Sweep gradients #435
Sweep gradients #435
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Implements support for rendering sweep gradients. Based on Skia's SkSweepGradient shader.
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For reviewers: 0x254 = 0b001001_0_101_00 |
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Should this also be added to the fine cpu shader (on a best-effort basis, given we can't really test it)? We probably should have a coherent policy on that (see also #386)
Otherwise, I've checked code quality. Haven't checked the maths, but it works in the test scenes you've created, on both CPU and GPU
| let is_radial = y & 1 != 0; | ||
| for (y, kind) in [Kind::Linear, Kind::Radial, Kind::Sweep] | ||
| .into_iter() | ||
| .enumerate() |
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These now go off-screen in the default resolution. I think the resolution field of params can be set to counteract this (see #453)
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I wasn't aware this existed! Added to this scene and made sure it scales properly.
src/cpu_shader/draw_leaf.rs
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| let z = xform.0; | ||
| let inv_det = (z[0] * z[3] - z[1] * z[2]).recip(); | ||
| let inv_mat = [ | ||
| z[3] * inv_det, | ||
| -z[1] * inv_det, | ||
| -z[2] * inv_det, | ||
| z[0] * inv_det, | ||
| ]; | ||
| let inv_tr = [ | ||
| -(inv_mat[0] * z[4] + inv_mat[2] * z[5]), | ||
| -(inv_mat[1] * z[4] + inv_mat[3] * z[5]), | ||
| ]; |
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Is it worth adding the inverse method to Transform directly?
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Definitely. I considered this but side-stepped it when adding the code.
Done.
- use params.resolution to fit test scene to current viewport - move repeated inverse calculation to Transform::inverse() method Also add CPU implementation of radial gradients in draw_leaf.rs
Since we're still missing texture bindings in the CPU pipeline, we can't do much with this and my preference is to defer until that is more fully fleshed out. I did however go ahead and sneak the CPU-side radial gradient fixes into this PR. |
Implements support for rendering sweep gradients. Just had an itch to get this done, mostly to support COLRv1 fonts.
Based on Skia's
SkSweepGradientshader.Here's a comparison of a sweep gradient with the three extend modes. Skia on top and Vello on bottom.
