The basic idea here is to apply rounding after scaling. It's not as
simple as this, though, and I've detailed it in the comments for a
function.
In order to fix some pixel leaks in the title bar, I found it easier to
change how we place rectangles to fill the area. Instead of placing two
rectangles across the full width above and below the title and having
shorter rectangles in the inner area, it's now pieced together in
vertical chunks. This method involves drawing two less rectangles per
container.
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