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8ded1072ce
This data structure has all of the metrics needed to render a font and is in `Au`. We'll need more of these metrics for implementing `vertical-align` and its use doesn't increase the size of the Fragment tree (as the BoxFragment is still larger). In addition, this will be helpful when switching layout to `Au`.
2319 lines
93 KiB
Rust
2319 lines
93 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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use std::cell::OnceCell;
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use std::mem;
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use std::vec::IntoIter;
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use app_units::Au;
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use atomic_refcell::AtomicRef;
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use gfx::font::FontMetrics;
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use gfx::text::glyph::GlyphStore;
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use gfx::text::text_run::GlyphRun;
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use log::warn;
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use serde::Serialize;
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use servo_arc::Arc;
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use style::computed_values::white_space::T as WhiteSpace;
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use style::logical_geometry::WritingMode;
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use style::properties::ComputedValues;
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use style::values::computed::Length;
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use style::values::generics::text::LineHeight;
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use style::values::specified::text::{TextAlignKeyword, TextDecorationLine};
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use style::Zero;
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use webrender_api::FontInstanceKey;
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use xi_unicode::{linebreak_property, LineBreakLeafIter};
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use super::float::PlacementAmongFloats;
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use super::CollapsibleWithParentStartMargin;
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use crate::cell::ArcRefCell;
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use crate::context::LayoutContext;
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use crate::flow::float::{FloatBox, SequentialLayoutState};
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use crate::flow::FlowLayout;
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use crate::formatting_contexts::IndependentFormattingContext;
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use crate::fragment_tree::{
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AnonymousFragment, BaseFragmentInfo, BoxFragment, CollapsedBlockMargins, CollapsedMargin,
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Fragment, HoistedSharedFragment, TextFragment,
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};
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use crate::geom::{LogicalRect, LogicalVec2};
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use crate::positioned::{
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relative_adjustement, AbsolutelyPositionedBox, PositioningContext, PositioningContextLength,
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};
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use crate::sizing::ContentSizes;
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use crate::style_ext::{
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ComputedValuesExt, Display, DisplayGeneratingBox, DisplayOutside, PaddingBorderMargin,
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};
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use crate::ContainingBlock;
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// These constants are the xi-unicode line breaking classes that are defined in
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// `table.rs`. Unfortunately, they are only identified by number.
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const XI_LINE_BREAKING_CLASS_GL: u8 = 12;
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const XI_LINE_BREAKING_CLASS_WJ: u8 = 30;
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const XI_LINE_BREAKING_CLASS_ZWJ: u8 = 40;
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#[derive(Debug, Serialize)]
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pub(crate) struct InlineFormattingContext {
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pub(super) inline_level_boxes: Vec<ArcRefCell<InlineLevelBox>>,
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pub(super) text_decoration_line: TextDecorationLine,
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// Whether this IFC contains the 1st formatted line of an element
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// https://www.w3.org/TR/css-pseudo-4/#first-formatted-line
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pub(super) has_first_formatted_line: bool,
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pub(super) contains_floats: bool,
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/// Whether this IFC being constructed currently ends with whitespace. This is used to
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/// implement rule 4 of <https://www.w3.org/TR/css-text-3/#collapse>:
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///
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/// > Any collapsible space immediately following another collapsible space—even one
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/// > outside the boundary of the inline containing that space, provided both spaces are
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/// > within the same inline formatting context—is collapsed to have zero advance width.
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/// > (It is invisible, but retains its soft wrap opportunity, if any.)
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pub(super) ends_with_whitespace: bool,
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}
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#[derive(Debug, Serialize)]
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pub(crate) enum InlineLevelBox {
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InlineBox(InlineBox),
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TextRun(TextRun),
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OutOfFlowAbsolutelyPositionedBox(ArcRefCell<AbsolutelyPositionedBox>),
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OutOfFlowFloatBox(FloatBox),
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Atomic(IndependentFormattingContext),
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}
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#[derive(Debug, Serialize)]
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pub(crate) struct InlineBox {
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pub base_fragment_info: BaseFragmentInfo,
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#[serde(skip_serializing)]
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pub style: Arc<ComputedValues>,
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pub is_first_fragment: bool,
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pub is_last_fragment: bool,
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pub children: Vec<ArcRefCell<InlineLevelBox>>,
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}
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/// https://www.w3.org/TR/css-display-3/#css-text-run
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#[derive(Debug, Serialize)]
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pub(crate) struct TextRun {
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pub base_fragment_info: BaseFragmentInfo,
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#[serde(skip_serializing)]
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pub parent_style: Arc<ComputedValues>,
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pub text: String,
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pub has_uncollapsible_content: bool,
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}
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/// Information about the current line under construction for a particular
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/// [`InlineFormattingContextState`]. This tracks position and size information while
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/// [`LineItem`]s are collected and is used as input when those [`LineItem`]s are
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/// converted into [`Fragment`]s during the final phase of line layout. Note that this
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/// does not store the [`LineItem`]s themselves, as they are stored as part of the
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/// nesting state in the [`InlineFormattingContextState`].
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struct LineUnderConstruction {
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/// The position where this line will start once it is laid out. This includes any
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/// offset from `text-indent`.
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start_position: LogicalVec2<Length>,
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/// The current inline position in the line being laid out into [`LineItems`] in this
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/// [`InlineFormattingContext`] independent of the depth in the nesting level.
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inline_position: Length,
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/// The maximum block size of all boxes that ended and are in progress in this line.
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max_block_size: Length,
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/// Whether any active linebox has added a glyph or atomic element to this line, which
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/// indicates that the next run that exceeds the line length can cause a line break.
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has_content: bool,
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/// Whether or not there are floats that did not fit on the current line. Before
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/// the [`LineItems`] of this line are laid out, these floats will need to be
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/// placed directly below this line, but still as children of this line's Fragments.
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has_floats_waiting_to_be_placed: bool,
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/// A rectangular area (relative to the containing block / inline formatting
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/// context boundaries) where we can fit the line box without overlapping floats.
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/// Note that when this is not empty, its start corner takes precedence over
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/// [`LineUnderConstruction::start_position`].
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placement_among_floats: OnceCell<LogicalRect<Length>>,
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/// The LineItems for the current line under construction that have already
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/// been committed to this line.
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line_items: Vec<LineItem>,
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}
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impl LineUnderConstruction {
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fn new(start_position: LogicalVec2<Length>) -> Self {
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Self {
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inline_position: start_position.inline.clone(),
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start_position: start_position,
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max_block_size: Length::zero(),
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has_content: false,
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has_floats_waiting_to_be_placed: false,
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placement_among_floats: OnceCell::new(),
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line_items: Vec::new(),
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}
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}
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fn line_block_start_considering_placement_among_floats(&self) -> Length {
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match self.placement_among_floats.get() {
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Some(placement_among_floats) => placement_among_floats.start_corner.block,
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None => self.start_position.block,
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}
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}
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fn replace_placement_among_floats(&mut self, new_placement: LogicalRect<Length>) {
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self.placement_among_floats.take();
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let _ = self.placement_among_floats.set(new_placement);
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}
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}
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/// The current unbreakable segment under construction for an inline formatting context.
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/// Items accumulate here until we reach a soft line break opportunity during processing
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/// of inline content or we reach the end of the formatting context.
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struct UnbreakableSegmentUnderConstruction {
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/// The size of this unbreakable segment in both dimension.
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size: LogicalVec2<Length>,
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/// The LineItems for the segment under construction
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line_items: Vec<LineItem>,
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/// The depth in the inline box hierarchy at the start of this segment. This is used
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/// to prefix this segment when it is pushed to a new line.
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inline_box_hierarchy_depth: Option<usize>,
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/// Whether any active linebox has added a glyph or atomic element to this line
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/// segment, which indicates that the next run that exceeds the line length can cause
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/// a line break.
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has_content: bool,
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/// The inline size of any trailing whitespace in this segment.
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trailing_whitespace_size: Length,
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}
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impl UnbreakableSegmentUnderConstruction {
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fn new() -> Self {
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Self {
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size: LogicalVec2::zero(),
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line_items: Vec::new(),
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inline_box_hierarchy_depth: None,
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has_content: false,
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trailing_whitespace_size: Length::zero(),
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}
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}
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/// Reset this segment after its contents have been committed to a line.
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fn reset(&mut self) {
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assert!(self.line_items.is_empty()); // Preserve allocated memory.
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self.size = LogicalVec2::zero();
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self.inline_box_hierarchy_depth = None;
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self.has_content = false;
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self.trailing_whitespace_size = Length::zero();
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}
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/// Push a single line item to this segment. In addition, record the inline box
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/// hierarchy depth if this is the first segment. The hierarchy depth is used to
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/// duplicate the necessary `StartInlineBox` tokens if this segment is ultimately
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/// placed on a new empty line.
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fn push_line_item(&mut self, line_item: LineItem, inline_box_hierarchy_depth: usize) {
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if self.line_items.is_empty() {
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self.inline_box_hierarchy_depth = Some(inline_box_hierarchy_depth);
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}
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self.line_items.push(line_item);
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}
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/// Trim whitespace from the beginning of this UnbreakbleSegmentUnderConstruction.
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///
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/// From <https://www.w3.org/TR/css-text-3/#white-space-phase-2>:
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///
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/// > Then, the entire block is rendered. Inlines are laid out, taking bidi
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/// > reordering into account, and wrapping as specified by the text-wrap
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/// > property. As each line is laid out,
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/// > 1. A sequence of collapsible spaces at the beginning of a line is removed.
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///
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/// This prevents whitespace from being added to the beginning of a line.
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fn trim_leading_whitespace(&mut self) {
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let mut whitespace_trimmed = Length::zero();
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for item in self.line_items.iter_mut() {
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if !item.trim_whitespace_at_start(&mut whitespace_trimmed) {
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break;
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}
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}
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self.size.inline -= whitespace_trimmed;
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}
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/// Prepare this segment for placement on a new and empty line. This happens when the
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/// segment is too large to fit on the current line and needs to be placed on a new
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/// one.
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fn prepare_for_placement_on_empty_line(
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&mut self,
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line: &LineUnderConstruction,
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current_hierarchy_depth: usize,
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) {
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self.trim_leading_whitespace();
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// The segment may start in the middle of an already processed inline box. In that
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// case we need to duplicate the `StartInlineBox` tokens as a prefix of the new
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// lines. For instance if the following segment is going to be placed on a new line:
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//
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// line = [StartInlineBox "every"]
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// segment = ["good" EndInlineBox "boy"]
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//
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// Then the segment must be prefixed with `StartInlineBox` before it is committed
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// to the empty line.
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let mut hierarchy_depth = self
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.inline_box_hierarchy_depth
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.unwrap_or(current_hierarchy_depth);
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if hierarchy_depth == 0 {
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return;
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}
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let mut hierarchy = Vec::new();
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let mut skip_depth = 0;
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for item in line.line_items.iter().rev() {
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match item {
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// We need to skip over any inline boxes that are not in our hierarchy. If
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// any inline box ends, we skip until it starts.
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LineItem::StartInlineBox(_) if skip_depth > 0 => skip_depth -= 1,
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LineItem::EndInlineBox => skip_depth += 1,
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// Otherwise copy the inline box to the hierarchy we are collecting.
