[web] Calculate height and baseline for rich text (#23064)

lib/web_ui/lib/src/engine/text/layout_service.dart

@@ -175,6 +175,20 @@ class TextLayoutService {
       }
     }
 
+    // ************************************************** //
+    // *** PARAGRAPH BASELINE & HEIGHT & LONGEST LINE *** //
+    // ************************************************** //
+
+    for (final EngineLineMetrics line in lines) {
+      height += line.height;
+      if (alphabeticBaseline == -1.0) {
+        alphabeticBaseline = line.baseline;
+      }
+      if (longestLine < line.width) {
+        longestLine = line.width;
+      }
+    }
+
     // ******************************** //
     // *** MAX/MIN INTRINSIC WIDTHS *** //
     // ******************************** //
@@ -276,6 +290,7 @@ class LineBuilder {
     required this.maxWidth,
     required this.start,
     required this.lineNumber,
+    required this.accumulatedHeight,
   }) : end = start;
 
   /// Creates a [LineBuilder] for the first line in a paragraph.
@@ -290,6 +305,7 @@ class LineBuilder {
       maxWidth: maxWidth,
       lineNumber: 0,
       start: LineBreakResult.sameIndex(0, LineBreakType.prohibited),
+      accumulatedHeight: 0.0,
     );
   }
 
@@ -301,6 +317,10 @@ class LineBuilder {
   final LineBreakResult start;
   final int lineNumber;
 
+  /// The accumulated height of all preceding lines, excluding the current line.
+  final double accumulatedHeight;
+
+  /// The index of the end of the line so far.
   LineBreakResult end;
 
   /// The width of the line so far, excluding trailing white space.
@@ -312,6 +332,12 @@ class LineBuilder {
   /// The width of trailing white space in the line.
   double get widthOfTrailingSpace => widthIncludingSpace - width;
 
+  /// The alphabetic baseline of the line so far.
+  double alphabeticBaseline = 0.0;
+
+  /// The height of the line so far.
+  double height = 0.0;
+
   /// The last segment in this line.
   LineSegment get lastSegment => _segments.last;
 
@@ -360,6 +386,10 @@ class LineBuilder {
       'Cannot extend a line that ends with a hard break.',
     );
 
+    alphabeticBaseline =
+        math.max(alphabeticBaseline, spanometer.alphabeticBaseline);
+    height = math.max(height, spanometer.height);
+
     _addSegment(_createSegment(newEnd));
   }
 
@@ -508,23 +538,18 @@ class LineBuilder {
       availableWidth: availableWidthForSegment,
       allowEmpty: allowEmpty,
     );
-    extendTo(LineBreakResult.sameIndex(breakingPoint, LineBreakType.prohibited));
+    extendTo(
+        LineBreakResult.sameIndex(breakingPoint, LineBreakType.prohibited));
   }
 
   /// Builds the [EngineLineMetrics] instance that represents this line.
   EngineLineMetrics build({String? ellipsis}) {
-    double ellipsisWidth = 0.0;
-    String text = paragraph
-        .toPlainText()
-        .substring(start.index, end.indexWithoutTrailingNewlines);
-
-    if (ellipsis != null) {
-      ellipsisWidth = spanometer.measureText(ellipsis);
-      text += ellipsis;
-    }
+    final double ellipsisWidth =
+        ellipsis == null ? 0.0 : spanometer.measureText(ellipsis);
 
-    return EngineLineMetrics.withText(
-      text,
+    return EngineLineMetrics.rich(
+      lineNumber,
+      ellipsis: ellipsis,
       startIndex: start.index,
       endIndex: end.index,
       endIndexWithoutNewlines: end.indexWithoutTrailingNewlines,
@@ -532,7 +557,8 @@ class LineBuilder {
       width: width + ellipsisWidth,
       widthWithTrailingSpaces: widthIncludingSpace + ellipsisWidth,
       left: alignOffset,
-      lineNumber: lineNumber,
+      height: height,
+      baseline: accumulatedHeight + alphabeticBaseline,
     );
   }
 
