SDWebImage / SDWebImage/SDWebImageWebPCoder
Skipping frames for Animated WebP
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- Dominant language
- Objective-C
- Stars
- 277
- Forks
- 101
- PR merge metrics
- No merged PRs in 30d
Description
It would be good to have an option to skip frames for animated webP.
If I have a thumbnail trying to render an animated wepb image with 120 frames it could be good to render only 30 frames, to preserve speed and memory.
Maybe not the first 30 frames but skipping frames in a loop: the animation will not be very smooth obviously.
A simple, not nice looking solution to skip half of the frames:
SDImageWebPCoder.m
line 264
Adding a skipper in the loop and duplicating the duration
int skipper = 0;
do {
skipper++;
if ((skipper %2) == 0) {
continue;
}
@autoreleasepool {
CGImageRef imageRef = [self sd_drawnWebpImageWithCanvas:canvas iterator:iter colorSpace:colorSpace scaledSize:scaledSize];
if (!imageRef) {
continue;
}
#if SD_UIKIT || SD_WATCH
UIImage *image = [[UIImage alloc] initWithCGImage:imageRef scale:scale orientation:UIImageOrientationUp];
#else
UIImage *image = [[UIImage alloc] initWithCGImage:imageRef scale:scale orientation:kCGImagePropertyOrientationUp];
#endif
CGImageRelease(imageRef);
NSTimeInterval duration = [self sd_frameDurationWithIterator:iter];
SDImageFrame *frame = [SDImageFrame frameWithImage:image duration:(duration*2)];
[frames addObject:frame];
}
} while (WebPDemuxNextFrame(&iter));
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First steps
- Read the whole issue, then the project's contributing guide.
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- Open a pull request that references the issue number.
Research direction
Start in SDImageWebPCoder.m around line 264, where animated WebP frames are decoded and durations are collected. Determine how an opt-in frame-skipping option should be exposed and preserved across supported Apple platforms, then verify the resulting frame count and animation timing with an animated WebP fixture.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- objective-c
- Domain
- mobile-dev
- Issue type
- Feature
- Difficulty
- 4/5
- Estimated time
- 3-5 days
- Activity status
- Stale
- Clarity
- Mostly clear
- Newbie friendliness
- 35/100