P maps to 15     Note that P is the 15th letter after A
A maps to 0                P has ASCII value 80
N maps to 13               A has ASCII value 65
T maps to 19
H maps to 7      redAmount = 10 * ( (int) input.charAt(i) - 65 );
E maps to 4
R maps to 17     Color colorForRect = new Color( redAmount, 0, 255 );
S maps to 18     Letter A would have redAmount of 0, B would have 10,
                        C would have redAmount of 20, ... Z would have 250

         input = input.toUpperCase();
         for (int i = 0; i < input.length(); i++)
         {
             int charValue = (int) input.charAt(i) - 65;
             System.out.println( input.charAt(i) + " maps to " +
                                  charValue );
         }