reland "fix the widget span layout when text scale factor != 1" and h… (#60021)

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

@@ -79,6 +79,13 @@ class RenderParagraph extends RenderBox
     StrutStyle strutStyle,
     TextWidthBasis textWidthBasis = TextWidthBasis.parent,
     ui.TextHeightBehavior textHeightBehavior,
+    @Deprecated(
+      'This parameter is a temporary flag to migrate the internal tests and '
+      'should not be used in other contexts. For more details, please check '
+      'https://github.com/flutter/flutter/issues/59316. '
+      'This feature was deprecated after v1.19.0.'
+    )
+    bool applyTextScaleFactorToWidgetSpan = false,
     List<RenderBox> children,
   }) : assert(text != null),
        assert(text.debugAssertIsValid()),
@@ -91,6 +98,7 @@ class RenderParagraph extends RenderBox
        assert(textWidthBasis != null),
        _softWrap = softWrap,
        _overflow = overflow,
+       _applyTextScaleFactorToWidgetSpan = applyTextScaleFactorToWidgetSpan,
        _textPainter = TextPainter(
          text: text,
          textAlign: textAlign,
@@ -290,6 +298,8 @@ class RenderParagraph extends RenderBox
     markNeedsLayout();
   }
 
+  final bool _applyTextScaleFactorToWidgetSpan;
+
   @override
   double computeMinIntrinsicWidth(double height) {
     if (!_canComputeIntrinsics()) {
@@ -526,13 +536,17 @@ class RenderParagraph extends RenderBox
     RenderBox child = firstChild;
     _placeholderDimensions = List<PlaceholderDimensions>(childCount);
     int childIndex = 0;
+    BoxConstraints boxConstraints = BoxConstraints(maxWidth: constraints.maxWidth);
+    // The content will be enlarged by textScaleFactor during painting phase.
+    // We reduce constraint by textScaleFactor so that the content will fit
+    // into the box once it is enlarged.
+    if (_applyTextScaleFactorToWidgetSpan)
+      boxConstraints = boxConstraints / textScaleFactor;
     while (child != null) {
       // Only constrain the width to the maximum width of the paragraph.
       // Leave height unconstrained, which will overflow if expanded past.
       child.layout(
-        BoxConstraints(
-          maxWidth: constraints.maxWidth,
-        ),
+        boxConstraints,
         parentUsesSize: true,
       );
       double baselineOffset;

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

@@ -5144,6 +5144,13 @@ class RichText extends MultiChildRenderObjectWidget {
     this.strutStyle,
     this.textWidthBasis = TextWidthBasis.parent,
     this.textHeightBehavior,
+    @Deprecated(
+      'This parameter is a temporary flag to migrate the internal tests and '
+      'should not be used in other contexts. For more details, see '
+      'https://github.com/flutter/flutter/issues/59316. '
+      'This feature was deprecated after v1.19.0.'
+    )
+    bool applyTextScaleFactorToWidgetSpan = false,
   }) : assert(text != null),
        assert(textAlign != null),
        assert(softWrap != null),
@@ -5151,6 +5158,7 @@ class RichText extends MultiChildRenderObjectWidget {
        assert(textScaleFactor != null),
        assert(maxLines == null || maxLines > 0),
        assert(textWidthBasis != null),
+       _applyTextScaleFactorToWidgetSpan = applyTextScaleFactorToWidgetSpan,
        super(key: key, children: _extractChildren(text));
 
   // Traverses the InlineSpan tree and depth-first collects the list of
@@ -5228,6 +5236,8 @@ class RichText extends MultiChildRenderObjectWidget {
   /// {@macro flutter.dart:ui.textHeightBehavior}
   final ui.TextHeightBehavior textHeightBehavior;
 
+  final bool _applyTextScaleFactorToWidgetSpan;
+
   @override
   RenderParagraph createRenderObject(BuildContext context) {
     assert(textDirection != null || debugCheckHasDirectionality(context));
@@ -5241,6 +5251,7 @@ class RichText extends MultiChildRenderObjectWidget {
       strutStyle: strutStyle,
       textWidthBasis: textWidthBasis,
       textHeightBehavior: textHeightBehavior,
+      applyTextScaleFactorToWidgetSpan: _applyTextScaleFactorToWidgetSpan,
       locale: locale ?? Localizations.localeOf(context, nullOk: true),
     );
   }

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

@@ -361,6 +361,7 @@ class Text extends StatelessWidget {
          'A non-null String must be provided to a Text widget.',
        ),
        textSpan = null,
+       _applyTextScaleFactorToWidgetSpan = true,
        super(key: key);
 
