toHSV

import std.math : approxEqual;
with(RGB888(0, 0, 0).toHSV) {
	assert(hue == 0);
	assert(saturation == 0);
	assert(value == 0);
}
with(RGB888(0, 128, 192).toHSV) {
	assert(hue.approxEqual(0.5555555));
	assert(saturation.approxEqual(1.0));
	assert(value.approxEqual(0.752941));
}
with(RGB888(255, 255, 0).toHSV) {
	assert(hue.approxEqual(0.166667));
	assert(saturation.approxEqual(1.0));
	assert(value.approxEqual(1.0));
}
with(RGB888(255, 0, 0).toHSV) {
	assert(hue.approxEqual(0.0));
	assert(saturation.approxEqual(1.0));
	assert(value.approxEqual(1.0));
}
with(RGB888(255, 0, 255).toHSV) {
	assert(hue.approxEqual(0.833333));
	assert(saturation.approxEqual(1.0));
	assert(value.approxEqual(1.0));
}
with(RGB888(0, 255, 0).toHSV) {
	assert(hue.approxEqual(0.333333));
	assert(saturation.approxEqual(1.0));
	assert(value.approxEqual(1.0));
}
with(RGB888(0, 0, 255).toHSV) {
	assert(hue.approxEqual(0.666667));
	assert(saturation.approxEqual(1.0));
	assert(value.approxEqual(1.0));
}