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length.rs
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length.rs
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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 http://mozilla.org/MPL/2.0/. */
//! [Length values][length].
//!
//! [length]: https://drafts.csswg.org/css-values/#lengths
use app_units::{Au, MAX_AU, MIN_AU};
use cssparser::{Parser, Token, BasicParseError};
use euclid::Size2D;
use font_metrics::FontMetricsQueryResult;
use parser::{Parse, ParserContext};
use std::{cmp, fmt, mem};
use std::ascii::AsciiExt;
use std::ops::Mul;
use style_traits::{ToCss, ParseError, StyleParseError};
use style_traits::values::specified::AllowedLengthType;
use stylesheets::CssRuleType;
use super::{AllowQuirks, Number, ToComputedValue, Percentage};
use values::{Auto, CSSFloat, Either, FONT_MEDIUM_PX, None_, Normal};
use values::{ExtremumLength, serialize_dimension};
use values::computed::{self, Context};
use values::generics::NonNegative;
use values::specified::NonNegativeNumber;
use values::specified::calc::CalcNode;
pub use values::specified::calc::CalcLengthOrPercentage;
pub use super::image::{ColorStop, EndingShape as GradientEndingShape, Gradient};
pub use super::image::{GradientKind, Image};
/// Number of app units per pixel
pub const AU_PER_PX: CSSFloat = 60.;
/// Number of app units per inch
pub const AU_PER_IN: CSSFloat = AU_PER_PX * 96.;
/// Number of app units per centimeter
pub const AU_PER_CM: CSSFloat = AU_PER_IN / 2.54;
/// Number of app units per millimeter
pub const AU_PER_MM: CSSFloat = AU_PER_IN / 25.4;
/// Number of app units per quarter
pub const AU_PER_Q: CSSFloat = AU_PER_MM / 4.;
/// Number of app units per point
pub const AU_PER_PT: CSSFloat = AU_PER_IN / 72.;
/// Number of app units per pica
pub const AU_PER_PC: CSSFloat = AU_PER_PT * 12.;
/// Same as Gecko's AppUnitsToIntCSSPixels
///
/// Converts app units to integer pixel values,
/// rounding during the conversion
pub fn au_to_int_px(au: f32) -> i32 {
(au / AU_PER_PX).round() as i32
}
#[derive(Clone, Copy, Debug, PartialEq)]
#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
/// A font relative length.
pub enum FontRelativeLength {
/// A "em" value: https://drafts.csswg.org/css-values/#em
Em(CSSFloat),
/// A "ex" value: https://drafts.csswg.org/css-values/#ex
Ex(CSSFloat),
/// A "ch" value: https://drafts.csswg.org/css-values/#ch
Ch(CSSFloat),
/// A "rem" value: https://drafts.csswg.org/css-values/#rem
Rem(CSSFloat)
}
impl ToCss for FontRelativeLength {
fn to_css<W>(&self, dest: &mut W) -> fmt::Result
where W: fmt::Write
{
match *self {
FontRelativeLength::Em(length) => serialize_dimension(length, "em", dest),
FontRelativeLength::Ex(length) => serialize_dimension(length, "ex", dest),
FontRelativeLength::Ch(length) => serialize_dimension(length, "ch", dest),
FontRelativeLength::Rem(length) => serialize_dimension(length, "rem", dest)
}
}
}
/// A source to resolve font-relative units against
#[derive(Clone, Copy, Debug, PartialEq)]
pub enum FontBaseSize {
/// Use the font-size of the current element
CurrentStyle,
/// Use the inherited font-size
InheritedStyle,
/// Use a custom base size
Custom(Au),
}
impl FontBaseSize {
/// Calculate the actual size for a given context
pub fn resolve(&self, context: &Context) -> Au {
match *self {
FontBaseSize::Custom(size) => size,
FontBaseSize::CurrentStyle => context.style().get_font().clone_font_size().0,
FontBaseSize::InheritedStyle => context.style().get_parent_font().clone_font_size().0,
}
}
}
impl FontRelativeLength {
/// Computes the font-relative length. We use the base_size
/// flag to pass a different size for computing font-size and unconstrained font-size
pub fn to_computed_value(&self, context: &Context, base_size: FontBaseSize) -> Au {
fn query_font_metrics(context: &Context, reference_font_size: Au) -> FontMetricsQueryResult {
context.font_metrics_provider.query(context.style().get_font(),
reference_font_size,
context.style().writing_mode,
context.in_media_query,
context.device())
}
let reference_font_size = base_size.resolve(context);
match *self {
FontRelativeLength::Em(length) => reference_font_size.scale_by(length),
FontRelativeLength::Ex(length) => {
match query_font_metrics(context, reference_font_size) {
FontMetricsQueryResult::Available(metrics) => metrics.x_height.scale_by(length),
// https://drafts.csswg.org/css-values/#ex
//
// In the cases where it is impossible or impractical to
// determine the x-height, a value of 0.5em must be
// assumed.
