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-rw-r--r--servo/components/style/values/specified/easing.rs252
1 files changed, 252 insertions, 0 deletions
diff --git a/servo/components/style/values/specified/easing.rs b/servo/components/style/values/specified/easing.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 https://mozilla.org/MPL/2.0/. */
+
+//! Specified types for CSS Easing functions.
+use crate::parser::{Parse, ParserContext};
+use crate::piecewise_linear::{PiecewiseLinearFunction, PiecewiseLinearFunctionBuildParameters};
+use crate::values::computed::easing::TimingFunction as ComputedTimingFunction;
+use crate::values::computed::{Context, ToComputedValue};
+use crate::values::generics::easing::TimingFunction as GenericTimingFunction;
+use crate::values::generics::easing::{StepPosition, TimingKeyword};
+use crate::values::specified::{Integer, Number, Percentage};
+use cssparser::{Delimiter, Parser, Token};
+use selectors::parser::SelectorParseErrorKind;
+use std::iter::FromIterator;
+use style_traits::{ParseError, StyleParseErrorKind};
+
+/// An entry for linear easing function.
+#[derive(Clone, Copy, Debug, MallocSizeOf, PartialEq, SpecifiedValueInfo, ToCss, ToShmem)]
+pub struct LinearStop {
+ /// Output of the function at the given point.
+ pub output: Number,
+ /// Playback progress at which this output is given.
+ #[css(skip_if = "Option::is_none")]
+ pub input: Option<Percentage>,
+}
+
+/// A list of specified linear stops.
+#[derive(Clone, Default, Debug, MallocSizeOf, PartialEq, SpecifiedValueInfo, ToCss, ToShmem)]
+#[css(comma)]
+pub struct LinearStops {
+ #[css(iterable)]
+ entries: crate::OwnedSlice<LinearStop>,
+}
+
+impl LinearStops {
+ fn new(list: crate::OwnedSlice<LinearStop>) -> Self {
+ LinearStops { entries: list }
+ }
+}
+
+/// A specified timing function.
+pub type TimingFunction = GenericTimingFunction<Integer, Number, LinearStops>;
+
+#[cfg(feature = "gecko")]
+fn linear_timing_function_enabled() -> bool {
+ static_prefs::pref!("layout.css.linear-easing-function.enabled")
+}
+
+#[cfg(feature = "servo")]
+fn linear_timing_function_enabled() -> bool {
+ false
+}
+
+impl Parse for TimingFunction {
+ fn parse<'i, 't>(
+ context: &ParserContext,
+ input: &mut Parser<'i, 't>,
+ ) -> Result<Self, ParseError<'i>> {
+ if let Ok(keyword) = input.try_parse(TimingKeyword::parse) {
+ return Ok(GenericTimingFunction::Keyword(keyword));
+ }
+ if let Ok(ident) = input.try_parse(|i| i.expect_ident_cloned()) {
+ let position = match_ignore_ascii_case! { &ident,
+ "step-start" => StepPosition::Start,
+ "step-end" => StepPosition::End,
+ _ => {
+ return Err(input.new_custom_error(
+ SelectorParseErrorKind::UnexpectedIdent(ident.clone())
+ ));
+ },
+ };
+ return Ok(GenericTimingFunction::Steps(Integer::new(1), position));
+ }
+ let location = input.current_source_location();
+ let function = input.expect_function()?.clone();
+ input.parse_nested_block(move |i| {
+ match_ignore_ascii_case! { &function,
+ "cubic-bezier" => Self::parse_cubic_bezier(context, i),
+ "steps" => Self::parse_steps(context, i),
+ "linear" => Self::parse_linear_function(context, i),
+ _ => Err(location.new_custom_error(StyleParseErrorKind::UnexpectedFunction(function.clone()))),
+ }
+ })
+ }
+}
+
+impl TimingFunction {
+ fn parse_cubic_bezier<'i, 't>(
+ context: &ParserContext,
+ input: &mut Parser<'i, 't>,
+ ) -> Result<Self, ParseError<'i>> {
+ let x1 = Number::parse(context, input)?;
+ input.expect_comma()?;
+ let y1 = Number::parse(context, input)?;
+ input.expect_comma()?;
+ let x2 = Number::parse(context, input)?;
+ input.expect_comma()?;
+ let y2 = Number::parse(context, input)?;
+
+ if x1.get() < 0.0 || x1.get() > 1.0 || x2.get() < 0.0 || x2.get() > 1.0 {
+ return Err(input.new_custom_error(StyleParseErrorKind::UnspecifiedError));
+ }
+
+ Ok(GenericTimingFunction::CubicBezier { x1, y1, x2, y2 })
+ }
+
+ fn parse_steps<'i, 't>(
+ context: &ParserContext,
+ input: &mut Parser<'i, 't>,
+ ) -> Result<Self, ParseError<'i>> {
+ let steps = Integer::parse_positive(context, input)?;
+ let position = input
+ .try_parse(|i| {
+ i.expect_comma()?;
+ StepPosition::parse(context, i)
+ })
+ .unwrap_or(StepPosition::End);
+
+ // jump-none accepts a positive integer greater than 1.
