87 lines
2.2 KiB
Rust
87 lines
2.2 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 https://mozilla.org/MPL/2.0/. */
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//! Generic types for CSS values related to <ratio>.
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//! https://drafts.csswg.org/css-values/#ratios
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use std::fmt::{self, Write};
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use style_traits::{CssWriter, ToCss};
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use crate::{One, Zero};
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/// A generic value for the `<ratio>` value.
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#[derive(
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Clone,
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Copy,
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Debug,
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MallocSizeOf,
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PartialEq,
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SpecifiedValueInfo,
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ToAnimatedValue,
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ToComputedValue,
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ToResolvedValue,
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ToShmem,
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)]
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#[repr(C)]
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pub struct Ratio<N>(pub N, pub N);
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impl<N> ToCss for Ratio<N>
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where
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N: ToCss,
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{
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fn to_css<W>(&self, dest: &mut CssWriter<W>) -> fmt::Result
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where
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W: Write,
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{
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self.0.to_css(dest)?;
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// Even though 1 could be omitted, we don't per
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// https://drafts.csswg.org/css-values-4/#ratio-value:
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//
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// The second <number> is optional, defaulting to 1. However,
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// <ratio> is always serialized with both components.
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//
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// And for compat reasons, see bug 1669742.
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//
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// We serialize with spaces for consistency with all other
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// slash-delimited things, see
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// https://github.com/w3c/csswg-drafts/issues/4282
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dest.write_str(" / ")?;
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self.1.to_css(dest)?;
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Ok(())
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}
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}
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impl<N> Ratio<N>
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where
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N: Zero + One,
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{
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/// Returns true if this is a degenerate ratio.
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/// https://drafts.csswg.org/css-values/#degenerate-ratio
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#[inline]
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pub fn is_degenerate(&self) -> bool {
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self.0.is_zero() || self.1.is_zero()
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}
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/// Returns the used value. A ratio of 0/0 behaves as the ratio 1/0.
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/// https://drafts.csswg.org/css-values-4/#ratios
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pub fn used_value(self) -> Self {
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if self.0.is_zero() && self.1.is_zero() {
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Self(One::one(), Zero::zero())
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} else {
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self
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}
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}
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}
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impl<N> Zero for Ratio<N>
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where
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N: Zero + One,
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{
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fn zero() -> Self {
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Self(Zero::zero(), One::one())
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}
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fn is_zero(&self) -> bool {
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self.0.is_zero()
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}
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}
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