summaryrefslogtreecommitdiffstats
path: root/servo/components/style/values/specified/resolution.rs
diff options
context:
space:
mode:
Diffstat (limited to 'servo/components/style/values/specified/resolution.rs')
-rw-r--r--servo/components/style/values/specified/resolution.rs141
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())),
+ }
+ }
+}