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LineItem::StartInlineBox(inline_box) => {
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let mut cloned_inline_box = inline_box.clone();
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cloned_inline_box.is_first_fragment = false;
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hierarchy.push(LineItem::StartInlineBox(cloned_inline_box));
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hierarchy_depth -= 1;
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if hierarchy_depth == 0 {
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break;
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}
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},
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_ => {},
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}
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}
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let segment_items = mem::take(&mut self.line_items);
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self.line_items = hierarchy
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.into_iter()
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.rev()
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.chain(segment_items.into_iter())
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.collect();
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}
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}
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struct InlineContainerState {
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/// Whether or not we have processed any content (an atomic element or text) for
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/// this inline box on the current line OR any previous line.
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has_content: bool,
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/// Indicates whether this nesting level have text decorations in effect.
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/// From https://drafts.csswg.org/css-text-decor/#line-decoration
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// "When specified on or propagated to a block container that establishes
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// an IFC..."
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text_decoration_line: TextDecorationLine,
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/// The block size of this inline container maxed with the block sizes of all inline
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/// container ancestors. This isn't the block size of this container, but if this
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/// container adds content to a line, this is the block size necessary for that new
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/// content.
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nested_block_size: Length,
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}
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struct InlineBoxContainerState {
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/// The container state common to both [`InlineBox`] and the root of the
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/// [`InlineFormattingContext`].
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base: InlineContainerState,
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/// The style of this inline box.
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style: Arc<ComputedValues>,
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/// The [`BaseFragmentInfo`] of the [`InlineBox`] that this state tracks.
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base_fragment_info: BaseFragmentInfo,
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/// The [`PaddingBorderMargin`] of the [`InlineBox`] that this state tracks.
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pbm: PaddingBorderMargin,
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/// Whether this is the last fragment of this InlineBox. This may not be the case if
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/// the InlineBox is split due to an block-in-inline-split and this is not the last of
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/// that split.
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is_last_fragment: bool,
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}
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struct InlineFormattingContextState<'a, 'b> {
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positioning_context: &'a mut PositioningContext,
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containing_block: &'b ContainingBlock<'b>,
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sequential_layout_state: Option<&'a mut SequentialLayoutState>,
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layout_context: &'b LayoutContext<'b>,
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/// A vector of fragment that are laid out. This includes one [`Fragment::Anonymous`]
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/// per line that is currently laid out plus fragments for all floats, which
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/// are currently laid out at the top-level of each [`InlineFormattingContext`].
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fragments: Vec<Fragment>,
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/// Information about the line currently being laid out into [`LineItems`]s.
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current_line: LineUnderConstruction,
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/// Information about the unbreakable line segment currently being laid out into [`LineItems`]s.
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current_line_segment: UnbreakableSegmentUnderConstruction,
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/// After a forced line break (for instance from a `<br>` element) we wait to actually
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/// break the line until seeing more content. This allows ongoing inline boxes to finish,
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/// since in the case where they have no more content they should not be on the next
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/// line.
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///
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/// For instance:
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///
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/// ``` html
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/// <span style="border-right: 30px solid blue;">
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/// first line<br>
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/// </span>
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/// second line
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/// ```
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///
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/// In this case, the `<span>` should not extend to the second line. If we linebreak
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/// as soon as we encounter the `<br>` the `<span>`'s ending inline borders would be
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/// placed on the second line, because we add those borders in
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/// [`InlineFormattingContextState::finish_inline_box()`].
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linebreak_before_new_content: bool,
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/// The line breaking state for this inline formatting context.
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linebreaker: Option<LineBreakLeafIter>,
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/// Whether or not a soft wrap opportunity is queued. Soft wrap opportunities are
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/// queued after replaced content and they are processed when the next text content
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/// is encountered.
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have_deferred_soft_wrap_opportunity: bool,
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/// Whether or not a soft wrap opportunity should be prevented before the next atomic
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/// element encountered in the inline formatting context. See
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/// `char_prevents_soft_wrap_opportunity_when_before_or_after_atomic` for more
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/// details.
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prevent_soft_wrap_opportunity_before_next_atomic: bool,
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/// The currently white-space setting of this line. This is stored on the
|
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/// [`InlineFormattingContextState`] because when a soft wrap opportunity is defined
|
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/// by the boundary between two characters, the white-space property of their nearest
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/// common ancestor is used.
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white_space: WhiteSpace,
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/// The [`InlineContainerState`] for the container formed by the root of the
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/// [`InlineFormattingContext`].
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root_nesting_level: InlineContainerState,
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||
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/// A stack of [`InlineBoxContainerState`] that is used to produce [`LineItem`]s either when we
|
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/// reach the end of an inline box or when we reach the end of a line. Only at the end
|
||
/// of the inline box is the state popped from the stack.
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||
inline_box_state_stack: Vec<InlineBoxContainerState>,
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||
}
|
||
|
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impl<'a, 'b> InlineFormattingContextState<'a, 'b> {
|
||
fn current_inline_container_state(&self) -> &InlineContainerState {
|
||
match self.inline_box_state_stack.last() {
|
||
Some(inline_box_state) => &inline_box_state.base,
|
||
None => &self.root_nesting_level,
|
||
}
|
||
}
|
||
|
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fn current_inline_container_state_mut(&mut self) -> &mut InlineContainerState {
|
||
match self.inline_box_state_stack.last_mut() {
|
||
Some(inline_box_state) => &mut inline_box_state.base,
|
||
None => &mut self.root_nesting_level,
|
||
}
|
||
}
|
||
|
||
fn current_line_max_block_size(&self) -> Length {
|
||
self.current_inline_container_state()
|
||
.nested_block_size
|
||
.max(self.current_line.max_block_size)
|
||
}
|
||
|
||
fn propagate_current_nesting_level_white_space_style(&mut self) {
|
||
let style = match self.inline_box_state_stack.last() {
|
||
Some(inline_box_state) => &inline_box_state.style,
|
||
None => self.containing_block.style,
|
||
};
|
||
self.white_space = style.get_inherited_text().white_space;
|
||
}
|
||
|
||
/// Start laying out a particular [`InlineBox`] into line items. This will push
|
||
/// a new [`InlineBoxContainerState`] onto [`Self::inline_box_state_stack`].
|
||
fn start_inline_box(&mut self, inline_box: &InlineBox) {
|
||
let (text_decoration_of_parent, nested_block_size_of_parent) = {
|
||
let parent = self.current_inline_container_state();
|
||
(parent.text_decoration_line, parent.nested_block_size)
|
||
};
|
||
|
||
let mut inline_box_state = InlineBoxContainerState::new(
|
||
inline_box,
|
||
&self.containing_block,
|
||
text_decoration_of_parent,
|
||
nested_block_size_of_parent,
|
||
self.layout_context,
|
||
inline_box.is_last_fragment,
|
||
);
|
||
|
||
if inline_box.is_first_fragment {
|
||
self.current_line.inline_position += inline_box_state.pbm.padding.inline_start +
|
||
inline_box_state.pbm.border.inline_start +
|
||
inline_box_state
|
||
.pbm
|
||
.margin
|
||
.inline_start
|
||
.auto_is(Length::zero);
|
||
}
|
||
|
||
let line_item = inline_box_state.layout_into_line_item(
|
||
self.layout_context,
|
||
inline_box.is_first_fragment,
|
||
inline_box.is_last_fragment,
|
||
);
|
||
self.push_line_item_to_unbreakable_segment(LineItem::StartInlineBox(line_item));
|
||
self.inline_box_state_stack.push(inline_box_state);
|
||
}
|
||
|
||
/// Finish laying out a particular [`InlineBox`] into line items. This will add the
|
||
/// final [`InlineBoxLineItem`] to the state and pop its state off of
|
||
/// [`Self::inline_box_state_stack`].
|
||
fn finish_inline_box(&mut self) {
|
||
let inline_box_state = match self.inline_box_state_stack.pop() {
|
||
Some(inline_box_state) => inline_box_state,
|
||
None => return, // We are at the root.
|
||
};
|
||
|
||
self.push_line_item_to_unbreakable_segment(LineItem::EndInlineBox);
|
||
self.current_line_segment
|
||
.size
|
||
.block
|
||
.max_assign(inline_box_state.base.nested_block_size);
|
||
|
||
// If the inline box that we just finished had any content at all, we want to propagate
|
||
// the `white-space` property of its parent to future inline children. This is because
|
||
// when a soft wrap opportunity is defined by the boundary between two elements, the
|
||
// `white-space` used is that of their nearest common ancestor.
|
||
if inline_box_state.base.has_content {
|
||
self.propagate_current_nesting_level_white_space_style();
|
||
}
|
||
|
||
if inline_box_state.is_last_fragment {
|
||
let pbm_end = inline_box_state.pbm.padding.inline_end +
|
||
inline_box_state.pbm.border.inline_end +
|
||
inline_box_state.pbm.margin.inline_end.auto_is(Length::zero);
|
||
self.current_line_segment.size.inline += pbm_end;
|
||
}
|
||
}
|
||
|
||
/// Finish layout of all inline boxes for the current line. This will gather all
|
||
/// [`LineItem`]s and turn them into [`Fragment`]s, then reset the
|
||
/// [`InlineFormattingContextState`] preparing it for laying out a new line.
|
||
fn finish_current_line_and_reset(&mut self) {
|
||
let mut line_items = std::mem::take(&mut self.current_line.line_items);
|
||
|
||
// From <https://www.w3.org/TR/css-text-3/#white-space-phase-2>:
|
||
// > 3. A sequence of collapsible spaces at the end of a line is removed,
|
||
// > as well as any trailing U+1680 OGHAM SPACE MARK whose white-space
|
||
// > property is normal, nowrap, or pre-line.
|
||
let mut whitespace_trimmed = Length::zero();
|
||
for item in line_items.iter_mut().rev() {
|
||
if !item.trim_whitespace_at_end(&mut whitespace_trimmed) {
|
||
break;
|
||
}
|
||
}
|
||
|
||
let inline_start_position =
|
||
self.calculate_inline_start_for_current_line(self.containing_block, whitespace_trimmed);
|
||
let block_start_position = self
|
||
.current_line
|
||
.line_block_start_considering_placement_among_floats();
|
||
|
||
let had_inline_advance =
|
||
self.current_line.inline_position != self.current_line.start_position.inline;
|
||
|
||
let effective_block_advance = if self.current_line.has_content ||
|
||
had_inline_advance ||
|
||
self.linebreak_before_new_content
|
||
{
|
||
self.current_line_max_block_size()
|
||
} else {
|
||
Length::zero()
|
||
};
|
||
let block_end_position = block_start_position + effective_block_advance;
|
||
|
||
if let Some(sequential_layout_state) = self.sequential_layout_state.as_mut() {
|
||
// This amount includes both the block size of the line and any extra space
|
||
// added to move the line down in order to avoid overlapping floats.
