Create a bitmap caching Asset class
Add an implementation of Asset that caches the bitmaps
returned by decodeBitmap.
Bug: 128923737
Change-Id: I3ee7816bdb568aa669db74f1526bb4113aa57261
diff --git a/src/com/android/wallpaper/asset/BitmapCachingAsset.java b/src/com/android/wallpaper/asset/BitmapCachingAsset.java
new file mode 100644
index 0000000..86170b3
--- /dev/null
+++ b/src/com/android/wallpaper/asset/BitmapCachingAsset.java
@@ -0,0 +1,105 @@
+/*
+ * Copyright (C) 2019 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.android.wallpaper.asset;
+
+import android.app.Activity;
+import android.graphics.Bitmap;
+import android.graphics.Rect;
+import android.util.LruCache;
+
+import androidx.annotation.Nullable;
+
+import java.util.Objects;
+
+/**
+ * Implementation of {@link Asset} that wraps another {@link Asset} but keeps an LRU cache of
+ * bitmaps generated by {@link #decodeBitmap(int, int, BitmapReceiver)} to avoid having to decode
+ * the same bitmap multiple times.
+ * The cache key is the wrapped Asset and the target Width and Height requested, so that we only
+ * reuse bitmaps of the same size.
+ */
+public class BitmapCachingAsset extends Asset {
+
+ private static class CacheKey {
+ final Asset asset;
+ final int width;
+ final int height;
+
+ CacheKey(Asset asset, int width, int height) {
+ this.asset = asset;
+ this.width = width;
+ this.height = height;
+ }
+
+ @Override
+ public int hashCode() {
+ return Objects.hash(asset, width, height);
+ }
+
+ @Override
+ public boolean equals(Object obj) {
+ return obj instanceof CacheKey
+ && ((CacheKey)obj).asset == this.asset
+ && ((CacheKey)obj).width == this.width
+ && ((CacheKey)obj).height == this.height;
+ }
+ }
+
+ private static int cacheSize = 100 * 1024 * 1024; // 100MiB
+ private static LruCache<CacheKey, Bitmap> sCache = new LruCache<CacheKey, Bitmap>(cacheSize) {
+ @Override protected int sizeOf(CacheKey key, Bitmap value) {
+ return value.getByteCount();
+ }
+ };
+
+ private final Asset mOriginalAsset;
+
+ public BitmapCachingAsset(Asset originalAsset) {
+ mOriginalAsset = originalAsset;
+ }
+
+ @Override
+ public void decodeBitmap(int targetWidth, int targetHeight, BitmapReceiver receiver) {
+ CacheKey key = new CacheKey(mOriginalAsset, targetWidth, targetHeight);
+ Bitmap cached = sCache.get(key);
+ if (cached != null) {
+ receiver.onBitmapDecoded(cached);
+ } else {
+ mOriginalAsset.decodeBitmap(targetWidth, targetHeight, bitmap -> {
+ if (bitmap != null) {
+ sCache.put(key, bitmap);
+ }
+ receiver.onBitmapDecoded(bitmap);
+ });
+ }
+ }
+
+ @Override
+ public void decodeBitmapRegion(Rect rect, int targetWidth, int targetHeight,
+ BitmapReceiver receiver) {
+ mOriginalAsset.decodeBitmapRegion(rect, targetWidth, targetHeight, receiver);
+ }
+
+ @Override
+ public void decodeRawDimensions(@Nullable Activity activity, DimensionsReceiver receiver) {
+ mOriginalAsset.decodeRawDimensions(activity, receiver);
+ }
+
+ @Override
+ public boolean supportsTiling() {
+ return mOriginalAsset.supportsTiling();
+ }
+}