Using Apple's ImageIO on iOS 17 cause APNG pictures flicker abnormally

[fuguangxin]

New Issue Checklist

• I have read and understood the CONTRIBUTING guide
• I have read the Documentation
• I have searched for a similar issue in the project and found none

Issue Info

Info	Value
Platform Name	e.g. ios
Platform Version	e.g. 17.0 +
SDWebImage Version	e.g. 5.19.1
Integration Method	e.g. cocoapods
Xcode Version	e.g. Xcode 15.2
Repro rate	e.g. all the time (100%)
Repro with our demo prj	e.g. does it happen with our demo project?
Demo project link	e.g. link to a demo project that highlights the issue

Issue Description and Steps

YYImage doesn't have this problem。

Behave as follows
https://recite-words.oss-cn-hangzhou.aliyuncs.com/web/tmp/RPReplay_Final1712828721.MP4 
The code is as follows

The apng is as follows
https://recite-words.oss-cn-hangzhou.aliyuncs.com/headframe/e592f78bf9cb0ffde9520e02879da7b1.png

[dreampiggy]

Why not try use SDAnimatedImageView ?

Also, update SD to the latest version and test both on iOS 16(any 16.x) && 17.3+

iOS 17.0-17.2 has a global PNG decode bug, if you test on this version maybe we can not help

But why YYImage can do xxx on PNG

This seems YY does not use ImageIO, it use a copy of libpng (a third part PNG codec) (Maybe because at that time, ImageIO does not support APNG, 7 years ago)

Using third party codec is the last choice, because it can not use Hardware Media Decoder to accelerate, which may consume more CPU/Battery so we usually don't (unless we found something buggy and will provide a custom plugin instead. see readme about plugin system)

[dreampiggy]

tagged as Apple's ImageIO bug currently

[fuguangxin]

Why not try use SDAnimatedImageView ?

Also, update SD to the latest version and test both on iOS 16(any 16.x) && 17.3+

iOS 17.0-17.2 has a global PNG decode bug, if you test on this version maybe we can not help

But why YYImage can do xxx on PNG

This seems YY does not use ImageIO, it use a copy of libpng (a third part PNG codec) (Maybe because at that time, ImageIO does not support APNG, 7 years ago)

Using third party codec is the last choice, because it can not use Hardware Media Decoder to accelerate, which may consume more CPU/Battery so we usually don't (unless we found something buggy and will provide a custom plugin instead. see readme about plugin system)

Thanks , I will try. I'm sure iOS 17 has some bug on Apng, because some of my static png in the asset abnormally either.

[dreampiggy]

Reopen if you tested on iOS 17.3 and it's still broken

[dreampiggy]

Anyway, SDWebImage's coder is plugin based

If you don't want to use Apple's ImageIO, OK.

Just see (https://github.com/SDWebImage/SDWebImage/wiki/Coder-Plugin-List) and use libpng(https://github.com/rickytan/libpng-apng) to write a custom coder for APNG, like what YYImage's done.

libpng with APNG is not merged into upstream, many many people fork their own and copy the code from Mozilla 😂, even like https://github.com/onevcat/libpng/

[dreampiggy]

In history there is a talk to whether SDWebImage org should provide a PNG plugin using libpng, as well as a JPEG plugin using libjpeg-turbo (beyond that ImageIO, Apple's close-sourced image codec)

But was rejected because we think Apple's media team is good at it. Integrate another codec is bad for both code size and performance.

See more:

#3605
#2991

However, seems Apple's media team code quality is lower and lower these years🤮

[dreampiggy]

@fuguangxin A stupid way:

Use https://github.com/SDWebImage/SDWebImageYYPlugin

This wrap a YYImageDecoder into SDWebImage's coder plugin API (means, conforms to SDImageCoder protocol)

You can use this coder to force load PNG without Apple's ImageIO if you want.

var context: [SDWebImageContextOption: AnyObject] = [:]
if url.pathExtension == ".png" {
   context[.imageCoder] = SDImageYYCoder.shared // magic here
}
view.sd_setImage(with: url, placeholderImage: nil, options: [], context: context)

or you can wrap it as a global coder well, by override the canDecode(with: Data) and only return true for PNG data.