+ // FIXME(emilio): The spec asks us to avoid rejecting it at parse
+ // time except until computed value time.
+ //
+ // It's not totally clear it's worth it though, and no other browser
+ // does this.
+ if position == StepPosition::JumpNone && steps.value() <= 1 {
+ return Err(input.new_custom_error(StyleParseErrorKind::UnspecifiedError));
+ }
+ Ok(GenericTimingFunction::Steps(steps, position))
+ }
+
+ fn parse_linear_function<'i, 't>(
+ context: &ParserContext,
+ input: &mut Parser<'i, 't>,
+ ) -> Result<Self, ParseError<'i>> {
+ if !linear_timing_function_enabled() {
+ return Err(input.new_custom_error(StyleParseErrorKind::ExperimentalProperty));
+ }
+ let mut result = vec![];
+ // Closely follows `parse_comma_separated`, but can generate multiple entries for one comma-separated entry.
+ loop {
+ input.parse_until_before(Delimiter::Comma, |i| {
+ let mut input_start = i.try_parse(|i| Percentage::parse(context, i)).ok();
+ let mut input_end = i.try_parse(|i| Percentage::parse(context, i)).ok();
+
+ let output = Number::parse(context, i)?;
+ if input_start.is_none() {
+ debug_assert!(input_end.is_none(), "Input end parsed without input start?");
+ input_start = i.try_parse(|i| Percentage::parse(context, i)).ok();
+ input_end = i.try_parse(|i| Percentage::parse(context, i)).ok();
+ }
+ result.push(LinearStop {
+ output,
+ input: input_start.into(),
+ });
+ if input_end.is_some() {
+ debug_assert!(
+ input_start.is_some(),
+ "Input end valid but not input start?"
+ );
+ result.push(LinearStop {
+ output,
+ input: input_end.into(),
+ });
+ }
+
+ Ok(())
+ })?;
+
+ match input.next() {
+ Err(_) => break,
+ Ok(&Token::Comma) => continue,
+ Ok(_) => unreachable!(),
+ }
+ }
+ if result.len() < 2 {
+ return Err(input.new_custom_error(StyleParseErrorKind::UnspecifiedError));
+ }
+
+ Ok(GenericTimingFunction::LinearFunction(LinearStops::new(
+ crate::OwnedSlice::from(result),
+ )))
+ }
+}
+
+impl LinearStop {
+ /// Convert this type to entries that can be used to build PiecewiseLinearFunction.
+ pub fn to_piecewise_linear_build_parameters(
+ x: &LinearStop,
+ ) -> PiecewiseLinearFunctionBuildParameters {
+ (x.output.get(), x.input.map(|x| x.get()))
+ }
+}
+
+// We need this for converting the specified TimingFunction into computed TimingFunction without
+// Context (for some FFIs in glue.rs). In fact, we don't really need Context to get the computed
+// value of TimingFunction.
+impl TimingFunction {
+ /// Generate the ComputedTimingFunction without Context.
+ pub fn to_computed_value_without_context(&self) -> ComputedTimingFunction {
+ match &self {
+ GenericTimingFunction::Steps(steps, pos) => {
+ GenericTimingFunction::Steps(steps.value(), *pos)
+ },
+ GenericTimingFunction::CubicBezier { x1, y1, x2, y2 } => {
+ GenericTimingFunction::CubicBezier {
+ x1: x1.get(),
+ y1: y1.get(),
+ x2: x2.get(),
+ y2: y2.get(),
+ }
+ },
+ GenericTimingFunction::Keyword(keyword) => GenericTimingFunction::Keyword(*keyword),
+ GenericTimingFunction::LinearFunction(steps) => {
+ GenericTimingFunction::LinearFunction(PiecewiseLinearFunction::from_iter(
+ steps
+ .entries
+ .iter()
+ .map(|e| LinearStop::to_piecewise_linear_build_parameters(e)),
+ ))
+ },
+ }
+ }
+}
+
+impl ToComputedValue for TimingFunction {
+ type ComputedValue = ComputedTimingFunction;
+ fn to_computed_value(&self, _: &Context) -> Self::ComputedValue {
+ self.to_computed_value_without_context()
+ }
+
+ fn from_computed_value(computed: &Self::ComputedValue) -> Self {
+ match &computed {
+ ComputedTimingFunction::Steps(steps, pos) => Self::Steps(Integer::new(*steps), *pos),
+ ComputedTimingFunction::CubicBezier { x1, y1, x2, y2 } => Self::CubicBezier {
+ x1: Number::new(*x1),
+ y1: Number::new(*y1),
+ x2: Number::new(*x2),
+ y2: Number::new(*y2),
+ },
+ ComputedTimingFunction::Keyword(keyword) => GenericTimingFunction::Keyword(*keyword),
+ ComputedTimingFunction::LinearFunction(function) => {
+ GenericTimingFunction::LinearFunction(LinearStops {
+ entries: crate::OwnedSlice::from_iter(function.iter().map(|e| LinearStop {
+ output: Number::new(e.y),
+ input: Some(Percentage::new(e.x)).into(),
+ })),
+ })
+ },
+ }
+ }
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-05-22 17:44:37 +0000