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/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at https://mozilla.org/MPL/2.0/. */
//! Values for CSS Box Alignment properties
//!
//! https://drafts.csswg.org/css-align/
use crate::values::computed::{Context, ToComputedValue};
use crate::values::specified;
pub use super::specified::{
AlignContent, AlignItems, AlignTracks, ContentDistribution, JustifyContent, JustifyTracks,
SelfAlignment,
};
pub use super::specified::{AlignSelf, JustifySelf};
/// The computed value for the `justify-items` property.
///
/// Need to carry around both the specified and computed value to handle the
/// special legacy keyword without destroying style sharing.
///
/// In particular, `justify-items` is a reset property, so we ought to be able
/// to share its computed representation across elements as long as they match
/// the same rules. Except that it's not true if the specified value for
/// `justify-items` is `legacy` and the computed value of the parent has the
/// `legacy` modifier.
///
/// So instead of computing `legacy` "normally" looking at get_parent_position(),
/// marking it as uncacheable, we carry the specified value around and handle
/// the special case in `StyleAdjuster` instead, only when the result of the
/// computation would vary.
///
/// Note that we also need to special-case this property in matching.rs, in
/// order to properly handle changes to the legacy keyword... This all kinda
/// sucks :(.
///
/// See the discussion in https://bugzil.la/1384542.
#[derive(Clone, Copy, Debug, Eq, MallocSizeOf, PartialEq, ToCss, ToResolvedValue)]
#[repr(C)]
pub struct ComputedJustifyItems {
/// The specified value for the property. Can contain the bare `legacy`
/// keyword.
#[css(skip)]
pub specified: specified::JustifyItems,
/// The computed value for the property. Cannot contain the bare `legacy`
/// keyword, but note that it could contain it in combination with other
/// keywords like `left`, `right` or `center`.
pub computed: specified::JustifyItems,
}
pub use self::ComputedJustifyItems as JustifyItems;
impl JustifyItems {
/// Returns the `legacy` value.
pub fn legacy() -> Self {
Self {
specified: specified::JustifyItems::legacy(),
computed: specified::JustifyItems::normal(),
}
}
}
impl ToComputedValue for specified::JustifyItems {
type ComputedValue = JustifyItems;
/// <https://drafts.csswg.org/css-align/#valdef-justify-items-legacy>
fn to_computed_value(&self, _context: &Context) -> JustifyItems {
use crate::values::specified::align;
let specified = *self;
let computed = if self.0 != align::AlignFlags::LEGACY {
*self
} else {
// If the inherited value of `justify-items` includes the
// `legacy` keyword, `legacy` computes to the inherited value, but
// we assume it computes to `normal`, and handle that special-case
// in StyleAdjuster.
Self::normal()
};
JustifyItems {
specified,
computed,
}
}
#[inline]
fn from_computed_value(computed: &JustifyItems) -> Self {
computed.specified
}
}
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