@fimbul-works/vec-color/dist/alpha.js

A comprehensive, type-safe color manipulation library for TypeScript that provides a wide range of color space conversions, blending operations, and accessibility utilities.

import { Vec3, Vec4 } from "@fimbul-works/vec";
/**
 * Adds an alpha channel to RGB
 * @param color - Color as Vec3 RGB (each channel from 0 to 1)
 * @param alpha - Alpha value (0 to 1)
 * @returns Vec4 containing RGBA values
 */
export function withAlpha(color, alpha = 1) {
    return new Vec4(color.x, color.y, color.z, alpha);
}
/**
 * Converts a color with alpha to premultiplied RGBA
 * @param color - Color as Vec3 RGB (each channel from 0 to 1)
 * @param alpha - Alpha value (0 to 1)
 * @returns Vec4 containing premultiplied RGBA values
 */
export function toPremultipliedAlpha(color, alpha = 1) {
    return new Vec4(color.x * alpha, color.y * alpha, color.z * alpha, alpha);
}
/**
 * Converts a premultiplied RGBA color back to straight RGB and alpha
 * @param premultiplied - Premultiplied color as Vec4 RGBA
 * @returns [Vec3, number] tuple containing RGB color and alpha value
 */
export function fromPremultipliedAlpha(premultiplied) {
    const alpha = premultiplied.w;
    if (alpha === 0)
        return [new Vec3(0, 0, 0), 0];
    return [
        new Vec3(premultiplied.x / alpha, premultiplied.y / alpha, premultiplied.z / alpha),
        alpha,
    ];
}