Add TextOverflow into TextStyle (#78927)

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

@@ -21,6 +21,24 @@ export 'package:flutter/services.dart' show TextRange, TextSelection;
 // defaults set in the engine (eg, LibTxt's text_style.h, paragraph_style.h).
 const double _kDefaultFontSize = 14.0;
 
+/// How overflowing text should be handled.
+///
+/// A [TextOverflow] can be passed to [Text] and [RichText] via their
+/// [Text.overflow] and [RichText.overflow] properties respectively.
+enum TextOverflow {
+  /// Clip the overflowing text to fix its container.
+  clip,
+
+  /// Fade the overflowing text to transparent.
+  fade,
+
+  /// Use an ellipsis to indicate that the text has overflowed.
+  ellipsis,
+
+  /// Render overflowing text outside of its container.
+  visible,
+}
+
 /// Holds the [Size] and baseline required to represent the dimensions of
 /// a placeholder in text.
 ///

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

@@ -10,6 +10,7 @@ import 'package:flutter/foundation.dart';
 import 'basic_types.dart';
 import 'colors.dart';
 import 'strut_style.dart';
+import 'text_painter.dart';
 
 const String _kDefaultDebugLabel = 'unknown';
 
@@ -480,6 +481,7 @@ class TextStyle with Diagnosticable {
     String? fontFamily,
     List<String>? fontFamilyFallback,
     String? package,
+    this.overflow,
   }) : fontFamily = package == null ? fontFamily : 'packages/$package/$fontFamily',
        _fontFamilyFallback = fontFamilyFallback,
        _package = package,
@@ -758,6 +760,9 @@ class TextStyle with Diagnosticable {
   /// these variants will be used for rendering.
   final List<ui.FontFeature>? fontFeatures;
 
+  /// How visual text overflow should be handled.
+  final TextOverflow? overflow;
+
   /// Creates a copy of this text style but with the given fields replaced with
   /// the new values.
   ///
@@ -791,6 +796,7 @@ class TextStyle with Diagnosticable {
     TextDecorationStyle? decorationStyle,
     double? decorationThickness,
     String? debugLabel,
+    TextOverflow? overflow,
   }) {
     assert(color == null || foreground == null, _kColorForegroundWarning);
     assert(backgroundColor == null || background == null, _kColorBackgroundWarning);
@@ -824,6 +830,7 @@ class TextStyle with Diagnosticable {
       decorationStyle: decorationStyle ?? this.decorationStyle,
       decorationThickness: decorationThickness ?? this.decorationThickness,
       debugLabel: newDebugLabel,
+      overflow: overflow ?? this.overflow
     );
   }
 
@@ -881,6 +888,7 @@ class TextStyle with Diagnosticable {
     Locale? locale,
     List<ui.Shadow>? shadows,
     List<ui.FontFeature>? fontFeatures,
+    TextOverflow? overflow,
   }) {
     assert(fontSizeFactor != null);
     assert(fontSizeDelta != null);
@@ -929,6 +937,7 @@ class TextStyle with Diagnosticable {
       decorationColor: decorationColor ?? this.decorationColor,
       decorationStyle: decorationStyle ?? this.decorationStyle,
       decorationThickness: decorationThickness == null ? null : decorationThickness! * decorationThicknessFactor + decorationThicknessDelta,
+      overflow: overflow ?? this.overflow,
       debugLabel: modifiedDebugLabel,
     );
   }
@@ -989,6 +998,7 @@ class TextStyle with Diagnosticable {
       decorationColor: other.decorationColor,
       decorationStyle: other.decorationStyle,
       decorationThickness: other.decorationThickness,
+      overflow: other.overflow,
       debugLabel: mergedDebugLabel,
     );
   }
@@ -1043,6 +1053,7 @@ class TextStyle with Diagnosticable {
         decorationColor: Color.lerp(null, b.decorationColor, t),
         decorationStyle: t < 0.5 ? null : b.decorationStyle,
         decorationThickness: t < 0.5 ? null : b.decorationThickness,
+        overflow: t < 0.5 ? null : b.overflow,
         debugLabel: lerpDebugLabel,
       );
     }
@@ -1071,6 +1082,7 @@ class TextStyle with Diagnosticable {
         decorationColor: Color.lerp(a.decorationColor, null, t),
         decorationStyle: t < 0.5 ? a.decorationStyle : null,
         decorationThickness: t < 0.5 ? a.decorationThickness : null,
+        overflow: t < 0.5 ? a.overflow : null,
         debugLabel: lerpDebugLabel,
       );
     }
@@ -1106,6 +1118,7 @@ class TextStyle with Diagnosticable {
       decorationColor: Color.lerp(a.decorationColor, b.decorationColor, t),
       decorationStyle: t < 0.5 ? a.decorationStyle : b.decorationStyle,
       decorationThickness: ui.lerpDouble(a.decorationThickness ?? b.decorationThickness, b.decorationThickness ?? a.decorationThickness, t),
+      overflow: t < 0.5 ? a.overflow : b.overflow,
       debugLabel: lerpDebugLabel,
     );
   }
@@ -1218,7 +1231,8 @@ class TextStyle with Diagnosticable {
         background != other.background ||
         !listEquals(shadows, other.shadows) ||
         !listEquals(fontFeatures, other.fontFeatures) ||
-        !listEquals(fontFamilyFallback, other.fontFamilyFallback))
+        !listEquals(fontFamilyFallback, other.fontFamilyFallback) ||
+        overflow != other.overflow)
       return RenderComparison.layout;
     if (color != other.color ||
         backgroundColor != other.backgroundColor ||
@@ -1258,7 +1272,8 @@ class TextStyle with Diagnosticable {
         && other.decorationThickness == decorationThickness
         && listEquals(other.shadows, shadows)
         && listEquals(other.fontFeatures, fontFeatures)
-        && listEquals(other.fontFamilyFallback, fontFamilyFallback);
+        && listEquals(other.fontFamilyFallback, fontFamilyFallback)
+        && other.overflow == overflow;
   }
 
