Support animated-WebP for all API level about coil

[colinrtwhite]

Unfortunately, this isn't very straightforward to support. Fresco uses native libraries to load animated WebP images on pre-Android P, which I'm against adding to the Coil main repo.

I think this would be a good candidate for an external repository that depends Coil. If anyone writes a Decoder for this, let me know and I'll add it to the documentation.

[skgmn]

Hello @colinrtwhite! It's quite long ago, but I've done this recently using libwebp so I'm just letting you know as you said. 🙂
Check this out: https://github.com/skgmn/AnimatedWebPDecoder
Thank you.

[ShowMeThe]

Hi @colinrtwhite
I suggest this repository https://github.com/penfeizhou/APNG4Android
we can decode Animated PNG and Animated Webp by using the code(Only Java code , no C,C++ ) from this repository and make a custom Coil's Decoder ourselves.
My Coil's decoder bases on Coil's 2.0.0-alpha01

Here is my demo:
AnimatedWebPDrawable-Release.zip
Here is my demo link : https://github.com/ShowMeThe/AnimatedWebPDrawable

The testing on phone :

The left one is Coil's Decoder using code from APNG4Android repository , the right side is using Android Api ImageDecoder.decodeDrawable

Will it help Coil to support the Animated-webp or Animater-Png ?
Thanks you.

[colinrtwhite]

@skgmn Sorry for the late reply, this looks awesome! I'll set up a list of external libraries and add it to the list.

@ShowMeThe Thanks for letting me know about this library! It looks like it could work well with Coil 2.0, which exposes ImageSource.file(). Bonus that it's an 100% Java solution.

[colinrtwhite]

@ShowMeThe I think it might be possible to simplify your animated WebP decoder to just:

class AnimatedWebPDecoder(private val source: ImageSource) : Decoder {

    override suspend fun decode(): DecodeResult {
        return DecodeResult(
            drawable = WebPDrawable.fromFile(source.file().path),
            isSampled = false
        )
    }

    class Factory : Decoder.Factory {

        override fun create(result: SourceResult, options: Options, imageLoader: ImageLoader): Decoder? {
            if (WebPParser.isAWebP(result.source.file().path)) {
                return AnimatedWebPDecoder(result.source)
            } else {
                return null
            }
        }
    }
}

Though, I haven't tested the above code out.