Have a try, if this repo does not work as expected please ping me (2 years after the last update from me?)

[fuguangxin]

Reopen if you tested on iOS 17.3 and it's still broken

Yes, it's still broken , my device version is 17.3.1

[dreampiggy]

What about this ? Use https://github.com/SDWebImage/SDWebImageYYPlugin

Actually, that https://github.com/SDWebImage/SDWebImageYYPlugin/blob/master/SDWebImageYYPlugin/Classes/YYImage/YYImageBridge/SDImageYYCoder.m

[fuguangxin]

What about this ? Use https://github.com/SDWebImage/SDWebImageYYPlugin

Actually, that https://github.com/SDWebImage/SDWebImageYYPlugin/blob/master/SDWebImageYYPlugin/Classes/YYImage/YYImageBridge/SDImageYYCoder.m

It's ok，but need add code like this
[SDImageCodersManager.sharedManager addCoder:SDImageYYCoder.sharedCoder];

[dreampiggy]

So this is concluded as Apple's Bug ?

Should we fix this ? (provide a libpng based codec ?)

or update to #3605

A new bug in iOS 17's ImageIO APNG decoder (not SDWebImage's issue)

[fuguangxin]

So this is concluded as Apple's Bug ?

Should we fix this ? (provide a libpng based codec ?)

or update to #3605

A new bug in iOS 17's ImageIO APNG decoder (not SDWebImage's issue)

I suggest that we can provide a way to solve this problem.Apple has not solved this problem for too long.

[dreampiggy]

I suggest that we can provide a way to solve this problem.Apple has not solved this problem for too long.

Is there any open-source libpng (A objc/C++/swift wrapper is better) available ?

Must support at least CocoaPods package manager (SwiftPM is better)

Or can you help for some PR ?

---

Because it's Apple's bug, in most cases, I don't want to waste my time to fix it. Until the fixing cost is low

Only if there are something like https://github.com/SDWebImage/libwebp-Xcode available for APNG, I can spend days to fix.

[awxkee]

I suggest that we can provide a way to solve this problem.Apple has not solved this problem for too long.

Is there any open-source libpng (A objc/C++/swift wrapper is better) available ?

Must support at least CocoaPods package manager (SwiftPM is better)

Or can you help for some PR ?

Because it's Apple's bug, in most cases, I don't want to waste my time to fix it. Until the fixing cost is low

Only if there are something like https://github.com/SDWebImage/libwebp-Xcode available for APNG, I can spend days to fix.

It will take some time any way to integrate APNG. APNG stores each frame in different size and expects that you will position and blend next frame into last one, and do not provide integrated method to do so.

Download and apply a APNG patch for libpng and create SPM, or find one, it is easiest part I think:)

[awxkee]

Also libpng itself depends on zlib, so link against z is required, but there are known serious vulnerability in zlib before iOS 15.5 and that means compile zlib or zlib-ng and link to it required also to avoid publish with known vulnerabilities.

Perhaps, integrating libpng may not worth it

[dreampiggy]

YYImage do the simple thing to add extensions to apng, why not just continue to use that ?

You can filter only PNG format and iOS 17.0 (means , buggy version you want to support) use that YYImageDecoder

[dreampiggy]

It will take some time any way to integrate APNG. APNG stores each frame in different size and expects that you will position and blend next frame into last one, and do not provide integrated method to do so.

THIS IS ACTUALLY THE EASIEST PART.

Because I already written at least 5 times of this code, like webp avif bpg. Use a CGcontext as canvas is easy: https://github.com/SDWebImage/SDWebImageWebPCoder/blob/fed1583714dc02489ec69debdaf6fafb1dc0581a/SDWebImageWebPCoder/Classes/SDImageWebPCoder.m#L544

But anyway, I still think OS provided codec should handle this, the API (CGImageSourceCreateImageAtIndex) should always return the final one, instead of internal-mixing part of frame