Better Glyph Constraint Logic (#7809)

This is a big'un.

- **Glyph constraint logic is now done fully on the CPU** at the
rasterization stage, so it only needs to be done once per glyph instead
of every frame. This also lets us eliminate padding between glyphs on
the atlas because we're doing nearest-neighbor sampling instead of
interpolating-- which ever so slightly increases our packing efficiency.
- **Special constraints for nerd font glyphs** are applied based roughly
on the constraints they use in their patcher. It's a simplification of
what they do, the largest difference being that they scale groups of
glyphs based on a shared bounding box so that they maintain relative
size to one another, but that would require loading all glyphs on the
group and I'd want to do that on font load TBH and at that point I'd
basically be re-implementing the nerd fonts patcher in Zig to patch
fonts at load time which is way beyond the scope I want to have. (Fixes
#7069)
- These constraints allow for **perfectly sized and centered emojis**,
this is very nice.
- **Changed the default embedded fonts** from 4 copies (regular, italic,
bold, bold italic) of a patched (and outdated) JetBrains Mono to a
single JetBrains Mono variable font and a single Nerd Fonts Symbols Only
font. This cuts the weight of those down from 9MB to 3MB!
- **FreeType's `renderGlyph` is significantly reworked**, and the new
code is, IMO, much cleaner- although there are probably some edge case
behavior differences I've introduced.

> [!NOTE]
> One breaking change I definitely introduced is changing the
`monochrome` freetype load flag config from its previous completely
backwards meaning to instead the correct one (I also changed the
default, so this won't affect any user who hasn't touched it, but users
who set the `monochrome` flag will find their fonts quite crispy after
this change because they will have no anti-aliasing anymore)

### Future work

Following this change I want to get to work on automatic font size
matching (a la CSS
[`font-size-adjust`](https://developer.mozilla.org/en-US/docs/Web/CSS/font-size-adjust)).
I set the stage for that quite some time ago so it shouldn't be too much
work and it will be a big benefit for users who regularly use multiple
writing systems and so have multiple fonts for them that aren't
necessarily size-compatible.

1 files changed, 16 insertions, 0 deletions

diff --git a/build.zig.zon.nix b/build.zig.zon.nix
index 9d50a6fc6..52260181e 100644
--- a/build.zig.zon.nix
+++ b/build.zig.zon.nix
@@ -170,6 +170,14 @@ in
       };
     }
     {
+      name = "N-V-__8AAIC5lwAVPJJzxnCAahSvZTIlG-HhtOvnM1uh-66x";
+      path = fetchZigArtifact {
+        name = "jetbrains_mono";
+        url = "https://deps.files.ghostty.org/JetBrainsMono-2.304.tar.gz";
+        hash = "sha256-xXppHouCrQmLWWPzlZAy5AOPORCHr3cViFulkEYQXMQ=";
+      };
+    }
+    {
       name = "N-V-__8AAJrvXQCqAT8Mg9o_tk6m0yf5Fz-gCNEOKLyTSerD";
       path = fetchZigArtifact {
         name = "libpng";
@@ -194,6 +202,14 @@ in
       };
     }
     {
+      name = "N-V-__8AAMVLTABmYkLqhZPLXnMl-KyN38R8UVYqGrxqO26s";
+      path = fetchZigArtifact {
+        name = "nerd_fonts_symbols_only";
+        url = "https://deps.files.ghostty.org/NerdFontsSymbolsOnly-3.4.0.tar.gz";
+        hash = "sha256-EWTRuVbUveJI17LwmYxDzJT1ICQxoVZKeTiVsec7DQQ=";
+      };
+    }
+    {
       name = "N-V-__8AAHjwMQDBXnLq3Q2QhaivE0kE2aD138vtX2Bq1g7c";
       path = fetchZigArtifact {
         name = "oniguruma";