mirror of
https://github.com/servo/servo.git
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124 lines
3.8 KiB
Rust
124 lines
3.8 KiB
Rust
/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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//! Computed angles.
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use num_traits::Zero;
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use std::{f32, f64};
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use std::f64::consts::PI;
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use std::ops::Add;
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use values::CSSFloat;
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use values::animated::{Animate, Procedure};
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use values::distance::{ComputeSquaredDistance, SquaredDistance};
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/// A computed angle.
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#[animate(fallback = "Self::animate_fallback")]
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#[cfg_attr(feature = "servo", derive(Deserialize, Serialize))]
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#[derive(Animate, Clone, Copy, Debug, MallocSizeOf, PartialEq, PartialOrd, ToAnimatedZero, ToCss)]
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pub enum Angle {
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/// An angle with degree unit.
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#[css(dimension)]
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Deg(CSSFloat),
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/// An angle with gradian unit.
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#[css(dimension)]
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Grad(CSSFloat),
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/// An angle with radian unit.
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#[css(dimension)]
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Rad(CSSFloat),
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/// An angle with turn unit.
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#[css(dimension)]
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Turn(CSSFloat),
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}
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impl Angle {
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/// Creates a computed `Angle` value from a radian amount.
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pub fn from_radians(radians: CSSFloat) -> Self {
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Angle::Rad(radians)
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}
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/// Returns the amount of radians this angle represents.
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#[inline]
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pub fn radians(&self) -> CSSFloat {
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self.radians64().min(f32::MAX as f64).max(f32::MIN as f64) as f32
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}
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/// Returns the amount of radians this angle represents as a `f64`.
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///
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/// Gecko stores angles as singles, but does this computation using doubles.
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/// See nsCSSValue::GetAngleValueInRadians.
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/// This is significant enough to mess up rounding to the nearest
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/// quarter-turn for 225 degrees, for example.
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#[inline]
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pub fn radians64(&self) -> f64 {
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const RAD_PER_DEG: f64 = PI / 180.0;
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const RAD_PER_GRAD: f64 = PI / 200.0;
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const RAD_PER_TURN: f64 = PI * 2.0;
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let radians = match *self {
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Angle::Deg(val) => val as f64 * RAD_PER_DEG,
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Angle::Grad(val) => val as f64 * RAD_PER_GRAD,
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Angle::Turn(val) => val as f64 * RAD_PER_TURN,
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Angle::Rad(val) => val as f64,
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};
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radians.min(f64::MAX).max(f64::MIN)
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}
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/// Return the value in degrees.
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pub fn degrees(&self) -> f32 {
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use std::f32::consts::PI;
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self.radians() * 360. / (2. * PI)
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}
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/// <https://drafts.csswg.org/css-transitions/#animtype-number>
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#[inline]
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fn animate_fallback(&self, other: &Self, procedure: Procedure) -> Result<Self, ()> {
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Ok(Angle::from_radians(self.radians().animate(&other.radians(), procedure)?))
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}
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}
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impl AsRef<Angle> for Angle {
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#[inline]
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fn as_ref(&self) -> &Self {
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self
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}
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}
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impl Add for Angle {
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type Output = Self;
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#[inline]
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fn add(self, rhs: Self) -> Self {
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match (self, rhs) {
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(Angle::Deg(x), Angle::Deg(y)) => Angle::Deg(x + y),
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(Angle::Grad(x), Angle::Grad(y)) => Angle::Grad(x + y),
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(Angle::Turn(x), Angle::Turn(y)) => Angle::Turn(x + y),
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(Angle::Rad(x), Angle::Rad(y)) => Angle::Rad(x + y),
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_ => Angle::from_radians(self.radians() + rhs.radians()),
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}
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}
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}
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impl Zero for Angle {
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#[inline]
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fn zero() -> Self {
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Angle::from_radians(0.0)
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}
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#[inline]
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fn is_zero(&self) -> bool {
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match *self {
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Angle::Deg(val) | Angle::Grad(val) | Angle::Turn(val) | Angle::Rad(val) => val == 0.,
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}
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}
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}
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impl ComputeSquaredDistance for Angle {
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#[inline]
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fn compute_squared_distance(&self, other: &Self) -> Result<SquaredDistance, ()> {
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// Use the formula for calculating the distance between angles defined in SVG:
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// https://www.w3.org/TR/SVG/animate.html#complexDistances
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self.radians64()
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.compute_squared_distance(&other.radians64())
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}
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}
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