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Viewing changes to src/Engine/TextColorTools.cs

  • Committer: Package Import Robot
  • Author(s): Mirco Bauer
  • Date: 2013-05-25 22:11:31 UTC
  • mfrom: (1.2.12)
  • Revision ID: package-import@ubuntu.com-20130525221131-nd2mc0kzubuwyx20
Tags: 0.8.11-1
* [22d13d5] Imported Upstream version 0.8.11
* [6d2b95a] Refreshed patches
* [89eb66e] Added ServiceStack libraries to smuxi-engine package
* [848ab10] Enable Campfire engine
* [c6dbdc7] Always build db4o for predictable build result
* [13ec489] Exclude OS X specific libraries from dh_clideps

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src/Engine/TextColorTools.cs
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                          114d * color2.Blue) / 1000d;
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            return Math.Abs(br1 - br2);
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        }
 
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        // algorithm ported from JavaScript to C# from:
 
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        // http://mjijackson.com/2008/02/rgb-to-hsl-and-rgb-to-hsv-color-model-conversion-algorithms-in-javascript
 
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        internal static HslColor ToHSL(TextColor color)
 
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        {
 
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            var R = color.Red / 255d;
 
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            var G = color.Green / 255d;
 
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            var B = color.Blue / 255d;
 
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            var max = Math.Max(Math.Max(R, G), B);
 
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            var min = Math.Min(Math.Min(R, G), B);
 
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            double H = 0d, S, L;
 
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            var range = max + min;
 
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            L = range / 2d;
 
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            if (max == min) {
 
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                S = 0d; // achromatic
 
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            } else {
 
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                var diff = max - min;
 
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                S = L > 0.5d ? diff / (2 - diff) : diff / range;
 
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                if (max == R) {
 
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                    H = (G - B) / diff + (G < B ? 6d : 0d);
 
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                } else if (max == G) {
 
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                    H = (B - R) / diff + 2;
 
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                } else if (max == B) {
 
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                    H = (R - G) / diff + 4;
 
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                }
 
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                H /= 6;
 
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            }
 
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            return new HslColor(H, S, L);
 
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        }
 
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        public static TextColor GetNearestColor(TextColor color, IEnumerable<TextColor> palette)
 
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        {
 
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            if (palette == null) {
 
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                throw new ArgumentNullException("palette");
 
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            }
 
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            var hslColor1 = ToHSL(color);
 
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            TextColor nearestColor = null;
 
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            double nearestDifference = Double.MaxValue;
 
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            foreach (var color2 in palette) {
 
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                // compute the Euclidean distance between the two HSL colors
 
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                // without root square as we only compare the values
 
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                // see http://en.wikipedia.org/wiki/Color_difference#Delta_E
 
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                var hslColor2 = ToHSL(color2);
 
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                var H1 = hslColor1.Hue;
 
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                var S1 = hslColor1.Saturation;
 
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                var L1 = hslColor1.Lightness;
 
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                var H2 = hslColor2.Hue;
 
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                var S2 = hslColor2.Saturation;
 
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                var L2 = hslColor2.Lightness;
 
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                var Hdelta = H1 - H2;
 
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                var Sdelta = S1 - S2;
 
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                var Ldelta = L1 - L2;
 
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                var deltaE = (Hdelta * Hdelta) +
 
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                             (Sdelta * Sdelta) +
 
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                             (Ldelta * Ldelta);
 
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                if (deltaE < nearestDifference) {
 
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                    nearestDifference = deltaE;
 
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                    nearestColor = color2;
 
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                }
 
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                if (deltaE == 0d) {
 
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                    // found perfect match, can't get better than that
 
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                    break;
 
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                }
 
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            }
 
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            return nearestColor;
 
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        }
 
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        internal class HslColor
 
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        {
 
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            public double Hue { get; set; }
 
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            public double Saturation { get; set; }
 
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            public double Lightness { get; set; }
 
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            public HslColor(double H, double S, double L)
 
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            {
 
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                Hue = H;
 
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                Saturation = S;
 
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                Lightness = L;
 
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            }
 
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        }
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    }
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}