 
-  /// Style for paragraph nodes in the document.
-  late final BlockStyle paragraphStyle;
+  FlameTextStyle get text => _text!;
+  FlameTextStyle get boldText => _boldText!;
+  FlameTextStyle get italicText => _italicText!;
 
-  /// Style for level-1 headers.
-  late final BlockStyle header1Style;
+  /// Style for [ParagraphNode]s.
+  BlockStyle get paragraph => _paragraph!;
 
-  /// Style for level-2 headers.
-  late final BlockStyle header2Style;
+  /// Styles for [HeaderNode]s, levels 1 to 6.
+  BlockStyle get header1 => _header1!;
+  BlockStyle get header2 => _header2!;
+  BlockStyle get header3 => _header3!;
+  BlockStyle get header4 => _header4!;
+  BlockStyle get header5 => _header5!;
+  BlockStyle get header6 => _header6!;
 
-  /// Style for level-3 headers.
-  late final BlockStyle header3Style;
-
-  /// Style for level-4 headers.
-  late final BlockStyle header4Style;
-
-  /// Style for level-5 headers.
-  late final BlockStyle header5Style;
-
-  /// Style for level-6 headers.
-  late final BlockStyle header6Style;
-
-  static BlockStyle defaultParagraphStyle = BlockStyle();
-  static BlockStyle defaultHeader1Style = BlockStyle();
-  static BlockStyle defaultHeader2Style = BlockStyle();
-  static BlockStyle defaultHeader3Style = BlockStyle();
-  static BlockStyle defaultHeader4Style = BlockStyle();
-  static BlockStyle defaultHeader5Style = BlockStyle();
-  static BlockStyle defaultHeader6Style = BlockStyle();
+  static FlameTextStyle defaultTextStyle = FlameTextStyle(fontSize: 16.0);
 
   @override
-  DocumentStyle clone() => copyWith();
-
-  DocumentStyle copyWith({
-    double? width,
-    double? height,
-    EdgeInsets? padding,
-    BackgroundStyle? background,
-    BlockStyle? paragraphStyle,
-    BlockStyle? header1Style,
-    BlockStyle? header2Style,
-    BlockStyle? header3Style,
-    BlockStyle? header4Style,
-    BlockStyle? header5Style,
-    BlockStyle? header6Style,
-  }) {
+  DocumentStyle copyWith(DocumentStyle other) {
     return DocumentStyle(
-      width: width ?? this.width,
-      height: height ?? this.height,
-      padding: padding ?? this.padding,
-      background: background ?? backgroundStyle,
-      paragraphStyle: paragraphStyle ?? this.paragraphStyle,
-      header1Style: header1Style ?? this.header1Style,
-      header2Style: header2Style ?? this.header2Style,
-      header3Style: header3Style ?? this.header3Style,
-      header4Style: header4Style ?? this.header4Style,
-      header5Style: header5Style ?? this.header5Style,
-      header6Style: header6Style ?? this.header6Style,
+      width: other.width ?? width,
+      height: other.height ?? height,
+      padding: other.padding,
+      background: merge(other.background, background)! as BackgroundStyle,
+      paragraph: merge(other.paragraph, paragraph)! as BlockStyle,
+      header1: merge(other.header1, header1)! as BlockStyle,
+      header2: merge(other.header2, header2)! as BlockStyle,
+      header3: merge(other.header3, header3)! as BlockStyle,
+      header4: merge(other.header4, header4)! as BlockStyle,
+      header5: merge(other.header5, header5)! as BlockStyle,
+      header6: merge(other.header6, header6)! as BlockStyle,
     );
   }
 