//
FontMetricsQueryResult::NotAvailable => reference_font_size.scale_by(0.5 * length),
}
},
FontRelativeLength::Ch(length) => {
match query_font_metrics(context, reference_font_size) {
FontMetricsQueryResult::Available(metrics) => metrics.zero_advance_measure.scale_by(length),
// https://drafts.csswg.org/css-values/#ch
//
// In the cases where it is impossible or impractical to
// determine the measure of the “0” glyph, it must be
// assumed to be 0.5em wide by 1em tall. Thus, the ch
// unit falls back to 0.5em in the general case, and to
// 1em when it would be typeset upright (i.e.
// writing-mode is vertical-rl or vertical-lr and
// text-orientation is upright).
//
FontMetricsQueryResult::NotAvailable => {
if context.style().writing_mode.is_vertical() {
reference_font_size.scale_by(length)
} else {
reference_font_size.scale_by(0.5 * length)
}
}
}
}
FontRelativeLength::Rem(length) => {
// https://drafts.csswg.org/css-values/#rem:
//
// When specified on the font-size property of the root
// element, the rem units refer to the property’s initial
// value.
//
if context.is_root_element {
reference_font_size.scale_by(length)
} else {
context.device().root_font_size().scale_by(length)
}
}
}
}
}
#[derive(Clone, Copy, Debug, PartialEq)]
#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
/// A viewport-relative length.
///
/// https://drafts.csswg.org/css-values/#viewport-relative-lengths
pub enum ViewportPercentageLength {
/// A vw unit: https://drafts.csswg.org/css-values/#vw
Vw(CSSFloat),
/// A vh unit: https://drafts.csswg.org/css-values/#vh
Vh(CSSFloat),
/// https://drafts.csswg.org/css-values/#vmin
Vmin(CSSFloat),
/// https://drafts.csswg.org/css-values/#vmax
Vmax(CSSFloat)
}
impl ToCss for ViewportPercentageLength {
fn to_css<W>(&self, dest: &mut W) -> fmt::Result where W: fmt::Write {
match *self {
ViewportPercentageLength::Vw(length) => serialize_dimension(length, "vw", dest),
ViewportPercentageLength::Vh(length) => serialize_dimension(length, "vh", dest),
ViewportPercentageLength::Vmin(length) => serialize_dimension(length, "vmin", dest),
ViewportPercentageLength::Vmax(length) => serialize_dimension(length, "vmax", dest)
}
}
}
impl ViewportPercentageLength {
/// Computes the given viewport-relative length for the given viewport size.
pub fn to_computed_value(&self, viewport_size: Size2D<Au>) -> Au {
macro_rules! to_unit {
($viewport_dimension:expr) => {
$viewport_dimension.to_f32_px() / 100.0
}
}
let value = match *self {
ViewportPercentageLength::Vw(length) =>
length * to_unit!(viewport_size.width),
ViewportPercentageLength::Vh(length) =>
length * to_unit!(viewport_size.height),
ViewportPercentageLength::Vmin(length) =>
length * to_unit!(cmp::min(viewport_size.width, viewport_size.height)),
ViewportPercentageLength::Vmax(length) =>
length * to_unit!(cmp::max(viewport_size.width, viewport_size.height)),
};
Au::from_f32_px(value)
}
}
/// HTML5 "character width", as defined in HTML5 § 14.5.4.
#[derive(Clone, Copy, Debug, PartialEq)]
#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
pub struct CharacterWidth(pub i32);
impl CharacterWidth {
/// Computes the given character width.
pub fn to_computed_value(&self, reference_font_size: Au) -> Au {
// This applies the *converting a character width to pixels* algorithm as specified
// in HTML5 § 14.5.4.
