servo/components/style/values/computed/font.rs
2017-09-24 00:47:54 -07:00

98 lines
2.9 KiB
Rust

/* 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 http://mozilla.org/MPL/2.0/. */
//! Computed values for font properties
use app_units::Au;
use std::fmt;
use style_traits::ToCss;
use values::animated::ToAnimatedValue;
use values::computed::NonNegativeLength;
use values::specified::font as specified;
#[derive(Animate, ComputeSquaredDistance, ToAnimatedZero)]
#[derive(Clone, Copy, Debug, PartialEq)]
#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
#[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
/// The computed value of font-size
pub struct FontSize {
/// The size.
pub size: NonNegativeLength,
/// If derived from a keyword, the keyword and additional transformations applied to it
pub keyword_info: Option<KeywordInfo>,
}
#[derive(Animate, ComputeSquaredDistance, ToAnimatedValue, ToAnimatedZero)]
#[derive(Clone, Copy, Debug, PartialEq)]
#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
#[cfg_attr(feature = "gecko", derive(MallocSizeOf))]
/// Additional information for keyword-derived font sizes.
pub struct KeywordInfo {
/// The keyword used
pub kw: specified::KeywordSize,
/// A factor to be multiplied by the computed size of the keyword
pub factor: f32,
/// An additional Au offset to add to the kw*factor in the case of calcs
pub offset: NonNegativeLength,
}
impl KeywordInfo {
/// Given a parent keyword info (self), apply an additional factor/offset to it
pub fn compose(self, factor: f32, offset: NonNegativeLength) -> Self {
KeywordInfo {
kw: self.kw,
factor: self.factor * factor,
offset: self.offset.scale_by(factor) + offset,
}
}
/// KeywordInfo value for font-size: medium
pub fn medium() -> Self {
specified::KeywordSize::Medium.into()
}
}
impl From<specified::KeywordSize> for KeywordInfo {
fn from(x: specified::KeywordSize) -> Self {
KeywordInfo {
kw: x,
factor: 1.,
offset: Au(0).into(),
}
}
}
impl FontSize {
/// The actual computed font size.
pub fn size(self) -> Au {
self.size.into()
}
}
impl ToCss for FontSize {
fn to_css<W>(&self, dest: &mut W) -> fmt::Result where W: fmt::Write {
self.size.to_css(dest)
}
}
/// XXXManishearth it might be better to
/// animate this as computed, however this complicates
/// clamping and might not be the right thing to do.
/// We should figure it out.
impl ToAnimatedValue for FontSize {
type AnimatedValue = NonNegativeLength;
#[inline]
fn to_animated_value(self) -> Self::AnimatedValue {
self.size
}
#[inline]
fn from_animated_value(animated: Self::AnimatedValue) -> Self {
FontSize {
size: animated.clamp(),
keyword_info: None,
}
}
}