CachableRed src = (CachableRed)getSources().get(0);
Rectangle srcR = src.getBounds();
Rectangle wrR = wr.getBounds();
if (wrR.intersects(srcR)) {
Rectangle r = wrR.intersection(srcR);
// Limit the raster I send to my source to his rect.
WritableRaster srcWR;
srcWR = wr.createWritableChild(r.x, r.y, r.width, r.height,