// By amnon.owed, http://forum.processing.org/topic/extract-circle-texture-from-background-with-alpha-channel
public PImage getCircularImage(PImage img, int radius, int feather) {
PGraphics temp = p.createGraphics(img.width, img.height, PConstants.JAVA2D);
temp.beginDraw();
temp.smooth();
temp.translate(temp.width / 2, temp.height / 2);
temp.imageMode(PConstants.CENTER);
temp.image(img, 0, 0);
temp.endDraw();
PImage saveArea = p.createImage(temp.width, temp.height, PConstants.ARGB);
for (int y = 0; y < saveArea.height; y++) {