@@ -549,6 +575,7 @@ class LineBuilder {
       maxWidth: maxWidth,
       start: end,
       lineNumber: lineNumber + 1,
+      accumulatedHeight: accumulatedHeight + height,
     );
   }
 }
@@ -567,11 +594,18 @@ class Spanometer {
   final CanvasParagraph paragraph;
   final html.CanvasRenderingContext2D context;
 
+  static RulerHost _rulerHost = RulerHost();
+
+  static Map<TextHeightStyle, TextHeightRuler> _rulers =
+      <TextHeightStyle, TextHeightRuler>{};
+
   String _cssFontString = '';
 
   double? get letterSpacing => _currentSpan!.style._letterSpacing;
 
+  TextHeightRuler? _currentRuler;
   FlatTextSpan? _currentSpan;
+
   FlatTextSpan? get currentSpan => _currentSpan;
   set currentSpan(FlatTextSpan? span) {
     if (span == _currentSpan) {
@@ -581,9 +615,20 @@ class Spanometer {
 
     // No need to update css font string when `span` is null.
     if (span == null) {
+      _currentRuler = null;
       return;
     }
 
+    // Update the height ruler.
+    // If the ruler doesn't exist in the cache, create a new one and cache it.
+    final TextHeightStyle heightStyle = span.style.heightStyle;
+    TextHeightRuler? ruler = _rulers[heightStyle];
+    if (ruler == null) {
+      ruler = TextHeightRuler(heightStyle, _rulerHost);
+      _rulers[heightStyle] = ruler;
+    }
+    _currentRuler = ruler;
+
     // Update the font string if it's different from the previous span.
     final String cssFontString = span.style.cssFontString;
     if (_cssFontString != cssFontString) {
@@ -592,6 +637,12 @@ class Spanometer {
     }
   }
 
+  /// The alphabetic baseline for the current span.
+  double get alphabeticBaseline => _currentRuler!.alphabeticBaseline;
+
+  /// The line height of the current span.
+  double get height => _currentRuler!.height;
+
   /// Measures the width of text between two line breaks.
   ///
   /// Doesn't include the width of any trailing white space.

lib/web_ui/lib/src/engine/text/paragraph.dart

@@ -21,6 +21,7 @@ class EngineLineMetrics implements ui.LineMetrics {
     required this.baseline,
     required this.lineNumber,
   })  : displayText = null,
+        ellipsis = null,
         startIndex = -1,
         endIndex = -1,
         endIndexWithoutNewlines = -1,
@@ -44,15 +45,39 @@ class EngineLineMetrics implements ui.LineMetrics {
         assert(width != null), // ignore: unnecessary_null_comparison
         assert(left != null), // ignore: unnecessary_null_comparison
         assert(lineNumber != null && lineNumber >= 0), // ignore: unnecessary_null_comparison
+        ellipsis = null,
         ascent = double.infinity,
         descent = double.infinity,
         unscaledAscent = double.infinity,
         height = double.infinity,
         baseline = double.infinity;
 
+  EngineLineMetrics.rich(
+    this.lineNumber, {
+    required this.ellipsis,
+    required this.startIndex,
+    required this.endIndex,
+    required this.endIndexWithoutNewlines,
+    required this.hardBreak,
+    required this.width,
+    required this.widthWithTrailingSpaces,
+    required this.left,
+    required this.height,
+    required this.baseline,
+  })  : displayText = null,
+        ascent = double.infinity,
+        descent = double.infinity,
+        unscaledAscent = double.infinity;
+
   /// The text to be rendered on the screen representing this line.
   final String? displayText;
 
+  /// The string to be displayed as an overflow indicator.
+  ///
+  /// When the value is non-null, it means this line is overflowing and the
+  /// [ellipsis] needs to be displayed at the end of it.
+  final String? ellipsis;
+
   /// The index (inclusive) in the text where this line begins.
   final int startIndex;
 
@@ -1035,6 +1060,19 @@ class EngineTextStyle implements ui.TextStyle {
     );
   }
 
