code: public boolean isInside( double x, double y ) {
  		return x >= 0 && y >= 0 && x <= image.getWidth() && y <= image.getHeight();
  	}
docs: <p>
  Return true if the coordinate is inside the image or false if not.<br>
  0 &le; x &le; width<br>
  0 &le; y &le; height
  </p>
  <p>Note: while the image is defined up to width and height, including coordinates up to that point contribute
  nothing towards the line integral since they are infinitesimally small.</p>
  
  @param x x-coordinate in pixel coordinates
  @param y y-coordinate in pixel coordinates
  @return true if inside or false if outside