Add an image delegate to dynamically change images (#130)

And allow to use an imageProviderFactory with a zip file.

example/test/dynamic_image_test.dart

@@ -0,0 +1,74 @@
+import 'dart:async';
+import 'dart:io';
+import 'dart:ui' as ui;
+import 'package:flutter/widgets.dart';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:lottie/lottie.dart';
+import 'utils.dart';
+
+void main() {
+  testWidgets('Can specify ImageProvider with zip file ', (tester) async {
+    var size = Size(500, 400);
+    tester.binding.window.physicalSizeTestValue = size;
+    tester.binding.window.devicePixelRatioTestValue = 1.0;
+
+    var callCount = 0;
+    LottieImageProviderFactory imageProviderFactory = (image) {
+      ++callCount;
+      return FileImage(File('assets/Images/WeAccept/img_0.png'));
+    };
+
+    var composition = (await tester.runAsync(() => FileLottie(
+            File('assets/spinning_carrousel.zip'),
+            imageProviderFactory: imageProviderFactory)
+        .load()))!;
+
+    await tester.pumpWidget(FilmStrip(composition, size: size));
+
+    expect(callCount, 2);
+    await expectLater(find.byType(FilmStrip),
+        matchesGoldenFile('goldens/dynamic_image/zip_with_provider.png'));
+  });
+
+  testWidgets('Can specify image delegate', (tester) async {
+    var size = Size(500, 400);
+    tester.binding.window.physicalSizeTestValue = size;
+    tester.binding.window.devicePixelRatioTestValue = 1.0;
+
+    var image = await tester.runAsync(
+        () => loadImage(FileImage(File('assets/Images/WeAccept/img_0.png'))));
+
+    var composition = (await tester.runAsync(
+        () => FileLottie(File('assets/spinning_carrousel.zip')).load()))!;
+
+    var delegates = LottieDelegates(image: (composition, asset) {
+      return image;
+    });
+    await tester.pumpWidget(FilmStrip(
+      composition,
+      size: size,
+      delegates: delegates,
+    ));
+
+    await expectLater(find.byType(FilmStrip),
+        matchesGoldenFile('goldens/dynamic_image/delegate.png'));
+  });
+}
+
+Future<ui.Image?> loadImage(ImageProvider provider) {
+  var completer = Completer<ui.Image?>();
+  var imageStream = provider.resolve(ImageConfiguration.empty);
+  late ImageStreamListener listener;
+  listener = ImageStreamListener((image, synchronousLoaded) {
+    imageStream.removeListener(listener);
+
+    completer.complete(image.image);
+  }, onError: (dynamic e, __) {
+    imageStream.removeListener(listener);
+
+    completer.complete();
+  });
+  imageStream.addListener(listener);
+
+  return completer.future;
+}

lib/lottie.dart

@@ -9,6 +9,7 @@ export 'src/model/marker.dart' show Marker;
 export 'src/options.dart' show LottieOptions;
 export 'src/providers/asset_provider.dart' show AssetLottie;
 export 'src/providers/file_provider.dart' show FileLottie;
+export 'src/providers/load_image.dart' show LottieImageProviderFactory;
 export 'src/providers/lottie_provider.dart' show LottieProvider;
 export 'src/providers/memory_provider.dart' show MemoryLottie;
 export 'src/providers/network_provider.dart' show NetworkLottie;

lib/src/animation/content/base_stroke_content.dart

@@ -241,8 +241,7 @@ abstract class BaseStrokeContent
     var bounds = _path.getBounds();
 
     var width = _widthAnimation.value;
-    bounds = Rect.fromLTRB(bounds.left - width / 2.0, bounds.top - width / 2.0,
-        bounds.right + width / 2.0, bounds.bottom + width / 2.0);
+    bounds = bounds.inflate(width / 2.0);
     // Add padding to account for rounding errors.
     bounds = bounds.inflate(1);
     L.endSection('StrokeContent#getBounds');

lib/src/composition.dart

@@ -34,12 +34,14 @@ class CompositionParameters {
 }
 
 class LottieComposition {
-  static Future<LottieComposition> fromByteData(ByteData data, {String? name}) {
-    return fromBytes(data.buffer.asUint8List(), name: name);
+  static Future<LottieComposition> fromByteData(ByteData data,
+      {String? name, LottieImageProviderFactory? imageProviderFactory}) {
+    return fromBytes(data.buffer.asUint8List(),
+        name: name, imageProviderFactory: imageProviderFactory);
   }
 
   static Future<LottieComposition> fromBytes(Uint8List bytes,
-      {String? name}) async {
+      {String? name, LottieImageProviderFactory? imageProviderFactory}) async {
     Archive? archive;
     if (bytes[0] == 0x50 && bytes[1] == 0x4B) {
       archive = ZipDecoder().decodeBytes(bytes);
@@ -55,8 +57,18 @@ class LottieComposition {
         var imagePath = p.posix.join(image.dirName, image.fileName);
         var found = archive.files.firstWhereOrNull(
             (f) => f.name.toLowerCase() == imagePath.toLowerCase());
+
+        ImageProvider? provider;
+        if (imageProviderFactory != null) {
+          provider = imageProviderFactory(image);
+        }
+
+        if (provider != null) {
+          image.loadedImage = await loadImage(composition, image, provider);
+        }
+
         if (found != null) {
-          image.loadedImage = await loadImage(
+          image.loadedImage ??= await loadImage(
               composition, image, MemoryImage(found.content as Uint8List));
         }
       }

lib/src/lottie_delegates.dart

@@ -1,4 +1,6 @@
+import 'dart:ui' as ui;
 import 'package:flutter/widgets.dart';
+import '../lottie.dart';
 import 'lottie_drawable.dart';
 import 'value_delegate.dart';
 