|
||
let increment = block_end_position - self.current_line.start_position.block;
|
||
sequential_layout_state.advance_block_position(increment);
|
||
}
|
||
|
||
if self.current_line.has_floats_waiting_to_be_placed {
|
||
place_pending_floats(self, &mut line_items);
|
||
}
|
||
|
||
let mut state = LineItemLayoutState {
|
||
inline_position: inline_start_position,
|
||
inline_start_of_parent: Length::zero(),
|
||
ifc_containing_block: self.containing_block,
|
||
positioning_context: &mut self.positioning_context,
|
||
line_block_start: block_start_position,
|
||
};
|
||
|
||
let positioning_context_length = state.positioning_context.len();
|
||
let mut saw_end = false;
|
||
let fragments = layout_line_items(
|
||
&mut line_items.into_iter(),
|
||
self.layout_context,
|
||
&mut state,
|
||
&mut saw_end,
|
||
);
|
||
|
||
let size = LogicalVec2 {
|
||
inline: self.containing_block.inline_size,
|
||
block: effective_block_advance,
|
||
};
|
||
|
||
// The inline part of this start offset was taken into account when determining
|
||
// the inline start of the line in `calculate_inline_start_for_current_line` so
|
||
// we do not need to include it in the `start_corner` of the line's main Fragment.
|
||
let start_corner = LogicalVec2 {
|
||
inline: Length::zero(),
|
||
block: block_start_position,
|
||
};
|
||
|
||
let line_had_content =
|
||
!fragments.is_empty() || state.positioning_context.len() != positioning_context_length;
|
||
if line_had_content {
|
||
state
|
||
.positioning_context
|
||
.adjust_static_position_of_hoisted_fragments_with_offset(
|
||
&start_corner,
|
||
positioning_context_length,
|
||
);
|
||
|
||
self.fragments
|
||
.push(Fragment::Anonymous(AnonymousFragment::new(
|
||
LogicalRect { start_corner, size },
|
||
fragments,
|
||
self.containing_block.style.writing_mode,
|
||
)));
|
||
}
|
||
|
||
self.current_line = LineUnderConstruction::new(LogicalVec2 {
|
||
inline: Length::zero(),
|
||
block: block_end_position,
|
||
});
|
||
}
|
||
|
||
/// Given the amount of whitespace trimmed from the line and taking into consideration
|
||
/// the `text-align` property, calculate where the line under construction starts in
|
||
/// the inline axis.
|
||
fn calculate_inline_start_for_current_line(
|
||
&self,
|
||
containing_block: &ContainingBlock,
|
||
whitespace_trimmed: Length,
|
||
) -> Length {
|
||
enum TextAlign {
|
||
Start,
|
||
Center,
|
||
End,
|
||
}
|
||
let line_left_is_inline_start = containing_block
|
||
.style
|
||
.writing_mode
|
||
.line_left_is_inline_start();
|
||
let text_align = match containing_block.style.clone_text_align() {
|
||
TextAlignKeyword::Start => TextAlign::Start,
|
||
TextAlignKeyword::Center => TextAlign::Center,
|
||
TextAlignKeyword::End => TextAlign::End,
|
||
TextAlignKeyword::Left => {
|
||
if line_left_is_inline_start {
|
||
TextAlign::Start
|
||
} else {
|
||
TextAlign::End
|
||
}
|
||
},
|
||
TextAlignKeyword::Right => {
|
||
if line_left_is_inline_start {
|
||
TextAlign::End
|
||
} else {
|
||
TextAlign::Start
|
||
}
|
||
},
|
||
TextAlignKeyword::Justify => {
|
||
// TODO: Add support for justfied text.
|
||
TextAlign::Start
|
||
},
|
||
TextAlignKeyword::ServoCenter |
|
||
TextAlignKeyword::ServoLeft |
|
||
TextAlignKeyword::ServoRight => {
|
||
// TODO: Implement these modes which seem to be used by quirks mode.
|
||
TextAlign::Start
|
||
},
|
||
};
|
||
|
||
let (line_start, available_space) = match self.current_line.placement_among_floats.get() {
|
||
Some(placement_among_floats) => (
|
||
placement_among_floats.start_corner.inline,
|
||
placement_among_floats.size.inline,
|
||
),
|
||
None => (Length::zero(), self.containing_block.inline_size),
|
||
};
|
||
|
||
// Properly handling text-indent requires that we do not align the text
|
||
// into the text-indent.
|
||
// See <https://drafts.csswg.org/css-text/#text-indent-property>
|
||
// "This property specifies the indentation applied to lines of inline content in
|
||
// a block. The indent is treated as a margin applied to the start edge of the
|
||
// line box."
|
||
let text_indent = self.current_line.start_position.inline;
|
||
let line_length = self.current_line.inline_position - whitespace_trimmed - text_indent;
|
||
line_start +
|
||
match text_align {
|
||
TextAlign::Start => text_indent,
|
||
TextAlign::End => (available_space - line_length).max(text_indent),
|
||
TextAlign::Center => (available_space - line_length + text_indent) / 2.,
|
||
}
|
||
}
|
||
|
||
fn place_float_fragment(&mut self, fragment: &mut BoxFragment) {
|
||
let state = self
|
||
.sequential_layout_state
|
||
.as_mut()
|
||
.expect("Tried to lay out a float with no sequential placement state!");
|
||
|
||
let block_offset_from_containining_block_top = state
|
||
.current_block_position_including_margins() -
|
||
state.current_containing_block_offset();
|
||
state.place_float_fragment(
|
||
fragment,
|
||
CollapsedMargin::zero(),
|
||
block_offset_from_containining_block_top,
|
||
);
|
||
}
|
||
|
||
/// Place a FloatLineItem. This is done when an unbreakable segment is committed to
|
||
/// the current line. Placement of FloatLineItems might need to be deferred until the
|
||
/// line is complete in the case that floats stop fitting on the current line.
|
||
///
|
||
/// When placing floats we do not want to take into account any trailing whitespace on
|
||
/// the line, because that whitespace will be trimmed in the case that the line is
|
||
/// broken. Thus this function takes as an argument the new size (without whitespace) of
|
||
/// the line that these floats are joining.
|
||
fn place_float_line_item_for_commit_to_line(
|
||
&mut self,
|
||
float_item: &mut FloatLineItem,
|
||
line_inline_size_without_trailing_whitespace: Length,
|
||
) {
|
||
let margin_box = float_item
|
||
.fragment
|
||
.border_rect()
|
||
.inflate(&float_item.fragment.margin);
|
||
let inline_size = margin_box.size.inline.max(Length::zero());
|
||
|
||
let available_inline_size = match self.current_line.placement_among_floats.get() {
|
||
Some(placement_among_floats) => placement_among_floats.size.inline,
|
||
None => self.containing_block.inline_size,
|
||
} - line_inline_size_without_trailing_whitespace;
|
||
|
||
// If this float doesn't fit on the current line or a previous float didn't fit on
|
||
// the current line, we need to place it starting at the next line BUT still as
|
||
// children of this line's hierarchy of inline boxes (for the purposes of properly
|
||
// parenting in their stacking contexts). Once all the line content is gathered we
|
||
// will place them later.
|
||
let has_content = self.current_line.has_content || self.current_line_segment.has_content;
|
||
let fits_on_line = !has_content || inline_size <= available_inline_size;
|
||
let needs_placement_later =
|
||
self.current_line.has_floats_waiting_to_be_placed || !fits_on_line;
|
||
|
||
if needs_placement_later {
|
||
self.current_line.has_floats_waiting_to_be_placed = true;
|
||
} else {
|
||
self.place_float_fragment(&mut float_item.fragment);
|
||
float_item.needs_placement = false;
|
||
}
|
||
|
||
// We've added a new float to the IFC, but this may have actually changed the
|
||
// position of the current line. In order to determine that we regenerate the
|
||
// placement among floats for the current line, which may adjust its inline
|
||
// start position.
|
||
let new_placement = self.place_line_among_floats(&LogicalVec2 {
|
||
inline: line_inline_size_without_trailing_whitespace,
|
||
block: self.current_line.max_block_size,
|
||
});
|
||
self.current_line
|
||
.replace_placement_among_floats(new_placement);
|
||
}
|
||
|
||
/// Given a new potential line size for the current line, create a "placement" for that line.
|
||
/// This tells us whether or not the new potential line will fit in the current block position
|
||
/// or need to be moved. In addition, the placement rect determines the inline start and end
|
||
/// of the line if it's used as the final placement among floats.
|
||
fn place_line_among_floats(
|
||
&self,
|
||
potential_line_size: &LogicalVec2<Length>,
|
||
) -> LogicalRect<Length> {
|
||
let sequential_layout_state = self
|
||
.sequential_layout_state
|
||
.as_ref()
|
||
.expect("Should not have called this function without having floats.");
|
||
|
||
let ifc_offset_in_float_container = LogicalVec2 {
|
||
inline: sequential_layout_state
|
||
.floats
|
||
.containing_block_info
|
||
.inline_start,
|
||
block: sequential_layout_state.current_containing_block_offset(),
|
||
};
|
||
|
||
let ceiling = self
|
||
.current_line
|
||
.line_block_start_considering_placement_among_floats();
|
||
let mut placement = PlacementAmongFloats::new(
|
||
&sequential_layout_state.floats,
|
||
ceiling + ifc_offset_in_float_container.block,
|
||
potential_line_size.clone(),
|
||
&PaddingBorderMargin::zero(),
|
||
);
|
||
|
||
let mut placement_rect = placement.place();
|
||
placement_rect.start_corner = &placement_rect.start_corner - &ifc_offset_in_float_container;
|
||
placement_rect
|
||
}
|
||
|
||
/// Returns true if a new potential line size for the current line would require a line
|
||
/// break. This takes into account floats and will also update the "placement among
|
||
/// floats" for this line if the potential line size would not cause a line break.
|
||
/// Thus, calling this method has side effects and should only be done while in the
|
||
/// process of laying out line content that is always going to be committed to this
|
||
/// line or the next.
|
||
fn new_potential_line_size_causes_line_break(
|
||
&mut self,
|
||
potential_line_size: &LogicalVec2<Length>,
|
||
) -> bool {
|
||
let available_line_space = if self.sequential_layout_state.is_some() {
|
||
self.current_line
|
||
.placement_among_floats
|
||
.get_or_init(|| self.place_line_among_floats(potential_line_size))
|
||
.size
|
||
.clone()
|
||
} else {
|
||
LogicalVec2 {
|
||
inline: self.containing_block.inline_size,
|
||
block: Length::new(f32::INFINITY),
|
||
}
|
||
};
|
||
|
||
let inline_would_overflow = potential_line_size.inline > available_line_space.inline;
|
||
let block_would_overflow = potential_line_size.block > available_line_space.block;
|
||
|
||
// The first content that is added to a line cannot trigger a line break and
|
||
// the `white-space` propertly can also prevent all line breaking.
|
||
let can_break = self.current_line.has_content;
|
||
|
||
// If this is the first content on the line and we already have a float placement,
|
||
// that means that the placement was initialized by a leading float in the IFC.
|
||
// This placement needs to be updated, because the first line content might push
|
||
// the block start of the line downward. If there is no float placement, we want
|
||
// to make one to properly set the block position of the line.
|
||
if !can_break {
|
||
// Even if we cannot break, adding content to this line might change its position.
|
||
// In that case we need to redo our placement among floats.
