We now clear the computed font cache whenever a `@font-feature-values`
rule is added, removed, or has one of it's descriptors modified.
This isn't observable yet since we don't actually respect
`@font-feature-values` rules, but that will come in a later commit
Instead of calling invalidate_style(CSSFontLoaded) which marks the
entire subtree for style recomputation, use set_needs_style_update(true)
to mark only individual elements that reference the loaded font family.
This is correct because element_uses_font_family() checks the computed
(inherited) font-family value, so descendants inheriting the font will
match individually, while descendants that override font-family to a
different font are skipped entirely.
The spec requires us to follow the steps in FontFace::load() whenever a
font is loaded. The simplest way to do so, is to make that the only way
we load fonts. :^)
To support this, FontFace::load() uses its connected CSSFontFaceRule's
ParsedFontFace if it's available.
The 1 regression in generic-family-keywords-003.html seems to be a false
positive: we don't support the system-ui font keyword.
Remove 11 heavy includes from Document.h that were only needed for
pointer/reference types (already forward-declared in Forward.h), and
extract the nested ViewportClient interface to a standalone header.
This reduces Document.h's recompilation cascade from ~1228 files to
~717 files (42% reduction). Headers like BrowsingContext.h that were
previously transitively included see even larger improvements (from
~1228 down to ~73 dependents).
Previously we would resolve font features
(https://drafts.csswg.org/css-fonts-4/#feature-variation-precedence)
per element, while this works for the current subset of the font feature
resolution algorithm that we support, some as yet unimplemented parts
require us to know whether we are resolving against a CSS @font-face
rule, and if so which one (e.g. applying descriptors from the @font-face
rule, deciding which @font-feature-values rules to apply, etc).
To achieve this we store the data required to resolve font features in a
struct and pass that to `FontComputer` which resolves the font features
and stores them with the computed `Font`.
We no longer need to invalidate the font shaping cache when features
change since the features are defined per font (and therefore won't ever
change).
While our default font supporting variations is unlikely, this is
nevertheless required for our fallback font to be considered equal to
it's non-default/fallback equivalent (i.e. `font-family: serif`) which
in turn is required for LineBuilder to merge chunks into a single
fragment.
Previously, when a @font-face font finished loading, we would clear the
entire computed font cache and invalidate style for the whole document.
This was overly conservative since most elements don't use the newly
loaded font. We now take a targeted approach inspired by Firefox:
1. Only clear cache entries that reference the loaded font family
2. Walk the DOM tree (including shadow trees) and only invalidate
elements whose font-family property (or pseudo-elements' font-family)
actually references the loaded font
This significantly reduces style invalidation work on pages with many
elements but only some using custom fonts.
This method was only called when `font_matching_algorithm` failed to
match a font (i.e. there are no fonts with a matching family name) in
which case this method would also fail to match a font.
Previously we wouldn't respect font-variation-settings for fonts matched
through `font_matching_algorithm` (i.e. any fonts which didn't have an
exact loaded match).
The `VectorFont` type was renamed to `Typeface` in d5926a3 but this
member variable was never updated.
The getter for this was also unused so has been removed
When rendering text, if none of the fonts in the cascade list contain a
glyph for a given code point, we now query Skia's font manager to find
a system font that can render it.
Computing the font for an element in `compute_font` is premature since
we are yet to apply animated properties - instead we should compute the
value on the fly (with a cache to avoid unnecessary work) to ensure we
are respecting the latest values
Font computation and loading is distinct enough from style computation
that it makes more sense to have this in it's own class.
This will be useful later when we move the font loading process to
`ComputedProperties` in order to respect animated values.
