fn compute_extra_draws() {
  for full_redraw_rect in rects_to_fully_redraw.iter() {
    for elem in compositor_state.elements.iter() {
      for visible_region in elem.drawable_rects().iter() {
        if visible_region.intersects_with(full_redraw_rect) {
          let intersection = visible_region
            .area_overlapping_with(full_redraw_rect)
            .unwrap();
          compositor_state.queue_extra_draw(elem, intersection);
        }
      }
    }
  }
}

fn compute_extra_draws() {
  for full_redraw_rect in rects_to_fully_redraw.iter() {
    let nearby_regions = spatial_index.query(full_redraw_rect);
    for (elem, visible_region) in nearby_regions.iter() {
      let intersection = visible_region
        .area_overlapping_with(full_redraw_rect)
        .unwrap();
      compositor_state.queue_extra_draw(elem, intersection);
    }
  }
}