//
// TODO(pcwalton): Find these from the font.
let average_advance = reference_font_size.scale_by(0.5);
let max_advance = reference_font_size;
average_advance.scale_by(self.0 as CSSFloat - 1.0) + max_advance
}
}
/// Helper to convert a floating point length to application units
fn to_au_round(length: CSSFloat, au_per_unit: CSSFloat) -> Au {
Au(
((length * au_per_unit) as f64)
.min(MAX_AU.0 as f64)
.max(MIN_AU.0 as f64)
.round() as i32
)
}
/// Represents an absolute length with its unit
#[derive(Clone, Copy, Debug, PartialEq)]
#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
pub enum AbsoluteLength {
/// An absolute length in pixels (px)
Px(CSSFloat),
/// An absolute length in inches (in)
In(CSSFloat),
/// An absolute length in centimeters (cm)
Cm(CSSFloat),
/// An absolute length in millimeters (mm)
Mm(CSSFloat),
/// An absolute length in quarter-millimeters (q)
Q(CSSFloat),
/// An absolute length in points (pt)
Pt(CSSFloat),
/// An absolute length in pica (pc)
Pc(CSSFloat),
}
impl AbsoluteLength {
fn is_zero(&self) -> bool {
match *self {
AbsoluteLength::Px(v)
| AbsoluteLength::In(v)
| AbsoluteLength::Cm(v)
| AbsoluteLength::Mm(v)
| AbsoluteLength::Q(v)
| AbsoluteLength::Pt(v)
| AbsoluteLength::Pc(v) => v == 0.,
}
}
}
impl ToComputedValue for AbsoluteLength {
type ComputedValue = Au;
fn to_computed_value(&self, _: &Context) -> Au {
Au::from(*self)
}
fn from_computed_value(computed: &Au) -> AbsoluteLength {
AbsoluteLength::Px(computed.to_f32_px())
}
}
impl From<AbsoluteLength> for Au {
fn from(length: AbsoluteLength) -> Au {
match length {
AbsoluteLength::Px(value) => to_au_round(value, AU_PER_PX),
AbsoluteLength::In(value) => to_au_round(value, AU_PER_IN),
AbsoluteLength::Cm(value) => to_au_round(value, AU_PER_CM),
AbsoluteLength::Mm(value) => to_au_round(value, AU_PER_MM),
AbsoluteLength::Q(value) => to_au_round(value, AU_PER_Q),
AbsoluteLength::Pt(value) => to_au_round(value, AU_PER_PT),
AbsoluteLength::Pc(value) => to_au_round(value, AU_PER_PC),
}
}
}
impl ToCss for AbsoluteLength {
fn to_css<W>(&self, dest: &mut W) -> fmt::Result where W: fmt::Write {
match *self {
AbsoluteLength::Px(length) => serialize_dimension(length, "px", dest),
AbsoluteLength::In(length) => serialize_dimension(length, "in", dest),
AbsoluteLength::Cm(length) => serialize_dimension(length, "cm", dest),
AbsoluteLength::Mm(length) => serialize_dimension(length, "mm", dest),
AbsoluteLength::Q(length) => serialize_dimension(length, "q", dest),
AbsoluteLength::Pt(length) => serialize_dimension(length, "pt", dest),
AbsoluteLength::Pc(length) => serialize_dimension(length, "pc", dest),
}
}
}
impl Mul<CSSFloat> for AbsoluteLength {
type Output = AbsoluteLength;
#[inline]
fn mul(self, scalar: CSSFloat) -> AbsoluteLength {
match self {
AbsoluteLength::Px(v) => AbsoluteLength::Px(v * scalar),
AbsoluteLength::In(v) => AbsoluteLength::In(v * scalar),
AbsoluteLength::Cm(v) => AbsoluteLength::Cm(v * scalar),
AbsoluteLength::Mm(v) => AbsoluteLength::Mm(v * scalar),
AbsoluteLength::Q(v) => AbsoluteLength::Q(v * scalar),
AbsoluteLength::Pt(v) => AbsoluteLength::Pt(v * scalar),
AbsoluteLength::Pc(v) => AbsoluteLength::Pc(v * scalar),
}
}
}
/// Represents a physical length (mozmm) based on DPI
#[derive(Clone, Copy, Debug, PartialEq)]
#[cfg(feature = "gecko")]
pub struct PhysicalLength(pub CSSFloat);
#[cfg(feature = "gecko")]
impl PhysicalLength {
fn is_zero(&self) -> bool {
self.0 == 0.
}
/// Computes the given character width.
pub fn to_computed_value(&self, context: &Context) -> Au {
use gecko_bindings::bindings;
// Same as Gecko
const MM_PER_INCH: f32 = 25.4;
let physical_inch = unsafe {
bindings::Gecko_GetAppUnitsPerPhysicalInch(context.device().pres_context())
};
let inch = self.0 / MM_PER_INCH;
to_au_round(inch, physical_inch as f32)
}
}
#[cfg(feature = "gecko")]
impl ToCss for PhysicalLength {
fn to_css<W>(&self, dest: &mut W) -> fmt::Result where W: fmt::Write {
serialize_dimension(self.0, "mozmm", dest)
}
}
#[cfg(feature = "gecko")]
impl Mul<CSSFloat> for PhysicalLength {
type Output = PhysicalLength;
#[inline]
fn mul(self, scalar: CSSFloat) -> PhysicalLength {
PhysicalLength(self.0 * scalar)
}
}
/// A `<length>` without taking `calc` expressions into account
///
/// https://drafts.csswg.org/css-values/#lengths
#[derive(Clone, Copy, Debug, PartialEq)]
#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
pub enum NoCalcLength {
/// An absolute length
///
/// https://drafts.csswg.org/css-values/#absolute-length
Absolute(AbsoluteLength),
/// A font-relative length:
///
/// https://drafts.csswg.org/css-values/#font-relative-lengths
FontRelative(FontRelativeLength),
/// A viewport-relative length.
