colour.js

colour.js

function srgb2lrgb(r, g, b)
{
	if (r instanceof Array)
	{
		b = r[2];
		g = r[1];
		r = r[0];
	}

	return [
		r > 0.04045 ? Math.pow((r + 0.055) / 1.055, 2.4) : r / 12.92,
		g > 0.04045 ? Math.pow((g + 0.055) / 1.055, 2.4) : g / 12.92,
		b > 0.04045 ? Math.pow((b + 0.055) / 1.055, 2.4) : b / 12.92,
	];
}

function lrgb2srgb(r, g, b)
{
	if (r instanceof Array)
	{
		b = r[2];
		g = r[1];
		r = r[0];
	}

	return [
		r > 0.0031308 ? Math.pow(r, 1 / 2.4) * 1.055 - 0.055 : r * 12.92,
		g > 0.0031308 ? Math.pow(g, 1 / 2.4) * 1.055 - 0.055 : r * 12.92,
		b > 0.0031308 ? Math.pow(b, 1 / 2.4) * 1.055 - 0.055 : r * 12.92,
	]
}

function gamma2lrgb(gamma, r, g, b)
{
	if (r instanceof Array)
	{
		b = r[2];
		g = r[1];
		r = r[0];
	}

	return [
		Math.pow(r, gamma),
		Math.pow(g, gamma),
		Math.pow(b, gamma),
	];
}

function lrgb2gamma(gamma, r, g, b)
{
	if (r instanceof Array)
	{
		b = r[2];
		g = r[1];
		r = r[0];
	}

	return [
		Math.pow(r, 1 / gamma),
		Math.pow(g, 1 / gamma),
		Math.pow(b, 1 / gamma),
	];
}

function srgb2gamma(gamma, r, g, b)
{
	return lrgb2gamma(gamma, srgb2lrgb(r, g, b));
}

function gamma2srgb(gamma, r, g, b)
{
	return lrgb2srgb(gamma2lrgb(gamma, r, g, b));
}

function rgb2ycrcb(kb, kr, r, g, b)
{
	var y;

	if (r instanceof Array)
	{
		b = r[2];
		g = r[1];
		r = r[0];
	}

	return [
		(y = kr * r + (1 - kr - kb) * g + kb * b),
		(b - y) / (1 - kb) * 0.5,
		(r - y) / (1 - kr) * 0.5,
	];
}

function rgb2bt601(r, g, b)
{
	return rgb2ycrcb(0.114, 0.299, r, g, b);
}

function rgb2bt709(r, g, b)
{
	return rgb2ycrcb(0.0722, 0.2126, r, g, b);
}

function lrgb2bt709(r, g, b)
{
	return rgb2bt709(lrgb2gamma(2.35, r, g, b));
}

function srgb2bt709(r, g, b)
{
	return rgb2bt709(srgb2gamma(2.35, r, g, b));
}