// all values are in the range of 0 to 1.0
RGBA32 makeRGBAFromHSLA(double h, double s, double l, double a)
{
double temp2 = l < 0.5 ? l * (1.0 + s) : l + s - l * s;
double temp1 = 2.0 * l - temp2;
return makeRGBA(static_cast<int>(calcHue(temp1, temp2, h + 1.0 / 3.0) * 255),
static_cast<int>(calcHue(temp1, temp2, h) * 255),
static_cast<int>(calcHue(temp1, temp2, h - 1.0 / 3.0) * 255),
static_cast<int>(a * 255));
}
// all values are in the range of 0 to 1.0
RGBA32 makeRGBAFromHSLA(double hue, double saturation, double lightness, double alpha)
{
const double scaleFactor = nextafter(256.0, 0.0);
if (!saturation) {
int greyValue = static_cast<int>(lightness * scaleFactor);
return makeRGBA(greyValue, greyValue, greyValue, static_cast<int>(alpha * scaleFactor));
}
double temp2 = lightness < 0.5 ? lightness * (1.0 + saturation) : lightness + saturation - lightness * saturation;
double temp1 = 2.0 * lightness - temp2;
return makeRGBA(static_cast<int>(calcHue(temp1, temp2, hue + 1.0 / 3.0) * scaleFactor),
static_cast<int>(calcHue(temp1, temp2, hue) * scaleFactor),
static_cast<int>(calcHue(temp1, temp2, hue - 1.0 / 3.0) * scaleFactor),
static_cast<int>(alpha * scaleFactor));
}