/*
 * A filter to convert to sepia tone.
 */

// Or can load an image from a URL
PImage slu = loadImage("http://business.slu.edu/uploads/2012/11/08/slu-homepage-campus4.jpg");

int w = slu.width;
int h = slu.height;

for (int x=0; x < w; x++) {
  for (int y=0; y < h; y++) {
    color c = slu.get(x,y);
    float newRed = 0.393 * red(c) + 0.769 * green(c) + 0.189 * blue(c);
    float newGreen = 0.349 * red(c) + 0.686 * green(c) + 0.168 * blue(c);
    float newBlue = 0.272 * red(c) + 0.534 * green(c) + 0.131 * blue(c);
    color replace = color(min(newRed,255), min(newGreen,255), min(newBlue,255));
    slu.set(x,y,replace);
  }
}

// time to display it
size(w,h);
image(slu,0,0);