Merge pull request #2815 from dreampiggy/feature_animated_clear_when_stop

Support to clear frame buffer or reset frame index when stopped for SDAnimatedImageView

SDWebImage/Core/SDAnimatedImageView.h

@@ -58,6 +58,20 @@
  */
 @property (nonatomic, assign) BOOL shouldIncrementalLoad;
 
+/**
+ Whether or not to clear the frame buffer cache when animation stopped. See `maxBufferSize`
+ This is useful when you want to limit the memory usage during frequently visibility changes (such as image view inside a list view, then push and pop)
+ Default is NO.
+ */
+@property (nonatomic, assign) BOOL clearBufferWhenStopped;
+
+/**
+ Whether or not to reset the current frame index when animation stopped.
+ For some of use case, you may want to reset the frame index to 0 when stop, but some other want to keep the current frame index.
+ Default is NO.
+ */
+@property (nonatomic, assign) BOOL resetFrameIndexWhenStopped;
+
 #if SD_UIKIT
 /**
  You can specify a runloop mode to let it rendering.

SDWebImage/Core/SDAnimatedImageView.m

@@ -149,21 +149,15 @@ static NSUInteger SDDeviceFreeMemory() {
     self.animatedImage = nil;
     self.totalFrameCount = 0;
     self.totalLoopCount = 0;
-    self.currentFrame = nil;
-    self.currentFrameIndex = 0;
-    self.currentLoopCount = 0;
-    self.currentTime = 0;
-    self.bufferMiss = NO;
+    // reset current state
+    [self resetCurrentFrameIndex];
     self.shouldAnimate = NO;
     self.isProgressive = NO;
     self.maxBufferCount = 0;
     self.animatedImageScale = 1;
     [_fetchQueue cancelAllOperations];
-    _fetchQueue = nil;
-    SD_LOCK(self.lock);
-    [_frameBuffer removeAllObjects];
-    _frameBuffer = nil;
-    SD_UNLOCK(self.lock);
+    // clear buffer cache
+    [self clearFrameBuffer];
 }
 
 - (void)resetProgressiveImage
@@ -179,6 +173,22 @@ static NSUInteger SDDeviceFreeMemory() {
     // preserve buffer cache
 }
 
+- (void)resetCurrentFrameIndex
+{
+    self.currentFrame = nil;
+    self.currentFrameIndex = 0;
+    self.currentLoopCount = 0;
+    self.currentTime = 0;
+    self.bufferMiss = NO;
+}
+
+- (void)clearFrameBuffer
+{
+    SD_LOCK(self.lock);
+    [_frameBuffer removeAllObjects];
+    SD_UNLOCK(self.lock);
+}
+
 #pragma mark - Accessors
 #pragma mark Public
 
@@ -466,6 +476,12 @@ static NSUInteger SDDeviceFreeMemory() {
 #else
         _displayLink.paused = YES;
 #endif
+        if (self.resetFrameIndexWhenStopped) {
+            [self resetCurrentFrameIndex];
+        }
+        if (self.clearBufferWhenStopped) {
+            [self clearFrameBuffer];
+        }
     } else {
 #if SD_UIKIT
         [super stopAnimating];

Tests/Tests/SDAnimatedImageTest.m

@@ -16,6 +16,7 @@ static const NSUInteger kTestGIFFrameCount = 5; // local TestImage.gif loop coun
 @interface SDAnimatedImageView ()
 
 @property (nonatomic, assign) BOOL isProgressive;
+@property (nonatomic, strong) NSMutableDictionary<NSNumber *, UIImage *> *frameBuffer;
 
 @end
 
@@ -206,6 +207,7 @@ static const NSUInteger kTestGIFFrameCount = 5; // local TestImage.gif loop coun
 #else
             imageView.animates = NO;
 #endif
+            [imageView removeFromSuperview];
             [expectation fulfill];
         }
     }];
@@ -298,6 +300,80 @@ static const NSUInteger kTestGIFFrameCount = 5; // local TestImage.gif loop coun
     [self waitForExpectationsWithCommonTimeout];
 }
 
+- (void)test25AnimatedImageStopAnimatingNormal {
+    XCTestExpectation *expectation = [self expectationWithDescription:@"test SDAnimatedImageView stopAnimating normal behavior"];
+    
+    SDAnimatedImageView *imageView = [SDAnimatedImageView new];
+    
+#if SD_UIKIT
+    [self.window addSubview:imageView];
+#else
+    [self.window.contentView addSubview:imageView];
+#endif
+    // This APNG duration is 2s
+    SDAnimatedImage *image = [SDAnimatedImage imageWithData:[self testAPNGPData]];
+    imageView.image = image;
+    
+    dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(0.5 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{
+        // 0.5s is not finished, frame index should not be 0
+        expect(imageView.frameBuffer.count).beGreaterThan(0);
+        expect(imageView.currentFrameIndex).beGreaterThan(0);
+    });
+    
+    dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(1 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{
+#if SD_UIKIT
+        [imageView stopAnimating];
+#else
+        imageView.animates = NO;
+#endif
+        expect(imageView.frameBuffer.count).beGreaterThan(0);
+        expect(imageView.currentFrameIndex).beGreaterThan(0);
+        
+        [imageView removeFromSuperview];
+        [expectation fulfill];
+    });
+    
+    [self waitForExpectationsWithCommonTimeout];
+}
+
+- (void)test25AnimatedImageStopAnimatingClearBuffer {
+    XCTestExpectation *expectation = [self expectationWithDescription:@"test SDAnimatedImageView stopAnimating clear buffer when stopped"];
+    
+    SDAnimatedImageView *imageView = [SDAnimatedImageView new];
+    imageView.clearBufferWhenStopped = YES;
+    imageView.resetFrameIndexWhenStopped = YES;
+    
+#if SD_UIKIT
+    [self.window addSubview:imageView];
+#else
+    [self.window.contentView addSubview:imageView];
+#endif
+    // This APNG duration is 2s
+    SDAnimatedImage *image = [SDAnimatedImage imageWithData:[self testAPNGPData]];
+    imageView.image = image;
+    
+    dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(0.5 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{
+        // 0.5s is not finished, frame index should not be 0
+        expect(imageView.frameBuffer.count).beGreaterThan(0);
+        expect(imageView.currentFrameIndex).beGreaterThan(0);
+    });
+    
+    dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(1 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{
+#if SD_UIKIT
+        [imageView stopAnimating];
+#else
+        imageView.animates = NO;
+#endif
+        expect(imageView.frameBuffer.count).equal(0);
+        expect(imageView.currentFrameIndex).equal(0);
+        
+        [imageView removeFromSuperview];
+        [expectation fulfill];
+    });
+    
+    [self waitForExpectationsWithCommonTimeout];
+}
+
 #pragma mark - Helper
 - (UIWindow *)window {
     if (!_window) {