+  late final TextHeightStyle heightStyle = _createHeightStyle();
+
+  TextHeightStyle _createHeightStyle() {
+    return TextHeightStyle(
+      fontFamily: _effectiveFontFamily,
+      fontSize: _fontSize ?? DomRenderer.defaultFontSize,
+      height: _height,
+      // TODO(mdebbar): Pass the actual value when font features become supported
+      //                https://github.com/flutter/flutter/issues/64595
+      fontFeatures: null,
+    );
+  }
+
   @override
   bool operator ==(Object other) {
     if (identical(this, other)) {

lib/web_ui/test/text/layout_service_helper.dart

@@ -13,9 +13,11 @@ TestLine l(
   int? endIndex, {
   int?  endIndexWithoutNewlines,
   bool? hardBreak,
+  double? height,
   double? width,
   double? widthWithTrailingSpaces,
   double? left,
+  double? baseline,
 }) {
   return TestLine(
     displayText: displayText,
@@ -23,13 +25,16 @@ TestLine l(
     endIndex: endIndex,
     endIndexWithoutNewlines: endIndexWithoutNewlines,
     hardBreak: hardBreak,
+    height: height,
     width: width,
     widthWithTrailingSpaces: widthWithTrailingSpaces,
     left: left,
+    baseline: baseline,
   );
 }
 
 void expectLines(CanvasParagraph paragraph, List<TestLine> expectedLines) {
+  final String text = paragraph.toPlainText();
   final List<EngineLineMetrics> lines =
       paragraph.computeLineMetrics() as List<EngineLineMetrics>;
   expect(lines, hasLength(expectedLines.length));
@@ -43,8 +48,11 @@ void expectLines(CanvasParagraph paragraph, List<TestLine> expectedLines) {
       reason: '${i}th line had the wrong `lineNumber`. Expected: $i. Actual: ${line.lineNumber}',
     );
     if (expectedLine.displayText != null) {
+      final String substring =
+          text.substring(line.startIndex, line.endIndexWithoutNewlines);
+      final String ellipsis = line.ellipsis ?? '';
       expect(
-        line.displayText,
+        substring + ellipsis,
         expectedLine.displayText,
         reason:
             '${i}th line had a different `displayText` value: "${line.displayText}" vs. "${expectedLine.displayText}"',
@@ -128,6 +136,7 @@ class TestLine {
     this.width,
     this.widthWithTrailingSpaces,
     this.left,
+    this.baseline,
   });
 
   final String? displayText;
@@ -139,4 +148,5 @@ class TestLine {
   final double? width;
   final double? widthWithTrailingSpaces;
   final double? left;
-}
\ No newline at end of file
+  final double? baseline;
+}

lib/web_ui/test/text/layout_service_plain_test.dart

@@ -49,7 +49,7 @@ void testMain() async {
     paragraph = plain(ahemStyle, '   abc')..layout(constrain(double.infinity));
     expect(paragraph.maxIntrinsicWidth, 60);
     expect(paragraph.minIntrinsicWidth, 30);
-    // expect(paragraph.height, 10);
+    expect(paragraph.height, 10);
     expectLines(paragraph, [
       l('   abc', 0, 6, hardBreak: true, width: 60.0),
     ]);
@@ -58,7 +58,7 @@ void testMain() async {
     paragraph = plain(ahemStyle, 'abc   ')..layout(constrain(double.infinity));
     expect(paragraph.maxIntrinsicWidth, 60);
     expect(paragraph.minIntrinsicWidth, 30);
-    // expect(paragraph.height, 10);
+    expect(paragraph.height, 10);
     expectLines(paragraph, [
       l('abc   ', 0, 6, hardBreak: true, width: 30.0),
     ]);
@@ -68,7 +68,7 @@ void testMain() async {
       ..layout(constrain(double.infinity));
     expect(paragraph.maxIntrinsicWidth, 100);
     expect(paragraph.minIntrinsicWidth, 20);
-    // expect(paragraph.height, 10);
+    expect(paragraph.height, 10);
     expectLines(paragraph, [
       l('  ab   c  ', 0, 10, hardBreak: true, width: 80.0, left: 0.0),
     ]);
@@ -77,7 +77,7 @@ void testMain() async {
     paragraph = plain(ahemStyle, ' ')..layout(constrain(double.infinity));
     expect(paragraph.maxIntrinsicWidth, 10);
     expect(paragraph.minIntrinsicWidth, 0);
-    // expect(paragraph.height, 10);
+    expect(paragraph.height, 10);
     expectLines(paragraph, [
       l(' ', 0, 1, hardBreak: true, width: 0.0, left: 0.0),
     ]);
@@ -86,7 +86,7 @@ void testMain() async {
     paragraph = plain(ahemStyle, '     ')..layout(constrain(double.infinity));
     expect(paragraph.maxIntrinsicWidth, 50);
     expect(paragraph.minIntrinsicWidth, 0);
-    // expect(paragraph.height, 10);
+    expect(paragraph.height, 10);
     expectLines(paragraph, [
       l('     ', 0, 5, hardBreak: true, width: 0.0, left: 0.0),
     ]);
@@ -97,25 +97,27 @@ void testMain() async {
       ..layout(constrain(50.0));
 
