/**
  * Update the pixels[] buffer to the PGraphics image.
  *
  * <p>Unlike in PImage, where updatePixels() only requests that the update happens, in
  * PGraphicsJava2D, this will happen immediately.
  */
 public void updatePixels(int x, int y, int c, int d) {
   // if ((x == 0) && (y == 0) && (c == width) && (d == height)) {
   if ((x != 0) || (y != 0) || (c != width) || (d != height)) {
     // Show a warning message, but continue anyway.
     showVariationWarning("updatePixels(x, y, w, h)");
   }
   updatePixels();
 }