///
/// https://drafts.csswg.org/css-values/#viewport-relative-lengths
ViewportPercentage(ViewportPercentageLength),
/// HTML5 "character width", as defined in HTML5 § 14.5.4.
///
/// This cannot be specified by the user directly and is only generated by
/// `Stylist::synthesize_rules_for_legacy_attributes()`.
ServoCharacterWidth(CharacterWidth),
/// A physical length (mozmm) based on DPI
#[cfg(feature = "gecko")]
Physical(PhysicalLength),
}
impl ToCss for NoCalcLength {
fn to_css<W>(&self, dest: &mut W) -> fmt::Result where W: fmt::Write {
match *self {
NoCalcLength::Absolute(length) => length.to_css(dest),
NoCalcLength::FontRelative(length) => length.to_css(dest),
NoCalcLength::ViewportPercentage(length) => length.to_css(dest),
/* This should only be reached from style dumping code */
NoCalcLength::ServoCharacterWidth(CharacterWidth(i)) => {
dest.write_str("CharWidth(")?;
i.to_css(dest)?;
dest.write_char(')')
}
#[cfg(feature = "gecko")]
NoCalcLength::Physical(length) => length.to_css(dest),
}
}
}
impl Mul<CSSFloat> for NoCalcLength {
type Output = NoCalcLength;
#[inline]
fn mul(self, scalar: CSSFloat) -> NoCalcLength {
match self {
NoCalcLength::Absolute(v) => NoCalcLength::Absolute(v * scalar),
NoCalcLength::FontRelative(v) => NoCalcLength::FontRelative(v * scalar),
NoCalcLength::ViewportPercentage(v) => NoCalcLength::ViewportPercentage(v * scalar),
NoCalcLength::ServoCharacterWidth(_) => panic!("Can't multiply ServoCharacterWidth!"),
#[cfg(feature = "gecko")]
NoCalcLength::Physical(v) => NoCalcLength::Physical(v * scalar),
}
}
}
impl NoCalcLength {
/// Parse a given absolute or relative dimension.
pub fn parse_dimension(context: &ParserContext, value: CSSFloat, unit: &str)
-> Result<NoCalcLength, ()> {
let in_page_rule = context.rule_type.map_or(false, |rule_type| rule_type == CssRuleType::Page);
match_ignore_ascii_case! { unit,
"px" => Ok(NoCalcLength::Absolute(AbsoluteLength::Px(value))),
"in" => Ok(NoCalcLength::Absolute(AbsoluteLength::In(value))),
"cm" => Ok(NoCalcLength::Absolute(AbsoluteLength::Cm(value))),
"mm" => Ok(NoCalcLength::Absolute(AbsoluteLength::Mm(value))),
"q" => Ok(NoCalcLength::Absolute(AbsoluteLength::Q(value))),
"pt" => Ok(NoCalcLength::Absolute(AbsoluteLength::Pt(value))),
"pc" => Ok(NoCalcLength::Absolute(AbsoluteLength::Pc(value))),
// font-relative
"em" => Ok(NoCalcLength::FontRelative(FontRelativeLength::Em(value))),
"ex" => Ok(NoCalcLength::FontRelative(FontRelativeLength::Ex(value))),
"ch" => Ok(NoCalcLength::FontRelative(FontRelativeLength::Ch(value))),
"rem" => Ok(NoCalcLength::FontRelative(FontRelativeLength::Rem(value))),
// viewport percentages
"vw" => {
if in_page_rule {
return Err(())
}
Ok(NoCalcLength::ViewportPercentage(ViewportPercentageLength::Vw(value)))
},
"vh" => {
if in_page_rule {
return Err(())
}
Ok(NoCalcLength::ViewportPercentage(ViewportPercentageLength::Vh(value)))
},
"vmin" => {
if in_page_rule {
return Err(())
}
Ok(NoCalcLength::ViewportPercentage(ViewportPercentageLength::Vmin(value)))
},
"vmax" => {
if in_page_rule {
return Err(())
}
Ok(NoCalcLength::ViewportPercentage(ViewportPercentageLength::Vmax(value)))
},
#[cfg(feature = "gecko")]
"mozmm" => Ok(NoCalcLength::Physical(PhysicalLength(value))),
_ => Err(())
}
}
#[inline]
/// Returns a `zero` length.
pub fn zero() -> NoCalcLength {
NoCalcLength::Absolute(AbsoluteLength::Px(0.))
