code: public void genImage() {
  		if (image == null) {
  			ImageBuffer buffer = new ImageBuffer(128,16);
  			for (int i=0;i<128;i++) {
  				Color col = getColorAt(i / 128.0f);
  				for (int j=0;j<16;j++) {
  					buffer.setRGBA(i, j, col.getRedByte(), col.getGreenByte(), col.getBlueByte(), col.getAlphaByte());
  				}
  			}
  			image = buffer.getImage();
  		}
  	}
docs: Generate the image used for texturing the gradient across shapes