IMG.c: Loader now keeps trying other formats, if other supported format(s) failed to load an image

[Retro52]

Hi

This PR makes IMG.c keep trying to load an image if another format fails.

The reason I even had this problem comes from trying to load this WebP image on iOS (I could not attach it to PR as GitHub does not support this format)

For some reason, this image was recognized as a TIF format image by the UTTypeConformsTo. I tried replacing it with the UTTypeEqual, but got the same result. The image load was failing because the TIF format check was performed before checking against WEBP.

While the problem I had is likely some rare edge case, I believe it would still be a good thing to try to handle such rare hiccups.

[slouken]

This means that if we fail to load an image the error will always be "Unsupported image format" and we lose any informative error set by the loader.

[slouken]

The TIFF image format is well defined, I'm not sure why this RIFF/WEBP image would be detected as TIFF.

[Retro52]

The TIFF image format is well defined, I'm not sure why this RIFF/WEBP image would be detected as TIFF.

I suspect that the image is, maybe, too small, but that's not the bug that SDL could fix.

[slouken]

We could also move TIFF to the bottom of the list.

Did you see this comment?

This means that if we fail to load an image the error will always be "Unsupported image format" and we lose any informative error set by the loader.

[Retro52]

We could also move TIFF to the bottom of the list.

Did you see this comment?

This means that if we fail to load an image the error will always be "Unsupported image format" and we lose any informative error set by the loader.

Yep, just thinking if there is a nice way to handle that :)

[Retro52]

Moving TIFF to the bottom would probably fix my issue; However, I'm a little bit worried that it may cause others.

What's your opinion on that? Moving TIFF to the bottom is the easiest way, but I could spend some more time & fix the SDL_GetError() issue in my PR.

[slouken]

Fixing the GetError() issue is probably the best route.

[Retro52]

GetError() issue is now fixed by tracking how many load attempts we've made.
Btw, I tried to follow the coding standard of the file, but if there is something you'd like to change, just let me know

[slouken]

You actually need to save off the error in the case where an image load was attempted, as the error might be overridden by a subsequent is() call.

[Retro52]

Did not account for that, sry
Fixed (?)

[slouken]

Looks good. We need to do the same in IMG_LoadAnimationTyped_IO()

[sezero]

I'm not 100% comfortable with this patch

[Retro52]

I can see why, it may be too much to fix, possibly, one small edge case

We are going to keep the original version of it anyway, cause without it, I'd have to go and manually find all the broken images & convert them to other formats, like PNG.

On the other hand, I hate to modify original source code, and since Apple is (almost) definitely not going to do anything about it, I thought that maybe an official fix is possible