}
#[inline]
/// Checks whether the length value is zero.
pub fn is_zero(&self) -> bool {
match *self {
NoCalcLength::Absolute(length) => length.is_zero(),
#[cfg(feature = "gecko")]
NoCalcLength::Physical(length) => length.is_zero(),
_ => false
}
}
#[inline]
/// Returns a `medium` length.
pub fn medium() -> NoCalcLength {
NoCalcLength::Absolute(AbsoluteLength::Px(FONT_MEDIUM_PX as f32))
}
/// Get an absolute length from a px value.
#[inline]
pub fn from_px(px_value: CSSFloat) -> NoCalcLength {
NoCalcLength::Absolute(AbsoluteLength::Px(px_value))
}
}
/// An extension to `NoCalcLength` to parse `calc` expressions.
/// This is commonly used for the `<length>` values.
///
/// https://drafts.csswg.org/css-values/#lengths
#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
#[derive(Clone, Debug, PartialEq, ToCss)]
pub enum Length {
/// The internal length type that cannot parse `calc`
NoCalc(NoCalcLength),
/// A calc expression.
///
/// https://drafts.csswg.org/css-values/#calc-notation
Calc(Box<CalcLengthOrPercentage>),
}
impl From<NoCalcLength> for Length {
#[inline]
fn from(len: NoCalcLength) -> Self {
Length::NoCalc(len)
}
}
impl Mul<CSSFloat> for Length {
type Output = Length;
#[inline]
fn mul(self, scalar: CSSFloat) -> Length {
match self {
Length::NoCalc(inner) => Length::NoCalc(inner * scalar),
Length::Calc(..) => panic!("Can't multiply Calc!"),
}
}
}
impl Mul<CSSFloat> for FontRelativeLength {
type Output = FontRelativeLength;
#[inline]
fn mul(self, scalar: CSSFloat) -> FontRelativeLength {
match self {
FontRelativeLength::Em(v) => FontRelativeLength::Em(v * scalar),
FontRelativeLength::Ex(v) => FontRelativeLength::Ex(v * scalar),
FontRelativeLength::Ch(v) => FontRelativeLength::Ch(v * scalar),
FontRelativeLength::Rem(v) => FontRelativeLength::Rem(v * scalar),
}
}
}
impl Mul<CSSFloat> for ViewportPercentageLength {
type Output = ViewportPercentageLength;
#[inline]
fn mul(self, scalar: CSSFloat) -> ViewportPercentageLength {
match self {
ViewportPercentageLength::Vw(v) => ViewportPercentageLength::Vw(v * scalar),
ViewportPercentageLength::Vh(v) => ViewportPercentageLength::Vh(v * scalar),
ViewportPercentageLength::Vmin(v) => ViewportPercentageLength::Vmin(v * scalar),
ViewportPercentageLength::Vmax(v) => ViewportPercentageLength::Vmax(v * scalar),
}
}
}
impl Length {
#[inline]
/// Returns a `zero` length.
pub fn zero() -> Length {
Length::NoCalc(NoCalcLength::zero())
}
/// Parse a given absolute or relative dimension.
pub fn parse_dimension(context: &ParserContext, value: CSSFloat, unit: &str)
-> Result<Length, ()> {
NoCalcLength::parse_dimension(context, value, unit).map(Length::NoCalc)
}
#[inline]
fn parse_internal<'i, 't>(context: &ParserContext,
input: &mut Parser<'i, 't>,
num_context: AllowedLengthType,
allow_quirks: AllowQuirks)
-> Result<Length, ParseError<'i>> {
// FIXME: remove early returns when lifetimes are non-lexical
{
let token = input.next()?;
match *token {
Token::Dimension { value, ref unit, .. } if num_context.is_ok(context.parsing_mode, value) => {
return Length::parse_dimension(context, value, unit)
.map_err(|()| BasicParseError::UnexpectedToken(token.clone()).into())
}
Token::Number { value, .. } if num_context.is_ok(context.parsing_mode, value) => {
if value != 0. &&
!context.parsing_mode.allows_unitless_lengths() &&
!allow_quirks.allowed(context.quirks_mode) {
return Err(StyleParseError::UnspecifiedError.into())
}
return Ok(Length::NoCalc(NoCalcLength::Absolute(AbsoluteLength::Px(value))))
},
Token::Function(ref name) if name.eq_ignore_ascii_case("calc") => {}
ref token => return Err(BasicParseError::UnexpectedToken(token.clone()).into())
}
}
input.parse_nested_block(|input| {
CalcNode::parse_length(context, input, num_context).map(|calc| Length::Calc(Box::new(calc)))
})
}
/// Parse a non-negative length
#[inline]
pub fn parse_non_negative<'i, 't>(context: &ParserContext, input: &mut Parser<'i, 't>)
-> Result<Length, ParseError<'i>> {
Self::parse_non_negative_quirky(context, input, AllowQuirks::No)
}
/// Parse a non-negative length, allowing quirks.
