[image_picker] GIF resize loses animation

[ozzy1873]

Specifying maxWidth and maxHeight when picking a GIF will cause the animation to be lost.

[cyanglaz]

This should have been fixed with flutter/plugins#1638. Please close the issue if you can confirm the same.

[ozzy1873]

I upgraded to 0.6.1 and now animations are lost even without attempting to resize.

[cyanglaz]

@ozzy1873 GIFs animation works for me. Could you please post a mini sample code to reproduce the issue?

[AmolGangadhare]

@cyanglaz I noticed this when we try to resize the gif. So what happening is, when we select gif file and apply height or width or imageQuality, the bitmap factory(in Android) compresses it, which causes loss of animation. It simply becomes an image. To achieve this, we need to split the frames from gif first, after that apply all resize factors(i.e. height/width/imageQuality) to that every frame(which is simply bitmap). Then again composite all frames to create a gif.
I think this would be the solution to this, please correct me if I'm wrong or there is any better solution available.

[cyanglaz]

@AmolGangadhare Yes it is the right solution! We are doing the same thing on iOS already.
Do you want to work on this and put up a PR for it?

[AmolGangadhare]

@cyanglaz i would like to do it. I'll keep you updated with same.

[cyanglaz]

@AmolGangadhare Great! Thanks!

[AmolGangadhare]

@cyanglaz Sorry for the late response. I've made the changes for gif compression. But there are some important things needs to consider. I did some research and have some finding: (As android doesn't have any built-in things to compress (encode and decode) gif, everything needs to be done manually. I've referred some OS resources to encode and decode gif)

1. I have gone through several gif tries and found that 99% of cases the image compression was not working for imageQuality factor as the frames were of png. They can be resized only on height and width.
2. Even if we apply imageQuality factor, that makes operation extremely slow(depending upon the gif) as everything is going to be a manual process and the plugin doesn't have any additional activity to make user interactive while processing.

I've not made a PR yet as there is a visible lag in processing, I'm trying to further optimize it. You can refer to my repo (https://github.com/AmolGangadhare/plugins) for the changes I made. Any inputs from you will be much more helpful.

Thanks