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Diffstat (limited to '')
-rw-r--r-- | servo/components/style/values/specified/resolution.rs | 141 |
1 files changed, 141 insertions, 0 deletions
diff --git a/servo/components/style/values/specified/resolution.rs b/servo/components/style/values/specified/resolution.rs new file mode 100644 index 0000000000..87284615e6 --- /dev/null +++ b/servo/components/style/values/specified/resolution.rs @@ -0,0 +1,141 @@ +/* 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/. */ + +//! Resolution values: +//! +//! https://drafts.csswg.org/css-values/#resolution + +use crate::parser::{Parse, ParserContext}; +use crate::values::specified::CalcNode; +use crate::values::CSSFloat; +use cssparser::{Parser, Token}; +use std::fmt::{self, Write}; +use style_traits::{CssWriter, ParseError, StyleParseErrorKind, ToCss}; + +/// A specified resolution. +#[derive(Clone, Debug, MallocSizeOf, PartialEq, SpecifiedValueInfo, ToShmem)] +pub struct Resolution { + value: CSSFloat, + unit: ResolutionUnit, + was_calc: bool, +} + +#[derive(Clone, Copy, Debug, MallocSizeOf, PartialEq, SpecifiedValueInfo, ToCss, ToShmem)] +enum ResolutionUnit { + /// Dots per inch. + Dpi, + /// An alias unit for dots per pixel. + X, + /// Dots per pixel. + Dppx, + /// Dots per centimeter. + Dpcm, +} + +impl ResolutionUnit { + fn as_str(self) -> &'static str { + match self { + Self::Dpi => "dpi", + Self::X => "x", + Self::Dppx => "dppx", + Self::Dpcm => "dpcm", + } + } +} + +impl Resolution { + /// Returns a resolution value from dppx units. + pub fn from_dppx(value: CSSFloat) -> Self { + Self { + value, + unit: ResolutionUnit::Dppx, + was_calc: false, + } + } + + /// Returns a resolution value from dppx units. + pub fn from_x(value: CSSFloat) -> Self { + Self { + value, + unit: ResolutionUnit::X, + was_calc: false, + } + } + + /// Returns a resolution value from dppx units. + pub fn from_dppx_calc(value: CSSFloat) -> Self { + Self { + value, + unit: ResolutionUnit::Dppx, + was_calc: true, + } + } + + /// Convert this resolution value to dppx units. + pub fn dppx(&self) -> CSSFloat { + match self.unit { + ResolutionUnit::X | ResolutionUnit::Dppx => self.value, + _ => self.dpi() / 96.0, + } + } + + /// Convert this resolution value to dpi units. + pub fn dpi(&self) -> CSSFloat { + match self.unit { + ResolutionUnit::Dpi => self.value, + ResolutionUnit::X | ResolutionUnit::Dppx => self.value * 96.0, + ResolutionUnit::Dpcm => self.value * 2.54, + } + } + + /// Parse a resolution given a value and unit. + pub fn parse_dimension<'i, 't>(value: CSSFloat, unit: &str) -> Result<Self, ()> { + let unit = match_ignore_ascii_case! { &unit, + "dpi" => ResolutionUnit::Dpi, + "dppx" => ResolutionUnit::Dppx, + "dpcm" => ResolutionUnit::Dpcm, + "x" => ResolutionUnit::X, + _ => return Err(()) + }; + Ok(Self { + value, + unit, + was_calc: false, + }) + } +} + +impl ToCss for Resolution { + fn to_css<W>(&self, dest: &mut CssWriter<W>) -> fmt::Result + where + W: Write, + { + crate::values::serialize_specified_dimension( + self.value, + self.unit.as_str(), + self.was_calc, + dest, + ) + } +} + +impl Parse for Resolution { + fn parse<'i, 't>( + context: &ParserContext, + input: &mut Parser<'i, 't>, + ) -> Result<Self, ParseError<'i>> { + let location = input.current_source_location(); + match *input.next()? { + Token::Dimension { + value, ref unit, .. + } => Self::parse_dimension(value, unit) + .map_err(|()| location.new_custom_error(StyleParseErrorKind::UnspecifiedError)), + Token::Function(ref name) => { + let function = CalcNode::math_function(context, name, location)?; + CalcNode::parse_resolution(context, input, function) + }, + ref t => return Err(location.new_unexpected_token_error(t.clone())), + } + } +} |