// result image is as large as the region's bounds
// with black pixels inside and white pixels outside the region
srecord noeq RegionToBWImage(IImageRegion region) {
  settable Rect bounds;
  BWImage image;
  
  settable int bgColor = 0xFF;
  settable int color = 0x00;
  
  run {
    bounds if null = region.bounds();
    int x1 = bounds.x, y1 = bounds.y, w = bounds.w, h = bounds.h, i = 0;
    byte[] pixels = new[w*h];
    if (bgColor != 0) fillArray(pixels, (byte) bgColor);
    for y to h:
      for x to w: {
        if (region.contains(x1+x, y1+y))
          pixels[i] = (byte) color;
        i++;
      }
      
    image = new BWImage(w, h, pixels);
  }
  
  BWImage get() {
    if (image == null) run();
    ret image;
  }
}