|
||
if self.sequential_layout_state.is_some() &&
|
||
(inline_would_overflow || block_would_overflow)
|
||
{
|
||
let new_placement = self.place_line_among_floats(potential_line_size);
|
||
self.current_line
|
||
.replace_placement_among_floats(new_placement);
|
||
}
|
||
|
||
return false;
|
||
}
|
||
|
||
// If the potential line is larger than the containing block we do not even need to consider
|
||
// floats. We definitely have to do a linebreak.
|
||
if potential_line_size.inline > self.containing_block.inline_size {
|
||
return true;
|
||
}
|
||
|
||
// Not fitting in the block space means that our block size has changed and we had a
|
||
// placement among floats that is no longer valid. This same placement might just
|
||
// need to be expanded or perhaps we need to line break.
|
||
if block_would_overflow {
|
||
// If we have a limited block size then we are wedging this line between floats.
|
||
assert!(self.sequential_layout_state.is_some());
|
||
let new_placement = self.place_line_among_floats(potential_line_size);
|
||
if new_placement.start_corner.block !=
|
||
self.current_line
|
||
.line_block_start_considering_placement_among_floats()
|
||
{
|
||
return true;
|
||
} else {
|
||
self.current_line
|
||
.replace_placement_among_floats(new_placement);
|
||
return false;
|
||
}
|
||
}
|
||
|
||
// Otherwise the new potential line size will require a newline if it fits in the
|
||
// inline space available for this line. This space may be smaller than the
|
||
// containing block if floats shrink the available inline space.
|
||
inline_would_overflow
|
||
}
|
||
|
||
fn defer_forced_line_break(&mut self) {
|
||
// If this hard line break happens in the middle of an unbreakable segment, there are two
|
||
// scenarios:
|
||
// 1. The current portion of the unbreakable segment fits on the current line in which
|
||
// case we commit it.
|
||
// 2. The current portion of the unbreakable segment does not fit in which case we
|
||
// need to put it on a new line *before* actually triggering the hard line break.
|
||
//
|
||
// `process_soft_wrap_opportunity` handles both of these cases.
|
||
self.process_soft_wrap_opportunity();
|
||
|
||
// Defer the actual line break until we've cleared all ending inline boxes.
|
||
self.linebreak_before_new_content = true;
|
||
|
||
// We need to ensure that the appropriate space for a linebox is created even if there
|
||
// was no other content on this line. We mark the line as having content (needing a
|
||
// advance) and having at least the height associated with this nesting of inline boxes.
|
||
//self.current_line.has_content = true;
|
||
self.current_line
|
||
.max_block_size
|
||
.max_assign(self.current_line_max_block_size());
|
||
}
|
||
|
||
fn possibly_flush_deferred_forced_line_break(&mut self) {
|
||
if !self.linebreak_before_new_content {
|
||
return;
|
||
}
|
||
|
||
self.commit_current_segment_to_line();
|
||
self.process_line_break();
|
||
self.linebreak_before_new_content = false;
|
||
}
|
||
|
||
fn push_line_item_to_unbreakable_segment(&mut self, line_item: LineItem) {
|
||
self.current_line_segment
|
||
.push_line_item(line_item, self.inline_box_state_stack.len());
|
||
}
|
||
|
||
fn push_glyph_store_to_unbreakable_segment(
|
||
&mut self,
|
||
glyph_store: std::sync::Arc<GlyphStore>,
|
||
base_fragment_info: BaseFragmentInfo,
|
||
parent_style: &Arc<ComputedValues>,
|
||
font_metrics: &FontMetrics,
|
||
font_key: FontInstanceKey,
|
||
) {
|
||
let inline_advance = Length::from(glyph_store.total_advance());
|
||
|
||
let is_non_preserved_whitespace = glyph_store.is_whitespace() &&
|
||
!parent_style
|
||
.get_inherited_text()
|
||
.white_space
|
||
.preserve_spaces();
|
||
if is_non_preserved_whitespace {
|
||
self.current_line_segment.trailing_whitespace_size = inline_advance;
|
||
}
|
||
|
||
match self.current_line_segment.line_items.last_mut() {
|
||
Some(LineItem::TextRun(text_run)) => {
|
||
debug_assert!(font_key == text_run.font_key);
|
||
text_run.text.push(glyph_store);
|
||
self.current_line_segment.size.inline += inline_advance;
|
||
|
||
if !is_non_preserved_whitespace {
|
||
self.current_line_segment.has_content = true;
|
||
}
|
||
return;
|
||
},
|
||
_ => {},
|
||
}
|
||
self.push_content_line_item_to_unbreakable_segment(
|
||
inline_advance,
|
||
LineItem::TextRun(TextRunLineItem {
|
||
text: vec![glyph_store],
|
||
base_fragment_info: base_fragment_info.into(),
|
||
parent_style: parent_style.clone(),
|
||
font_metrics: font_metrics.clone(),
|
||
font_key,
|
||
text_decoration_line: self.current_inline_container_state().text_decoration_line,
|
||
}),
|
||
!is_non_preserved_whitespace,
|
||
);
|
||
}
|
||
|
||
fn push_content_line_item_to_unbreakable_segment(
|
||
&mut self,
|
||
inline_size: Length,
|
||
line_item: LineItem,
|
||
counts_as_content: bool,
|
||
) {
|
||
if counts_as_content {
|
||
self.current_line_segment.has_content = true;
|
||
}
|
||
|
||
self.current_line_segment.size.inline += inline_size;
|
||
self.current_line_segment
|
||
.size
|
||
.block
|
||
.max_assign(self.current_inline_container_state().nested_block_size);
|
||
self.current_line_segment
|
||
.size
|
||
.block
|
||
.max_assign(line_item.block_size());
|
||
self.push_line_item_to_unbreakable_segment(line_item);
|
||
|
||
// We need to update the size of the current segment and also propagate the
|
||
// whitespace setting to the current nesting level.
|
||
let current_nesting_level = self.current_inline_container_state_mut();
|
||
current_nesting_level.has_content = true;
|
||
self.propagate_current_nesting_level_white_space_style();
|
||
}
|
||
|
||
fn process_line_break(&mut self) {
|
||
self.current_line_segment
|
||
.prepare_for_placement_on_empty_line(
|
||
&self.current_line,
|
||
self.inline_box_state_stack.len(),
|
||
);
|
||
self.finish_current_line_and_reset();
|
||
}
|
||
|
||
/// Process a soft wrap opportunity. This will either commit the current unbreakble
|
||
/// segment to the current line, if it fits within the containing block and float
|
||
/// placement boundaries, or do a line break and then commit the segment.
|
||
fn process_soft_wrap_opportunity(&mut self) {
|
||
if self.current_line_segment.line_items.is_empty() {
|
||
return;
|
||
}
|
||
if !self.white_space.allow_wrap() {
|
||
return;
|
||
}
|
||
|
||
let potential_line_size = LogicalVec2 {
|
||
inline: self.current_line.inline_position + self.current_line_segment.size.inline -
|
||
self.current_line_segment.trailing_whitespace_size,
|
||
block: self
|
||
.current_line_max_block_size()
|
||
.max(self.current_line_segment.size.block),
|
||
};
|
||
|
||
if self.new_potential_line_size_causes_line_break(&potential_line_size) {
|
||
self.process_line_break();
|
||
}
|
||
self.commit_current_segment_to_line();
|
||
}
|
||
|
||
/// Commit the current unbrekable segment to the current line. In addition, this will
|
||
/// place all floats in the unbreakable segment and expand the line dimensions.
|
||
fn commit_current_segment_to_line(&mut self) {
|
||
if self.current_line_segment.line_items.is_empty() {
|
||
return;
|
||
}
|
||
|
||
if !self.current_line.has_content {
|
||
self.current_line_segment.trim_leading_whitespace();
|
||
}
|
||
|
||
self.current_line.inline_position += self.current_line_segment.size.inline;
|
||
self.current_line.max_block_size = self
|
||
.current_line_max_block_size()
|
||
.max(self.current_line_segment.size.block);
|
||
let line_inline_size_without_trailing_whitespace =
|
||
self.current_line.inline_position - self.current_line_segment.trailing_whitespace_size;
|
||
|
||
// Place all floats in this unbreakable segment.
|
||
let mut segment_items = mem::take(&mut self.current_line_segment.line_items);
|
||
for item in segment_items.iter_mut() {
|
||
match item {
|
||
LineItem::Float(float_item) => {
|
||
self.place_float_line_item_for_commit_to_line(
|
||
float_item,
|
||
line_inline_size_without_trailing_whitespace,
|
||
);
|
||
},
|
||
_ => {},
|
||
}
|
||
}
|
||
|
||
// If the current line was never placed among floats, we need to do that now based on the
|
||
// new size. Calling `new_potential_line_size_causes_line_break()` here triggers the
|
||
// new line to be positioned among floats. This should never ask for a line
|
||
// break because it is the first content on the line.
|
||
if self.current_line.line_items.is_empty() {
|
||
let will_break = self.new_potential_line_size_causes_line_break(&LogicalVec2 {
|
||
inline: line_inline_size_without_trailing_whitespace,
|
||
block: self.current_line_segment.size.block,
|
||
});
|
||
assert!(!will_break);
|
||
}
|
||
|
||
// Try to merge all TextRuns in the line.
|
||
let to_skip = match (
|
||
self.current_line.line_items.last_mut(),
|
||
segment_items.first_mut(),
|
||
) {
|
||
(
|
||
Some(LineItem::TextRun(last_line_item)),
|
||
Some(LineItem::TextRun(first_segment_item)),
|
||
) => {
|
||
last_line_item.text.append(&mut first_segment_item.text);
|
||
1
|
||
},
|
||
_ => 0,
|
||
};
|
||
|
||
self.current_line
|
||
.line_items
|
||
.extend(segment_items.into_iter().skip(to_skip));
|
||
self.current_line.has_content |= self.current_line_segment.has_content;
|
||
|
||
self.current_line_segment.reset();
|
||
}
|
||
}
|
||
|
||
impl InlineFormattingContext {
|
||
pub(super) fn new(
|
||
text_decoration_line: TextDecorationLine,
|
||
has_first_formatted_line: bool,
|
||
ends_with_whitespace: bool,
|
||
) -> InlineFormattingContext {
|
||
InlineFormattingContext {
|
||
inline_level_boxes: Default::default(),
|
||
text_decoration_line,
|
||
has_first_formatted_line,
|
||
contains_floats: false,
|
||
ends_with_whitespace,
|
||
}
|
||
}
|
||
|
||
// This works on an already-constructed `InlineFormattingContext`,
|
||
// Which would have to change if/when
|
||
// `BlockContainer::construct` parallelize their construction.
|
||
pub(super) fn inline_content_sizes(
|
||
&self,
|
||
layout_context: &LayoutContext,
|
||
containing_block_writing_mode: WritingMode,
|
||
) -> ContentSizes {
|
||
struct Computation<'a> {
|
||
layout_context: &'a LayoutContext<'a>,
|
||
containing_block_writing_mode: WritingMode,
|
||
paragraph: ContentSizes,
|
||
current_line: ContentSizes,
|
||
/// Size for whitepsace pending to be added to this line.
|
||
pending_whitespace: Length,
|
||
/// Whether or not this IFC has seen any non-whitespace content.
|
||
had_non_whitespace_content_yet: bool,
|
||
/// The global linebreaking state.