#[inline]
pub fn parse_non_negative_quirky<'i, 't>(context: &ParserContext,
input: &mut Parser<'i, 't>,
allow_quirks: AllowQuirks)
-> Result<Length, ParseError<'i>> {
Self::parse_internal(context, input, AllowedLengthType::NonNegative, allow_quirks)
}
/// Get an absolute length from a px value.
#[inline]
pub fn from_px(px_value: CSSFloat) -> Length {
Length::NoCalc(NoCalcLength::from_px(px_value))
}
/// Extract inner length without a clone, replacing it with a 0 Au
///
/// Use when you need to move out of a length array without cloning
#[inline]
pub fn take(&mut self) -> Self {
mem::replace(self, Length::zero())
}
}
impl Parse for Length {
fn parse<'i, 't>(context: &ParserContext, input: &mut Parser<'i, 't>) -> Result<Self, ParseError<'i>> {
Self::parse_quirky(context, input, AllowQuirks::No)
}
}
impl Length {
/// Parses a length, with quirks.
pub fn parse_quirky<'i, 't>(context: &ParserContext,
input: &mut Parser<'i, 't>,
allow_quirks: AllowQuirks)
-> Result<Self, ParseError<'i>> {
Self::parse_internal(context, input, AllowedLengthType::All, allow_quirks)
}
}
impl<T: Parse> Either<Length, T> {
/// Parse a non-negative length
#[inline]
pub fn parse_non_negative_length<'i, 't>(context: &ParserContext, input: &mut Parser<'i, 't>)
-> Result<Self, ParseError<'i>> {
if let Ok(v) = input.try(|input| T::parse(context, input)) {
return Ok(Either::Second(v));
}
Length::parse_internal(context, input, AllowedLengthType::NonNegative, AllowQuirks::No).map(Either::First)
}
}
/// A wrapper of Length, whose value must be >= 0.
pub type NonNegativeLength = NonNegative<Length>;
impl From<NoCalcLength> for NonNegativeLength {
#[inline]
fn from(len: NoCalcLength) -> Self {
NonNegative::<Length>(Length::NoCalc(len))
}
}
impl From<Length> for NonNegativeLength {
#[inline]
fn from(len: Length) -> Self {
NonNegative::<Length>(len)
}
}
impl<T: Parse> Parse for Either<NonNegativeLength, T> {
#[inline]
fn parse<'i, 't>(context: &ParserContext, input: &mut Parser<'i, 't>) -> Result<Self, ParseError<'i>> {
if let Ok(v) = input.try(|input| T::parse(context, input)) {
return Ok(Either::Second(v));
}
Length::parse_internal(context, input, AllowedLengthType::NonNegative, AllowQuirks::No)
.map(NonNegative::<Length>).map(Either::First)
}
}
impl NonNegativeLength {
/// Returns a `zero` length.
#[inline]
pub fn zero() -> Self {
Length::zero().into()
}
/// Get an absolute length from a px value.
#[inline]
pub fn from_px(px_value: CSSFloat) -> Self {
Length::from_px(px_value.max(0.)).into()
}
}
/// Either a NonNegativeLength or the `normal` keyword.
pub type NonNegativeLengthOrNormal = Either<NonNegativeLength, Normal>;
/// Either a NonNegativeLength or the `auto` keyword.
pub type NonNegativeLengthOrAuto = Either<NonNegativeLength, Auto>;
/// Either a NonNegativeLength or a NonNegativeNumber value.
pub type NonNegativeLengthOrNumber = Either<NonNegativeLength, NonNegativeNumber>;
/// A length or a percentage value.
