letters should not be rendered off-screen

[markstos]

This is a minor/rare issue that affects floating windows where the left edge is not visible.

For partially visible windows, wmfocus should check to see if the letter would be rendered off-screen. If so, the letter should be moved to the right until it on a visible portion of the window.

Use case

Even with a tiling window manager, when I screenshot part of the screen with Swappy, the result a floating window. While these floating windows are present, I may have move them to the side so I can see what's behind them. In this case, part of the screenshot window may be off-screen.

[svenstaro]

I already do this for a good chunk of the placement code to check, for example, whether there would be overlapping letters. It should be easy to account for your case. Do you want to take a stab at it?

[markstos]

I think I'll pass. I'm a Rust beginner and am not familiar with X11 programming either. I'd have a lot of overhead just to find where to start for what seems like a small change once I got up to speed.

Also, my other larger PR for Sway supposrt hasn't been merged, so that doesn't help my motivation either.