This change adds support for variable fonts via the
[`font-variation-settings`](https://developer.mozilla.org/en-US/docs/Web/CSS/font-variation-settings)
property.
There are three areas where we need to set the variation values:
* Webrender (`compositor.rs`), for drawing the glyphs
* Harfbuzz (`shaper.rs`), for most shaping tasks
* PlatformFont (`fonts/platform/`), for horizontal advances and kerning
For now, freetype is the only platform shaper that supports variable
fonts. I can't easily test the fonts with non-freetype shapers. Thats
why variable fonts are behind the `layout_variable_fonts_enabled` pref,
which is disabled by default.
<img width="1250" height="710" alt="image"
src="https://github.com/user-attachments/assets/1aee1407-f3a2-42f6-a106-af0443fcd588"
/>
<details><summary>HTML test file</summary>
```html
<style>
@font-face {
font-family: "Amstelvar VF";
src: url("https://mdn.github.io/shared-assets/fonts/variable-fonts/AmstelvarAlpha-VF.woff2")
format("woff2-variations");
font-weight: 300 900;
font-stretch: 35% 100%;
font-style: normal;
font-display: swap;
}
p {
font:
1.2em "Amstelvar VF",
Georgia,
serif;
font-size: 4rem;
margin: 1rem;
display: inline-block;
}
.p1 {
font-variation-settings: "wght" 300;
}
.p2 {
font-variation-settings: "wght" 625;
}
.p3 {
font-variation-settings: "wght" 900;
}
</style>
<div>
<p class="p1">Weight</p>
<span>(font-variation-settings: "wght" 300)</span>
</div>
<div>
<p class="p2">Weight</p>
<span>(font-variation-settings: "wght" 625)</span>
</div>
<div>
<p class="p3">Weight</p>
<span>(font-variation-settings: "wght" 900)</span>
</div>
</div>
```
</details>
https://github.com/user-attachments/assets/9e21101a-796a-49fe-b82c-8999d8fa9ee1
Testing: Needs decision on whether we want to enable the pref in CI
Works towards https://github.com/servo/servo/issues/37236
Depends on https://github.com/servo/stylo/pull/230
---------
Signed-off-by: Simon Wülker <simon.wuelker@arcor.de>
`TextRun`s use their parent style to render. Previously, these styles
were cloned and stored directly in the box tree `TextRun` and resulting
`TextFragment`s. This presents a problem for incremental layout.
Wrapping the style in another layer of shared ownership and mutability
will allow updating all `TextFragment`s during repaint-only incremental
layout by simply updating the box tree styles of the original text
parents.
This adds a new set of borrows when accessing text styles, but also
makes it so that during box tree block construction
`InlineFormattingContext`s are created lazily and now
`InlineFormattingContextBuilder::finish` consumes the builder, making
the API make a bit more sense. This should also improve performance of
box tree block construction slightly.
Testing: This should not change observable behavior and thus is covered
by existing WPT tests.
Signed-off-by: Martin Robinson <mrobinson@igalia.com>
Co-authored-by: Oriol Brufau <obrufau@igalia.com>
Now that legacy layout has been removed, the name `layout_2020` doesn't
make much sense any longer, also it's 2025 now for better or worse. The
split between the "layout thread" and "layout" also doesn't make as much
sense since layout doesn't run on it's own thread. There's a possibility
that it will in the future, but that should be something that the user
of the crate controls rather than layout iself.
This is part of the larger layout interface cleanup and optimization
that
@Looriool and I are doing.
Testing: Covered by existing tests as this is just code movement.
Signed-off-by: Martin Robinson <mrobinson@igalia.com>
2025-04-19 10:17:03 +00:00
Renamed from components/layout_2020/flow/inline/text_run.rs (Browse further)
