X-Git-Url: http://source.jalview.org/gitweb/?a=blobdiff_plain;f=src%2Fjalview%2Futil%2FColorUtils.java;fp=src%2Fjalview%2Futil%2FColorUtils.java;h=d7829dfdc01507e022ea430ab57c59cb033b0559;hb=2595e9d4ee0dbbd3406a98c4e49a61ccde806479;hp=31d1dedad331641c63e5da78df030bd8321c57d0;hpb=e20075ba805d744d7cc4976e2b8d5e5840fb0a8d;p=jalview.git

diff --git a/src/jalview/util/ColorUtils.java b/src/jalview/util/ColorUtils.java
index 31d1ded..d7829df 100644
--- a/src/jalview/util/ColorUtils.java
+++ b/src/jalview/util/ColorUtils.java
@@ -142,4 +142,216 @@ 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);
+    }
+  }
+
+  /**
+   * Parses a string into a Color, where the accepted formats are
+   * <ul>
+   * <li>an AWT colour name e.g. white</li>
+   * <li>a hex colour value (without prefix) e.g. ff0000</li>
+   * <li>an rgb triple e.g. 100,50,150</li>
+   * </ul>
+   * 
+   * @param colour
+   * @return the parsed colour, or null if parsing fails
+   */
+  public static Color parseColourString(String colour)
+  {
+    if (colour == null)
+    {
+      return null;
+    }
+    colour = colour.trim();
+  
+    Color col = null;
+    try
+    {
+      int value = Integer.parseInt(colour, 16);
+      col = new Color(value);
+    } catch (NumberFormatException ex)
+    {
+    }
+  
+    if (col == null)
+    {
+      col = ColorUtils.getAWTColorFromName(colour);
+    }
+  
+    if (col == null)
+    {
+      try
+      {
+        String[] tokens = colour.split(",");
+        if (tokens.length == 3)
+        {
+          int r = Integer.parseInt(tokens[0].trim());
+          int g = Integer.parseInt(tokens[1].trim());
+          int b = Integer.parseInt(tokens[2].trim());
+          col = new Color(r, g, b);
+        }
+      } catch (Exception ex)
+      {
+        // non-numeric token or out of 0-255 range
+      }
+    }
+  
+    return col;
+  }
+
+  /**
+   * Constructs a colour from a text string. The hashcode of the whole string is
+   * scaled to the range 0-135. This is added to RGB values made from the
+   * hashcode of each third of the string, and scaled to the range 20-229.
+   * 
+   * @param name
+   * @return
+   */
+  public static Color createColourFromName(String name)
+  {
+    if (name == null)
+    {
+      return Color.white;
+    }
+    int lsize = name.length();
+    int start = 0;
+    int end = lsize / 3;
+  
+    int rgbOffset = Math.abs(name.hashCode() % 10) * 15; // 0-135
+  
+    /*
+     * red: first third
+     */
+    int r = Math.abs(name.substring(start, end).hashCode() + rgbOffset) % 210 + 20;
+    start = end;
+    end += lsize / 3;
+    if (end > lsize)
+    {
+      end = lsize;
+    }
+  
+    /*
+     * green: second third
+     */
+    int g = Math.abs(name.substring(start, end).hashCode() + rgbOffset) % 210 + 20;
+  
+    /*
+     * blue: third third
+     */
+    int b = Math.abs(name.substring(end).hashCode() + rgbOffset) % 210 + 20;
+  
+    Color color = new Color(r, g, b);
+  
+    return color;
+  }
+
+  /**
+   * Returns the Color constant for a given colour name e.g. "pink", or null if
+   * the name is not recognised
+   * 
+   * @param name
+   * @return
+   */
+  public static Color getAWTColorFromName(String name)
+  {
+    if (name == null)
+    {
+      return null;
+    }
+    Color col = null;
+    name = name.toLowerCase();
+  
+    // or make a static map; or use reflection on the field name
+    switch (name)
+    {
+    case "black":
+      col = Color.black;
+      break;
+    case "blue":
+      col = Color.blue;
+      break;
+    case "cyan":
+      col = Color.cyan;
+      break;
+    case "darkgray":
+      col = Color.darkGray;
+      break;
+    case "gray":
+      col = Color.gray;
+      break;
+    case "green":
+      col = Color.green;
+      break;
+    case "lightgray":
+      col = Color.lightGray;
+      break;
+    case "magenta":
+      col = Color.magenta;
+      break;
+    case "orange":
+      col = Color.orange;
+      break;
+    case "pink":
+      col = Color.pink;
+      break;
+    case "red":
+      col = Color.red;
+      break;
+    case "white":
+      col = Color.white;
+      break;
+    case "yellow":
+      col = Color.yellow;
+      break;
+    }
+  
+    return col;
+  }
 }