Avoid drawing recycled Bitmaps in GifDrawable.

Fixes #202.

library/src/androidTest/java/com/bumptech/glide/load/resource/gif/GifDrawableTest.java

@@ -67,7 +67,8 @@ public class GifDrawableTest {
     public void testShouldNotDrawNullBitmapFrame() {
         Canvas canvas = mock(Canvas.class);
         drawable = new GifDrawable(gifDecoder, frameManager, firstFrame, bitmapPool);
-        drawable.onFrameRead(null, 0);
+        drawable.onFrameRead(0);
+        when(frameManager.getCurrentFrame()).thenReturn(null);
         drawable.draw(canvas);
 
         verify(canvas).drawBitmap(eq(firstFrame), anyInt(), anyInt(), any(Paint.class));
@@ -82,6 +83,17 @@ public class GifDrawableTest {
         verify(canvas, never()).drawBitmap(any(Bitmap.class), anyInt(), anyInt(), any(Paint.class));
     }
 
+    @Test
+    public void testDoesDrawCurrentFrameIfOneIsAvailable() {
+        Canvas canvas = mock(Canvas.class);
+        Bitmap currentFrame = Bitmap.createBitmap(100123, 123141, Bitmap.Config.ARGB_4444);
+        when(frameManager.getCurrentFrame()).thenReturn(currentFrame);
+
+        drawable.draw(canvas);
+        verify(canvas).drawBitmap(eq(currentFrame), anyInt(), anyInt(), any(Paint.class));
+        verify(canvas, never()).drawBitmap(eq(firstFrame), anyInt(), anyInt(), any(Paint.class));
+    }
+
     @Test
     public void testRequestsNextFrameOnStart() {
         drawable.setVisible(true, true);
@@ -156,7 +168,7 @@ public class GifDrawableTest {
     @Test
     public void testStartsLoadingNextFrameWhenCurrentFinishes() {
         drawable.setIsRunning(true);
-        drawable.onFrameRead(Bitmap.createBitmap(100, 100, Bitmap.Config.ARGB_8888), 0);
+        drawable.onFrameRead(0);
 
         verify(frameManager).getNextFrame(eq(drawable));
     }
@@ -164,7 +176,7 @@ public class GifDrawableTest {
     @Test
     public void testInvalidatesSelfWhenFrameReady() {
         drawable.setIsRunning(true);
-        drawable.onFrameRead(Bitmap.createBitmap(100, 100, Bitmap.Config.RGB_565), 0);
+        drawable.onFrameRead(0);
 
         verify(cb).invalidateDrawable(eq(drawable));
     }
@@ -172,7 +184,7 @@ public class GifDrawableTest {
     @Test
     public void testDoesNotStartLoadingNextFrameWhenCurrentFinishesIfNotRunning() {
         drawable.setIsRunning(false);
-        drawable.onFrameRead(Bitmap.createBitmap(10, 100, Bitmap.Config.ARGB_8888), 0);
+        drawable.onFrameRead(0);
 
         verify(frameManager, never()).getNextFrame(eq(drawable));
     }
@@ -181,7 +193,7 @@ public class GifDrawableTest {
     public void testDoesNotStartLoadingNextFrameWhenCurrentFinishesIfHasNoCallback() {
         drawable.setIsRunning(true);
         drawable.setCallback(null);
-        drawable.onFrameRead(Bitmap.createBitmap(1, 2, Bitmap.Config.ARGB_8888), 0);
+        drawable.onFrameRead(0);
 
         verify(frameManager, never()).getNextFrame(eq(drawable));
     }
@@ -190,7 +202,7 @@ public class GifDrawableTest {
     public void testStopsWhenCurrentFrameFinishesIfHasNoCallback() {
         drawable.setIsRunning(true);
         drawable.setCallback(null);
-        drawable.onFrameRead(Bitmap.createBitmap(2, 1, Bitmap.Config.ARGB_8888), 0);
+        drawable.onFrameRead(0);
 
         assertFalse(drawable.isRunning());
     }
@@ -382,13 +394,13 @@ public class GifDrawableTest {
         drawable.setVisible(true, true);
         drawable.start();
 
-        drawable.onFrameRead(getBitmap(), 0);
-        drawable.onFrameRead(getBitmap(), 1);
+        drawable.onFrameRead(0);
+        drawable.onFrameRead(1);
 
         drawable.start();
 