|
||
linebreaker: Option<LineBreakLeafIter>,
|
||
}
|
||
impl Computation<'_> {
|
||
fn traverse(&mut self, inline_level_boxes: &[ArcRefCell<InlineLevelBox>]) {
|
||
for inline_level_box in inline_level_boxes {
|
||
match &mut *inline_level_box.borrow_mut() {
|
||
InlineLevelBox::InlineBox(inline_box) => {
|
||
let padding =
|
||
inline_box.style.padding(self.containing_block_writing_mode);
|
||
let border = inline_box
|
||
.style
|
||
.border_width(self.containing_block_writing_mode);
|
||
let margin =
|
||
inline_box.style.margin(self.containing_block_writing_mode);
|
||
macro_rules! add {
|
||
($condition: ident, $side: ident) => {
|
||
if inline_box.$condition {
|
||
// For margins and paddings, a cyclic percentage is resolved against zero
|
||
// for determining intrinsic size contributions.
|
||
// https://drafts.csswg.org/css-sizing-3/#min-percentage-contribution
|
||
let zero = Length::zero();
|
||
let mut length = padding.$side.percentage_relative_to(zero) + border.$side;
|
||
if let Some(lp) = margin.$side.non_auto() {
|
||
length += lp.percentage_relative_to(zero)
|
||
}
|
||
self.add_length(length);
|
||
}
|
||
};
|
||
}
|
||
|
||
add!(is_first_fragment, inline_start);
|
||
self.traverse(&inline_box.children);
|
||
add!(is_last_fragment, inline_end);
|
||
},
|
||
InlineLevelBox::TextRun(text_run) => {
|
||
let result = text_run
|
||
.break_and_shape(self.layout_context, &mut self.linebreaker);
|
||
let BreakAndShapeResult {
|
||
runs,
|
||
break_at_start,
|
||
..
|
||
} = match result {
|
||
Ok(result) => result,
|
||
Err(_) => return,
|
||
};
|
||
|
||
if break_at_start {
|
||
self.line_break_opportunity()
|
||
}
|
||
for run in &runs {
|
||
let advance = Length::from(run.glyph_store.total_advance());
|
||
|
||
if !run.glyph_store.is_whitespace() {
|
||
self.had_non_whitespace_content_yet = true;
|
||
self.current_line.min_content += advance;
|
||
self.current_line.max_content +=
|
||
self.pending_whitespace + advance;
|
||
self.pending_whitespace = Length::zero();
|
||
} else {
|
||
// If this run is a forced line break, we *must* break the line
|
||
// and start measuring from the inline origin once more.
|
||
if text_run
|
||
.glyph_run_is_whitespace_ending_with_preserved_newline(run)
|
||
{
|
||
self.had_non_whitespace_content_yet = true;
|
||
self.forced_line_break();
|
||
self.current_line = ContentSizes::zero();
|
||
continue;
|
||
}
|
||
|
||
// Discard any leading whitespace in the IFC. This will always be trimmed.
|
||
if !self.had_non_whitespace_content_yet {
|
||
continue;
|
||
}
|
||
|
||
// Wait to take into account other whitespace until we see more content.
|
||
// Whitespace at the end of the IFC will always be trimmed.
|
||
self.line_break_opportunity();
|
||
self.pending_whitespace += advance;
|
||
}
|
||
}
|
||
},
|
||
InlineLevelBox::Atomic(atomic) => {
|
||
let outer = atomic.outer_inline_content_sizes(
|
||
self.layout_context,
|
||
self.containing_block_writing_mode,
|
||
);
|
||
|
||
self.current_line.min_content +=
|
||
self.pending_whitespace + outer.min_content;
|
||
self.current_line.max_content += outer.max_content;
|
||
self.pending_whitespace = Length::zero();
|
||
self.had_non_whitespace_content_yet = true;
|
||
},
|
||
InlineLevelBox::OutOfFlowFloatBox(_) |
|
||
InlineLevelBox::OutOfFlowAbsolutelyPositionedBox(_) => {},
|
||
}
|
||
}
|
||
}
|
||
|
||
fn add_length(&mut self, l: Length) {
|
||
self.current_line.min_content += l;
|
||
self.current_line.max_content += l;
|
||
}
|
||
|
||
fn line_break_opportunity(&mut self) {
|
||
self.paragraph
|
||
.min_content
|
||
.max_assign(take(&mut self.current_line.min_content));
|
||
}
|
||
|
||
fn forced_line_break(&mut self) {
|
||
self.line_break_opportunity();
|
||
self.paragraph
|
||
.max_content
|
||
.max_assign(take(&mut self.current_line.max_content));
|
||
}
|
||
}
|
||
fn take<T: Zero>(x: &mut T) -> T {
|
||
std::mem::replace(x, T::zero())
|
||
}
|
||
let mut computation = Computation {
|
||
layout_context,
|
||
containing_block_writing_mode,
|
||
paragraph: ContentSizes::zero(),
|
||
current_line: ContentSizes::zero(),
|
||
pending_whitespace: Length::zero(),
|
||
had_non_whitespace_content_yet: false,
|
||
linebreaker: None,
|
||
};
|
||
computation.traverse(&self.inline_level_boxes);
|
||
computation.forced_line_break();
|
||
computation.paragraph
|
||
}
|
||
|
||
pub(super) fn layout(
|
||
&self,
|
||
layout_context: &LayoutContext,
|
||
positioning_context: &mut PositioningContext,
|
||
containing_block: &ContainingBlock,
|
||
sequential_layout_state: Option<&mut SequentialLayoutState>,
|
||
collapsible_with_parent_start_margin: CollapsibleWithParentStartMargin,
|
||
) -> FlowLayout {
|
||
let first_line_inline_start = if self.has_first_formatted_line {
|
||
containing_block
|
||
.style
|
||
.get_inherited_text()
|
||
.text_indent
|
||
.to_used_value(containing_block.inline_size.into())
|
||
.into()
|
||
} else {
|
||
Length::zero()
|
||
};
|
||
|
||
let mut ifc = InlineFormattingContextState {
|
||
positioning_context,
|
||
containing_block,
|
||
sequential_layout_state,
|
||
layout_context,
|
||
fragments: Vec::new(),
|
||
current_line: LineUnderConstruction::new(LogicalVec2 {
|
||
inline: first_line_inline_start,
|
||
block: Length::zero(),
|
||
}),
|
||
current_line_segment: UnbreakableSegmentUnderConstruction::new(),
|
||
linebreak_before_new_content: false,
|
||
white_space: containing_block.style.get_inherited_text().white_space,
|
||
linebreaker: None,
|
||
have_deferred_soft_wrap_opportunity: false,
|
||
prevent_soft_wrap_opportunity_before_next_atomic: false,
|
||
root_nesting_level: InlineContainerState {
|
||
nested_block_size: line_height_from_style(layout_context, &containing_block.style),
|
||
has_content: false,
|
||
text_decoration_line: self.text_decoration_line,
|
||
},
|
||
inline_box_state_stack: Vec::new(),
|
||
};
|
||
|
||
// FIXME(pcwalton): This assumes that margins never collapse through inline formatting
|
||
// contexts (i.e. that inline formatting contexts are never empty). Is that right?
|
||
// FIXME(mrobinson): This should not happen if the IFC collapses through.
|
||
if let Some(ref mut sequential_layout_state) = ifc.sequential_layout_state {
|
||
sequential_layout_state.collapse_margins();
|
||
// FIXME(mrobinson): Collapse margins in the containing block offsets as well??
|
||
}
|
||
|
||
let mut iterator = InlineBoxChildIter::from_formatting_context(self);
|
||
let mut parent_iterators = Vec::new();
|
||
loop {
|
||
let next = iterator.next();
|
||
|
||
// Any new box should flush a pending hard line break.
|
||
if next.is_some() {
|
||
ifc.possibly_flush_deferred_forced_line_break();
|
||
}
|
||
|
||
match next {
|
||
Some(child) => match &mut *child.borrow_mut() {
|
||
InlineLevelBox::InlineBox(inline_box) => {
|
||
ifc.start_inline_box(inline_box);
|
||
parent_iterators.push(iterator);
|
||
iterator = InlineBoxChildIter::from_inline_level_box(child.clone());
|
||
},
|
||
InlineLevelBox::TextRun(run) => {
|
||
run.layout_into_line_items(layout_context, &mut ifc)
|
||
},
|
||
InlineLevelBox::Atomic(atomic_formatting_context) => {
|
||
atomic_formatting_context.layout_into_line_items(layout_context, &mut ifc);
|
||
},
|
||
InlineLevelBox::OutOfFlowAbsolutelyPositionedBox(box_) => ifc
|
||
.push_line_item_to_unbreakable_segment(LineItem::AbsolutelyPositioned(
|
||
AbsolutelyPositionedLineItem {
|
||
absolutely_positioned_box: box_.clone(),
|
||
},
|
||
)),
|
||
InlineLevelBox::OutOfFlowFloatBox(float_box) => {
|
||
float_box.layout_into_line_items(layout_context, &mut ifc);
|
||
},
|
||
},
|
||
None => {
|
||
match parent_iterators.pop() {
|
||
// If we have a parent iterator, then we are working on an
|
||
// InlineBox and we just finished it.
|
||
Some(parent_iterator) => {
|
||
ifc.finish_inline_box();
|
||
iterator = parent_iterator;
|
||
continue;
|
||
},
|
||
// If we have no more parents, we are at the end of the root
|
||
// iterator ie at the end of this InlineFormattingContext.
|
||
None => break,
|
||
};
|
||
},
|
||
}
|
||
}
|
||
|
||
// We are at the end of the IFC, and we need to do a few things to make sure that
|
||
// the current segment is committed and that the final line is finished.
|
||
//
|
||
// A soft wrap opportunity makes it so the current segment is placed on a new line
|
||
// if it doesn't fit on the current line under construction.
|
||
ifc.process_soft_wrap_opportunity();
|
||
|
||
// `process_soft_line_wrap_opportunity` does not commit the segment to a line if
|
||
// there is no line wrapping, so this forces the segment into the current line.
|
||
ifc.commit_current_segment_to_line();
|
||
|
||
// Finally we finish the line itself and convert all of the LineItems into
|
||
// fragments.
|
||
ifc.finish_current_line_and_reset();
|
||
|
||
let mut collapsible_margins_in_children = CollapsedBlockMargins::zero();
|
||
let content_block_size = ifc.current_line.start_position.block;
|
||
collapsible_margins_in_children.collapsed_through =
|
||
content_block_size == Length::zero() && collapsible_with_parent_start_margin.0;
|
||
|
||
return FlowLayout {
|
||
fragments: ifc.fragments,
|
||
content_block_size,
|
||
collapsible_margins_in_children,
|
||
};
|
||
}
|
||
|
||
/// Return true if this [InlineFormattingContext] is empty for the purposes of ignoring
|
||
/// during box tree construction. An IFC is empty if it only contains TextRuns with
|
||
/// completely collapsible whitespace. When that happens it can be ignored completely.
