Fix the issue when WebP contains the ICC Profile with colorSpace other than RGB, which cause the CGImageCreate failed

[dreampiggy]

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This merge request fixes / refers to the following issues: #2626

Pull Request Description

See #2626

In the 4.4.5 version, we add support to load WebP images' ICC Profile. However, current code seems does not check whether the ICC Profile color space is RGB. When using the color space other than RGB (such as Monochrome, CMYK), the CGImageCreate call will fail, so this cause the decoding failed.

So, we must do filter of the ICC Profile's color space before using. To ensure we only use RGB color mode to feed the CGImageCreate built-in API.

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SDWebImage/SDWebImageWebPCoder.m	80.8% <0%> (ø)

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[kinarobin]

This can fix CGImageCreate failed bug, Thanks @dreampiggy.

[zhongwuzw]

I don't think CGImageCreate don't support Monochrome, two reasons leads created failed, one is we passed wrong bitsPerPixel, Monochrome has only one component, you can try CGImageRef imageRef = CGImageCreate(width, height, 8, 8, config.output.u.RGBA.stride, colorSpaceRef, bitmapInfo, provider, NULL, NO, renderingIntent); , at least, image can show proportional. Other reason, it's also why it's show proportional is we already decode it to RGB data.

[dreampiggy]

......Maybe you misunderstand something.

We ask libwebp, to output a RGB/RGBA bitmap buffer. Even it's original encoded with Monochrome(grey style) which contains 1 component. The ouput bitmap buffer is always 3/4 components (transformed by libwebp from Monochrome to RGB).

    config.output.colorspace = config.input.has_alpha ? MODE_rgbA : MODE_RGB; // <--- This cause libwebp to always ouput 3 or 4 components RGB bitmap buffer

If you supply 1 component to CGImageCreate, your dataProvider, actually is wrong. Because the bitmapBuffer is RGB(3 components), the colorSpace is Monochrome(1 component). It's also not correct..The correct way, is to supply either a Monochrome colorSpace + Monochrome bitmap data buffer, or a RGB colorSpace + RGB bitmap buffer, but not mix them together...

Actually, we can use ColorSync and vImage framework, to convert a ICC Profile from Monochrome to RGB, or even CMYK(YUV), but I really don't think it's necessary. 😓

We have never designed to be a professional image processing tools or decoding tools. If you build apps like Photoshop iOS and your customer is worry about the color sync, you have to write many many codes with professional color sync knowledge and low level APIs. This PR is just fix the problem of some rare WebP images on the modern Internet.

[zhongwuzw]

@dreampiggy ...Emm, maybe you don't get what I want to say 😂 , I only want to explain why CGImageCreate failed, there have two reasons. So the comments in this PR is wrong, I made a PR #2629 to update.

[ducnv2910]

Hello .

I can not play webP with this link: https://storage.googleapis.com/myscoop/scoops/webp/mtu1mdcxnju3ns40mju4ntuy_320.webp
- some : Error Domain=NSURLErrorDomain Code=-1001 "The request timed out." UserInfo={_kCFStreamErrorCodeKey=-2102, NSUnderlyingError=0x2837563d0 {Error Domain=kCFErrorDomainCFNetwork Code=-1001 "(null)" UserInfo={_kCFStreamErrorCodeKey=-2102, _kCFStreamErrorDomainKey=4}}, _NSURLErrorFailingURLSessionTaskErrorKey=LocalDataTask <18471379-5B42-4074-9C2F-18B5844EC0DF>.<14>, _NSURLErrorRelatedURLSessionTaskErrorKey=( "LocalDataTask <18471379-5B42-4074-9C2F-18B5844EC0DF>.<14>" ), NSLocalizedDescription=The request timed out., NSErrorFailingURLStringKey=https://storage.googleapis.com/myscoop/scoops/webp/mtu1mdcxnju3ns40mju4ntuy_320.webp, NSErrorFailingURLKey=https://storage.googleapis.com/myscoop/scoops/webp/mtu1mdcxnju3ns40mju4ntuy_320.webp, _kCFStreamErrorDomainKey=4}

[dreampiggy]

@ducnv2910 Seems the error code is network, but not WebP decoding.

And I can successlly load this webp image url. Maybe it's something of your code that cause the issue ?

[ducnv2910]

@dreampiggy which version that you are using. I am using 4.4.6

And can you show me your code load webp.

Thank you so much

[dreampiggy]

@ducnv2910 Using our SDWebImage repo's demo.
Change your image url in MasterViewController.m, Run "SDWebImage iOS Demo" target...

[nvduc2910]

Thanks. it works now.