Fixed animated image rendering for dynamic frame dimensions

Summary:
This fixes animated image rendering for frames with varying dimensions.
Our temp bitmap will increase in size during the first animated image loop and we will then draw the correct bounds of the set bitmap.

Fixes #2015

Reviewed By: erikandre

Differential Revision: D6726703

fbshipit-source-id: 57602c925bb59481885be3a7ef44e9c85dc76035

animated-base/src/main/java/com/facebook/imagepipeline/animated/impl/AnimatedDrawableBackendImpl.java

@@ -21,6 +21,7 @@
 import com.facebook.imagepipeline.animated.base.AnimatedImageFrame;
 import com.facebook.imagepipeline.animated.base.AnimatedImageResult;
 import com.facebook.imagepipeline.animated.util.AnimatedDrawableUtil;
+import javax.annotation.Nullable;
 import javax.annotation.concurrent.GuardedBy;
 
 /**
@@ -41,7 +42,7 @@ public class AnimatedDrawableBackendImpl implements AnimatedDrawableBackend {
   private final Rect mRenderDstRect = new Rect();
 
   @GuardedBy("this")
-  private Bitmap mTempBitmap;
+  private @Nullable Bitmap mTempBitmap;
 
   public AnimatedDrawableBackendImpl(
       AnimatedDrawableUtil animatedDrawableUtil,
@@ -185,12 +186,12 @@ public void renderFrame(int frameNumber, Canvas canvas) {
     }
   }
 
-  private void prepareTempBitmapForThisSize(int width, int height) {
+  private synchronized void prepareTempBitmapForThisSize(int width, int height) {
     // Different gif frames can be different size,
     // So we need to ensure we can fit next frame to temporary bitmap
     if (mTempBitmap != null
         && (mTempBitmap.getWidth() < width || mTempBitmap.getHeight() < height)) {
-      dropCaches();
+      clearTempBitmap();
     }
     if (mTempBitmap == null) {
       mTempBitmap = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888);
@@ -208,12 +209,14 @@ private void renderImageSupportsScaling(Canvas canvas, AnimatedImageFrame frame)
     int yOffset = (int) (frame.getYOffset() * yScale);
 
     synchronized (this) {
-      prepareTempBitmapForThisSize(mRenderedBounds.width(), mRenderedBounds.height());
+      int renderedWidth = mRenderedBounds.width();
+      int renderedHeight = mRenderedBounds.height();
+      // Update the temp bitmap to be >= rendered dimensions
+      prepareTempBitmapForThisSize(renderedWidth, renderedHeight);
       frame.renderFrame(frameWidth, frameHeight, mTempBitmap);
-
       // Temporary bitmap can be bigger than frame, so we should draw only rendered area of bitmap
-      mRenderSrcRect.set(0, 0, mRenderedBounds.width(), mRenderedBounds.height());
-      mRenderDstRect.set(xOffset, yOffset, mRenderedBounds.width(), mRenderedBounds.height());
+      mRenderSrcRect.set(0, 0, renderedWidth, renderedHeight);
+      mRenderDstRect.set(xOffset, yOffset, xOffset + renderedWidth, yOffset + renderedHeight);
 
       canvas.drawBitmap(mTempBitmap, mRenderSrcRect, mRenderDstRect, null);
     }
@@ -244,6 +247,10 @@ private void renderImageDoesNotSupportScaling(Canvas canvas, AnimatedImageFrame
 
   @Override
   public synchronized void dropCaches() {
+    clearTempBitmap();
+  }
+
+  private synchronized void clearTempBitmap() {
     if (mTempBitmap != null) {
       mTempBitmap.recycle();
       mTempBitmap = null;