X-Git-Url: http://source.jalview.org/gitweb/?a=blobdiff_plain;f=src%2Fjalview%2Futil%2FColorUtils.java;fp=src%2Fjalview%2Futil%2FColorUtils.java;h=525bfdbce880941c4c9276d63d9bdff1e3dbac04;hb=7d67fb613ec026dc9a265e351e7fab542e3f1d61;hp=31d1dedad331641c63e5da78df030bd8321c57d0;hpb=02e38bb826828ab2991584cf4b737c0138cb6c44;p=jalview.git

diff --git a/src/jalview/util/ColorUtils.java b/src/jalview/util/ColorUtils.java
index 31d1ded..525bfdb 100644
--- a/src/jalview/util/ColorUtils.java
+++ b/src/jalview/util/ColorUtils.java
@@ -142,4 +142,53 @@ public class ColorUtils
             * (maxColour.getBlue() - minColour.getBlue());
     return new Color(r / 255, g / 255, b / 255);
   }
+
+  /**
+   * 'Fades' the given colour towards white by the specified proportion. A
+   * factor of 1 or more results in White, a factor of 0 leaves the colour
+   * unchanged, and a factor between 0 and 1 results in a proportionate change
+   * of RGB values towards (255, 255, 255).
+   * <p>
+   * A negative bleachFactor can be specified to darken the colour towards Black
+   * (0, 0, 0).
+   * 
+   * @param colour
+   * @param bleachFactor
+   * @return
+   */
+  public static Color bleachColour(Color colour, float bleachFactor)
+  {
+    if (bleachFactor >= 1f)
+    {
+      return Color.WHITE;
+    }
+    if (bleachFactor <= -1f)
+    {
+      return Color.BLACK;
+    }
+    if (bleachFactor == 0f)
+    {
+      return colour;
+    }
+
+    int red = colour.getRed();
+    int green = colour.getGreen();
+    int blue = colour.getBlue();
+
+    if (bleachFactor > 0)
+    {
+      red += (255 - red) * bleachFactor;
+      green += (255 - green) * bleachFactor;
+      blue += (255 - blue) * bleachFactor;
+      return new Color(red, green, blue);
+    }
+    else
+    {
+      float factor = 1 + bleachFactor;
+      red *= factor;
+      green *= factor;
+      blue *= factor;
+      return new Color(red, green, blue);
+    }
+  }
 }