|
||
pub fn is_empty(&self) -> bool {
|
||
fn inline_level_boxes_are_empty(boxes: &[ArcRefCell<InlineLevelBox>]) -> bool {
|
||
boxes
|
||
.iter()
|
||
.all(|inline_level_box| inline_level_box_is_empty(&*inline_level_box.borrow()))
|
||
}
|
||
|
||
fn inline_level_box_is_empty(inline_level_box: &InlineLevelBox) -> bool {
|
||
match inline_level_box {
|
||
InlineLevelBox::InlineBox(_) => false,
|
||
InlineLevelBox::TextRun(text_run) => !text_run.has_uncollapsible_content,
|
||
InlineLevelBox::OutOfFlowAbsolutelyPositionedBox(_) => false,
|
||
InlineLevelBox::OutOfFlowFloatBox(_) => false,
|
||
InlineLevelBox::Atomic(_) => false,
|
||
}
|
||
}
|
||
|
||
inline_level_boxes_are_empty(&self.inline_level_boxes)
|
||
}
|
||
}
|
||
|
||
impl InlineBoxContainerState {
|
||
fn new(
|
||
inline_box: &InlineBox,
|
||
containing_block: &ContainingBlock,
|
||
text_decoration_of_parent: TextDecorationLine,
|
||
nested_block_size_of_parent: Length,
|
||
layout_context: &LayoutContext,
|
||
is_last_fragment: bool,
|
||
) -> Self {
|
||
let style = inline_box.style.clone();
|
||
let text_decoration_line = text_decoration_of_parent | style.clone_text_decoration_line();
|
||
Self {
|
||
base: InlineContainerState {
|
||
has_content: false,
|
||
text_decoration_line,
|
||
nested_block_size: nested_block_size_of_parent
|
||
.max(line_height_from_style(layout_context, &style)),
|
||
},
|
||
style,
|
||
base_fragment_info: inline_box.base_fragment_info,
|
||
pbm: inline_box.style.padding_border_margin(containing_block),
|
||
is_last_fragment,
|
||
}
|
||
}
|
||
|
||
fn layout_into_line_item(
|
||
&mut self,
|
||
layout_context: &LayoutContext,
|
||
is_first_fragment: bool,
|
||
is_last_fragment_of_ib_split: bool,
|
||
) -> InlineBoxLineItem {
|
||
InlineBoxLineItem {
|
||
base_fragment_info: self.base_fragment_info,
|
||
style: self.style.clone(),
|
||
block_size: line_gap_from_style(layout_context, &self.style),
|
||
pbm: self.pbm.clone(),
|
||
is_first_fragment,
|
||
is_last_fragment_of_ib_split,
|
||
}
|
||
}
|
||
}
|
||
|
||
impl IndependentFormattingContext {
|
||
fn layout_into_line_items(
|
||
&mut self,
|
||
layout_context: &LayoutContext,
|
||
ifc: &mut InlineFormattingContextState,
|
||
) {
|
||
let style = self.style();
|
||
let pbm = style.padding_border_margin(&ifc.containing_block);
|
||
let margin = pbm.margin.auto_is(Length::zero);
|
||
let pbm_sums = &(&pbm.padding + &pbm.border) + &margin;
|
||
let mut child_positioning_context = None;
|
||
|
||
// We need to know the inline size of the atomic before deciding whether to do the line break.
|
||
let fragment = match self {
|
||
IndependentFormattingContext::Replaced(replaced) => {
|
||
let size = replaced.contents.used_size_as_if_inline_element(
|
||
ifc.containing_block,
|
||
&replaced.style,
|
||
None,
|
||
&pbm,
|
||
);
|
||
let fragments = replaced
|
||
.contents
|
||
.make_fragments(&replaced.style, size.clone());
|
||
let content_rect = LogicalRect {
|
||
start_corner: pbm_sums.start_offset(),
|
||
size,
|
||
};
|
||
BoxFragment::new(
|
||
replaced.base_fragment_info,
|
||
replaced.style.clone(),
|
||
fragments,
|
||
content_rect,
|
||
pbm.padding,
|
||
pbm.border,
|
||
margin,
|
||
None,
|
||
CollapsedBlockMargins::zero(),
|
||
)
|
||
},
|
||
IndependentFormattingContext::NonReplaced(non_replaced) => {
|
||
let box_size = non_replaced
|
||
.style
|
||
.content_box_size(&ifc.containing_block, &pbm);
|
||
let max_box_size = non_replaced
|
||
.style
|
||
.content_max_box_size(&ifc.containing_block, &pbm);
|
||
let min_box_size = non_replaced
|
||
.style
|
||
.content_min_box_size(&ifc.containing_block, &pbm)
|
||
.auto_is(Length::zero);
|
||
|
||
// https://drafts.csswg.org/css2/visudet.html#inlineblock-width
|
||
let tentative_inline_size = box_size.inline.auto_is(|| {
|
||
let available_size = ifc.containing_block.inline_size - pbm_sums.inline_sum();
|
||
non_replaced
|
||
.inline_content_sizes(layout_context)
|
||
.shrink_to_fit(available_size)
|
||
});
|
||
|
||
// https://drafts.csswg.org/css2/visudet.html#min-max-widths
|
||
// In this case “applying the rules above again” with a non-auto inline-size
|
||
// always results in that size.
|
||
let inline_size = tentative_inline_size
|
||
.clamp_between_extremums(min_box_size.inline, max_box_size.inline);
|
||
|
||
let containing_block_for_children = ContainingBlock {
|
||
inline_size,
|
||
block_size: box_size.block,
|
||
style: &non_replaced.style,
|
||
};
|
||
assert_eq!(
|
||
ifc.containing_block.style.writing_mode,
|
||
containing_block_for_children.style.writing_mode,
|
||
"Mixed writing modes are not supported yet"
|
||
);
|
||
|
||
// This always collects for the nearest positioned ancestor even if the parent positioning
|
||
// context doesn't. The thing is we haven't kept track up to this point and there isn't
|
||
// any harm in keeping the hoisted boxes separate.
|
||
child_positioning_context = Some(PositioningContext::new_for_subtree(
|
||
true, /* collects_for_nearest_positioned_ancestor */
|
||
));
|
||
let independent_layout = non_replaced.layout(
|
||
layout_context,
|
||
child_positioning_context.as_mut().unwrap(),
|
||
&containing_block_for_children,
|
||
);
|
||
|
||
// https://drafts.csswg.org/css2/visudet.html#block-root-margin
|
||
let tentative_block_size = box_size
|
||
.block
|
||
.auto_is(|| independent_layout.content_block_size);
|
||
|
||
// https://drafts.csswg.org/css2/visudet.html#min-max-heights
|
||
// In this case “applying the rules above again” with a non-auto block-size
|
||
// always results in that size.
|
||
let block_size = tentative_block_size
|
||
.clamp_between_extremums(min_box_size.block, max_box_size.block);
|
||
|
||
let content_rect = LogicalRect {
|
||
start_corner: pbm_sums.start_offset(),
|
||
size: LogicalVec2 {
|
||
block: block_size,
|
||
inline: inline_size,
|
||
},
|
||
};
|
||
|
||
BoxFragment::new(
|
||
non_replaced.base_fragment_info,
|
||
non_replaced.style.clone(),
|
||
independent_layout.fragments,
|
||
content_rect,
|
||
pbm.padding,
|
||
pbm.border,
|
||
margin,
|
||
None,
|
||
CollapsedBlockMargins::zero(),
|
||
)
|
||
},
|
||
};
|
||
|
||
let soft_wrap_opportunity_prevented = mem::replace(
|
||
&mut ifc.prevent_soft_wrap_opportunity_before_next_atomic,
|
||
false,
|
||
);
|
||
if ifc.white_space.allow_wrap() && !soft_wrap_opportunity_prevented {
|
||
ifc.process_soft_wrap_opportunity();
|
||
}
|
||
|
||
let size = &pbm_sums.sum() + &fragment.content_rect.size;
|
||
ifc.push_content_line_item_to_unbreakable_segment(
|
||
size.inline,
|
||
LineItem::Atomic(AtomicLineItem {
|
||
fragment,
|
||
size,
|
||
positioning_context: child_positioning_context,
|
||
}),
|
||
true,
|
||
);
|
||
|
||
// Defer a soft wrap opportunity for when we next process text content.
|
||
ifc.have_deferred_soft_wrap_opportunity = true;
|
||
}
|
||
}
|
||
|
||
struct BreakAndShapeResult {
|
||
font_metrics: FontMetrics,
|
||
font_key: FontInstanceKey,
|
||
runs: Vec<GlyphRun>,
|
||
break_at_start: bool,
|
||
}
|
||
|
||
impl TextRun {
|
||
fn break_and_shape(
|
||
&self,
|
||
layout_context: &LayoutContext,
|
||
linebreaker: &mut Option<LineBreakLeafIter>,
|
||
) -> Result<BreakAndShapeResult, &'static str> {
|
||
use gfx::font::ShapingFlags;
|
||
use style::computed_values::text_rendering::T as TextRendering;
|
||
use style::computed_values::word_break::T as WordBreak;
|
||
|
||
let font_style = self.parent_style.clone_font();
|
||
let inherited_text_style = self.parent_style.get_inherited_text();
|
||
let letter_spacing = if inherited_text_style.letter_spacing.0.px() != 0. {
|
||
Some(app_units::Au::from(inherited_text_style.letter_spacing.0))
|
||
} else {
|
||
None
|
||
};
|
||
|
||
let mut flags = ShapingFlags::empty();
|
||
if letter_spacing.is_some() {
|
||
flags.insert(ShapingFlags::IGNORE_LIGATURES_SHAPING_FLAG);
|
||
}
|
||
if inherited_text_style.text_rendering == TextRendering::Optimizespeed {
|
||
flags.insert(ShapingFlags::IGNORE_LIGATURES_SHAPING_FLAG);
|
||
flags.insert(ShapingFlags::DISABLE_KERNING_SHAPING_FLAG)
|
||
}
|
||
if inherited_text_style.word_break == WordBreak::KeepAll {
|
||
flags.insert(ShapingFlags::KEEP_ALL_FLAG);
|
||
}
|
||
|
||
crate::context::with_thread_local_font_context(layout_context, |font_context| {
|
||
let font_group = font_context.font_group(font_style);
|
||
let font = match font_group.borrow_mut().first(font_context) {
|
||
Some(font) => font,
|
||
None => return Err("Could not find find for TextRun."),
|
||
};
|
||
let mut font = font.borrow_mut();
|
||
|
||
let word_spacing = &inherited_text_style.word_spacing;
|
||
let word_spacing = word_spacing
|
||
.to_length()
|
||
.map(|l| l.into())
|
||
.unwrap_or_else(|| {
|
||
let space_width = font
|
||
.glyph_index(' ')
|
||
.map(|glyph_id| font.glyph_h_advance(glyph_id))
|
||
.unwrap_or(gfx::font::LAST_RESORT_GLYPH_ADVANCE);
|
||
word_spacing.to_used_value(Au::from_f64_px(space_width))
|
||
});
|
||
|
||
let shaping_options = gfx::font::ShapingOptions {
|
||
letter_spacing,
|
||
word_spacing,
|
||
script: unicode_script::Script::Common,
|
||
flags,
|
||
};
|
||
|
||
let (runs, break_at_start) = gfx::text::text_run::TextRun::break_and_shape(
|
||
&mut font,
|
||
&self.text,
|
||
&shaping_options,
|
||
linebreaker,
|
||
);
|
||
|
||
Ok(BreakAndShapeResult {
|
||
font_metrics: font.metrics.clone(),
|
||
font_key: font.font_key,
|
||
runs,
|
||
break_at_start,
|
||
})
|
||
})
|
||
}
|
||
|
||
fn glyph_run_is_whitespace_ending_with_preserved_newline(&self, run: &GlyphRun) -> bool {
|
||
if !run.glyph_store.is_whitespace() {
|
||
return false;
|
||
}
|
||
if !self
|
||
.parent_style
|
||
.get_inherited_text()
|
||
.white_space
|
||
.preserve_newlines()
|
||
{
|
||
return false;
|
||
}
|
||
|
||
let last_byte = self.text.as_bytes().get(run.range.end().to_usize() - 1);
|
||
last_byte == Some(&b'\n')
|
||
}
|
||
|
||
fn layout_into_line_items(
|
||
&self,
|
||
layout_context: &LayoutContext,
|
||
ifc: &mut InlineFormattingContextState,
|
||
) {
|
||
let result = self.break_and_shape(layout_context, &mut ifc.linebreaker);
|
||
let BreakAndShapeResult {
|
||
font_metrics,
|
||
font_key,
|
||
runs,
|
||
break_at_start,
|
||
} = match result {
|
||
Ok(result) => result,
|
||
Err(string) => {
|
||
warn!("Could not render TextRun: {string}");
|
||
return;
|
||
},
|
||
};
|
||
|
||
// We either have a soft wrap opportunity if specified by the breaker or if we are
|
||
// following replaced content.