-  @internal
-  BlockStyle styleFor(BlockNode node) {
-    if (node is ParagraphNode) {
-      return paragraphStyle;
+  final Map<Style, Map<Style, Style>> _mergedStylesCache = {};
+  Style? merge(Style? style1, Style? style2) {
+    if (style1 == null) {
+      return style2;
+    } else if (style2 == null) {
+      return style1;
+    } else {
+      return (_mergedStylesCache[style1] ??= {})[style2] ??=
+          style1.copyWith(style2);
     }
-    if (node is HeaderNode) {
-      switch (node.level) {
-        case 1:
-          return header1Style;
-        case 2:
-          return header2Style;
-        case 3:
-          return header3Style;
-        case 4:
-          return header4Style;
-        case 5:
-          return header5Style;
-        default:
-          return header6Style;
-      }
-    }
-    return BlockStyle();
   }
 }

packages/flame/lib/src/text/styles/flame_text_style.dart

@@ -0,0 +1,55 @@
+import 'package:flame/src/text/formatters/text_formatter.dart';
+import 'package:flame/src/text/formatters/text_painter_text_formatter.dart';
+import 'package:flame/src/text/styles/style.dart';
+import 'package:flutter/rendering.dart';
+import 'package:meta/meta.dart';
+
+@immutable
+class FlameTextStyle extends Style {
+  FlameTextStyle({
+    this.color,
+    this.fontFamily,
+    this.fontSize,
+    this.fontScale,
+    this.fontWeight,
+    this.fontStyle,
+    this.letterSpacing,
+  });
+
+  final Color? color;
+  final String? fontFamily;
+  final double? fontSize;
+  final double? fontScale;
+  final FontWeight? fontWeight;
+  final FontStyle? fontStyle;
+  final double? letterSpacing;
+
+  late final TextFormatter formatter = asTextFormatter();
+
+  @override
+  FlameTextStyle copyWith(FlameTextStyle other) {
+    return FlameTextStyle(
+      color: color ?? other.color,
+      fontFamily: fontFamily ?? other.fontFamily,
+      fontSize: fontSize ?? other.fontSize,
+      fontScale: fontScale ?? other.fontScale,
+      fontWeight: fontWeight ?? other.fontWeight,
+      fontStyle: fontStyle ?? other.fontStyle,
+      letterSpacing: letterSpacing ?? other.letterSpacing,
+    );
+  }
+
+  @internal
+  TextPainterTextFormatter asTextFormatter() {
+    return TextPainterTextFormatter(
+      style: TextStyle(
+        color: color,
+        fontFamily: fontFamily,
+        fontSize: fontSize! * (fontScale ?? 1.0),
+        fontWeight: fontWeight,
+        fontStyle: fontStyle,
+        letterSpacing: letterSpacing,
+      ),
+    );
+  }
+}

packages/flame/lib/src/text/styles/style.dart

@@ -1,5 +1,4 @@
 import 'package:flame/src/text/styles/document_style.dart';
-import 'package:meta/meta.dart';
 
 /// A [Style] is a base class for several classes that collectively describe
 /// the desired visual appearance of a "rich-text" document.
@@ -14,27 +13,18 @@ import 'package:meta/meta.dart';
 ///
 /// The tree of [Style]s is roughly equivalent to a CSS stylesheet.
 abstract class Style {
-  /// The owner of the current style.
-  ///
-  /// Usually, styles are organized into a tree, and this property allows
-  /// traversing up this tree. This property can be null when the style hasn't
-  /// been put into a tree yet, or when it is the root of the tree.
-  Style? get parent => _parent;
-  Style? _parent;
+  const Style();
 
-  /// Creates and returns a copy of the current object.
-  Style clone();
+  Style copyWith(covariant Style other);
 
-  /// Marks [style] as being owned by the current object and returns it.
-  /// However, if the [style] is already owned by some other object, then clones
-  /// the [style], marks the copy as being owned, and returns it.
-  @protected
-  S? acquire<S extends Style>(S? style) {
-    if (style == null) {
-      return null;
+  static T? merge<T extends Style>(T? style1, T? style2) {
+    if (style1 == null) {
+      return style2;
+    } else if (style2 == null) {
+      return style1;
+    } else {
+      assert(style1.runtimeType == style2.runtimeType);
+      return style1.copyWith(style2) as T;
     }
-    final useStyle = style._parent == null ? style : style.clone() as S;
-    useStyle._parent = this;
-    return useStyle;
   }
 }

