!7

p {

  RGBImage rgb = loadImage(#1006358);

  int w = rgb.w(), h = rgb.h();

  *float[h] data;

  for y to h:

    data[y] = rangeLength(printStruct(wideBlack(rgb, w/2, y)));

  showImageWithVerticalGraph(rgb, data);

}

static Range wideBlack(RGBImage img, int x, int y) {

  int w = img.w();

  int x1 = x, x2 = x;

  while (x1 > 0 && img.getPixel(x1-1, y).getBrightness() < 0.1) --x1;

  while (x2 < w && img.getPixel(x2, y).getBrightness() < 0.1) ++x2;

  ret new Range(x1, x2);

}