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author | David Morrissey <davemorrissey@gmail.com> | 2017-11-23 13:52:04 +0000 |
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committer | David Morrissey <davemorrissey@gmail.com> | 2017-11-23 13:52:04 +0000 |
commit | c947ca46810bb0da96be490ab40897487ba3073b (patch) | |
tree | 299d42595acbd7dd1cc239d6efba0bfb4163b989 /library/src/main/java/com/davemorrissey/labs | |
parent | aca4271b9333ded7faceaa7ef3810864b7e2945d (diff) | |
download | subsampling-scale-image-view-c947ca46810bb0da96be490ab40897487ba3073b.tar.gz |
Use ReadWriteLock to allow multiple threads to decode tiles while preventing simultaneous recycling
Diffstat (limited to 'library/src/main/java/com/davemorrissey/labs')
-rw-r--r-- | library/src/main/java/com/davemorrissey/labs/subscaleview/decoder/SkiaImageRegionDecoder.java | 46 |
1 files changed, 35 insertions, 11 deletions
diff --git a/library/src/main/java/com/davemorrissey/labs/subscaleview/decoder/SkiaImageRegionDecoder.java b/library/src/main/java/com/davemorrissey/labs/subscaleview/decoder/SkiaImageRegionDecoder.java index c3ffb6c..9d216f6 100644 --- a/library/src/main/java/com/davemorrissey/labs/subscaleview/decoder/SkiaImageRegionDecoder.java +++ b/library/src/main/java/com/davemorrissey/labs/subscaleview/decoder/SkiaImageRegionDecoder.java @@ -11,17 +11,24 @@ import android.text.TextUtils; import java.io.InputStream; import java.util.List; +import java.util.concurrent.locks.ReadWriteLock; +import java.util.concurrent.locks.ReentrantReadWriteLock; /** * Default implementation of {@link com.davemorrissey.labs.subscaleview.decoder.ImageRegionDecoder} * using Android's {@link android.graphics.BitmapRegionDecoder}, based on the Skia library. This * works well in most circumstances and has reasonable performance due to the cached decoder instance, * however it has some problems with grayscale, indexed and CMYK images. + * + * A {@link ReadWriteLock} is used to delegate responsibility for multi threading behaviour to the + * {@link BitmapRegionDecoder} instance, whilst allowing this class to block until no tiles are being + * loaded before recycling the decoder. In practice, {@link BitmapRegionDecoder} is single threaded + * so this has no real impact on performance. */ public class SkiaImageRegionDecoder implements ImageRegionDecoder { private BitmapRegionDecoder decoder; - private final Object decoderLock = new Object(); + private final ReadWriteLock decoderLock = new ReentrantReadWriteLock(true); private static final String FILE_PREFIX = "file://"; private static final String ASSET_PREFIX = FILE_PREFIX + "/android_asset/"; @@ -90,25 +97,42 @@ public class SkiaImageRegionDecoder implements ImageRegionDecoder { @Override public Bitmap decodeRegion(Rect sRect, int sampleSize) { - synchronized (decoderLock) { - BitmapFactory.Options options = new BitmapFactory.Options(); - options.inSampleSize = sampleSize; - options.inPreferredConfig = bitmapConfig; - Bitmap bitmap = decoder.decodeRegion(sRect, options); - if (bitmap == null) { - throw new RuntimeException("Skia image decoder returned null bitmap - image format may not be supported"); + decoderLock.readLock().lock(); + try { + if (decoder != null && !decoder.isRecycled()) { + BitmapFactory.Options options = new BitmapFactory.Options(); + options.inSampleSize = sampleSize; + options.inPreferredConfig = bitmapConfig; + Bitmap bitmap = decoder.decodeRegion(sRect, options); + if (bitmap == null) { + throw new RuntimeException("Skia image decoder returned null bitmap - image format may not be supported"); + } + return bitmap; + } else { + throw new IllegalStateException("Cannot decode region after decoder has been recycled"); } - return bitmap; + } finally { + decoderLock.readLock().unlock(); } } @Override public boolean isReady() { - return decoder != null && !decoder.isRecycled(); + decoderLock.readLock().lock(); + try { + return decoder != null && !decoder.isRecycled(); + } finally { + decoderLock.readLock().unlock(); + } } @Override public void recycle() { - decoder.recycle(); + decoderLock.writeLock().lock(); + try { + decoder.recycle(); + } finally { + decoderLock.writeLock().unlock(); + } } } |