packages/flame/lib/text.dart

@@ -3,21 +3,36 @@ export 'src/text/common/glyph.dart' show Glyph;
 export 'src/text/common/glyph_data.dart' show GlyphData;
 export 'src/text/common/line_metrics.dart' show LineMetrics;
 export 'src/text/common/sprite_font.dart' show SpriteFont;
-export 'src/text/common/text_line.dart' show TextLine;
+export 'src/text/elements/block_element.dart' show BlockElement;
 export 'src/text/elements/element.dart' show Element;
+export 'src/text/elements/rect_element.dart' show RectElement;
+export 'src/text/elements/rrect_element.dart' show RRectElement;
+export 'src/text/elements/sprite_font_text_element.dart'
+    show SpriteFontTextElement;
 export 'src/text/elements/text_element.dart' show TextElement;
+export 'src/text/elements/text_painter_text_element.dart'
+    show TextPainterTextElement;
 export 'src/text/formatters/sprite_font_text_formatter.dart'
     show SpriteFontTextFormatter;
 export 'src/text/formatters/text_formatter.dart' show TextFormatter;
 export 'src/text/formatters/text_painter_text_formatter.dart'
     show TextPainterTextFormatter;
 export 'src/text/nodes/block_node.dart' show BlockNode;
+export 'src/text/nodes/bold_text_node.dart' show BoldTextNode;
+export 'src/text/nodes/column_node.dart' show ColumnNode;
 export 'src/text/nodes/document_node.dart' show DocumentNode;
+export 'src/text/nodes/group_text_node.dart' show GroupTextNode;
 export 'src/text/nodes/header_node.dart' show HeaderNode;
+export 'src/text/nodes/italic_text_node.dart' show ItalicTextNode;
 export 'src/text/nodes/paragraph_node.dart' show ParagraphNode;
+export 'src/text/nodes/plain_text_node.dart' show PlainTextNode;
+export 'src/text/nodes/text_block_node.dart' show TextBlockNode;
+export 'src/text/nodes/text_node.dart' show TextNode;
 export 'src/text/sprite_font_renderer.dart' show SpriteFontRenderer;
 export 'src/text/styles/background_style.dart' show BackgroundStyle;
 export 'src/text/styles/block_style.dart' show BlockStyle;
 export 'src/text/styles/document_style.dart' show DocumentStyle;
+export 'src/text/styles/flame_text_style.dart' show FlameTextStyle;
+export 'src/text/styles/style.dart' show Style;
 export 'src/text/text_paint.dart' show TextPaint;
 export 'src/text/text_renderer.dart' show TextRenderer;

packages/flame/test/text/text_paint_test.dart

@@ -1,12 +1,11 @@
-import 'package:flame/components.dart';
 import 'package:flame/text.dart';
-import 'package:flutter/material.dart';
+import 'package:flutter/rendering.dart' as flutter;
 import 'package:test/test.dart';
 
 void main() {
   group('TextPaint', () {
     test('copyWith returns a new instance with the new values', () {
-      const style = TextStyle(fontSize: 12, fontFamily: 'Times');
+      const style = flutter.TextStyle(fontSize: 12, fontFamily: 'Times');
       final tp = TextPaint(style: style)
           .copyWith((t) => t.copyWith(fontFamily: 'Helvetica'));
       expect(tp.style.fontSize, 12);

packages/flame_test/lib/src/debug_text_formatter.dart

@@ -27,7 +27,7 @@ class DebugTextFormatter extends TextFormatter {
   TextElement format(String text) => _DebugTextElement(this, text);
 }
 
-class _DebugTextElement extends TextElement implements TextLine {
+class _DebugTextElement extends TextElement {
   _DebugTextElement(this.style, this.text) {
     final charWidth = style.fontSize * 1.0;
     final charHeight = style.fontSize;
@@ -52,9 +52,6 @@ class _DebugTextElement extends TextElement implements TextLine {
   @override
   late final LineMetrics metrics;
 
-  @override
-  TextLine get lastLine => this;
-
   @override
   void render(Canvas canvas) {
     canvas.save();