Added a filterQuality parameter to texture (#59966)

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

@@ -581,11 +581,12 @@ class PictureLayer extends Layer {
 class TextureLayer extends Layer {
   /// Creates a texture layer bounded by [rect] and with backend texture
   /// identified by [textureId], if [freeze] is true new texture frames will not be
-  /// populated to the texture.
+  /// populated to the texture, and use [filterQuality] to set layer's [FilterQuality].
   TextureLayer({
     @required this.rect,
     @required this.textureId,
     this.freeze = false,
+    this.filterQuality = ui.FilterQuality.low,
   }) : assert(rect != null),
        assert(textureId != null);
 
@@ -604,6 +605,9 @@ class TextureLayer extends Layer {
   /// un-freezes it when it is certain that a frame with the new size is ready.
   final bool freeze;
 
+  /// {@macro FilterQuality}
+  final ui.FilterQuality filterQuality;
+
   @override
   void addToScene(ui.SceneBuilder builder, [ Offset layerOffset = Offset.zero ]) {
     final Rect shiftedRect = layerOffset == Offset.zero ? rect : rect.shift(layerOffset);
@@ -613,6 +617,7 @@ class TextureLayer extends Layer {
       width: shiftedRect.width,
       height: shiftedRect.height,
       freeze: freeze,
+      filterQuality: filterQuality,
     );
   }
 

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

@@ -37,10 +37,14 @@ import 'object.dart';
 ///  * <https://api.flutter.dev/objcdoc/Protocols/FlutterTextureRegistry.html>
 ///    for how to create and manage backend textures on iOS.
 class TextureBox extends RenderBox {
-  /// Creates a box backed by the texture identified by [textureId].
-  TextureBox({ @required int textureId })
-    : assert(textureId != null),
-      _textureId = textureId;
+  /// Creates a box backed by the texture identified by [textureId], and use
+  /// [filterQuality] to set texture's [FilterQuality].
+  TextureBox({
+    @required int textureId,
+    FilterQuality filterQuality = FilterQuality.low,
+  }) : assert(textureId != null),
+      _textureId = textureId,
+      _filterQuality = filterQuality;
 
   /// The identity of the backend texture.
   int get textureId => _textureId;
@@ -53,6 +57,17 @@ class TextureBox extends RenderBox {
     }
   }
 
+  /// {@macro FilterQuality}
+  FilterQuality get filterQuality => _filterQuality;
+  FilterQuality _filterQuality;
+  set filterQuality(FilterQuality value) {
+    assert(value != null);
+    if (value == _filterQuality)
+      return;
+    _filterQuality = value;
+    markNeedsPaint();
+  }
+
   @override
   bool get sizedByParent => true;
 
@@ -77,6 +92,7 @@ class TextureBox extends RenderBox {
     context.addLayer(TextureLayer(
       rect: Rect.fromLTWH(offset.dx, offset.dy, size.width, size.height),
       textureId: _textureId,
+      filterQuality: _filterQuality,
     ));
   }
 }

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

@@ -35,21 +35,34 @@ import 'framework.dart';
 ///  * <https://api.flutter.dev/objcdoc/Protocols/FlutterTextureRegistry.html>
 ///    for how to create and manage backend textures on iOS.
 class Texture extends LeafRenderObjectWidget {
-  /// Creates a widget backed by the texture identified by [textureId].
+  /// Creates a widget backed by the texture identified by [textureId], and use
+  /// [filterQuality] to set texture's [FilterQuality].
   const Texture({
     Key key,
     @required this.textureId,
+    this.filterQuality = FilterQuality.low,
   }) : assert(textureId != null),
        super(key: key);
 
   /// The identity of the backend texture.
   final int textureId;
 
+  /// {@template FilterQuality}
+  /// The quality of sampling the texture and rendering it on screen.
+  ///
+  /// When the texture is scaled, a default [FilterQuality.low] is used for a higher quality but slower
+  /// interpolation (typically bilinear). It can be changed to [FilterQuality.none] for a lower quality but
+  /// faster interpolation (typically nearest-neighbor). See also [FilterQuality.medium] and
+  /// [FilterQuality.high] for more options.
+  /// {@endtemplate}
+  final FilterQuality filterQuality;
+
   @override
-  TextureBox createRenderObject(BuildContext context) => TextureBox(textureId: textureId);
+  TextureBox createRenderObject(BuildContext context) => TextureBox(textureId: textureId, filterQuality: filterQuality);
 
