Support for FilterQuality in FadeInImage (#110096)

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

@@ -65,9 +65,12 @@ class FadeInImage extends StatefulWidget {
   /// The [placeholder] and [image] may be composed in a [ResizeImage] to provide
   /// a custom decode/cache size.
   ///
-  /// The [placeholder] and [image] may be have their own BoxFit settings via [fit]
+  /// The [placeholder] and [image] may have their own BoxFit settings via [fit]
   /// and [placeholderFit].
   ///
+  /// The [placeholder] and [image] may have their own FilterQuality settings via [filterQuality]
+  /// and [placeholderFilterQuality].
+  ///
   /// The [placeholder], [image], [fadeOutDuration], [fadeOutCurve],
   /// [fadeInDuration], [fadeInCurve], [alignment], [repeat], and
   /// [matchTextDirection] arguments must not be null.
@@ -89,6 +92,8 @@ class FadeInImage extends StatefulWidget {
     this.height,
     this.fit,
     this.placeholderFit,
+    this.filterQuality = FilterQuality.low,
+    this.placeholderFilterQuality,
     this.alignment = Alignment.center,
     this.repeat = ImageRepeat.noRepeat,
     this.matchTextDirection = false,
@@ -148,6 +153,8 @@ class FadeInImage extends StatefulWidget {
     this.height,
     this.fit,
     this.placeholderFit,
+    this.filterQuality = FilterQuality.low,
+    this.placeholderFilterQuality,
     this.alignment = Alignment.center,
     this.repeat = ImageRepeat.noRepeat,
     this.matchTextDirection = false,
@@ -219,6 +226,8 @@ class FadeInImage extends StatefulWidget {
     this.height,
     this.fit,
     this.placeholderFit,
+    this.filterQuality = FilterQuality.low,
+    this.placeholderFilterQuality,
     this.alignment = Alignment.center,
     this.repeat = ImageRepeat.noRepeat,
     this.matchTextDirection = false,
@@ -301,6 +310,16 @@ class FadeInImage extends StatefulWidget {
   /// If not value set, it will fallback to [fit].
   final BoxFit? placeholderFit;
 
+  /// The rendering quality of the image.
+  ///
+  /// {@macro flutter.widgets.image.filterQuality}
+  final FilterQuality filterQuality;
+
+  /// The rendering quality of the placeholder image.
+  ///
+  /// {@macro flutter.widgets.image.filterQuality}
+  final FilterQuality? placeholderFilterQuality;
+
   /// How to align the image within its bounds.
   ///
   /// The alignment aligns the given position in the image to the given position
@@ -379,6 +398,7 @@ class _FadeInImageState extends State<FadeInImage> {
     ImageErrorWidgetBuilder? errorBuilder,
     ImageFrameBuilder? frameBuilder,
     BoxFit? fit,
+    required FilterQuality filterQuality,
     required Animation<double> opacity,
   }) {
     assert(image != null);
@@ -390,6 +410,7 @@ class _FadeInImageState extends State<FadeInImage> {
       width: widget.width,
       height: widget.height,
       fit: fit,
+      filterQuality: filterQuality,
       alignment: widget.alignment,
       repeat: widget.repeat,
       matchTextDirection: widget.matchTextDirection,
@@ -405,6 +426,7 @@ class _FadeInImageState extends State<FadeInImage> {
       errorBuilder: widget.imageErrorBuilder,
       opacity: _imageAnimation,
       fit: widget.fit,
+      filterQuality: widget.filterQuality,
       frameBuilder: (BuildContext context, Widget child, int? frame, bool wasSynchronouslyLoaded) {
         if (wasSynchronouslyLoaded || frame != null) {
           targetLoaded = true;
@@ -417,6 +439,7 @@ class _FadeInImageState extends State<FadeInImage> {
             errorBuilder: widget.placeholderErrorBuilder,
             opacity: _placeholderAnimation,
             fit: widget.placeholderFit ?? widget.fit,
+            filterQuality: widget.placeholderFilterQuality ?? widget.filterQuality,
           ),
           placeholderProxyAnimation: _placeholderAnimation,
           isTargetLoaded: targetLoaded,

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

@@ -870,6 +870,7 @@ class Image extends StatefulWidget {
 
   /// The rendering quality of the image.
   ///
+  /// {@template flutter.widgets.image.filterQuality}
   /// If the image is of a high quality and its pixels are perfectly aligned
   /// with the physical screen pixels, extra quality enhancement may not be
   /// necessary. If so, then [FilterQuality.none] would be the most efficient.
@@ -884,6 +885,7 @@ class Image extends StatefulWidget {
   ///
   ///  * [FilterQuality], the enum containing all possible filter quality
   ///    options.
+  /// {@endtemplate}
   final FilterQuality filterQuality;
 
   /// Used to combine [color] with this image.

packages/flutter/test/widgets/fade_in_image_test.dart

@@ -52,6 +52,7 @@ class FadeInImageElements {
   RawImage get rawImage => rawImageElement.widget as RawImage;
   double get opacity => rawImage.opacity?.value ?? 1.0;
   BoxFit? get fit => rawImage.fit;
+  FilterQuality? get filterQuality => rawImage.filterQuality;
 }
 
 class LoadTestImageProvider extends ImageProvider<Object> {
@@ -517,5 +518,36 @@ Future<void> main() async {
         expect(findFadeInImage(tester).placeholder!.fit, equals(BoxFit.fill));
       });
     });
+
+    group("placeholder's FilterQuality", () {
+      testWidgets("should be the image's FilterQuality when not set", (WidgetTester tester) async {
+        final TestImageProvider placeholderProvider = TestImageProvider(placeholderImage);
+        final TestImageProvider imageProvider = TestImageProvider(targetImage);
+
+        await tester.pumpWidget(FadeInImage(
+          placeholder: placeholderProvider,
+          image: imageProvider,
+          filterQuality: FilterQuality.medium,
+        ));
+
+        expect(findFadeInImage(tester).placeholder!.filterQuality, equals(findFadeInImage(tester).target.filterQuality));
+        expect(findFadeInImage(tester).placeholder!.filterQuality, equals(FilterQuality.medium));
+      });
+
+      testWidgets('should be the given value when set', (WidgetTester tester) async {
+        final TestImageProvider placeholderProvider = TestImageProvider(placeholderImage);
+        final TestImageProvider imageProvider = TestImageProvider(targetImage);
+
+        await tester.pumpWidget(FadeInImage(
+          placeholder: placeholderProvider,
+          image: imageProvider,
+          filterQuality: FilterQuality.medium,
+          placeholderFilterQuality: FilterQuality.high,
+        ));
+
+        expect(findFadeInImage(tester).target.filterQuality, equals(FilterQuality.medium));
+        expect(findFadeInImage(tester).placeholder!.filterQuality, equals(FilterQuality.high));
+      });
+    });
   });
 }