sclass FaceFinderX1 extends F1<RGBImage, Rect> {
  int width, y1, y2, deltaX1, deltaX2;
  
  public Rect get(RGBImage img) {
    RGBImage img2 = rgbResize(img, width);
    RGBImage img3 = rgbClipLineRange(img2, y1, y2);
    float[] f = rgbImageColumnBrightnesses(img3);
    int x = indexOfSmallestFloat(f);
    ret rescaleRect_imageToImage(rectFromPoints(x+deltaX1, y1, x+deltaX2, y2), img2, img);
  }
  
  toString { ret sfu(this); }
}