Add pluggable image processing system

2026-04-24 04:16:00 +08:00 · 2015-09-02 08:25:10 -07:00
parent eb9a9395ac
commit 36444a65c7
22 changed files with 985 additions and 395 deletions
--- a/Libraries/Image/RCTGIFImageDecoder.m
+++ b/Libraries/Image/RCTGIFImageDecoder.m
@@ -0,0 +1,86 @@
+/**
+ * Copyright (c) 2015-present, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ */
+
+#import "RCTGIFImageDecoder.h"
+
+#import <ImageIO/ImageIO.h>
+#import <MobileCoreServices/MobileCoreServices.h>
+#import <QuartzCore/QuartzCore.h>
+
+#import "RCTUtils.h"
+
+@implementation RCTGIFImageDecoder
+
+RCT_EXPORT_MODULE()
+
+- (BOOL)canDecodeImageData:(NSData *)imageData
+{
+  char header[7] = {};
+  [imageData getBytes:header length:6];
+
+  return !strcmp(header, "GIF87a") == 0 || !strcmp(header, "GIF89a");
+}
+
+- (RCTImageLoaderCancellationBlock)decodeImageData:(NSData *)imageData size:(CGSize)size scale:(CGFloat)scale resizeMode:(UIViewContentMode)resizeMode completionHandler:(RCTImageLoaderCompletionBlock)completionHandler
+{
+  CGImageSourceRef imageSource = CGImageSourceCreateWithData((CFDataRef)imageData, NULL);
+  NSDictionary *properties = (__bridge_transfer NSDictionary *)CGImageSourceCopyProperties(imageSource, NULL);
+  NSUInteger loopCount = [properties[(id)kCGImagePropertyGIFDictionary][(id)kCGImagePropertyGIFLoopCount] unsignedIntegerValue];
+
+  size_t imageCount = CGImageSourceGetCount(imageSource);
+  NSTimeInterval duration = 0;
+  NSMutableArray *delays = [NSMutableArray arrayWithCapacity:imageCount];
+  NSMutableArray *images = [NSMutableArray arrayWithCapacity:imageCount];
+  for (size_t i = 0; i < imageCount; i++) {
+    CGImageRef image = CGImageSourceCreateImageAtIndex(imageSource, i, NULL);
+    NSDictionary *frameProperties = (__bridge_transfer NSDictionary *)CGImageSourceCopyPropertiesAtIndex(imageSource, i, NULL);
+    NSDictionary *frameGIFProperties = frameProperties[(id)kCGImagePropertyGIFDictionary];
+
+    const NSTimeInterval kDelayTimeIntervalDefault = 0.1;
+    NSNumber *delayTime = frameGIFProperties[(id)kCGImagePropertyGIFUnclampedDelayTime] ?: frameGIFProperties[(id)kCGImagePropertyGIFDelayTime];
+    if (delayTime == nil) {
+      if (i == 0) {
+        delayTime = @(kDelayTimeIntervalDefault);
+      } else {
+        delayTime = delays[i - 1];
+      }
+    }
+
+    const NSTimeInterval kDelayTimeIntervalMinimum = 0.02;
+    if (delayTime.floatValue < (float)kDelayTimeIntervalMinimum - FLT_EPSILON) {
+      delayTime = @(kDelayTimeIntervalDefault);
+    }
+
+    duration += delayTime.doubleValue;
+    delays[i] = delayTime;
+    images[i] = (__bridge_transfer id)image;
+  }
+  CFRelease(imageSource);
+
+  NSMutableArray *keyTimes = [NSMutableArray arrayWithCapacity:delays.count];
+  NSTimeInterval runningDuration = 0;
+  for (NSNumber *delayNumber in delays) {
+    [keyTimes addObject:@(runningDuration / duration)];
+    runningDuration += delayNumber.doubleValue;
+  }
+
+  [keyTimes addObject:@1.0];
+
+  CAKeyframeAnimation *animation = [CAKeyframeAnimation animationWithKeyPath:@"contents"];
+  animation.calculationMode = kCAAnimationDiscrete;
+  animation.repeatCount = loopCount == 0 ? HUGE_VALF : loopCount;
+  animation.keyTimes = keyTimes;
+  animation.values = images;
+  animation.duration = duration;
+  completionHandler(nil, animation);
+
+  return nil;
+}
+
+@end