Casting a negative number to u32

[dobryak]

Hello.
The result of this subtraction can be negative, that in turn leads to large values in sub.x and sub.y since they are casted to u32.
Also, this will cause u32 overflow in the .copy_from method.

shotgun/src/main.rs

Lines 207 to 208 in 1e5f5d7

	x: screen.x - sel.x,
	y: screen.y - sel.y,

[9ary]

Good catch. I see what's going on now. Recent changes turned this:

shotgun/src/main.rs

Line 143 in 2fc0d2e

screens.filter_map(|s| s.intersection(sel)).collect();

into

shotgun/src/main.rs

Lines 193 to 197 in 1e5f5d7

	let screens: Vec<util::Rect> = screen_rects
	.iter()
	.filter(|s| s.intersection(sel).is_some())
	.cloned()
	.collect();

This is a bug.