This switches our wasm build to use "shared" memory. Shared memory can
be shared across multiple web workers, which is something we'll want to
support for our multi-threaded behaviors later.
Shared memory has a number of different restrictions so this updates
zig-js to support it as well as updates some of our functions that need
to be aware of it.
We don't need the Atlas API for wasm at all, but its a good way to test
things work incrementally and its a pretty cool thing to have as a wasm
library really.
Most emoji fonts are massive glyphs (128x128, 256x256, etc.). This means
the texture we need to store emoji is also massive. For a 128x128 emoji
font (both Apple and Noto), we can only store 12 emoji before resizing
prior to this commit.
This commit now threads through a max height through to the font face
and resizes the bitmap in memory before putting it in the atlas. This
results in significant savings. The max height is the cell height. We
allow the glyphs to be as wide as necessary due to double (and more)
wide glyphs.
For the unicode emoji test file, the atlas size before and after:
Before: 262 MB
After: 16 MB
This implements font discovery so the `--font-family` flag works for macOS. Fonts are looked up using the Core Text API so any installed font on the Mac system can be used.
We still use FreeType for rendering, and CoreText doesn't _quite_ give us all the information we need to build the exact face in FreeType. So a TODO after this is to now implement glyph _rendering_ using Core Text and Core Graphics. Until then, a couple fonts don't quite work (i.e. Monaco, a big one!) but many do!