@@ -43,12 +45,31 @@ class LottieDelegates {
   /// ```
   final List<ValueDelegate>? values;
 
-  //TODO(xha): imageDelegate to change the image to display?
+  /// A callback to dynamically change an image of the animation.
+  ///
+  /// Example:
+  /// ```dart
+  /// Lottie.asset(
+  //   'assets/data.json',
+  //   delegates: LottieDelegates(
+  //     image: (composition, image) {
+  //       if (image.id == 'img_0' && _isMouseOver) {
+  //         return myCustomImage;
+  //       }
+  //
+  //       // Use the default method: composition.images[image.id].loadedImage;
+  //       return null;
+  //     },
+  //   )
+  // )
+  /// ```
+  final ui.Image? Function(LottieComposition, LottieImageAsset)? image;
 
   LottieDelegates({
     this.text,
     TextStyle Function(LottieFontStyle)? textStyle,
     this.values,
+    this.image,
   }) : textStyle = textStyle;
 
   @override

lib/src/lottie_drawable.dart

@@ -79,7 +79,13 @@ class LottieDrawable {
   ui.Image? getImageAsset(String? ref) {
     var imageAsset = composition.images[ref];
     if (imageAsset != null) {
-      return imageAsset.loadedImage;
+      var imageDelegate = delegates?.image;
+      ui.Image? image;
+      if (imageDelegate != null) {
+        image = imageDelegate(composition, imageAsset);
+      }
+
+      return image ?? imageAsset.loadedImage;
     } else {
       return null;
     }

lib/src/model/layer/base_layer.dart

@@ -261,10 +261,7 @@ abstract class BaseLayer implements DrawingContent, KeyPathElement {
   void _clearCanvas(Canvas canvas, Rect bounds) {
     L.beginSection('Layer#clearLayer');
     // If we don't pad the clear draw, some phones leave a 1px border of the graphics buffer.
-    canvas.drawRect(
-        Rect.fromLTRB(bounds.left - 1, bounds.top - 1, bounds.right + 1,
-            bounds.bottom + 1),
-        _clearPaint);
+    canvas.drawRect(bounds.inflate(1), _clearPaint);
     L.endSection('Layer#clearLayer');
   }
 

lib/src/parser/lottie_composition_parser.dart

@@ -101,14 +101,13 @@ class LottieCompositionParser {
       }
       layers.add(layer);
       layerMap[layer.id] = layer;
-
+    }
     if (imageCount > 4) {
       composition.addWarning(
           'You have $imageCount images. Lottie should primarily be '
           'used with shapes. If you are using Adobe Illustrator, convert the Illustrator layers'
           ' to shape layers.');
     }
-    }
     reader.endArray();
   }
 

lib/src/providers/asset_provider.dart

@@ -33,7 +33,8 @@ class AssetLottie extends LottieProvider {
       var data = await chosenBundle.load(keyName);
 
       var composition = await LottieComposition.fromByteData(data,
-          name: p.url.basenameWithoutExtension(keyName));
+          name: p.url.basenameWithoutExtension(keyName),
+          imageProviderFactory: imageProviderFactory);
 
       for (var image in composition.images.values) {
         image.loadedImage ??= await _loadImage(composition, image);

lib/src/providers/file_provider.dart

@@ -18,7 +18,8 @@ class FileLottie extends LottieProvider {
     return sharedLottieCache.putIfAbsent(cacheKey, () async {
       var bytes = await io.loadFile(file);
       var composition = await LottieComposition.fromBytes(bytes,
-          name: p.basenameWithoutExtension(io.filePath(file)));
+          name: p.basenameWithoutExtension(io.filePath(file)),
+          imageProviderFactory: imageProviderFactory);
 
       for (var image in composition.images.values) {
         image.loadedImage ??= await _loadImage(composition, image);

lib/src/providers/load_image.dart

@@ -4,7 +4,7 @@ import 'package:flutter/widgets.dart';
 import '../composition.dart';
 import '../lottie_image_asset.dart';
 
-typedef LottieImageProviderFactory = ImageProvider Function(LottieImageAsset);
+typedef LottieImageProviderFactory = ImageProvider? Function(LottieImageAsset);
 
 Future<ui.Image?> loadImage(LottieComposition composition,
     LottieImageAsset lottieImage, ImageProvider provider) {

lib/src/providers/memory_provider.dart

@@ -18,7 +18,8 @@ class MemoryLottie extends LottieProvider {
     // TODO(xha): hash the list content
     var cacheKey = 'memory-${bytes.hashCode}-${bytes.lengthInBytes}';
     return sharedLottieCache.putIfAbsent(cacheKey, () async {
-      var composition = await LottieComposition.fromBytes(bytes);
+      var composition = await LottieComposition.fromBytes(bytes,
+          imageProviderFactory: imageProviderFactory);
       for (var image in composition.images.values) {
         image.loadedImage ??= await _loadImage(composition, image);
       }

lib/src/providers/network_provider.dart

@@ -24,7 +24,8 @@ class NetworkLottie extends LottieProvider {
       var bytes = await network.loadHttp(resolved, headers: headers);
 
       var composition = await LottieComposition.fromBytes(bytes,
-          name: p.url.basenameWithoutExtension(url));
+          name: p.url.basenameWithoutExtension(url),
+          imageProviderFactory: imageProviderFactory);
 
       for (var image in composition.images.values) {
         image.loadedImage ??= await _loadImage(resolved, composition, image);

pubspec.yaml

@@ -1,6 +1,6 @@
 name: lottie
 description: Render After Effects animations natively on Flutter. This package is a pure Dart implementation of a Lottie player.
-version: 0.8.0-nullsafety.2
+version: 0.8.0-nullsafety.3
 homepage: https://github.com/xvrh/lottie-flutter
 
 environment: