toHSVA

import std.math : isClose;
with(RGB888(255, 0, 0).toHSVA) {
	assert(hue.isClose(0.0));
	assert(saturation.isClose(1.0));
	assert(value.isClose(1.0));
	assert(alpha.isClose(1.0));
}
with(RGBA8888(255, 0, 0, 255).toHSVA) {
	assert(hue.isClose(0.0));
	assert(saturation.isClose(1.0));
	assert(value.isClose(1.0));
	assert(alpha.isClose(1.0));
}
with(RGBA8888(255, 0, 0, 0).toHSVA) {
	assert(hue.isClose(0.0));
	assert(saturation.isClose(1.0));
	assert(value.isClose(1.0));
	assert(alpha.isClose(0.0));
}