Add image decode listeners

lib/src/rive_core/assets/image_asset.dart

@@ -12,6 +12,10 @@ class ImageAsset extends ImageAssetBase {
   ui.Image? _image;
   ui.Image? get image => _image;
 
+  /// A list of Images that need to know when the underlying bytes have been
+  ///   successfully decoded.
+  List<Image>? _decodeListeners;
+
   ImageAsset();
 
   @visibleForTesting
@@ -22,12 +26,22 @@ class ImageAsset extends ImageAssetBase {
     _image = image;
   }
 
+  /// Registers [asset] to know when these image bytes have been decoded.
+  void addDecodeListener(Image asset) {
+    (_decodeListeners ??= []).add(asset);
+  }
+
   @override
   Future<void> decode(Uint8List bytes) {
     final completer = Completer<void>();
     ui.decodeImageFromList(bytes, (value) {
       _image = value;
       completer.complete();
+
+      // Tell listeners that the image is ready to be drawn: mark them dirty.
+      _decodeListeners
+        ?..forEach((e) => e.context.markNeedsAdvance())
+        ..clear();
     });
     return completer.future;
   }

lib/src/rive_core/shapes/image.dart

@@ -37,8 +37,9 @@ class Image extends ImageBase
 
   @override
   void draw(ui.Canvas canvas) {
-    var uiImage = asset?.image;
+    final uiImage = asset?.image;
     if (uiImage == null) {
+      print('No image yet?! ${asset?.name} $uiImage');
       return;
     }
     bool clipped = clip(canvas);
@@ -84,7 +85,6 @@ class Image extends ImageBase
     }
   }
 
-
   @override
   int get assetIdPropertyKey => ImageBase.assetIdPropertyKey;
 
@@ -100,6 +100,9 @@ class Image extends ImageBase
   void copy(covariant Image source) {
     super.copy(source);
     asset = source.asset;
+    if (asset?.image == null) {
+      asset?.addDecodeListener(this);
+    }
   }
 
   @override