|
||
let have_deferred_soft_wrap_opportunity =
|
||
mem::replace(&mut ifc.have_deferred_soft_wrap_opportunity, false);
|
||
let mut break_at_start = break_at_start || have_deferred_soft_wrap_opportunity;
|
||
|
||
if have_deferred_soft_wrap_opportunity {
|
||
if let Some(first_character) = self.text.chars().nth(0) {
|
||
break_at_start = break_at_start &&
|
||
!char_prevents_soft_wrap_opportunity_when_before_or_after_atomic(
|
||
first_character,
|
||
)
|
||
}
|
||
}
|
||
|
||
if let Some(last_character) = self.text.chars().last() {
|
||
ifc.prevent_soft_wrap_opportunity_before_next_atomic =
|
||
char_prevents_soft_wrap_opportunity_when_before_or_after_atomic(last_character);
|
||
}
|
||
|
||
for (run_index, run) in runs.into_iter().enumerate() {
|
||
ifc.possibly_flush_deferred_forced_line_break();
|
||
|
||
// If this whitespace forces a line break, queue up a hard line break the next time we
|
||
// see any content. We don't line break immediately, because we'd like to finish processing
|
||
// any ongoing inline boxes before ending the line.
|
||
if self.glyph_run_is_whitespace_ending_with_preserved_newline(&run) {
|
||
ifc.defer_forced_line_break();
|
||
continue;
|
||
}
|
||
|
||
// Break before each unbrekable run in this TextRun, except the first unless the
|
||
// linebreaker was set to break before the first run.
|
||
if run_index != 0 || break_at_start {
|
||
ifc.process_soft_wrap_opportunity();
|
||
}
|
||
|
||
ifc.push_glyph_store_to_unbreakable_segment(
|
||
run.glyph_store,
|
||
self.base_fragment_info,
|
||
&self.parent_style,
|
||
&font_metrics,
|
||
font_key,
|
||
);
|
||
}
|
||
}
|
||
}
|
||
|
||
impl FloatBox {
|
||
fn layout_into_line_items(
|
||
&mut self,
|
||
layout_context: &LayoutContext,
|
||
ifc: &mut InlineFormattingContextState,
|
||
) {
|
||
let fragment = self.layout(
|
||
layout_context,
|
||
ifc.positioning_context,
|
||
ifc.containing_block,
|
||
);
|
||
ifc.push_line_item_to_unbreakable_segment(LineItem::Float(FloatLineItem {
|
||
fragment,
|
||
needs_placement: true,
|
||
}));
|
||
}
|
||
}
|
||
|
||
enum InlineBoxChildIter<'box_tree> {
|
||
InlineFormattingContext(std::slice::Iter<'box_tree, ArcRefCell<InlineLevelBox>>),
|
||
InlineBox {
|
||
inline_level_box: ArcRefCell<InlineLevelBox>,
|
||
child_index: usize,
|
||
},
|
||
}
|
||
|
||
impl<'box_tree> InlineBoxChildIter<'box_tree> {
|
||
fn from_formatting_context(
|
||
inline_formatting_context: &'box_tree InlineFormattingContext,
|
||
) -> InlineBoxChildIter<'box_tree> {
|
||
InlineBoxChildIter::InlineFormattingContext(
|
||
inline_formatting_context.inline_level_boxes.iter(),
|
||
)
|
||
}
|
||
|
||
fn from_inline_level_box(
|
||
inline_level_box: ArcRefCell<InlineLevelBox>,
|
||
) -> InlineBoxChildIter<'box_tree> {
|
||
InlineBoxChildIter::InlineBox {
|
||
inline_level_box,
|
||
child_index: 0,
|
||
}
|
||
}
|
||
}
|
||
|
||
impl<'box_tree> Iterator for InlineBoxChildIter<'box_tree> {
|
||
type Item = ArcRefCell<InlineLevelBox>;
|
||
fn next(&mut self) -> Option<ArcRefCell<InlineLevelBox>> {
|
||
match *self {
|
||
InlineBoxChildIter::InlineFormattingContext(ref mut iter) => iter.next().cloned(),
|
||
InlineBoxChildIter::InlineBox {
|
||
ref inline_level_box,
|
||
ref mut child_index,
|
||
} => match *inline_level_box.borrow() {
|
||
InlineLevelBox::InlineBox(ref inline_box) => {
|
||
if *child_index >= inline_box.children.len() {
|
||
return None;
|
||
}
|
||
|
||
let kid = inline_box.children[*child_index].clone();
|
||
*child_index += 1;
|
||
Some(kid)
|
||
},
|
||
_ => unreachable!(),
|
||
},
|
||
}
|
||
}
|
||
}
|
||
|
||
/// State used when laying out the [`LineItem`]s collected for the line currently being
|
||
/// laid out.
|
||
struct LineItemLayoutState<'a> {
|
||
inline_position: Length,
|
||
|
||
/// The inline start position of the parent (the inline box that established this state)
|
||
/// relative to the edge of the containing block of this [`InlineFormattingCotnext`].
|
||
inline_start_of_parent: Length,
|
||
|
||
ifc_containing_block: &'a ContainingBlock<'a>,
|
||
positioning_context: &'a mut PositioningContext,
|
||
line_block_start: Length,
|
||
}
|
||
|
||
fn layout_line_items(
|
||
iterator: &mut IntoIter<LineItem>,
|
||
layout_context: &LayoutContext,
|
||
state: &mut LineItemLayoutState,
|
||
saw_end: &mut bool,
|
||
) -> Vec<Fragment> {
|
||
let mut fragments = vec![];
|
||
while let Some(item) = iterator.next() {
|
||
match item {
|
||
LineItem::TextRun(text_line_item) => {
|
||
if let Some(fragment) = text_line_item.layout(state) {
|
||
fragments.push(Fragment::Text(fragment));
|
||
}
|
||
},
|
||
LineItem::StartInlineBox(box_line_item) => {
|
||
if let Some(fragment) = box_line_item.layout(iterator, layout_context, state) {
|
||
fragments.push(Fragment::Box(fragment))
|
||
}
|
||
},
|
||
LineItem::EndInlineBox => {
|
||
*saw_end = true;
|
||
break;
|
||
},
|
||
LineItem::Atomic(atomic_line_item) => {
|
||
fragments.push(Fragment::Box(atomic_line_item.layout(state)));
|
||
},
|
||
LineItem::AbsolutelyPositioned(absolute_line_item) => {
|
||
fragments.push(Fragment::AbsoluteOrFixedPositioned(
|
||
absolute_line_item.layout(state),
|
||
));
|
||
},
|
||
LineItem::Float(float_line_item) => {
|
||
fragments.push(Fragment::Float(float_line_item.layout(state)));
|
||
},
|
||
}
|
||
}
|
||
fragments
|
||
}
|
||
|
||
fn place_pending_floats(ifc: &mut InlineFormattingContextState, line_items: &mut Vec<LineItem>) {
|
||
for item in line_items.into_iter() {
|
||
match item {
|
||
LineItem::Float(float_line_item) => {
|
||
if float_line_item.needs_placement {
|
||
ifc.place_float_fragment(&mut float_line_item.fragment);
|
||
}
|
||
},
|
||
_ => {},
|
||
}
|
||
}
|
||
}
|
||
|
||
enum LineItem {
|
||
TextRun(TextRunLineItem),
|
||
StartInlineBox(InlineBoxLineItem),
|
||
EndInlineBox,
|
||
Atomic(AtomicLineItem),
|
||
AbsolutelyPositioned(AbsolutelyPositionedLineItem),
|
||
Float(FloatLineItem),
|
||
}
|
||
|
||
impl LineItem {
|
||
fn trim_whitespace_at_end(&mut self, whitespace_trimmed: &mut Length) -> bool {
|
||
match self {
|
||
LineItem::TextRun(ref mut item) => item.trim_whitespace_at_end(whitespace_trimmed),
|
||
LineItem::StartInlineBox(_) => true,
|
||
LineItem::EndInlineBox => true,
|
||
LineItem::Atomic(_) => false,
|
||
LineItem::AbsolutelyPositioned(_) => true,
|
||
LineItem::Float(_) => true,
|
||
}
|
||
}
|
||
|
||
fn trim_whitespace_at_start(&mut self, whitespace_trimmed: &mut Length) -> bool {
|
||
match self {
|
||
LineItem::TextRun(ref mut item) => item.trim_whitespace_at_start(whitespace_trimmed),
|
||
LineItem::StartInlineBox(_) => true,
|
||
LineItem::EndInlineBox => true,
|
||
LineItem::Atomic(_) => false,
|
||
LineItem::AbsolutelyPositioned(_) => true,
|
||
LineItem::Float(_) => true,
|
||
}
|
||
}
|
||
|
||
fn block_size(&self) -> Length {
|
||
match self {
|
||
LineItem::TextRun(text_run) => text_run.line_height(),
|
||
LineItem::StartInlineBox(_) => {
|
||
// TODO(mrobinson): This should get the line height from the font.
