servo/components/style/values/computed/text.rs
2019-05-07 12:56:02 +02:00

215 lines
7.3 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 https://mozilla.org/MPL/2.0/. */
//! Computed types for text properties.
#[cfg(feature = "servo")]
use crate::properties::StyleBuilder;
use crate::values::computed::length::{Length, LengthPercentage};
use crate::values::computed::{Context, NonNegativeLength, NonNegativeNumber, ToComputedValue};
use crate::values::generics::text::InitialLetter as GenericInitialLetter;
use crate::values::generics::text::LineHeight as GenericLineHeight;
use crate::values::generics::text::Spacing;
use crate::values::specified::text::{self as specified, TextOverflowSide};
use crate::values::specified::text::{TextEmphasisFillMode, TextEmphasisShapeKeyword};
use crate::values::{CSSFloat, CSSInteger};
use crate::Zero;
use std::fmt::{self, Write};
use style_traits::{CssWriter, ToCss};
pub use crate::values::specified::TextAlignKeyword as TextAlign;
pub use crate::values::specified::TextTransform;
pub use crate::values::specified::{OverflowWrap, WordBreak};
pub use crate::values::specified::{TextDecorationLine, TextEmphasisPosition};
/// A computed value for the `initial-letter` property.
pub type InitialLetter = GenericInitialLetter<CSSFloat, CSSInteger>;
/// A computed value for the `letter-spacing` property.
#[repr(transparent)]
#[derive(
Animate,
Clone,
ComputeSquaredDistance,
Copy,
Debug,
MallocSizeOf,
PartialEq,
ToAnimatedValue,
ToAnimatedZero,
ToResolvedValue,
)]
pub struct LetterSpacing(pub Length);
impl LetterSpacing {
/// Return the `normal` computed value, which is just zero.
#[inline]
pub fn normal() -> Self {
LetterSpacing(Length::zero())
}
}
impl ToCss for LetterSpacing {
fn to_css<W>(&self, dest: &mut CssWriter<W>) -> fmt::Result
where
W: Write,
{
// https://drafts.csswg.org/css-text/#propdef-letter-spacing
//
// For legacy reasons, a computed letter-spacing of zero yields a
// resolved value (getComputedStyle() return value) of normal.
if self.0.is_zero() {
return dest.write_str("normal");
}
self.0.to_css(dest)
}
}
impl ToComputedValue for specified::LetterSpacing {
type ComputedValue = LetterSpacing;
fn to_computed_value(&self, context: &Context) -> Self::ComputedValue {
match *self {
Spacing::Normal => LetterSpacing(Length::zero()),
Spacing::Value(ref v) => LetterSpacing(v.to_computed_value(context)),
}
}
fn from_computed_value(computed: &Self::ComputedValue) -> Self {
if computed.0.is_zero() {
return Spacing::Normal;
}
Spacing::Value(ToComputedValue::from_computed_value(&computed.0))
}
}
/// A computed value for the `word-spacing` property.
pub type WordSpacing = LengthPercentage;
impl ToComputedValue for specified::WordSpacing {
type ComputedValue = WordSpacing;
fn to_computed_value(&self, context: &Context) -> Self::ComputedValue {
match *self {
Spacing::Normal => LengthPercentage::zero(),
Spacing::Value(ref v) => v.to_computed_value(context),
}
}
fn from_computed_value(computed: &Self::ComputedValue) -> Self {
Spacing::Value(ToComputedValue::from_computed_value(computed))
}
}
/// A computed value for the `line-height` property.
pub type LineHeight = GenericLineHeight<NonNegativeNumber, NonNegativeLength>;
#[derive(Clone, Debug, MallocSizeOf, PartialEq, ToResolvedValue)]
/// text-overflow.
/// When the specified value only has one side, that's the "second"
/// side, and the sides are logical, so "second" means "end". The
/// start side is Clip in that case.
///
/// When the specified value has two sides, those are our "first"
/// and "second" sides, and they are physical sides ("left" and
/// "right").
pub struct TextOverflow {
/// First side
pub first: TextOverflowSide,
/// Second side
pub second: TextOverflowSide,
/// True if the specified value only has one side.
pub sides_are_logical: bool,
}
impl TextOverflow {
/// Returns the initial `text-overflow` value
pub fn get_initial_value() -> TextOverflow {
TextOverflow {
first: TextOverflowSide::Clip,
second: TextOverflowSide::Clip,
sides_are_logical: true,
}
}
}
impl ToCss for TextOverflow {
fn to_css<W>(&self, dest: &mut CssWriter<W>) -> fmt::Result
where
W: Write,
{
if self.sides_are_logical {
debug_assert_eq!(self.first, TextOverflowSide::Clip);
self.second.to_css(dest)?;
} else {
self.first.to_css(dest)?;
dest.write_str(" ")?;
self.second.to_css(dest)?;
}
Ok(())
}
}
/// A struct that represents the _used_ value of the text-decoration property.
///
/// FIXME(emilio): This is done at style resolution time, though probably should
/// be done at layout time, otherwise we need to account for display: contents
/// and similar stuff when we implement it.
///
/// FIXME(emilio): Also, should be just a bitfield instead of three bytes.
#[derive(Clone, Copy, Debug, Default, MallocSizeOf, PartialEq, ToResolvedValue)]
pub struct TextDecorationsInEffect {
/// Whether an underline is in effect.
pub underline: bool,
/// Whether an overline decoration is in effect.
pub overline: bool,
/// Whether a line-through style is in effect.
pub line_through: bool,
}
impl TextDecorationsInEffect {
/// Computes the text-decorations in effect for a given style.
#[cfg(feature = "servo")]
pub fn from_style(style: &StyleBuilder) -> Self {
use crate::values::computed::Display;
// Start with no declarations if this is an atomic inline-level box;
// otherwise, start with the declarations in effect and add in the text
// decorations that this block specifies.
let mut result = match style.get_box().clone_display() {
Display::InlineBlock | Display::InlineTable => Self::default(),
_ => style
.get_parent_inherited_text()
.text_decorations_in_effect
.clone(),
};
let line = style.get_text().clone_text_decoration_line();
result.underline |= line.contains(TextDecorationLine::UNDERLINE);
result.overline |= line.contains(TextDecorationLine::OVERLINE);
result.line_through |= line.contains(TextDecorationLine::LINE_THROUGH);
result
}
}
/// computed value for the text-emphasis-style property
#[derive(Clone, Debug, MallocSizeOf, PartialEq, ToCss, ToResolvedValue)]
pub enum TextEmphasisStyle {
/// Keyword value for the text-emphasis-style property (`filled` `open`)
Keyword(TextEmphasisKeywordValue),
/// `none`
None,
/// String (will be used only first grapheme cluster) for the text-emphasis-style property
String(String),
}
/// Keyword value for the text-emphasis-style property
#[derive(Clone, Debug, MallocSizeOf, PartialEq, ToCss, ToResolvedValue)]
pub struct TextEmphasisKeywordValue {
/// fill for the text-emphasis-style property
pub fill: TextEmphasisFillMode,
/// shape for the text-emphasis-style property
pub shape: TextEmphasisShapeKeyword,
}