Game Development Geek / Technical Linux Game Development

Screenshots Made Easy with Window Resizing Tool wmctrl

I needed to create screenshots for the iOS port of Toytles: Leaf Raking, my leaf-raking business simulation. My game doesn’t have a built-in screenshot shortcut key, and I needed screenshots that were 2688×1242, 2208×1242, and 2732×2048.

Immediately I knew I didn’t want to resize windows by hand, as it would be annoying and error-prone. Was there a tool that let me do it in a much more controlled manner?

I did a search, and I came across this Ask Ubuntu question about resizing windows to a particular width and height.

That’s when I learned about wmctrl. It is a tool that allows you to interact with the X window manager, which is the main windowing system used by GNU/Linux desktops.

I ran the following command to find the window of the running game:

wmctrl -l

It output a bunch of windows and showed me that I had:

0x0320000f 2 [machine name] Toytles: Leaf Raking

And then I used the ID corresponding to the game to resize that window:

wmctrl -i -r 0x0320000f -e 0,10,10,2688,1242
wmctrl -i -r 0x0320000f -e 0,10,10,2732,2048
wmctrl -i -r 0x0320000f -e 0,10,10,2208,1242

And then I just navigated around my game, found a good spot to take a screenshot, pressed Ctrl+PrtScn to take the screenshot, then resized and repeated for the various iOS sizes.

I then used Gimp to remove the top 30 pixels which was just the title bar of the window. I think I should be able to take screenshots without the window decorations, but I haven’t researched it yet.

I think I’d like to create a script to handle resizing, taking the screenshot, cropping the top 30 pixels, and placing into the appropriate screenshot folder, but I’ll probably create it next time I need to make screenshots, which might be sooner than I think.