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feat: support rendering theme colors with alpha components

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This commit is contained in:
CJ van den Berg 2024-11-04 22:16:04 +01:00
parent 3b28286c91
commit 0a43fa853f
Signed by: neurocyte
GPG key ID: 8EB1E1BB660E3FB9
9 changed files with 127 additions and 48 deletions
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24
src/color.zig
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@ -19,6 +19,14 @@ pub const RGB = struct {
return r | b | g;
}
pub inline fn from_u8s(v: [3]u8) RGB {
return .{ .r = v[0], .g = v[1], .b = v[2] };
}
pub fn to_u8s(v: RGB) [3]u8 {
return [_]u8{ v.r, v.g, v.b };
}
pub fn contrast(a_: RGB, b_: RGB) f32 {
const a = RGBf.from_RGB(a_).luminance();
const b = RGBf.from_RGB(b_).luminance();
@ -60,3 +68,19 @@ pub const RGBf = struct {
pub fn max_contrast(v: u24, a: u24, b: u24) u24 {
return RGB.max_contrast(RGB.from_u24(v), RGB.from_u24(a), RGB.from_u24(b)).to_u24();
}
pub fn apply_alpha(base: RGB, over: RGB, alpha_u8: u8) RGB {
const alpha: f64 = @as(f64, @floatFromInt(alpha_u8)) / @as(f64, @floatFromInt(0xFF));
return .{
.r = component_apply_alpha(base.r, over.r, alpha),
.g = component_apply_alpha(base.g, over.g, alpha),
.b = component_apply_alpha(base.b, over.b, alpha),
};
}
inline fn component_apply_alpha(base_u8: u8, over_u8: u8, alpha: f64) u8 {
const base: f64 = @floatFromInt(base_u8);
const over: f64 = @floatFromInt(over_u8);
const result = ((1 - alpha) * base) + (alpha * over);
return @intFromFloat(result);
}