core: add nominal size support

[vaxerski]

Adds support for an additional property (nominal_size) being a float describing what fraction of the destination size this image implies.

Example:

nominal_size = 0.8
define_size = 0, image.svg 

In this case, if the user asks for 32, this image will be treated as 32 / 0.8 = 40.

ref hyprwm/Hyprland#8713

Will need a spec bump.

[vaxerski]

alright, tested and seems to work.

[vaxerski]

merging, I dont see any opposition

[Covkie]

Oops i forgot to comment - but yeah it does work. One question though, are hotspots applied before or after the nominal size scaling?

[vaxerski]

hotspots are floats :) I can clarify it in spec (libhyprcursor doesn't do anything to the hotspot value it's just passed through) but they are always from the actual image size.

woops hyprcursor does pass them as ints if you are using rendering, but the rest stands.

hotspot.xy * image.wh

if you have a nominal size of 0.5 on 32x you get a 64x image where hotspot 0.25 0.25 would be 16x16