Playing with text() and pixels

 Two excellent examples using text, the first takes a picture and a text on top, and makes the letters bigger where the picture is brigther, a fine start for more experiments:

http://www.learningprocessing.com/exercises/chapter-17/exercise-17-7/

The second example is using textWidth:

x += textWidth(message.charAt(i));


So you can get the pixelNumber where your letter starts. In this way you can use letters of different sizes in the same bit of text.