Replace ab_glyph with Skrifa + vello_cpu; enable font hinting #7694
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Preview available at https://egui-pr-preview.github.io/pr/7694-skrifa View snapshot changes at kitdiff |
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I'm very excited for this! The readability improvements of the font hinting is pretty big imho. Also: colored emojis unlocked??? Before we merge I want to make sure we measure what impact this has on the .wasm blob size ( |
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Regarding the quality of the rendering, I have found that adding "font embolden" (aka stem darkening) to the skrifa-based renderers is (subjectively) a big additional improvement, at least on macOS (by tweaking the embolden parameter I can make the rendering very close if not identical to Skia/Chrome). There's no implementation for |
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Hey I just wanted to throw a vote behind this. Is there something blocking we at @tritium-legal can help with? Hinting on normal DPI platforms just makes a massive difference. |
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wasm size on so +600kB. I think that's well acceptable. |
| checksum = "68c7541fff44b35860c1a7a47a7cadf3e4a304c457b58f9870d9706ece028afc" | ||
| dependencies = [ | ||
| "kurbo", | ||
| "kurbo 0.11.1", |
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It's a shame we get a duplicate kurbo because of resvg, and resvg hasn't had a crate release in over 8 months :/
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We can fix that. I am working on a round of releases this month.
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All snapshots look good |
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I encourage everyone to follow this link to experience the improvements: https://rerun-io.github.io/kitdiff/?url=https://github.com/emilk/egui/pull/7694 |
- Followup to #7694 - Disables the `traversal` feature of `skrifa` which is not needed except internally by the fontations project - Should save a little compile time, and possibly some binary size. Signed-off-by: Nico Burns <[email protected]>
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I'll probably come back to this and clean it up a bit. This PR reimplements ab_glyph's functionality on top of Skrifa, a somewhat lower-level font API that's being used in Chrome now.
Skrifa doesn't perform rasterization itself, so I'm using vello_cpu from the Linebender project for rasterization. It's still in its early days, but I believe it's already quite fast. It also supports color and gradient fills, so color emoji support will be easier.
Skrifa also supports font hinting, which should make text look a bit nicer / less blurry.
Here's the current ab_glyph rendering:
Here's Skrifa without hinting--it looks almost identical, but there are some subpixel differences, probably due to rasterizer behavior:
Here's Skrifa with hinting:
Hinting does make the horizontal strokes look a bit bolder, which makes me wonder once again about increasing the font weight from "light" to "regular".