#[allow(missing_docs)]
#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
#[derive(Clone, Debug, PartialEq, ToCss)]
pub enum LengthOrPercentage {
Length(NoCalcLength),
Percentage(computed::Percentage),
Calc(Box<CalcLengthOrPercentage>),
}
impl From<Length> for LengthOrPercentage {
fn from(len: Length) -> LengthOrPercentage {
match len {
Length::NoCalc(l) => LengthOrPercentage::Length(l),
Length::Calc(l) => LengthOrPercentage::Calc(l),
}
}
}
impl From<NoCalcLength> for LengthOrPercentage {
#[inline]
fn from(len: NoCalcLength) -> Self {
LengthOrPercentage::Length(len)
}
}
impl From<Percentage> for LengthOrPercentage {
#[inline]
fn from(pc: Percentage) -> Self {
if pc.is_calc() {
LengthOrPercentage::Calc(Box::new(CalcLengthOrPercentage {
percentage: Some(computed::Percentage(pc.get())),
.. Default::default()
}))
} else {
LengthOrPercentage::Percentage(computed::Percentage(pc.get()))
}
}
}
impl From<computed::Percentage> for LengthOrPercentage {
#[inline]
fn from(pc: computed::Percentage) -> Self {
LengthOrPercentage::Percentage(pc)
}
}
impl LengthOrPercentage {
#[inline]
/// Returns a `zero` length.
pub fn zero() -> LengthOrPercentage {
LengthOrPercentage::Length(NoCalcLength::zero())
}
fn parse_internal<'i, 't>(context: &ParserContext,
input: &mut Parser<'i, 't>,
num_context: AllowedLengthType,
allow_quirks: AllowQuirks)
-> Result<LengthOrPercentage, ParseError<'i>>
{
// FIXME: remove early returns when lifetimes are non-lexical
{
let token = input.next()?;
match *token {
Token::Dimension { value, ref unit, .. } if num_context.is_ok(context.parsing_mode, value) => {
return NoCalcLength::parse_dimension(context, value, unit)
.map(LengthOrPercentage::Length)
.map_err(|()| BasicParseError::UnexpectedToken(token.clone()).into())
}
Token::Percentage { unit_value, .. } if num_context.is_ok(context.parsing_mode, unit_value) => {
return Ok(LengthOrPercentage::Percentage(computed::Percentage(unit_value)))
}
Token::Number { value, .. } if num_context.is_ok(context.parsing_mode, value) => {
if value != 0. &&
!context.parsing_mode.allows_unitless_lengths() &&
!allow_quirks.allowed(context.quirks_mode) {
return Err(BasicParseError::UnexpectedToken(token.clone()).into())
} else {
return Ok(LengthOrPercentage::Length(NoCalcLength::from_px(value)))
}
}
Token::Function(ref name) if name.eq_ignore_ascii_case("calc") => {}
_ => return Err(BasicParseError::UnexpectedToken(token.clone()).into())
}
}
let calc = input.parse_nested_block(|i| {
CalcNode::parse_length_or_percentage(context, i, num_context)
})?;
Ok(LengthOrPercentage::Calc(Box::new(calc)))
}
/// Parse a non-negative length.
#[inline]
pub fn parse_non_negative<'i, 't>(context: &ParserContext, input: &mut Parser<'i, 't>)
-> Result<LengthOrPercentage, ParseError<'i>> {
Self::parse_non_negative_quirky(context, input, AllowQuirks::No)
}
/// Parse a non-negative length, with quirks.
#[inline]
pub fn parse_non_negative_quirky<'i, 't>(context: &ParserContext,
input: &mut Parser<'i, 't>,
allow_quirks: AllowQuirks)
-> Result<LengthOrPercentage, ParseError<'i>> {
Self::parse_internal(context, input, AllowedLengthType::NonNegative, allow_quirks)
}
/// Parse a length, treating dimensionless numbers as pixels
///
/// https://www.w3.org/TR/SVG2/types.html#presentation-attribute-css-value
pub fn parse_numbers_are_pixels<'i, 't>(context: &ParserContext, input: &mut Parser<'i, 't>)
-> Result<LengthOrPercentage, ParseError<'i>> {
if let Ok(lop) = input.try(|i| Self::parse(context, i)) {
return Ok(lop)
}
// TODO(emilio): Probably should use Number::parse_non_negative to
// handle calc()?
let num = input.expect_number()?;
Ok(LengthOrPercentage::Length(NoCalcLength::Absolute(AbsoluteLength::Px(num))))
}
/// Parse a non-negative length, treating dimensionless numbers as pixels
///
/// This is nonstandard behavior used by Firefox for SVG
pub fn parse_numbers_are_pixels_non_negative<'i, 't>(context: &ParserContext,
input: &mut Parser<'i, 't>)
-> Result<LengthOrPercentage, ParseError<'i>> {
if let Ok(lop) = input.try(|i| Self::parse_non_negative(context, i)) {
return Ok(lop)
}
// TODO(emilio): Probably should use Number::parse_non_negative to
// handle calc()?
