Scale image if the dp scale changes (#2438)

Fixes #2216

lottie-compose/src/test/java/com/airbnb/lottie/compose/LottieClipSpecTest.kt

@@ -135,10 +135,11 @@ class LottieClipSpecTest {
             LongSparseArray(),
             emptyMap(),
             emptyMap(),
+            1f,
             SparseArrayCompat(),
             emptyMap(),
             markers,
         )
         return composition
     }
-}
+}

lottie/src/main/java/com/airbnb/lottie/LottieComposition.java

@@ -19,15 +19,18 @@
 import com.airbnb.lottie.parser.moshi.JsonReader;
 import com.airbnb.lottie.utils.Logger;
 import com.airbnb.lottie.utils.MiscUtils;
+import com.airbnb.lottie.utils.Utils;
 
 import org.json.JSONObject;
 
 import java.io.InputStream;
 import java.util.ArrayList;
 import java.util.Arrays;
+import java.util.Collection;
 import java.util.HashSet;
 import java.util.List;
 import java.util.Map;
+import java.util.Set;
 
 /**
  * After Effects/Bodymovin composition model. This is the serialized model from which the
@@ -44,6 +47,7 @@ public class LottieComposition {
   private final HashSet<String> warnings = new HashSet<>();
   private Map<String, List<Layer>> precomps;
   private Map<String, LottieImageAsset> images;
+  private float imagesDpScale;
   /**
    * Map of font names to fonts
    */
@@ -71,7 +75,7 @@ public class LottieComposition {
   @RestrictTo(RestrictTo.Scope.LIBRARY)
   public void init(Rect bounds, float startFrame, float endFrame, float frameRate,
       List<Layer> layers, LongSparseArray<Layer> layerMap, Map<String,
-      List<Layer>> precomps, Map<String, LottieImageAsset> images,
+      List<Layer>> precomps, Map<String, LottieImageAsset> images, float imagesDpScale,
       SparseArrayCompat<FontCharacter> characters, Map<String, Font> fonts,
       List<Marker> markers) {
     this.bounds = bounds;
@@ -82,6 +86,7 @@ public void init(Rect bounds, float startFrame, float endFrame, float frameRate,
     this.layerMap = layerMap;
     this.precomps = precomps;
     this.images = images;
+    this.imagesDpScale = imagesDpScale;
     this.characters = characters;
     this.fonts = fonts;
     this.markers = markers;
@@ -208,8 +213,19 @@ public boolean hasImages() {
    * Returns a map of image asset id to {@link LottieImageAsset}. These assets contain image metadata exported
    * from After Effects or other design tool. The resulting Bitmaps can be set directly on the image asset so
    * they can be loaded once and reused across compositions.
+   *
+   * If the context dp scale has changed since the last time images were retrieved, images will be rescaled.
    */
   public Map<String, LottieImageAsset> getImages() {
+    float dpScale = Utils.dpScale();
+    if (dpScale != imagesDpScale) {
+      imagesDpScale = dpScale;
+      Set<Map.Entry<String, LottieImageAsset>> entries = images.entrySet();
+
+      for (Map.Entry<String, LottieImageAsset> entry : entries) {
+        images.put(entry.getKey(), entry.getValue().copyWithScale(imagesDpScale / dpScale));
+      }
+    }
     return images;
   }
 
@@ -237,6 +253,7 @@ public String toString() {
    */
   @Deprecated
   public static class Factory {
+
     private Factory() {
     }
 
@@ -363,6 +380,7 @@ public static LottieComposition fromJsonSync(JsonReader reader) {
 
     @SuppressWarnings("deprecation")
     private static final class ListenerAdapter implements LottieListener<LottieComposition>, Cancellable {
+
       private final OnCompositionLoadedListener listener;
       private boolean cancelled = false;
 
@@ -382,4 +400,4 @@ private ListenerAdapter(OnCompositionLoadedListener listener) {
       }
     }
   }
-}
+}

lottie/src/main/java/com/airbnb/lottie/LottieImageAsset.java

@@ -70,6 +70,19 @@ public void setBitmap(@Nullable Bitmap bitmap) {
     this.bitmap = bitmap;
   }
 
+  /**
+   * Returns a new {@link LottieImageAsset} with the same properties as this one but with the
+   * dimensions and bitmap scaled.
+   */
+  public LottieImageAsset copyWithScale(float scale) {
+    LottieImageAsset newAsset = new LottieImageAsset((int) (width * scale), (int) (height * scale), id, fileName, dirName);
+    if (bitmap != null) {
+      Bitmap scaledBitmap = Bitmap.createScaledBitmap(bitmap, newAsset.width, newAsset.height, true);
+      newAsset.setBitmap(scaledBitmap);
+    }
+    return newAsset;
+  }
+
   /**
    * Returns whether this asset has an embedded Bitmap or whether the fileName is a base64 encoded bitmap.
    */

lottie/src/main/java/com/airbnb/lottie/parser/LottieCompositionMoshiParser.java

@@ -107,7 +107,7 @@ public static LottieComposition parse(JsonReader reader) throws IOException {
     Rect bounds = new Rect(0, 0, scaledWidth, scaledHeight);
 
     composition.init(bounds, startFrame, endFrame, frameRate, layers, layerMap, precomps,
-        images, characters, fonts, markers);
+        images, Utils.dpScale(), characters, fonts, markers);
 
     return composition;
   }

lottie/src/test/java/com/airbnb/lottie/LottieDrawableTest.java

@@ -36,10 +36,10 @@ public void setup() {
   @SuppressWarnings("SameParameterValue")
   private LottieComposition createComposition(int startFrame, int endFrame) {
     LottieComposition composition = new LottieComposition();
-    composition.init(new Rect(), startFrame, endFrame, 1000, new ArrayList<Layer>(),
-            new LongSparseArray<Layer>(0), new HashMap<String, List<Layer>>(0),
-            new HashMap<String, LottieImageAsset>(0), new SparseArrayCompat<FontCharacter>(0),
-            new HashMap<String, Font>(0), new ArrayList<Marker>());
+    composition.init(new Rect(), startFrame, endFrame, 1000, new ArrayList<>(),
+        new LongSparseArray<>(0), new HashMap<>(0),
+        new HashMap<>(0), 1f, new SparseArrayCompat<>(0),
+        new HashMap<>(0), new ArrayList<>());
     return composition;
   }
 

lottie/src/test/java/com/airbnb/lottie/LottieValueAnimatorUnitTest.java

@@ -60,10 +60,10 @@ private LottieValueAnimator createAnimator() {
 
   private LottieComposition createComposition(int startFrame, int endFrame) {
     LottieComposition composition = new LottieComposition();
-    composition.init(new Rect(), startFrame, endFrame, 1000, new ArrayList<Layer>(),
-            new LongSparseArray<Layer>(0), new HashMap<String, List<Layer>>(0),
-            new HashMap<String, LottieImageAsset>(0), new SparseArrayCompat<FontCharacter>(0),
-            new HashMap<String, Font>(0), new ArrayList<Marker>());
+    composition.init(new Rect(), startFrame, endFrame, 1000, new ArrayList<>(),
+        new LongSparseArray<>(0), new HashMap<>(0),
+        new HashMap<>(0), 1f, new SparseArrayCompat<>(0),
+        new HashMap<>(0), new ArrayList<>());
     return composition;
   }