     // Should fit on a single line.
+    expect(paragraph.alphabeticBaseline, 8);
     expect(paragraph.maxIntrinsicWidth, 50);
     expect(paragraph.minIntrinsicWidth, 50);
     expect(paragraph.width, 50);
-    // expect(paragraph.height, 10);
+    expect(paragraph.height, 10);
     expectLines(paragraph, [
-      l('12345', 0, 5, hardBreak: true, width: 50.0, left: 0.0),
+      l('12345', 0, 5, hardBreak: true, width: 50.0, left: 0.0, height: 10.0, baseline: 8.0),
     ]);
   });
 
   test('simple multi-line text', () {
     final CanvasParagraph paragraph = plain(ahemStyle, 'foo bar baz')
       ..layout(constrain(70.0));
+    expect(paragraph.alphabeticBaseline, 8);
     expect(paragraph.maxIntrinsicWidth, 110);
     expect(paragraph.minIntrinsicWidth, 30);
     expect(paragraph.width, 70);
-    // expect(paragraph.height, 20);
+    expect(paragraph.height, 20);
     expectLines(paragraph, [
-      l('foo bar ', 0, 8, hardBreak: false, width: 70.0, left: 0.0),
-      l('baz', 8, 11, hardBreak: true, width: 30.0, left: 0.0),
+      l('foo bar ', 0, 8, hardBreak: false, width: 70.0, left: 0.0, height: 10.0, baseline: 8.0),
+      l('baz', 8, 11, hardBreak: true, width: 30.0, left: 0.0, height: 10.0, baseline: 18.0),
     ]);
   });
 
@@ -124,73 +126,79 @@ void testMain() async {
 
     // The long text doesn't fit in 50px of width, so it needs to wrap.
     paragraph = plain(ahemStyle, '1234567890')..layout(constrain(50.0));
+    expect(paragraph.alphabeticBaseline, 8);
     expect(paragraph.maxIntrinsicWidth, 100);
     expect(paragraph.minIntrinsicWidth, 100);
     expect(paragraph.width, 50);
-    // expect(paragraph.height, 20);
+    expect(paragraph.height, 20);
     expectLines(paragraph, [
-      l('12345', 0, 5, hardBreak: false, width: 50.0, left: 0.0),
-      l('67890', 5, 10, hardBreak: true, width: 50.0, left: 0.0),
+      l('12345', 0, 5, hardBreak: false, width: 50.0, left: 0.0, height: 10.0, baseline: 8.0),
+      l('67890', 5, 10, hardBreak: true, width: 50.0, left: 0.0, height: 10.0, baseline: 18.0),
     ]);
 
