This code was updated from the Java source to work with Processing.js asynchronous image loading.
Calculates the histogram of an image. A histogram is the frequency distribution of the gray levels with the number of pure black values displayed on the left and number of pure white values on the right.
Original Processing.org Example: Histogram
// All Examples Written by Casey Reas and Ben Fry // unless otherwise stated. size(200, 200); colorMode(RGB, width); int[] hist = new int[width]; // Load an image from the data directory // Load a different image by modifying the comments PImage a; a = loadImage("data/cdi01_g.jpg", null, function(){ image(a, 0, 0); // Calculate the histogram for (int i=0; imaxval) { maxval = hist[i]; } } // Normalize the histogram to values between 0 and "height" for (int i=0; i