rgbToCmyk static method
Converts a RGB color to a CMYK color.
Implementation
static CmykColor rgbToCmyk(RgbColor rgbColor) {
final rgb = rgbColor.toFactoredList();
final cmy = rgb.map((rgbValue) => 1 - rgbValue).toList();
final k = cmy.reduce(math.min).clamp(0.0, 1.0);
final alpha = rgbColor.alpha / 255;
final cmyk = cmy
.map((cmyValue) => ((cmyValue - k) / (1 - k)).clamp(0.0, 1.0))
.toList()
..add(k)
..add(alpha);
return CmykColor.extrapolate(List<double>.from(cmyk));
}