public static Contrast GetContrast(GColor backGround, GColor frontColor)
{
GColor back = new FormColor(Color.FromArgb(backGround.A, backGround.R, backGround.G, backGround.B));
GColor front = new FormColor(Color.FromArgb(frontColor.A, frontColor.R, frontColor.G, frontColor.B));
#endif
if (back.A == 255)
{
if (front.A < 255)
front = OverlayOn(front, back);
double l1 = Luminance(back) + 0.05;
double l2 = Luminance(front) + 0.05;
double ratio = l2 > l1 ? l2 / l1 : l1 / l2;
ratio = Math.Round(ratio, 1);
return new Contrast()
{
Ratio = ratio,
Error = 0,
Min = ratio,
Max = ratio,
Closet = null,
Farthest = null
};
}
double onBlack = GetContrast(OverlayOn(back, Black), front).Ratio;
double onWhite = GetContrast(OverlayOn(back, White), front).Ratio;
double max = Math.Max(onBlack, onWhite);
#if NETFX_CORE || SILVERLIGHT
Color closest = Closest(backGround, frontColor);
#else
GColor closest = Closest(backGround, frontColor);
#endif
double min = GetContrast(OverlayOn(back, closest), front).Ratio;
return new Contrast()
{
Ratio = Math.Round((max + min) / 2, 2),
Error = Math.Round((max - min) / 2, 2),
Min = min,
Max = max,
Closet = closest,
Farthest = onWhite == max ? White : Black
};
}