-        drawable.onFrameRead(getBitmap(), 0);
-        drawable.onFrameRead(getBitmap(), 1);
+        drawable.onFrameRead(0);
+        drawable.onFrameRead(1);
 
         verify(frameManager, times(4)).getNextFrame(eq(drawable));
         assertFalse(drawable.isRunning());
@@ -437,10 +449,23 @@ public class GifDrawableTest {
         verify(frameManager, times(frameCount * loopCount)).getNextFrame(eq(drawable));
     }
 
+    @Test
+    public void testDoesNotDrawFrameAfterRecycle() {
+        Bitmap bitmap = Bitmap.createBitmap(100, 112341, Bitmap.Config.RGB_565);
+        drawable.setVisible(true, true);
+        drawable.start();
+        when(frameManager.getCurrentFrame()).thenReturn(bitmap);
+        drawable.onFrameRead(1);
+        drawable.recycle();
+        Canvas canvas = mock(Canvas.class);
+        drawable.draw(canvas);
+        verify(canvas, never()).drawBitmap(any(Bitmap.class), anyInt(), anyInt(), any(Paint.class));
+    }
+
     private void runLoops(int loopCount, int frameCount) {
         for (int loop = 0; loop < loopCount; loop++) {
             for (int frame = 0; frame < frameCount; frame++) {
-                drawable.onFrameRead(getBitmap(), frame);
+                drawable.onFrameRead(frame);
             }
         }
     }

library/src/main/java/com/bumptech/glide/load/resource/gif/GifDrawable.java

@@ -26,8 +26,6 @@ public class GifDrawable extends GlideDrawable implements GifFrameManager.FrameC
     private final GifState state;
     private final GifDecoder decoder;
 
-    /** The current frame to draw, or null if no frame has been loaded yet. */
-    private Bitmap currentFrame;
     /** True if the drawable is currently animating. */
     private boolean isRunning;
     /** True if the drawable should animate while visible. */
@@ -181,6 +179,10 @@ public class GifDrawable extends GlideDrawable implements GifFrameManager.FrameC
 
     @Override
     public void draw(Canvas canvas) {
+        if (isRecycled) {
+            return;
+        }
+        Bitmap currentFrame = frameManager.getCurrentFrame();
         Bitmap toDraw = currentFrame != null ? currentFrame : state.firstFrame;
         canvas.drawBitmap(toDraw, 0, 0, paint);
     }
@@ -203,7 +205,7 @@ public class GifDrawable extends GlideDrawable implements GifFrameManager.FrameC
 
     @TargetApi(Build.VERSION_CODES.HONEYCOMB)
     @Override
-    public void onFrameRead(Bitmap frame, int frameIndex) {
+    public void onFrameRead(int frameIndex) {
         if (Build.VERSION_CODES.HONEYCOMB <= Build.VERSION.SDK_INT && getCallback() == null) {
             stop();
             return;
@@ -212,10 +214,7 @@ public class GifDrawable extends GlideDrawable implements GifFrameManager.FrameC
             return;
         }
 
-        if (frame != null) {
-            currentFrame = frame;
-            invalidateSelf();
-        }
+        invalidateSelf();
 
         if (frameIndex == decoder.getFrameCount() - 1) {
             loopCount++;

library/src/main/java/com/bumptech/glide/load/resource/gif/GifFrameManager.java

@@ -2,6 +2,7 @@ package com.bumptech.glide.load.resource.gif;
 
 import android.content.Context;
 import android.graphics.Bitmap;
+import android.graphics.drawable.Drawable;
 import android.os.Handler;
 import android.os.Looper;
 import android.os.SystemClock;
@@ -35,7 +36,7 @@ class GifFrameManager {
     private DelayTarget next;
 
     public interface FrameCallback {
-        void onFrameRead(Bitmap frame, int index);
+        void onFrameRead(int index);
     }
 
     public GifFrameManager(Context context, GifDecoder decoder, Transformation<Bitmap> transformation, int targetWidth,
@@ -92,6 +93,10 @@ class GifFrameManager {
                 .into(next);
     }
 
+    public Bitmap getCurrentFrame() {
+        return current != null ? current.resource : null;
+    }
+
     public void clear() {
         if (current != null) {
             mainHandler.removeCallbacks(current);
@@ -127,11 +132,16 @@ class GifFrameManager {
 
         @Override
         public void run() {
-            cb.onFrameRead(resource, index);
+            cb.onFrameRead(index);
             if (current != null) {
                 Glide.clear(current);
             }
             current = this;
         }
+
+        @Override
+        public void onLoadCleared(Drawable placeholder) {
+            resource = null;
+        }
     }
 }