     // The first word is force-broken twice.
     paragraph = plain(ahemStyle, 'abcdefghijk lm')..layout(constrain(50.0));
+    expect(paragraph.alphabeticBaseline, 8);
     expect(paragraph.maxIntrinsicWidth, 140);
     expect(paragraph.minIntrinsicWidth, 110);
     expect(paragraph.width, 50);
-    // expect(paragraph.height, 30);
+    expect(paragraph.height, 30);
     expectLines(paragraph, [
-      l('abcde', 0, 5, hardBreak: false, width: 50.0, left: 0.0),
-      l('fghij', 5, 10, hardBreak: false, width: 50.0, left: 0.0),
-      l('k lm', 10, 14, hardBreak: true, width: 40.0, left: 0.0),
+      l('abcde', 0, 5, hardBreak: false, width: 50.0, left: 0.0, height: 10.0, baseline: 8.0),
+      l('fghij', 5, 10, hardBreak: false, width: 50.0, left: 0.0, height: 10.0, baseline: 18.0),
+      l('k lm', 10, 14, hardBreak: true, width: 40.0, left: 0.0, height: 10.0, baseline: 28.0),
     ]);
 
     // Constraints enough only for "abcdef" but not for the trailing space.
     paragraph = plain(ahemStyle, 'abcdef gh')..layout(constrain(60.0));
+    expect(paragraph.alphabeticBaseline, 8);
     expect(paragraph.maxIntrinsicWidth, 90);
     expect(paragraph.minIntrinsicWidth, 60);
     expect(paragraph.width, 60);
-    // expect(paragraph.height, 20);
+    expect(paragraph.height, 20);
     expectLines(paragraph, [
-      l('abcdef ', 0, 7, hardBreak: false, width: 60.0, left: 0.0),
-      l('gh', 7, 9, hardBreak: true, width: 20.0, left: 0.0),
+      l('abcdef ', 0, 7, hardBreak: false, width: 60.0, left: 0.0, height: 10.0, baseline: 8.0),
+      l('gh', 7, 9, hardBreak: true, width: 20.0, left: 0.0, height: 10.0, baseline: 18.0),
     ]);
 
     // Constraints aren't enough even for a single character. In this case,
     // we show a minimum of one character per line.
     paragraph = plain(ahemStyle, 'AA')..layout(constrain(8.0));
+    expect(paragraph.alphabeticBaseline, 8);
     expect(paragraph.maxIntrinsicWidth, 20);
     expect(paragraph.minIntrinsicWidth, 20);
     expect(paragraph.width, 8);
-    // expect(paragraph.height, 20);
+    expect(paragraph.height, 20);
     expectLines(paragraph, [
-      l('A', 0, 1, hardBreak: false, width: 10.0, left: 0.0),
-      l('A', 1, 2, hardBreak: true, width: 10.0, left: 0.0),
+      l('A', 0, 1, hardBreak: false, width: 10.0, left: 0.0, height: 10.0, baseline: 8.0),
+      l('A', 1, 2, hardBreak: true, width: 10.0, left: 0.0, height: 10.0, baseline: 18.0),
     ]);
 
     // Extremely narrow constraints with new line in the middle.
     paragraph = plain(ahemStyle, 'AA\nA')..layout(constrain(8.0));
+    expect(paragraph.alphabeticBaseline, 8);
     expect(paragraph.maxIntrinsicWidth, 20);
     expect(paragraph.minIntrinsicWidth, 20);
     expect(paragraph.width, 8);
-    // expect(paragraph.height, 30);
+    expect(paragraph.height, 30);
     expectLines(paragraph, [
-      l('A', 0, 1, hardBreak: false, width: 10.0, left: 0.0),
-      l('A', 1, 3, hardBreak: true, width: 10.0, left: 0.0),
-      l('A', 3, 4, hardBreak: true, width: 10.0, left: 0.0),
+      l('A', 0, 1, hardBreak: false, width: 10.0, left: 0.0, height: 10.0, baseline: 8.0),
+      l('A', 1, 3, hardBreak: true, width: 10.0, left: 0.0, height: 10.0, baseline: 18.0),
+      l('A', 3, 4, hardBreak: true, width: 10.0, left: 0.0, height: 10.0, baseline: 28.0),
     ]);
 
