mirror of
https://github.com/servo/servo.git
synced 2025-08-06 06:00:15 +01:00
Do "computed value" calculation with a trait with an associated type.
This commit is contained in:
Simon Sapin
parent
0a4c8c0e4c
commit
be599158e0
4 changed files with 543 additions and 351 deletions
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@ -49,6 +49,7 @@ macro_rules! define_css_keyword_enum {
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pub type CSSFloat = f64;
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pub mod specified {
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use std::ascii::AsciiExt;
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use std::f64::consts::PI;
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@ -60,7 +61,6 @@ pub mod specified {
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use text_writer::{self, TextWriter};
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use util::geometry::Au;
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use super::CSSFloat;
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use super::computed;
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#[derive(Clone, PartialEq)]
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pub struct CSSColor {
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@ -113,22 +113,6 @@ pub mod specified {
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}
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}
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#[derive(Clone, PartialEq)]
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pub struct CSSImage(pub Option<Image>);
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impl fmt::Debug for CSSImage {
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#[inline] fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result { self.fmt_to_css(f) }
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}
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impl ToCss for CSSImage {
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fn to_css<W>(&self, dest: &mut W) -> text_writer::Result where W: TextWriter {
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match self {
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&CSSImage(Some(ref image)) => image.to_css(dest),
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&CSSImage(None) => dest.write_str("none"),
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}
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}
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}
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#[derive(Clone, PartialEq, Copy)]
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pub enum Length {
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Au(Au), // application units
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@ -160,6 +144,31 @@ pub mod specified {
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}
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}
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impl Length {
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pub fn to_computed_value_with_font_size(&self, reference_font_size: Au, root_font_size: Au)
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-> Au {
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match *self {
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Length::Au(value) => value,
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Length::Em(value) => reference_font_size.scale_by(value),
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Length::Ex(value) => {
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let x_height = 0.5; // TODO: find that from the font
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reference_font_size.scale_by(value * x_height)
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},
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Length::Rem(value) => root_font_size.scale_by(value),
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Length::ServoCharacterWidth(value) => {
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// This applies the *converting a character width to pixels* algorithm as specified
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// in HTML5 § 14.5.4.
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//
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// TODO(pcwalton): Find these from the font.
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let average_advance = reference_font_size.scale_by(0.5);
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let max_advance = reference_font_size;
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average_advance.scale_by(value as CSSFloat - 1.0) + max_advance
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}
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}
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}
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}
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const AU_PER_PX: CSSFloat = 60.;
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const AU_PER_IN: CSSFloat = AU_PER_PX * 96.;
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const AU_PER_CM: CSSFloat = AU_PER_IN / 2.54;
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@ -493,16 +502,6 @@ pub mod specified {
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_ => Err(())
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}
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}
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pub fn to_computed_value(self, context: &computed::Context) -> computed::Image {
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match self {
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Image::Url(url) => computed::Image::Url(url),
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Image::LinearGradient(linear_gradient) => {
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computed::Image::LinearGradient(
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computed::LinearGradient::compute(linear_gradient, context))
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}
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}
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}
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}
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/// Specified values for a CSS linear gradient.
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@ -701,45 +700,41 @@ pub mod computed {
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// TODO, as needed: viewport size, etc.
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}
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#[allow(non_snake_case)]
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#[inline]
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pub fn compute_CSSColor(value: specified::CSSColor, _context: &Context) -> CSSColor {
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value.parsed
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pub trait ToComputedValue {
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type ComputedValue;
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#[inline]
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fn to_computed_value(&self, _context: &Context) -> Self::ComputedValue;
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}
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#[allow(non_snake_case)]
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#[inline]
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pub fn compute_BorderStyle(value: BorderStyle, _context: &Context) -> BorderStyle {
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value
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pub trait ComputedValueAsSpecified {}
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impl<T> ToComputedValue for T where T: ComputedValueAsSpecified + Clone {
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type ComputedValue = T;
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#[inline]
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fn to_computed_value(&self, _context: &Context) -> T {
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self.clone()
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}
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}
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#[allow(non_snake_case)]
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#[inline]
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pub fn compute_Au(value: specified::Length, context: &Context) -> Au {
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compute_Au_with_font_size(value, context.font_size, context.root_font_size)
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impl ToComputedValue for specified::CSSColor {
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type ComputedValue = CSSColor;
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#[inline]
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fn to_computed_value(&self, _context: &Context) -> CSSColor {
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self.parsed
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}
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}
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/// A special version of `compute_Au` used for `font-size`.
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#[allow(non_snake_case)]
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#[inline]
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pub fn compute_Au_with_font_size(value: specified::Length, reference_font_size: Au, root_font_size: Au) -> Au {
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match value {
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specified::Length::Au(value) => value,
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specified::Length::Em(value) => reference_font_size.scale_by(value),
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specified::Length::Ex(value) => {
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let x_height = 0.5; // TODO: find that from the font
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reference_font_size.scale_by(value * x_height)
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},
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specified::Length::Rem(value) => root_font_size.scale_by(value),
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specified::Length::ServoCharacterWidth(value) => {
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// This applies the *converting a character width to pixels* algorithm as specified
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// in HTML5 § 14.5.4.
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//
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// TODO(pcwalton): Find these from the font.