   @override
@@ -1285,6 +1300,7 @@ class TextStyle with Diagnosticable {
       hashList(shadows),
       hashList(fontFeatures),
       hashList(fontFamilyFallback),
+      overflow,
     ]);
   }
 
@@ -1355,5 +1371,7 @@ class TextStyle with Diagnosticable {
 
     if (!styleSpecified)
       properties.add(FlagProperty('inherit', value: inherit, ifTrue: '$prefix<all styles inherited>', ifFalse: '$prefix<no style specified>'));
+
+    styles.add(EnumProperty<TextOverflow>('${prefix}overflow', overflow, defaultValue: null));
   }
 }

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

@@ -16,24 +16,6 @@ import 'box.dart';
 import 'debug.dart';
 import 'object.dart';
 
-/// How overflowing text should be handled.
-///
-/// A [TextOverflow] can be passed to [Text] and [RichText] via their
-/// [Text.overflow] and [RichText.overflow] properties respectively.
-enum TextOverflow {
-  /// Clip the overflowing text to fix its container.
-  clip,
-
-  /// Fade the overflowing text to transparent.
-  fade,
-
-  /// Use an ellipsis to indicate that the text has overflowed.
-  ellipsis,
-
-  /// Render overflowing text outside of its container.
-  visible,
-}
-
 const String _kEllipsis = '\u2026';
 
 /// Parent data for use with [RenderParagraph].

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

@@ -467,7 +467,8 @@ class Text extends StatelessWidget {
 
   /// How visual overflow should be handled.
   ///
-  /// Defaults to retrieving the value from the nearest [DefaultTextStyle] ancestor.
+  /// If this is null [TextStyle.overflow] will be used, otherwise the value
+  /// from the nearest [DefaultTextStyle] ancestor will be used.
   final TextOverflow? overflow;
 
   /// The number of font pixels for each logical pixel.
@@ -526,7 +527,7 @@ class Text extends StatelessWidget {
       textDirection: textDirection, // RichText uses Directionality.of to obtain a default if this is null.
       locale: locale, // RichText uses Localizations.localeOf to obtain a default if this is null
       softWrap: softWrap ?? defaultTextStyle.softWrap,
-      overflow: overflow ?? defaultTextStyle.overflow,
+      overflow: overflow ?? effectiveTextStyle?.overflow ?? defaultTextStyle.overflow,
       textScaleFactor: textScaleFactor ?? MediaQuery.textScaleFactorOf(context),
       maxLines: maxLines ?? defaultTextStyle.maxLines,
       strutStyle: strutStyle,

packages/flutter/test/material/theme_test.dart

@@ -744,6 +744,8 @@ class _TextStyleProxy implements TextStyle {
   List<Shadow>? get shadows => _delegate.shadows;
   @override
   List<ui.FontFeature>? get fontFeatures => _delegate.fontFeatures;
+  @override
+  TextOverflow? get overflow => _delegate.overflow;
 
   @override
   String toString({ DiagnosticLevel minLevel = DiagnosticLevel.info }) =>
@@ -785,6 +787,7 @@ class _TextStyleProxy implements TextStyle {
     Locale? locale,
     List<ui.Shadow>? shadows,
     List<ui.FontFeature>? fontFeatures,
+    TextOverflow? overflow,
   }) {
     throw UnimplementedError();
   }
@@ -819,6 +822,7 @@ class _TextStyleProxy implements TextStyle {
     TextDecorationStyle? decorationStyle,
     double? decorationThickness,
     String? debugLabel,
+    TextOverflow? overflow,
   }) {
     throw UnimplementedError();
   }

packages/flutter/test/widgets/text_test.dart

@@ -1248,6 +1248,21 @@ void main() {
     // The inline spans are rendered in one vertical run, the widest one determines the min intrinsic width.
     expect(paragraph.getMinIntrinsicWidth(0.0), 200);
   });
+
+  testWidgets('Text uses TextStyle.overflow', (WidgetTester tester) async {
+    const TextOverflow overflow = TextOverflow.fade;
+
+    await tester.pumpWidget( const Text(
+      'Hello World',
+      textDirection: TextDirection.ltr,
+      style: TextStyle(overflow: overflow),
+    ));
+
+    final RichText richText = tester.firstWidget(find.byType(RichText));
+
+    expect(richText.overflow, overflow);
+    expect(richText.text.style!.overflow, overflow);
+  });
 }
 
 Future<void> _pumpTextWidget({