Background image alignment relative to desktop

[gfody]

Description of the new feature/enhancement

A background image alignment mode that's relative to the desktop. As you move the terminal around the image remains aligned with the desktop like wallpaper, eg:

..choose an image that complements the wallpaper for a pleasant effect

Ideally we could also configure the background image to follow a convention for when the desktop wallpaper is in slideshow mode. (disclaimer this is a feature in ConsoleZ)

Similar to issue #6497

[zadjii-msft]

I'll tag this up as a potential "extension" idea. Neat, sure. Definitely along the lines of #6497. But probably something we won't be building into the Terminal ourselves

[lhecker]

FYI This feature would likely require drawing the background image in our renderer. I suspect WinUI doesn't support updating an image at high refresh rates ¹ while also cropping it. Doing it ourselves however is both easy and performant.

Footnotes

1. 120Hz displays being the new norm for high end displays nowadays. Thanks, Apple! ↩