export function guaranteeInvisiblePixel(
input: Uint8Array<ArrayBuffer> | Uint8ClampedArray<ArrayBuffer>,
colors: Map<number, number>,
forGrayscale: boolean,
): number | undefined {
if (forGrayscale) {
for (let y = 0; y < 256; ++y) {
let colorExists = false;
for (const [color, _occurances] of colors) {
if (
y === (color >>> 24 & 0xFF) &&
255 === (color & 0xFF)
) {
colorExists = true;
break;
}
}
if (!colorExists) {
replaceTransparentPixels(input, y, y, y);
return y;
}
}
}
for (let r = 0; r < 256; ++r) {
for (let g = 0; g < 256; ++g) {
for (let b = 0; b < 256; ++b) {
let colorExists = false;
for (const [color, _occurances] of colors) {
if (
r === (color >>> 24 & 0xFF) &&
g === (color >>> 16 & 0xFF) &&
b === (color >>> 8 & 0xFF) &&
255 === (color & 0xFF)
) {
colorExists = true;
break;
}
}
if (!colorExists) {
replaceTransparentPixels(input, r, g, b);
return ((r * 256 + g) * 256 + b) * 256;
}
}
}
}
}
function replaceTransparentPixels(
input: Uint8Array<ArrayBuffer> | Uint8ClampedArray<ArrayBuffer>,
r: number,
g: number,
b: number,
): void {
for (let i = 0; i < input.length; i += 4) {
if (input[i + 3] === 0) {
input[i] = r;
input[i + 1] = g;
input[i + 2] = b;
}
}
}
export function toGrayscale(
input: Uint8Array<ArrayBuffer> | Uint8ClampedArray<ArrayBuffer>,
): Uint8Array<ArrayBuffer> | Uint8ClampedArray<ArrayBuffer> {
for (let i = 4; i < input.length; i += 4) input[i / 4] = input[i];
return input.subarray(0, input.length / 4);
}
export function toGrayscaleAlpha(
input: Uint8Array<ArrayBuffer> | Uint8ClampedArray<ArrayBuffer>,
): Uint8Array<ArrayBuffer> | Uint8ClampedArray<ArrayBuffer> {
input[1] = input[3];
for (let i = 4; i < input.length; i += 4) {
input[i / 2] = input[i];
input[i / 2 + 1] = input[i + 3];
}
return input.subarray(0, input.length / 2);
}
export function toTruecolor(
input: Uint8Array<ArrayBuffer> | Uint8ClampedArray<ArrayBuffer>,
): Uint8Array<ArrayBuffer> | Uint8ClampedArray<ArrayBuffer> {
for (let i = 4; i < input.length; i += 4) {
input[i / 4 * 3] = input[i];
input[i / 4 * 3 + 1] = input[i + 1];
input[i / 4 * 3 + 2] = input[i + 2];
}
return input.subarray(0, input.length / 4 * 3);
}
export function toIndex(
input: Uint8Array<ArrayBuffer> | Uint8ClampedArray<ArrayBuffer>,
palette: Uint32Array<ArrayBuffer>,
): Uint8Array<ArrayBuffer> | Uint8ClampedArray<ArrayBuffer> {
const view = new DataView(input.buffer, input.byteOffset, input.byteLength);
for (let i = 0; i < input.length; i += 4) {
input[i / 4] = palette.indexOf(view.getUint32(i));
}
return input.subarray(0, input.length / 4);
}
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