public ColorBrightnessDifference(Color color1, Color color2)
{
Color1 = color1;
Color2 = color2;
Diff = Math.Round(Math.Abs(ColorServices.GetBrightness(color1) - ColorServices.GetBrightness(color2)), 3);
Acceptable = Diff >= Threshold;
}
public ActionResult <double> GetLuminance(string color)
{
if (!int.TryParse(color, NumberStyles.HexNumber, CultureInfo.InvariantCulture, out _))
{
ModelState.AddModelError(nameof(color), $"The color [{color}] is invalid. This API endpoint accepts a HEX number as a color.");
return(BadRequest(ModelState));
}
return(ColorServices.GetLuminance(ColorTranslator.FromHtml("#" + color)));
}
public void GetColorContrastTests()
{
Assert.AreEqual(1.0, ColorServices.GetContrastRatio(Color.White, Color.White));
Assert.AreEqual(21.0, ColorServices.GetContrastRatio(Color.Black, Color.White));
// Pure red(#FF0000) has a ratio of 4:1. I am red text.
// Pure green (#00FF00) has a very low ratio of 1.4:1. I am green text.
// Pure blue (#0000FF) has a contrast ratio of 8.6:1.I am blue text.
Assert.AreEqual(3.998, ColorServices.GetContrastRatio(Color.Red, Color.White));
Assert.AreEqual(1.372, ColorServices.GetContrastRatio(Color.FromArgb(255, 0, 255, 0), Color.White));
Assert.AreEqual(8.592, ColorServices.GetContrastRatio(Color.Blue, Color.White));
Assert.AreEqual(1.0, ColorServices.GetContrastRatio(ColorTranslator.FromHtml("#a"), ColorTranslator.FromHtml("#b")));
}
public void GetLuminanceTests()
{
// the relative brightness of any point in a color space, normalized to 0 for darkest black and 1 for lightest white
Assert.AreEqual(0, ColorServices.GetLuminance(Color.Black));
Assert.AreEqual(1, ColorServices.GetLuminance(Color.White));
Assert.AreEqual(0.2126, ColorServices.GetLuminance(Color.Red));
Assert.AreEqual(0.48170267036309633, ColorServices.GetLuminance(Color.Orange));
Assert.AreEqual(0.9278, ColorServices.GetLuminance(Color.Yellow));
Assert.AreEqual(0.7152, ColorServices.GetLuminance(Color.FromArgb(255, 0, 255, 0)));
Assert.AreEqual(0.0722, ColorServices.GetLuminance(Color.Blue));
Assert.AreEqual(0.031075614863369856, ColorServices.GetLuminance(Color.Indigo));
Assert.AreEqual(0.40315452986676326, ColorServices.GetLuminance(Color.Violet));
}
public ColorContrastRatio(Color color1, Color color2)
{
Color1 = color1;
Color2 = color2;
Ratio = ColorServices.GetContrastRatio(color1, color2);
}
public void GetColorBrightnessTests(string hex, double brightness)
{
var color = ColorTranslator.FromHtml(hex);
Assert.AreEqual(brightness, ColorServices.GetBrightness(color));
}