   @override
   void updateRenderObject(BuildContext context, TextureBox renderObject) {
     renderObject.textureId = textureId;
+    renderObject.filterQuality = filterQuality;
   }
 }

packages/flutter/test/widgets/texture_test.dart

+// Copyright 2014 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import 'package:flutter_test/flutter_test.dart';
+import 'package:flutter/rendering.dart';
+import 'package:flutter/widgets.dart';
+
+void main() {
+  testWidgets('Texture with default FilterQuality', (WidgetTester tester) async {
+    await tester.pumpWidget(
+        const Center(child: Texture(textureId: 1,))
+    );
+
+    final Texture texture = tester.firstWidget(find.byType(Texture));
+    expect(texture, isNotNull);
+    expect(texture.textureId, 1);
+    expect(texture.filterQuality, FilterQuality.low);
+
+    final RenderObject renderObject = tester.firstRenderObject(find.byType(Texture));
+    expect(renderObject, isNotNull);
+    final TextureBox textureBox = renderObject as TextureBox;
+    expect(textureBox, isNotNull);
+    expect(textureBox.textureId, 1);
+    expect(textureBox.filterQuality, FilterQuality.low);
+
+    final ContainerLayer containerLayer = ContainerLayer();
+    final PaintingContext paintingContext = PaintingContext(containerLayer, Rect.zero);
+    textureBox.paint(paintingContext, Offset.zero);
+    final Layer layer = containerLayer.lastChild;
+    expect(layer, isNotNull);
+    final TextureLayer textureLayer = layer as TextureLayer;
+    expect(textureLayer, isNotNull);
+    expect(textureLayer.textureId, 1);
+    expect(textureLayer.filterQuality, FilterQuality.low);
+  });
+
+
+  testWidgets('Texture with FilterQuality.none', (WidgetTester tester) async {
+    await tester.pumpWidget(
+        const Center(child: Texture(textureId: 1, filterQuality: FilterQuality.none))
+    );
+
+    final Texture texture = tester.firstWidget(find.byType(Texture));
+    expect(texture, isNotNull);
+    expect(texture.textureId, 1);
+    expect(texture.filterQuality, FilterQuality.none);
+
+    final RenderObject renderObject = tester.firstRenderObject(find.byType(Texture));
+    expect(renderObject, isNotNull);
+    final TextureBox textureBox = renderObject as TextureBox;
+    expect(textureBox, isNotNull);
+    expect(textureBox.textureId, 1);
+    expect(textureBox.filterQuality, FilterQuality.none);
+
+    final ContainerLayer containerLayer = ContainerLayer();
+    final PaintingContext paintingContext = PaintingContext(containerLayer, Rect.zero);
+    textureBox.paint(paintingContext, Offset.zero);
+    final Layer layer = containerLayer.lastChild;
+    expect(layer, isNotNull);
+    final TextureLayer textureLayer = layer as TextureLayer;
+    expect(textureLayer, isNotNull);
+    expect(textureLayer.textureId, 1);
+    expect(textureLayer.filterQuality, FilterQuality.none);
+  });
+
+  testWidgets('Texture with FilterQuality.low', (WidgetTester tester) async {
+    await tester.pumpWidget(
+        const Center(child: Texture(textureId: 1, filterQuality: FilterQuality.low))
+    );
+
+    final Texture texture = tester.firstWidget(find.byType(Texture));
+    expect(texture, isNotNull);
+    expect(texture.textureId, 1);
+    expect(texture.filterQuality, FilterQuality.low);
+
+    final RenderObject renderObject = tester.firstRenderObject(find.byType(Texture));
+    expect(renderObject, isNotNull);
+    final TextureBox textureBox = renderObject as TextureBox;
+    expect(textureBox, isNotNull);
+    expect(textureBox.textureId, 1);
+    expect(textureBox.filterQuality, FilterQuality.low);
+
+    final ContainerLayer containerLayer = ContainerLayer();
+    final PaintingContext paintingContext = PaintingContext(containerLayer, Rect.zero);
+    textureBox.paint(paintingContext, Offset.zero);
+    final Layer layer = containerLayer.lastChild;
+    expect(layer, isNotNull);
+    final TextureLayer textureLayer = layer as TextureLayer;
+    expect(textureLayer, isNotNull);
+    expect(textureLayer.textureId, 1);
+    expect(textureLayer.filterQuality, FilterQuality.low);
+  });
+}