Preposition

• Add new Image mode keybinding F to scale image to fill window.
• Add new scale mode, "fill" mode. Possibly -s F.

Explanation

I want to make an image fill the sxiv window (scaled from the center), whether an image is wider or taller than the sxiv window. Basically, no black bars, please.

The W key does something similar where is automatically chooses the longest dimension to scale to. The preposed F key and fill mode would automatically scale the image by its shortest dimension, like choosing whichever e or E key would fill the window. That way, whatever dimensions the sxiv window and image is, there will be no surrounding "black bars", just image.

Notes

I want to be able to open an sxiv slideshow with no black bars.

sxiv  .  -s F  -S 1

I code but I don't now C, although I can't imaging this would be too hard to implement by refactoring the case statement at https://github.com/muennich/sxiv/blob/master/image.c#L394

Thank you for your consideration. Let me know if I've missed something.