Puzzle about ExtSelectClipRgn?

[Vincent Povirk]

This is possible if both regions are more complex shapes (not just one
rectangle) that do not share any pixels. For example, the clip region
could consist of the rectangles (693,5)-(694,6) and (762,27)-(763,28);
and hregion could be (762,5)-(763,6) and (693,27)-(694,28).

You can use GetRegionData to determine the exact set of rectangles in
the region.