     // Extremely narrow constraints with new line in the end.
     paragraph = plain(ahemStyle, 'AAA\n')..layout(constrain(8.0));
+    expect(paragraph.alphabeticBaseline, 8);
     expect(paragraph.maxIntrinsicWidth, 30);
     expect(paragraph.minIntrinsicWidth, 30);
     expect(paragraph.width, 8);
-    // expect(paragraph.height, 40);
+    expect(paragraph.height, 40);
     expectLines(paragraph, [
-      l('A', 0, 1, hardBreak: false, width: 10.0, left: 0.0),
-      l('A', 1, 2, hardBreak: false, width: 10.0, left: 0.0),
-      l('A', 2, 4, hardBreak: true, width: 10.0, left: 0.0),
-      l('', 4, 4, hardBreak: true, width: 0.0, left: 0.0),
+      l('A', 0, 1, hardBreak: false, width: 10.0, left: 0.0, height: 10.0, baseline: 8.0),
+      l('A', 1, 2, hardBreak: false, width: 10.0, left: 0.0, height: 10.0, baseline: 18.0),
+      l('A', 2, 4, hardBreak: true, width: 10.0, left: 0.0, height: 10.0, baseline: 28.0),
+      l('', 4, 4, hardBreak: true, width: 0.0, left: 0.0, height: 10.0, baseline: 38.0),
     ]);
   });
 
@@ -202,7 +210,7 @@ void testMain() async {
     expect(paragraph.maxIntrinsicWidth, 20);
     expect(paragraph.minIntrinsicWidth, 20);
     expect(paragraph.width, 50);
-    // expect(paragraph.height, 20);
+    expect(paragraph.height, 20);
     expectLines(paragraph, [
       l('12', 0, 3, hardBreak: true, width: 20.0, left: 0.0),
       l('34', 3, 5, hardBreak: true, width: 20.0, left: 0.0),
@@ -216,7 +224,7 @@ void testMain() async {
     paragraph = plain(ahemStyle, '\n\n1234')..layout(constrain(50.0));
     expect(paragraph.maxIntrinsicWidth, 40);
     expect(paragraph.minIntrinsicWidth, 40);
-    // expect(paragraph.height, 30);
+    expect(paragraph.height, 30);
     expectLines(paragraph, [
       l('', 0, 1, hardBreak: true, width: 0.0, left: 0.0),
       l('', 1, 2, hardBreak: true, width: 0.0, left: 0.0),
@@ -227,7 +235,7 @@ void testMain() async {
     paragraph = plain(ahemStyle, '12\n\n345')..layout(constrain(50.0));
     expect(paragraph.maxIntrinsicWidth, 30);
     expect(paragraph.minIntrinsicWidth, 30);
-    // expect(paragraph.height, 30);
+    expect(paragraph.height, 30);
     expectLines(paragraph, [
       l('12', 0, 3, hardBreak: true, width: 20.0, left: 0.0),
       l('', 3, 4, hardBreak: true, width: 0.0, left: 0.0),
@@ -238,7 +246,7 @@ void testMain() async {
     paragraph = plain(ahemStyle, '1234\n\n')..layout(constrain(50.0));
     expect(paragraph.maxIntrinsicWidth, 40);
     expect(paragraph.minIntrinsicWidth, 40);
-    // expect(paragraph.height, 30);
+    expect(paragraph.height, 30);
     expectLines(paragraph, [
       l('1234', 0, 5, hardBreak: true, width: 40.0, left: 0.0),
       l('', 5, 6, hardBreak: true, width: 0.0, left: 0.0),
@@ -255,7 +263,7 @@ void testMain() async {
       expect(paragraph.maxIntrinsicWidth, 70);
       expect(paragraph.minIntrinsicWidth, 30);
       expect(paragraph.width, double.infinity);
-      // expect(paragraph.height, 20);
+      expect(paragraph.height, 20);
       expectLines(paragraph, [
         l('123', 0, 4, hardBreak: true, width: 30.0, left: 0.0),
         l('456 789', 4, 11, hardBreak: true, width: 70.0, left: 0.0),
@@ -404,7 +412,7 @@ void testMain() async {
     )..layout(constrain(50.0));
     expect(longText.minIntrinsicWidth, 480);
     expect(longText.maxIntrinsicWidth, 480);
-    // expect(longText.height, 10);
+    expect(longText.height, 10);
     expectLines(longText, [
       l('AA...', 0, 2, hardBreak: false, width: 50.0, left: 0.0),
     ]);
@@ -417,7 +425,7 @@ void testMain() async {
     )..layout(constrain(50.0));
     expect(longTextShortPrefix.minIntrinsicWidth, 450);
     expect(longTextShortPrefix.maxIntrinsicWidth, 450);
-    // expect(longTextShortPrefix.height, 20);
+    expect(longTextShortPrefix.height, 20);
     expectLines(longTextShortPrefix, [
       l('AAA', 0, 4, hardBreak: true, width: 30.0, left: 0.0),
       l('AA...', 4, 6, hardBreak: false, width: 50.0, left: 0.0),
@@ -429,7 +437,7 @@ void testMain() async {
       ..layout(constrain(50.0));
     expect(trailingSpace.minIntrinsicWidth, 30);
     expect(trailingSpace.maxIntrinsicWidth, 60);
-    // expect(trailingSpace.height, 10);
+    expect(trailingSpace.height, 10);
     expectLines(trailingSpace, [
       l('AA...', 0, 2, hardBreak: false, width: 50.0, left: 0.0),
     ]);
@@ -439,7 +447,7 @@ void testMain() async {
       ..layout(constrain(30.0));
     expect(paragraph.minIntrinsicWidth, 40);
     expect(paragraph.maxIntrinsicWidth, 40);
-    // expect(paragraph.height, 10);
+    expect(paragraph.height, 10);
     expectLines(paragraph, [
       l('...', 0, 0, hardBreak: false, width: 30.0, left: 0.0),
     ]);
@@ -448,7 +456,7 @@ void testMain() async {
     paragraph.layout(constrain(10.0));
     expect(paragraph.minIntrinsicWidth, 40);
     expect(paragraph.maxIntrinsicWidth, 40);
-    // expect(paragraph.height, 10);
+    expect(paragraph.height, 10);
 
