Linux: Try a CosmicText based Text System

[h3mosphere]

This is a rebase of @gabydds text_system updates. with some small cleanups.

Currently cannot test this as build is not working in linux. Im just putting it up here before I forget about it.

[h3mosphere]

Updated to main. Hopefully good to go.

[h3mosphere]

Depends on #7555

[gabydd]

Did #7555 actually fix the rendering for you when I merged it and master too my branch with input it only half rendered and wouldn't expect input hopefully that was just a bad merge

[ForLoveOfCats]

Does this need to pull in swash directly? It looks like it only uses the re-exports provided by Cosmic Text?

[gabydd]

Doesn't need swash directly, that was just a historical artifact of how I was doing metrics conversion at one point

[h3mosphere]

Hey,

I cleaned this up a little for inclusion @kvark 's branch, as per discord discussion, but then it landed in main. It's raw, just really what @gabydd came to after an inspired hacking session. It gets zed to the point of running, a minimal baseline with which to hack further.

I probably should have continued on with the blade branch, and cleaned this code up, but got busy trying to get zed to work with main.

[gabydd]

No worries, of the top of my head here is a little Todo list:

What needs to be done:

• figure out why the scroll track is extra long(check against mac cause maybe this is just the regular behavior)
• figure out why the seperator between the gutter and editor disapears
• font loading
  • look at getting system font fallback to work, hopefully can do this with font-db if not maybe use font-kit or look what they do
  • figure out if we actually need load_family/should change how we query from font-db, right now when first querying for a font id we almost always fallback to creating a new one because the font given by font id is not in the map
  • test if font-loading is slow, seems to take a bit of time but maybe that is something else
• handle subpixel variant in rasterize glyph and raster bounds
• I would love some more eyes on render_line, I don't think we need to use cosmic-texts Buffer here because we already do caching(we are double caching glyph rasterization actually both gpui and cosmic text have a cache), but its definetly possible I am not interfacing with cosmic text properly and I did get a crash at one point but wasn't able to reproduce it
• optionally double check against font-kit that we are giving the correct metrics

What has been done:

• get a font id that corresponds to cosmic text font for a font query
• get usable metrics using a fonts swash representation, and bounds
• rasterize a glyph using swash
• render a line using cosmic-text
• text renders in the editor in what seems to be the right spot and looks pretty good in my opinion

[mikayla-maki]

With this PR, we can now render the hello world example!

[mikayla-maki]

What needs to be done:

Thank you for the comprehensive list! I think we can leave these for PRs as we go :)