style: Add ascent-, descent- and line-gap-override descriptors to the style system

Differential Revision: https://phabricator.services.mozilla.com/D109287
This commit is contained in:
Oriol Brufau 2023-05-16 10:57:00 +02:00
parent 5ef832b778
commit 1cd257d54f
2 changed files with 50 additions and 1 deletions

View file

@ -19,7 +19,7 @@ use crate::values::specified::font::SpecifiedFontFeatureSettings;
use crate::values::specified::font::SpecifiedFontStyle;
#[cfg(feature = "gecko")]
use crate::values::specified::font::SpecifiedFontVariationSettings;
use crate::values::specified::font::{AbsoluteFontWeight, FontStretch};
use crate::values::specified::font::{AbsoluteFontWeight, FontStretch, MetricsOverride};
use crate::values::specified::url::SpecifiedUrl;
use crate::values::specified::Angle;
#[cfg(feature = "gecko")]
@ -418,6 +418,15 @@ macro_rules! is_descriptor_enabled {
("font-variation-settings") => {
static_prefs::pref!("layout.css.font-variations.enabled")
};
("ascent-override") => {
static_prefs::pref!("layout.css.font-metrics-overrides.enabled")
};
("descent-override") => {
static_prefs::pref!("layout.css.font-metrics-overrides.enabled")
};
("line-gap-override") => {
static_prefs::pref!("layout.css.font-metrics-overrides.enabled")
};
($name:tt) => {
true
};
@ -576,6 +585,15 @@ font_face_descriptors! {
/// The language override of this font face.
"font-language-override" language_override / mFontLanguageOverride: font_language_override::SpecifiedValue,
/// The ascent override for this font face.
"ascent-override" ascent_override / mAscentOverride: MetricsOverride,
/// The descent override for this font face.
"descent-override" descent_override / mDescentOverride: MetricsOverride,
/// The line-gap override for this font face.
"line-gap-override" line_gap_override / mLineGapOverride: MetricsOverride,
]
}

View file

@ -2205,6 +2205,37 @@ impl Parse for VariationValue<Number> {
}
}
/// A metrics override value for a @font-face descriptor
///
/// https://drafts.csswg.org/css-fonts/#font-metrics-override-desc
#[derive(Clone, Copy, Debug, MallocSizeOf, Parse, PartialEq, SpecifiedValueInfo, ToCss, ToShmem)]
pub enum MetricsOverride {
/// A non-negative `<percentage>` of the computed font size
Override(NonNegativePercentage),
/// Normal metrics from the font.
Normal,
}
impl MetricsOverride {
#[inline]
/// Get default value with `normal`
pub fn normal() -> MetricsOverride {
MetricsOverride::Normal
}
/// The ToComputedValue implementation, used for @font-face descriptors.
///
/// Valid override percentages must be non-negative; we return -1.0 to indicate
/// the absence of an override (i.e. 'normal').
#[inline]
pub fn compute(&self) -> ComputedPercentage {
match *self {
MetricsOverride::Normal => ComputedPercentage(-1.0),
MetricsOverride::Override(percent) => ComputedPercentage(percent.0.get()),
}
}
}
#[derive(
Clone,
Copy,