     // TODO(flutter_web): https://github.com/flutter/flutter/issues/34346
     // expectLines(paragraph, [
@@ -469,7 +477,7 @@ void testMain() async {
     // The height should be that of a single line.
     final CanvasParagraph oneline = plain(maxlinesStyle, 'One line')
       ..layout(constrain(double.infinity));
-    // expect(oneline.height, 10);
+    expect(oneline.height, 10);
     expectLines(oneline, [
       l('One line', 0, 8, hardBreak: true, width: 80.0, left: 0.0),
     ]);
@@ -478,7 +486,7 @@ void testMain() async {
     final CanvasParagraph threelines =
         plain(maxlinesStyle, 'First\nSecond\nThird')
           ..layout(constrain(double.infinity));
-    // expect(threelines.height, 20);
+    expect(threelines.height, 20);
     expectLines(threelines, [
       l('First', 0, 6, hardBreak: true, width: 50.0, left: 0.0),
       l('Second', 6, 13, hardBreak: true, width: 60.0, left: 0.0),
@@ -489,7 +497,7 @@ void testMain() async {
       maxlinesStyle,
       'Lorem ipsum dolor sit amet, consectetur adipiscing elit.',
     )..layout(constrain(50.0));
-    // expect(veryLong.height, 20);
+    expect(veryLong.height, 20);
     expectLines(veryLong, [
       l('Lorem ', 0, 6, hardBreak: false, width: 50.0, left: 0.0),
       l('ipsum ', 6, 12, hardBreak: false, width: 50.0, left: 0.0),
@@ -500,7 +508,7 @@ void testMain() async {
       maxlinesStyle,
       'AAA AAAAAAAAAAAAAAAAAAA',
     )..layout(constrain(50.0));
-    // expect(veryLongLastLine.height, 20);
+    expect(veryLongLastLine.height, 20);
     expectLines(veryLongLastLine, [
       l('AAA ', 0, 4, hardBreak: false, width: 30.0, left: 0.0),
       l('AAAAA', 4, 9, hardBreak: false, width: 50.0, left: 0.0),
@@ -525,21 +533,21 @@ void testMain() async {
 