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let average_advance = reference_font_size.scale_by(0.5);
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let max_advance = reference_font_size;
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average_advance.scale_by(value as CSSFloat - 1.0) + max_advance
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}
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impl ComputedValueAsSpecified for specified::BorderStyle {}
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impl ToComputedValue for specified::Length {
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type ComputedValue = Au;
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#[inline]
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fn to_computed_value(&self, context: &Context) -> Au {
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self.to_computed_value_with_font_size(context.font_size, context.root_font_size)
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}
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}
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@ -757,14 +752,18 @@ pub mod computed {
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}
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}
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#[allow(non_snake_case)]
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pub fn compute_LengthOrPercentage(value: specified::LengthOrPercentage, context: &Context)
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-> LengthOrPercentage {
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match value {
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specified::LengthOrPercentage::Length(value) =>
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LengthOrPercentage::Length(compute_Au(value, context)),
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specified::LengthOrPercentage::Percentage(value) =>
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LengthOrPercentage::Percentage(value),
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impl ToComputedValue for specified::LengthOrPercentage {
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type ComputedValue = LengthOrPercentage;
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fn to_computed_value(&self, context: &Context) -> LengthOrPercentage {
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match *self {
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specified::LengthOrPercentage::Length(value) => {
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LengthOrPercentage::Length(value.to_computed_value(context))
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}
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specified::LengthOrPercentage::Percentage(value) => {
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LengthOrPercentage::Percentage(value)
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}
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}
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}
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}
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@ -783,16 +782,23 @@ pub mod computed {
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}
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}
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}
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#[allow(non_snake_case)]
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pub fn compute_LengthOrPercentageOrAuto(value: specified::LengthOrPercentageOrAuto,
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context: &Context) -> LengthOrPercentageOrAuto {
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match value {
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specified::LengthOrPercentageOrAuto::Length(value) =>
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LengthOrPercentageOrAuto::Length(compute_Au(value, context)),
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specified::LengthOrPercentageOrAuto::Percentage(value) =>
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LengthOrPercentageOrAuto::Percentage(value),
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specified::LengthOrPercentageOrAuto::Auto =>
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LengthOrPercentageOrAuto::Auto,
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impl ToComputedValue for specified::LengthOrPercentageOrAuto {
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type ComputedValue = LengthOrPercentageOrAuto;
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#[inline]
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fn to_computed_value(&self, context: &Context) -> LengthOrPercentageOrAuto {
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match *self {
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specified::LengthOrPercentageOrAuto::Length(value) => {
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LengthOrPercentageOrAuto::Length(value.to_computed_value(context))
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}
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specified::LengthOrPercentageOrAuto::Percentage(value) => {
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LengthOrPercentageOrAuto::Percentage(value)
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}
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specified::LengthOrPercentageOrAuto::Auto => {
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LengthOrPercentageOrAuto::Auto
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}
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}
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}
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}
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@ -811,19 +817,42 @@ pub mod computed {
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}
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}
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}
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#[allow(non_snake_case)]
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pub fn compute_LengthOrPercentageOrNone(value: specified::LengthOrPercentageOrNone,
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context: &Context) -> LengthOrPercentageOrNone {
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match value {
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specified::LengthOrPercentageOrNone::Length(value) =>
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LengthOrPercentageOrNone::Length(compute_Au(value, context)),
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specified::LengthOrPercentageOrNone::Percentage(value) =>
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LengthOrPercentageOrNone::Percentage(value),
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specified::LengthOrPercentageOrNone::None =>
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LengthOrPercentageOrNone::None,
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impl ToComputedValue for specified::LengthOrPercentageOrNone {
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type ComputedValue = LengthOrPercentageOrNone;
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#[inline]
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fn to_computed_value(&self, context: &Context) -> LengthOrPercentageOrNone {
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match *self {
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specified::LengthOrPercentageOrNone::Length(value) => {
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LengthOrPercentageOrNone::Length(value.to_computed_value(context))
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}
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specified::LengthOrPercentageOrNone::Percentage(value) => {
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LengthOrPercentageOrNone::Percentage(value)
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}
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specified::LengthOrPercentageOrNone::None => {
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LengthOrPercentageOrNone::None
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}
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}
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}
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}
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impl ToComputedValue for specified::Image {
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type ComputedValue = Image;
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#[inline]
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fn to_computed_value(&self, context: &Context) -> Image {
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match *self {
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specified::Image::Url(ref url) => Image::Url(url.clone()),
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specified::Image::LinearGradient(ref linear_gradient) => {
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Image::LinearGradient(linear_gradient.to_computed_value(context))
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}
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}
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}
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}
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/// Computed values for an image according to CSS-IMAGES.
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#[derive(Clone, PartialEq)]
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pub enum Image {
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@ -881,32 +910,28 @@ pub mod computed {
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}
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}
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impl LinearGradient {
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pub fn compute(value: specified::LinearGradient, context: &Context) -> LinearGradient {
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impl ToComputedValue for specified::LinearGradient {
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type ComputedValue = LinearGradient;
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#[inline]
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fn to_computed_value(&self, context: &Context) -> LinearGradient {
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let specified::LinearGradient {
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angle_or_corner,
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stops
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} = value;
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ref stops
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} = *self;
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LinearGradient {
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angle_or_corner: angle_or_corner,
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stops: stops.into_iter().map(|stop| {
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stops: stops.iter().map(|stop| {
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ColorStop {
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color: stop.color.parsed,
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position: match stop.position {
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None => None,
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Some(value) => Some(compute_LengthOrPercentage(value, context)),
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Some(value) => Some(value.to_computed_value(context)),
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},
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}
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}).collect()
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}
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}
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}
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#[allow(non_snake_case)]
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#[inline]
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pub fn compute_Length(value: specified::Length, context: &Context) -> Au {
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compute_Au(value, context)
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}
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pub type Length = Au;
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}
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