# Objective
- Fixes#20008 - Preconvert colors before sending them to the UI
gradients shader for better performance
## Solution
- Modified `prepare_gradient` in `gradient.rs` to convert colors from
`LinearRgba` to `Srgba` on the CPU before sending to the GPU
- Updated the gradient shader to remove per-pixel color space
conversions since colors are now pre-converted
- Added documentation to clarify that vertex colors are in sRGB space
This optimization reduces the number of power operations per pixel from
3 to 1:
- **Before**: Convert start color to sRGB, convert end color to sRGB,
mix, convert back to linear (3 pow operations per pixel)
- **After**: Colors pre-converted on CPU, mix in sRGB space, convert
back to linear (1 pow operation per pixel)
## Testing
- Verified that the UI gradient examples (`cargo run --example
gradients`) compile and render correctly
- The visual output should remain identical while performance improves,
especially for large gradient areas
- Changes maintain the same color interpolation behavior (mixing in sRGB
space)
To test:
1. Run `cargo run --example gradients` or `cargo run --example
stacked_gradients`
2. Verify gradients render correctly
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Co-authored-by: ickshonpe <david.curthoys@googlemail.com>
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