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112 lines
3.7 KiB
Rust
112 lines
3.7 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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//! https://drafts.csswg.org/css-sizing/
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use crate::style_ext::ComputedValuesExt;
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use style::properties::ComputedValues;
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use style::values::computed::{Length, LengthPercentage, Percentage};
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use style::Zero;
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#[derive(Clone, Debug)]
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pub(crate) struct ContentSizes {
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pub min_content: Length,
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pub max_content: Length,
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}
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/// https://drafts.csswg.org/css-sizing/#intrinsic-sizes
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impl ContentSizes {
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pub fn zero() -> Self {
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Self {
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min_content: Length::zero(),
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max_content: Length::zero(),
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}
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}
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pub fn max_assign(&mut self, other: &Self) {
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self.min_content.max_assign(other.min_content);
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self.max_content.max_assign(other.max_content);
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}
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/// Relevant to outer intrinsic inline sizes, for percentages from padding and margin.
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pub fn adjust_for_pbm_percentages(&mut self, percentages: Percentage) {
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// " Note that this may yield an infinite result, but undefined results
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// (zero divided by zero) must be treated as zero. "
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if self.max_content.px() == 0. {
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// Avoid a potential `NaN`.
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// Zero is already the result we want regardless of `denominator`.
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} else {
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let denominator = (1. - percentages.0).max(0.);
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self.max_content = Length::new(self.max_content.px() / denominator);
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}
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}
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}
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/// https://dbaron.org/css/intrinsic/#outer-intrinsic
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pub(crate) fn outer_inline_content_sizes(
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style: &ComputedValues,
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inner_content_sizes: &Option<ContentSizes>,
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) -> ContentSizes {
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let (mut outer, percentages) =
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outer_inline_content_sizes_and_percentages(style, inner_content_sizes);
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outer.adjust_for_pbm_percentages(percentages);
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outer
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}
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pub(crate) fn outer_inline_content_sizes_and_percentages(
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style: &ComputedValues,
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inner_content_sizes: &Option<ContentSizes>,
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) -> (ContentSizes, Percentage) {
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// FIXME: account for 'min-width', 'max-width', 'box-sizing'
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let specified = style.box_size().inline;
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// Percentages for 'width' are treated as 'auto'
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let specified = specified.map(|lp| lp.as_length());
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// The (inner) min/max-content are only used for 'auto'
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let mut outer = match specified.non_auto().flatten() {
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None => expect(inner_content_sizes).clone(),
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Some(length) => ContentSizes {
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min_content: length,
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max_content: length,
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},
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};
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let mut pbm_lengths = Length::zero();
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let mut pbm_percentages = Percentage::zero();
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let padding = style.padding();
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let border = style.border_width();
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let margin = style.margin();
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pbm_lengths += border.inline_start;
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pbm_lengths += border.inline_end;
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let mut add = |x: LengthPercentage| {
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pbm_lengths += x.length_component();
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pbm_percentages += x.percentage_component();
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};
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add(padding.inline_start);
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add(padding.inline_end);
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margin.inline_start.non_auto().map(&mut add);
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margin.inline_end.non_auto().map(&mut add);
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outer.min_content += pbm_lengths;
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outer.max_content += pbm_lengths;
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(outer, pbm_percentages)
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}
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/// https://drafts.csswg.org/css2/visudet.html#shrink-to-fit-float
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pub(crate) fn shrink_to_fit(
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content_sizes: &Option<ContentSizes>,
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available_size: Length,
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) -> Length {
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let content_sizes = expect(content_sizes);
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available_size
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.max(content_sizes.min_content)
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.min(content_sizes.max_content)
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}
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fn expect(content_sizes: &Option<ContentSizes>) -> &ContentSizes {
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content_sizes
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.as_ref()
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.expect("Accessing content size that was not requested")
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}
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