   /// Creates a text widget with a [InlineSpan].
@@ -388,11 +389,19 @@ class Text extends StatelessWidget {
     this.semanticsLabel,
     this.textWidthBasis,
     this.textHeightBehavior,
+    @Deprecated(
+      'This parameter is a temporary flag to migrate the internal tests and '
+      'should not be used in other contexts. For more details, please check '
+      'https://github.com/flutter/flutter/issues/59316. '
+      'This feature was deprecated after v1.19.0.'
+    )
+    bool applyTextScaleFactorToWidgetSpan = false,
   }) : assert(
          textSpan != null,
          'A non-null TextSpan must be provided to a Text.rich widget.',
        ),
        data = null,
+       _applyTextScaleFactorToWidgetSpan = applyTextScaleFactorToWidgetSpan,
        super(key: key);
 
   /// The text to display.
@@ -493,6 +502,8 @@ class Text extends StatelessWidget {
   /// {@macro flutter.dart:ui.textHeightBehavior}
   final ui.TextHeightBehavior textHeightBehavior;
 
+  final bool _applyTextScaleFactorToWidgetSpan;
+
   @override
   Widget build(BuildContext context) {
     final DefaultTextStyle defaultTextStyle = DefaultTextStyle.of(context);
@@ -512,6 +523,7 @@ class Text extends StatelessWidget {
       strutStyle: strutStyle,
       textWidthBasis: textWidthBasis ?? defaultTextStyle.textWidthBasis,
       textHeightBehavior: textHeightBehavior ?? defaultTextStyle.textHeightBehavior ?? DefaultTextHeightBehavior.of(context),
+      applyTextScaleFactorToWidgetSpan: _applyTextScaleFactorToWidgetSpan,
       text: TextSpan(
         style: effectiveTextStyle,
         text: data,

packages/flutter/test/widgets/text_test.dart

@@ -163,6 +163,70 @@ void main() {
     expect(tester.takeException(), null);
   }, skip: isBrowser); // TODO(yjbanov): https://github.com/flutter/flutter/issues/42086
 
+  testWidgets('inline widgets works with textScaleFactor', (WidgetTester tester) async {
+    // Regression test for https://github.com/flutter/flutter/issues/59316
+    final UniqueKey key = UniqueKey();
+    double textScaleFactor = 1.0;
+    await tester.pumpWidget(
+      MaterialApp(
+        home: Scaffold(
+          appBar: AppBar(title: const Text('title')),
+          body: Center(
+            child: Text.rich(
+              TextSpan(
+                children: <InlineSpan>[
+                  WidgetSpan(
+                    child: RichText(
+                      text: const TextSpan(text: 'widget should be truncated'),
+                      textDirection: TextDirection.ltr,
+                    ),
+                  ),
+                ],
+              ),
+              key: key,
+              textDirection: TextDirection.ltr,
+              textScaleFactor: textScaleFactor,
+              applyTextScaleFactorToWidgetSpan: true,
+            ),
+          ),
+        ),
+      ),
+    );
+    RenderBox renderText = tester.renderObject(find.byKey(key));
+    final double singleLineHeight = renderText.size.height;
+    // Now, increases the text scale factor by 5 times.
+    textScaleFactor = textScaleFactor * 5;
+    await tester.pumpWidget(
+      MaterialApp(
+        home: Scaffold(
+          appBar: AppBar(title: const Text('title')),
+          body: Center(
+            child: Text.rich(
+              TextSpan(
+                children: <InlineSpan>[
+                  WidgetSpan(
+                    child: RichText(
+                      text: const TextSpan(text: 'widget should be truncated'),
+                      textDirection: TextDirection.ltr,
+                    ),
+                  ),
+                ],
+              ),
+              key: key,
+              textDirection: TextDirection.ltr,
+              textScaleFactor: textScaleFactor,
+              applyTextScaleFactorToWidgetSpan: true,
+            ),
+          ),
+        ),
+      ),
+    );
+
+    renderText = tester.renderObject(find.byKey(key));
+    // The RichText in the widget span should wrap into three lines.
+    expect(renderText.size.height, singleLineHeight * textScaleFactor * 3);
+  }, skip: isBrowser); // TODO(yjbanov): https://github.com/flutter/flutter/issues/42086
+
   testWidgets('semanticsLabel can override text label', (WidgetTester tester) async {
     final SemanticsTester semantics = SemanticsTester(tester);
     await tester.pumpWidget(