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Optimize Color32::from_rgba_unmultiplied

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This commit is contained in:
Emil Ernerfeldt 2021-01-07 16:28:22 +01:00
parent 752c321a61
commit e8e53e9500
1 changed files with 13 additions and 4 deletions
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17
egui/src/paint/color.rs
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@ -57,11 +57,20 @@ impl Color32 {
/// From `sRGBA` WITHOUT premultiplied alpha. /// From `sRGBA` WITHOUT premultiplied alpha.
pub fn from_rgba_unmultiplied(r: u8, g: u8, b: u8, a: u8) -> Self { pub fn from_rgba_unmultiplied(r: u8, g: u8, b: u8, a: u8) -> Self {
if a == 255 { if a == 255 {
Self::from_rgba_premultiplied(r, g, b, a) // common-case optimization Self::from_rgba_premultiplied(r, g, b, 255) // common-case optimization
} else if a == 0 {
Self::TRANSPARENT // common-case optimization
} else { } else {
Rgba::from(Self::from_rgb(r, g, b)) let r_lin = linear_from_gamma_byte(r);
.multiply(a as f32 / 255.0) let g_lin = linear_from_gamma_byte(g);
.into() let b_lin = linear_from_gamma_byte(b);
let a_lin = linear_from_alpha_byte(a);
let r = gamma_byte_from_linear(r_lin * a_lin);
let g = gamma_byte_from_linear(g_lin * a_lin);
let b = gamma_byte_from_linear(b_lin * a_lin);
Self::from_rgba_premultiplied(r, g, b, a)
} }
} }