feat: better cover image generation

[arition]

Changed

• Changed: Resize and crop cover image instead of forcing it to resize to a specified resolution (which breaks its original aspect ratio).

[majora2007]

Please attach before and afters for the cover types listed in #2139.

[arition]

Standard

Square cover

Another square cover

Horizontal

Long

[majora2007]

I ran some tests with this and it doesn't behave well enough in my opinion.

Left is new code, Right is old

[arition]

Yeah, it is not perfect in every situation. At least I think we can give user an option to change between these two modes.

[majora2007]

That's not an avenue I'd want to go down. Could you add a check if the file is a webtoon, aka height is at least 2/3 more than width, and use the attention crop code there only?

This would add benefit for webtoon users while keeping it working for comic and Manga users out of the box.

[arition]

That's not an avenue I'd want to go down. Could you add a check if the file is a webtoon, aka height is at least 2/3 more than width, and use the attention crop code there only?

This would add benefit for webtoon users while keeping it working for comic and Manga users out of the box.

I think it should to be "width 2/3 more than height", width > height * 5 / 3?

[majora2007]

I think it should to be "width 2/3 more than height", width > height * 5 / 3?

I can't understand the math you're proposing. The goal is to identify if the image is a long panel (webtoon) and apply the new logic based on that.

[therobbiedavis]

I think it should to be "width 2/3 more than height", width > height * 5 / 3?

I can't understand the math you're proposing. The goal is to identify if the image is a long panel (webtoon) and apply the new logic based on that.

Very confused, would the conditional just be if (width === (2/3 * height)) { //Width is 2/3 of height }else{ //Width is not 2/3 of height} ?

[arition]

I can't understand the math you're proposing. The goal is to identify if the image is a long panel (webtoon) and apply the new logic based on that.

Got it. In my opinion, the new method also works well on wide images. Maybe we can apply it when width > height * 5 / 3 || height > width * 5 / 3?

[majora2007]

Hey I'm planning to take this code into a test branch sometime and tweak the code. I think there can be some benefit to this new code with a little more prodding into the source cover/archive. I want to do some pretty heavy investigation to improve webtoon cover generation and test this against more user's servers.

I have no plans when (as I'm in the middle of huge code refactors to support new features), but I wanted to share that I do plan to try this PR out in full for potential inclusion.

[arition]

Thank you! @majora2007

[majora2007]

I ended up taking a look at this and wrote my own logic along with a test suite to help tweak this in the future. Here are some of my results (original, old code, new code):