Disclaimer: my teammate Dellanoce actually coded this, but is too cool to blog, so I am blogging for him.
Mailtrust has many different customers, some of which like to have their own branded control panel or webmail interface. We allow them to customize many different facets of the user interface, including colors. This has some unintended consequences though. Sometimes, a user might select a white font color on top of a white background. This in turns causes support to get involved in fixing the problem, which wastes time on such a trivial problem.
But there is a better way. Use trigonometry, or more specifically the Pythagorean theorem! I had no idea how this worked, but Dellanoce coded up a few lines of C# to compare two colors. It returns a distance value which can be compared to a threshold value you can set.
private static double ColorDifference(string htmlColor1, string htmlColor2)
{
Color color1 = ColorTranslator.FromHtml(htmlColor1);
Color color2 = ColorTranslator.FromHtml(htmlColor2);
double rDiff = Convert.ToDouble(color1.R) - Convert.ToDouble(color2.R);
double gDiff = Convert.ToDouble(color1.G) - Convert.ToDouble(color2.G);
double bDiff = Convert.ToDouble(color1.B) - Convert.ToDouble(color2.B);
return Math.Sqrt((rDiff * rDiff) + (gDiff * gDiff) + (bDiff * bDiff));
}
I was quite impressed with the simplicity and elegance this solution provided. I should probably go give my, or his, trig teacher a hug.
If you want to learn more about how powerful Pythagorean theorem is to compare distance values of really any type of object, check this article out.