Test our SVG implementation with resvg-test-suite

[shlyakpavel]

This seems like a great opportunity to benchmark our SVG implementation against resvg-test-suite.

It appears that the test suite doesn't include a built-in runner, so we’ll need to create a script to run our SVG renderer and compare the output against the reference PNGs ourselves.

[shlyakpavel]

1680 tests done 1600 if them are not UB Final success rate for ladybird with all the tests: 27.5% This is not bad at all. We also have extraordinary low crash rate. Feel free to take data on github and analyze it yourself https://github.com/linebender/resvg-test-suite/pull/55

[shlyakpavel]

In my opinion, top priority for fixing these tests are: 1) Gradients (not positioned correctly) 2) Font rendering 3) Asian characters (Japanese and Arabic) 4) Blur (I guess we don't support it at all) 5) Nested images (inline pngs jpegs etc) 6) Markers (I think we don't support these at all) Other issues were very rare to occur

[gmta]

@shlyakpavel Do you have a simple reproduction case for one of the gradient mispositioning issues?

[shlyakpavel]

@gmta MDN has https://developer.mozilla.org/en-US/docs/Web/SVG/Tutorial/Gradients#basic_example Safari:

Ladybird:

[gmta]

This is how that page looks on my machine:

Can you still reproduce it with the latest master? What platform are you running on?

[gmta]

Ah, it does get mangled when you start to zoom in. I'm guessing this might be a difference in DPI

[shlyakpavel]

@gmta I have a 13 inch MacBook Air (m1) running macOS 15.1

[nico]

(Possibly a regression from moving to Skia; looks fine in Serenity's browser's mac port on retina.)

(This is the example in a standalone file; the full thing doesn't load in Serenity's browser apparently)

[gmta]

@nico No, you probably didn't cherry pick everything yet :-) this is the result of one of my changes in the way we deal with gradient coordinate spaces. I've got a fix underway.