     // Simple no overflow case.
     paragraph = plain(onelineStyle, 'abcdef')..layout(constrain(60.0));
-    // expect(paragraph.height, 10);
+    expect(paragraph.height, 10);
     expectLines(paragraph, [
       l('abcdef', 0, 6, hardBreak: true, width: 60.0, left: 0.0),
     ]);
 
     // Simple overflow case.
     paragraph = plain(onelineStyle, 'abcd efg')..layout(constrain(60.0));
-    // expect(paragraph.height, 10);
+    expect(paragraph.height, 10);
     expectLines(paragraph, [
       l('abc...', 0, 3, hardBreak: false, width: 60.0, left: 0.0),
     ]);
 
     // Another simple overflow case.
     paragraph = plain(onelineStyle, 'a bcde fgh')..layout(constrain(60.0));
-    // expect(paragraph.height, 10);
+    expect(paragraph.height, 10);
     expectLines(paragraph, [
       l('a b...', 0, 3, hardBreak: false, width: 60.0, left: 0.0),
     ]);
@@ -547,7 +555,7 @@ void testMain() async {
     // The ellipsis is supposed to go on the second line, but because the
     // 2nd line doesn't overflow, no ellipsis is shown.
     paragraph = plain(multilineStyle, 'abcdef ghijkl')..layout(constrain(60.0));
-    // expect(paragraph.height, 20);
+    expect(paragraph.height, 20);
     expectLines(paragraph, [
       l('abcdef ', 0, 7, hardBreak: false, width: 60.0, left: 0.0),
       l('ghijkl', 7, 13, hardBreak: true, width: 60.0, left: 0.0),
@@ -555,7 +563,7 @@ void testMain() async {
 
     // But when the 2nd line is long enough, the ellipsis is shown.
     paragraph = plain(multilineStyle, 'abcd efghijkl')..layout(constrain(60.0));
-    // expect(paragraph.height, 20);
+    expect(paragraph.height, 20);
     expectLines(paragraph, [
       l('abcd ', 0, 5, hardBreak: false, width: 40.0, left: 0.0),
       l('efg...', 5, 8, hardBreak: false, width: 60.0, left: 0.0),
@@ -565,7 +573,7 @@ void testMain() async {
     // insert the ellipsis.
     paragraph = plain(multilineStyle, 'abcde f gh ijk')
       ..layout(constrain(60.0));
-    // expect(paragraph.height, 20);
+    expect(paragraph.height, 20);
     expectLines(paragraph, [
       l('abcde ', 0, 6, hardBreak: false, width: 50.0, left: 0.0),
       l('f g...', 6, 9, hardBreak: false, width: 60.0, left: 0.0),
@@ -573,7 +581,7 @@ void testMain() async {
 
     // First line overflows but second line doesn't.
     paragraph = plain(multilineStyle, 'abcdefg hijk')..layout(constrain(60.0));
-    // expect(paragraph.height, 20);
+    expect(paragraph.height, 20);
     expectLines(paragraph, [
       l('abcdef', 0, 6, hardBreak: false, width: 60.0, left: 0.0),
       l('g hijk', 6, 12, hardBreak: true, width: 60.0, left: 0.0),
@@ -582,7 +590,7 @@ void testMain() async {
     // Both first and second lines overflow.
     paragraph = plain(multilineStyle, 'abcdefg hijklmnop')
       ..layout(constrain(60.0));
-    // expect(paragraph.height, 20);
+    expect(paragraph.height, 20);
     expectLines(paragraph, [
       l('abcdef', 0, 6, hardBreak: false, width: 60.0, left: 0.0),
       l('g h...', 6, 9, hardBreak: false, width: 60.0, left: 0.0),