Add support for no width and no height on images

[LaurenzV]

No description provided.

[LaurenzV]

Closes #714

[LaurenzV]

The images are linked by relative paths because that's how it was before and I didn't know if I should change it. Should I embed them as base64 strings instead?

[RazrFalcon]

Relative paths are fine.

As for the code, I would suggest using tiny_skia_path::Size::scale_to_width and scale_to_height. They are basically the same, but might make the code nicer. The current implementation is too verbose.
I would also suggest calling convert_user_length first and then matching Option<T> pair.

[LaurenzV]

As for the code, I would suggest using tiny_skia_path::Size::scale_to_width and scale_to_height.

Seems like this API is only available for IntSize and not Size?

[RazrFalcon]

Much better now.

Seems like this API is only available for IntSize and not Size?

Weird, ok.

Also about the PR name. We do support optional width/height. We do not support aspect preserving.
So I guess it should be called: "Preserve image aspect ratio when width or height are missing.". Does this sound ok?

[RazrFalcon]

Also, I think we need tests with non-rectangular images. Otherwise the aspect is always 1:1 and we're not testing anything. No?

[RazrFalcon]

I guess current tests are fine, because you do scale the image, but the aspect is always 1:1 right now. So I guess a single test with a non-rectangular image would be nice.

Let's use this image:

[LaurenzV]

Also, I think we need tests with non-rectangular images. Otherwise the aspect is always 1:1 and we're not testing anything. No?

It's not necessarily about the aspect.

Before: If we have an image with size 100x100, but set only the height to 200, then the image would be assumed to be 100x200 -> It will get shifted instead.

Now: If we have an image with size 100x100, but set only the height to 200, then the width will be increased by the same ratio that the height would increase/decrease, so in this case 200 -> the result is 200x200.

[LaurenzV]

I guess current tests are fine, because you do scale the image, but the aspect is always 1:1 right now. So I guess a single test with a non-rectangular image would be nice.

Okay, will add it.

[RazrFalcon]

Thanks!