Optimized MovieFrame#renderFrame

Reviewed By: oprisnik

Differential Revision: D8940188

fbshipit-source-id: de8186e95058214cbca263d53e50cc4d945c0490

animated-gif-lite/src/main/java/com/facebook/animated/giflite/GifDecoder.java

@@ -33,15 +33,15 @@ public CloseableImage decode(
  ImageDecodeOptions options) {
 
  Movie movie = Movie.decodeStream(encodedImage.getInputStream());
- MovieScaleHolder movieScaleHolder = new MovieScaleHolder(movie.width(), movie.height());
+ MovieDrawer drawer = new MovieDrawer(movie);
 
  List<Integer> frameStartTimes = getMovieFrameStartTimes(movie);
 
  MovieFrame[] frames = new MovieFrame[frameStartTimes.size()];
  for (int i = 0, N = frameStartTimes.size(); i < N; i++) {
  int frameStart = frameStartTimes.get(i);
  int frameDuration = (i == N - 1 ? movie.duration() : frameStartTimes.get(i + 1)) - frameStart;
- frames[i] = new MovieFrame(movie, movieScaleHolder, frameStart, frameDuration);
+ frames[i] = new MovieFrame(drawer, frameStart, frameDuration, movie.width(), movie.height());
  }
 
  return new CloseableAnimatedImage(

animated-gif-lite/src/main/java/com/facebook/animated/giflite/MovieDrawer.java

@@ -0,0 +1,52 @@
+/*
+ * Copyright (c) 2015-present, Facebook, Inc.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+package com.facebook.animated.giflite;
+
+import android.graphics.Bitmap;
+import android.graphics.Canvas;
+import android.graphics.Movie;
+import android.support.annotation.Nullable;
+
+/**
+ * Pronounced Draw-er Draws frames of a {@link Movie} to a bitmap. All methods are synchronized, so
+ * can be used in parallel. The underlying {@link #mMovie} is not threadsafe, and should therefore
+ * not be accessed outside of {@link MovieDrawer}. Attempts to optimize work done by the drawing
+ * {@link Canvas} by detecting if the underlying {@link Bitmap} has changed.
+ */
+class MovieDrawer {
+
+ private final Movie mMovie;
+ private final MovieScaleHolder mScaleHolder;
+ private final Canvas mCanvas;
+
+ private @Nullable Bitmap mPreviousBitmap;
+
+ public MovieDrawer(Movie movie) {
+ mMovie = movie;
+ mScaleHolder = new MovieScaleHolder(movie.width(), movie.height());
+ mCanvas = new Canvas();
+ }
+
+ public synchronized void drawFrame(int movieTime, int w, int h, Bitmap bitmap) {
+ mMovie.setTime(movieTime);
+
+ if (mPreviousBitmap != null && mPreviousBitmap.isRecycled()) {
+ mPreviousBitmap = null;
+ }
+ if (mPreviousBitmap != bitmap) {
+ mPreviousBitmap = bitmap;
+ mCanvas.setBitmap(bitmap);
+ }
+
+ mScaleHolder.updateViewPort(w, h);
+
+ mCanvas.save();
+ mCanvas.scale(mScaleHolder.getScale(), mScaleHolder.getScale());
+ mMovie.draw(mCanvas, mScaleHolder.getLeft(), mScaleHolder.getTop());
+ mCanvas.restore();
+ }
+}

animated-gif-lite/src/main/java/com/facebook/animated/giflite/MovieFrame.java

@@ -8,49 +8,35 @@
 package com.facebook.animated.giflite;
 
 import android.graphics.Bitmap;
-import android.graphics.Canvas;
-import android.graphics.Movie;
-import android.support.annotation.Nullable;
 import com.facebook.imagepipeline.animated.base.AnimatedImageFrame;
 
 /**
- * Simple wrapper for an animated image frame back by {@link Movie}. All {@link MovieFrame} for the
- * same {@link MovieAnimatedImage} will be backed by the same {@link Movie} and can therefore not be
- * used in parallel.
+ * Simple wrapper for an animated image frame back by {@link MovieDrawer}. All {@link MovieFrame}
+ * for the same {@link MovieAnimatedImage} will be backed by the same {@link MovieDrawer}.
  */
 class MovieFrame implements AnimatedImageFrame {
 
- private final Movie mMovie;
- private final MovieScaleHolder mScaleHolder;
+ private final MovieDrawer mMovieDrawer;
  private final int mFrameStart;
  private final int mFrameDuration;
- private @Nullable Canvas mCanvas;
+ private final int mFrameWidth;
+ private final int mFrameHeight;
 
- public MovieFrame(Movie movie, MovieScaleHolder scaleHolder, int frameStart, int frameDuration) {
- mMovie = movie;
- mScaleHolder = scaleHolder;
+ public MovieFrame(
+  MovieDrawer movieDrawer, int frameStart, int frameDuration, int frameWidth, int frameHeight) {
+ mMovieDrawer = movieDrawer;
  mFrameStart = frameStart;
  mFrameDuration = frameDuration;
+ mFrameWidth = frameWidth;
+ mFrameHeight = frameHeight;
  }
 
  @Override
  public void dispose() {}
 
  @Override
  public void renderFrame(int w, int h, Bitmap bitmap) {
- mMovie.setTime(mFrameStart);
-
- if (mCanvas == null) {
- mCanvas = new Canvas(bitmap);
- } else {
- mCanvas.setBitmap(bitmap);
- }
-
- mScaleHolder.updateViewPort(w, h);
- mCanvas.save();
- mCanvas.scale(mScaleHolder.getScale(), mScaleHolder.getScale());
- mMovie.draw(mCanvas, mScaleHolder.getLeft(), mScaleHolder.getTop());
- mCanvas.restore();
+ mMovieDrawer.drawFrame(mFrameStart, w, h, bitmap);
  }
 
  @Override
@@ -60,12 +46,12 @@ public int getDurationMs() {
 
  @Override
  public int getWidth() {
- return mMovie.width();
+ return mFrameWidth;
  }
 
  @Override
  public int getHeight() {
- return mMovie.height();
+ return mFrameHeight;
  }
 
  @Override