let num = input.expect_number()?;
if num >= 0. {
Ok(LengthOrPercentage::Length(NoCalcLength::Absolute(AbsoluteLength::Px(num))))
} else {
Err(StyleParseError::UnspecifiedError.into())
}
}
/// Extract value from ref without a clone, replacing it with a 0 Au
///
/// Use when you need to move out of a length array without cloning
#[inline]
pub fn take(&mut self) -> Self {
mem::replace(self, LengthOrPercentage::zero())
}
}
impl Parse for LengthOrPercentage {
#[inline]
fn parse<'i, 't>(context: &ParserContext, input: &mut Parser<'i, 't>) -> Result<Self, ParseError<'i>> {
Self::parse_quirky(context, input, AllowQuirks::No)
}
}
impl LengthOrPercentage {
/// Parses a length or a percentage, allowing the unitless length quirk.
/// https://quirks.spec.whatwg.org/#the-unitless-length-quirk
#[inline]
pub fn parse_quirky<'i, 't>(context: &ParserContext,
input: &mut Parser<'i, 't>,
allow_quirks: AllowQuirks) -> Result<Self, ParseError<'i>> {
Self::parse_internal(context, input, AllowedLengthType::All, allow_quirks)
}
}
/// Either a `<length>`, a `<percentage>`, or the `auto` keyword.
#[allow(missing_docs)]
#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
#[derive(Clone, Debug, PartialEq, ToCss)]
pub enum LengthOrPercentageOrAuto {
Length(NoCalcLength),
Percentage(computed::Percentage),
Auto,
Calc(Box<CalcLengthOrPercentage>),
}
impl From<NoCalcLength> for LengthOrPercentageOrAuto {
#[inline]
fn from(len: NoCalcLength) -> Self {
LengthOrPercentageOrAuto::Length(len)
}
}
impl From<computed::Percentage> for LengthOrPercentageOrAuto {
#[inline]
fn from(pc: computed::Percentage) -> Self {
LengthOrPercentageOrAuto::Percentage(pc)
}
}
impl LengthOrPercentageOrAuto {
fn parse_internal<'i, 't>(context: &ParserContext,
input: &mut Parser<'i, 't>,
num_context: AllowedLengthType,
allow_quirks: AllowQuirks)
-> Result<Self, ParseError<'i>> {
// FIXME: remove early returns when lifetimes are non-lexical
{
let token = input.next()?;
match *token {
Token::Dimension { value, ref unit, .. } if num_context.is_ok(context.parsing_mode, value) => {
return NoCalcLength::parse_dimension(context, value, unit)
.map(LengthOrPercentageOrAuto::Length)
.map_err(|()| BasicParseError::UnexpectedToken(token.clone()).into())
}
Token::Percentage { unit_value, .. } if num_context.is_ok(context.parsing_mode, unit_value) => {
return Ok(LengthOrPercentageOrAuto::Percentage(computed::Percentage(unit_value)))
}
Token::Number { value, .. } if num_context.is_ok(context.parsing_mode, value) => {
if value != 0. &&
!context.parsing_mode.allows_unitless_lengths() &&
!allow_quirks.allowed(context.quirks_mode) {
return Err(StyleParseError::UnspecifiedError.into())
}
return Ok(LengthOrPercentageOrAuto::Length(
NoCalcLength::Absolute(AbsoluteLength::Px(value))
))
}
Token::Ident(ref value) if value.eq_ignore_ascii_case("auto") => {
return Ok(LengthOrPercentageOrAuto::Auto)
}
Token::Function(ref name) if name.eq_ignore_ascii_case("calc") => {}
_ => return Err(BasicParseError::UnexpectedToken(token.clone()).into())
}
}
let calc = input.parse_nested_block(|i| {
CalcNode::parse_length_or_percentage(context, i, num_context)
})?;
Ok(LengthOrPercentageOrAuto::Calc(Box::new(calc)))
}
/// Parse a non-negative length, percentage, or auto.
#[inline]
pub fn parse_non_negative<'i, 't>(context: &ParserContext, input: &mut Parser<'i, 't>)
-> Result<LengthOrPercentageOrAuto, ParseError<'i>> {
Self::parse_non_negative_quirky(context, input, AllowQuirks::No)
}
/// Parse a non-negative length, percentage, or auto.
#[inline]
pub fn parse_non_negative_quirky<'i, 't>(context: &ParserContext,
input: &mut Parser<'i, 't>,
allow_quirks: AllowQuirks)
-> Result<Self, ParseError<'i>> {
Self::parse_internal(context, input, AllowedLengthType::NonNegative, allow_quirks)
}
/// Returns the `auto` value.
pub fn auto() -> Self {
LengthOrPercentageOrAuto::Auto