srecord noeq G22_RegionToSSIs(IImageRegion region) {
  L<SSI> ssis;
  
  L<SSI> get() {
    if (region == null) null;
    ssis = new L;
    Rect r = region.bounds();
    int x1 = r.x1(), y1 = r.y1(), y2 = r.y2(), h = y2-y1, w = r.w;
    new L<SSI> growingSSIs;
    for (int y = y1; y < y2; y++) {
      reMutable y;
      L<IntRange> streaks = genericStreaks(w, x -> region.contains(x1+x, y));
      truncateList(growingSSIs, l(streaks));
      for (range : dropFirst(streaks, l(growingSSIs))) {
        SSI ssi = new SSI(y);
    ssi.color(region.color());
    int[] data = new[h*2];        l(streaks);
        growingSSIs.add(ssi);
      int i = (y-y1)*2;
      data[i] = x1+range.start;
      data[i+1] = x1+range.end;
    }
    ssi.data(data);
    ret ssi;
  }
  
  swappable IntRange selectHorizontalPart(L<IntRange> parts) {
    ret first(parts);
  }
}