|
||
Length::zero()
|
||
},
|
||
LineItem::EndInlineBox => Length::zero(),
|
||
LineItem::Atomic(atomic) => atomic.size.block,
|
||
LineItem::AbsolutelyPositioned(_) => Length::zero(),
|
||
LineItem::Float(_) => Length::zero(),
|
||
}
|
||
}
|
||
}
|
||
|
||
struct TextRunLineItem {
|
||
base_fragment_info: BaseFragmentInfo,
|
||
parent_style: Arc<ComputedValues>,
|
||
text: Vec<std::sync::Arc<GlyphStore>>,
|
||
font_metrics: FontMetrics,
|
||
font_key: FontInstanceKey,
|
||
text_decoration_line: TextDecorationLine,
|
||
}
|
||
|
||
fn line_height(parent_style: &ComputedValues, font_metrics: &FontMetrics) -> Length {
|
||
let font_size = parent_style.get_font().font_size.computed_size();
|
||
match parent_style.get_inherited_text().line_height {
|
||
LineHeight::Normal => Length::from(font_metrics.line_gap),
|
||
LineHeight::Number(number) => font_size * number.0,
|
||
LineHeight::Length(length) => length.0,
|
||
}
|
||
}
|
||
|
||
fn line_gap_from_style(layout_context: &LayoutContext, style: &ComputedValues) -> Length {
|
||
crate::context::with_thread_local_font_context(layout_context, |font_context| {
|
||
let font_group = font_context.font_group(style.clone_font());
|
||
let font = match font_group.borrow_mut().first(font_context) {
|
||
Some(font) => font,
|
||
None => {
|
||
warn!("Could not find find for TextRun.");
|
||
return Length::zero();
|
||
},
|
||
};
|
||
let font = font.borrow();
|
||
Length::from(font.metrics.line_gap)
|
||
})
|
||
}
|
||
|
||
fn line_height_from_style(layout_context: &LayoutContext, style: &ComputedValues) -> Length {
|
||
crate::context::with_thread_local_font_context(layout_context, |font_context| {
|
||
let font_group = font_context.font_group(style.clone_font());
|
||
let font = match font_group.borrow_mut().first(font_context) {
|
||
Some(font) => font,
|
||
None => {
|
||
warn!("Could not find find for TextRun.");
|
||
return Length::zero();
|
||
},
|
||
};
|
||
let font = font.borrow();
|
||
line_height(style, &font.metrics)
|
||
})
|
||
}
|
||
|
||
impl TextRunLineItem {
|
||
fn trim_whitespace_at_end(&mut self, whitespace_trimmed: &mut Length) -> bool {
|
||
if self
|
||
.parent_style
|
||
.get_inherited_text()
|
||
.white_space
|
||
.preserve_spaces()
|
||
{
|
||
return false;
|
||
}
|
||
|
||
let index_of_last_non_whitespace = self
|
||
.text
|
||
.iter()
|
||
.rev()
|
||
.position(|glyph| !glyph.is_whitespace())
|
||
.map(|offset_from_end| self.text.len() - offset_from_end);
|
||
|
||
let first_whitespace_index = index_of_last_non_whitespace.unwrap_or(0);
|
||
*whitespace_trimmed += self
|
||
.text
|
||
.drain(first_whitespace_index..)
|
||
.map(|glyph| Length::from(glyph.total_advance()))
|
||
.sum();
|
||
|
||
// Only keep going if we only encountered whitespace.
|
||
index_of_last_non_whitespace.is_none()
|
||
}
|
||
|
||
fn trim_whitespace_at_start(&mut self, whitespace_trimmed: &mut Length) -> bool {
|
||
if self
|
||
.parent_style
|
||
.get_inherited_text()
|
||
.white_space
|
||
.preserve_spaces()
|
||
{
|
||
return false;
|
||
}
|
||
|
||
let index_of_first_non_whitespace = self
|
||
.text
|
||
.iter()
|
||
.position(|glyph| !glyph.is_whitespace())
|
||
.unwrap_or(self.text.len());
|
||
*whitespace_trimmed += self
|
||
.text
|
||
.drain(0..index_of_first_non_whitespace)
|
||
.map(|glyph| Length::from(glyph.total_advance()))
|
||
.sum();
|
||
|
||
// Only keep going if we only encountered whitespace.
|
||
self.text.is_empty()
|
||
}
|
||
|
||
fn line_height(&self) -> Length {
|
||
line_height(&self.parent_style, &self.font_metrics)
|
||
}
|
||
|
||
fn layout(self, state: &mut LineItemLayoutState) -> Option<TextFragment> {
|
||
if self.text.is_empty() {
|
||
return None;
|
||
}
|
||
|
||
let inline_advance: Length = self
|
||
.text
|
||
.iter()
|
||
.map(|glyph_store| Length::from(glyph_store.total_advance()))
|
||
.sum();
|
||
let rect = LogicalRect {
|
||
start_corner: LogicalVec2 {
|
||
block: Length::zero(),
|
||
inline: state.inline_position - state.inline_start_of_parent,
|
||
},
|
||
size: LogicalVec2 {
|
||
block: self.line_height(),
|
||
inline: inline_advance,
|
||
},
|
||
};
|
||
|
||
state.inline_position += inline_advance;
|
||
Some(TextFragment {
|
||
base: self.base_fragment_info.into(),
|
||
parent_style: self.parent_style,
|
||
rect,
|
||
font_metrics: self.font_metrics,
|
||
font_key: self.font_key,
|
||
glyphs: self.text,
|
||
text_decoration_line: self.text_decoration_line,
|
||
})
|
||
}
|
||
}
|
||
|
||
#[derive(Clone)]
|
||
struct InlineBoxLineItem {
|
||
base_fragment_info: BaseFragmentInfo,
|
||
style: Arc<ComputedValues>,
|
||
pbm: PaddingBorderMargin,
|
||
block_size: Length,
|
||
|
||
/// Whether this is the first fragment for this inline box. This means that it's the
|
||
/// first potentially split box of a block-in-inline-split (or only if there's no
|
||
/// split) and also the first appearance of this fragment on any line.
|
||
is_first_fragment: bool,
|
||
|
||
/// Whether this is the last fragment for this inline box. This means that it's the
|
||
/// last potentially split box of a block-in-inline-split (or the only fragment if
|
||
/// there's no split).
|
||
is_last_fragment_of_ib_split: bool,
|
||
}
|
||
|
||
impl InlineBoxLineItem {
|
||
fn layout(
|
||
self,
|
||
iterator: &mut IntoIter<LineItem>,
|
||
layout_context: &LayoutContext,
|
||
state: &mut LineItemLayoutState,
|
||
) -> Option<BoxFragment> {
|
||
let style = self.style.clone();
|
||
let mut padding = self.pbm.padding.clone();
|
||
let mut border = self.pbm.border.clone();
|
||
let mut margin = self.pbm.margin.auto_is(Length::zero);
|
||
|
||
if !self.is_first_fragment {
|
||
padding.inline_start = Length::zero();
|
||
border.inline_start = Length::zero();
|
||
margin.inline_start = Length::zero();
|
||
}
|
||
if !self.is_last_fragment_of_ib_split {
|
||
padding.inline_end = Length::zero();
|
||
border.inline_end = Length::zero();
|
||
margin.inline_end = Length::zero();
|
||
}
|
||
let pbm_sums = &(&padding + &border) + &margin;
|
||
state.inline_position += pbm_sums.inline_start;
|
||
|
||
let mut positioning_context = PositioningContext::new_for_style(&style);
|
||
let nested_positioning_context = match positioning_context.as_mut() {
|
||
Some(positioning_context) => positioning_context,
|
||
None => &mut state.positioning_context,
|
||
};
|
||
let original_nested_positioning_context_length = nested_positioning_context.len();
|
||
|
||
let mut nested_state = LineItemLayoutState {
|
||
inline_position: state.inline_position,
|
||
inline_start_of_parent: state.inline_position,
|
||
ifc_containing_block: state.ifc_containing_block,
|
||
positioning_context: nested_positioning_context,
|
||
line_block_start: state.line_block_start,
|
||
};
|
||
|
||
let mut saw_end = false;
|
||
let fragments =
|
||
layout_line_items(iterator, layout_context, &mut nested_state, &mut saw_end);
|
||
|
||
// Only add ending padding, border, margin if this is the last fragment of a
|
||
// potential block-in-inline split and this line included the actual end of this
|
||
// fragment (it doesn't continue on the next line).
|
||
if !self.is_last_fragment_of_ib_split || !saw_end {
|
||
padding.inline_end = Length::zero();
|
||
border.inline_end = Length::zero();
|
||
margin.inline_end = Length::zero();
|
||
}
|
||
let pbm_sums = &(&padding + &border) + &margin;
|
||
|
||
// If the inline box didn't have any content at all, don't add a Fragment for it.
|
||
let box_has_padding_border_or_margin = pbm_sums.inline_sum() > Length::zero();
|
||
let box_had_absolutes =
|
||
original_nested_positioning_context_length != nested_state.positioning_context.len();
|
||
if !self.is_first_fragment &&
|
||
fragments.is_empty() &&
|
||
!box_has_padding_border_or_margin &&
|
||
!box_had_absolutes
|
||
{
|
||
return None;
|
||
}
|
||
|
||
let mut content_rect = LogicalRect {
|
||
start_corner: LogicalVec2 {
|
||
inline: state.inline_position - state.inline_start_of_parent,
|
||
block: Length::zero(),
|
||
},
|
||
size: LogicalVec2 {
|
||
inline: nested_state.inline_position - state.inline_position,
|
||
block: self.block_size,
|
||
},
|
||
};
|
||
|
||
state.inline_position = nested_state.inline_position + pbm_sums.inline_end;
|
||
|
||
// Relative adjustment should not affect the rest of line layout, so we can
|
||
// do it right before creating the Fragment.
|
||
if style.clone_position().is_relative() {
|
||
content_rect.start_corner += &relative_adjustement(&style, state.ifc_containing_block);
|
||
}
|
||
|
||
let mut fragment = BoxFragment::new(
|
||
self.base_fragment_info,
|
||
self.style.clone(),
|
||
fragments,
|
||
content_rect,
|
||
padding,
|
||
border,
|
||
margin,
|
||
None,
|
||
CollapsedBlockMargins::zero(),
|
||
);
|
||
|
||
if let Some(mut positioning_context) = positioning_context.take() {
|
||
assert!(original_nested_positioning_context_length == PositioningContextLength::zero());
|
||
positioning_context.layout_collected_children(layout_context, &mut fragment);
|
||
positioning_context.adjust_static_position_of_hoisted_fragments_with_offset(
|
||
&fragment.content_rect.start_corner,
|
||
PositioningContextLength::zero(),
|
||
);
|
||
state.positioning_context.append(positioning_context);
|
||
} else {
|
||
state
|
||
.positioning_context
|
||
.adjust_static_position_of_hoisted_fragments_with_offset(
|
||
&fragment.content_rect.start_corner,
|
||
original_nested_positioning_context_length,
|
||
);
|
||
}
|
||
|
||
Some(fragment)
|
||
}
|
||
}
|
||
|
||
struct AtomicLineItem {
|
||
fragment: BoxFragment,
|
||
size: LogicalVec2<Length>,
|
||
positioning_context: Option<PositioningContext>,
|
||
}
|
||
|
||
impl AtomicLineItem {
|
||
fn layout(mut self, state: &mut LineItemLayoutState) -> BoxFragment {
|
||
// The initial `start_corner` of the Fragment is the PaddingBorderMargin sum
|
||
// start offset, which is the sum of the start component of the padding,
|
||
// border, and margin. Offset that value by the inline start position of the
|
||
// line layout.
|
||
self.fragment.content_rect.start_corner.inline +=
|
||
state.inline_position - state.inline_start_of_parent;
|
||
|
||
if self.fragment.style.clone_position().is_relative() {
|
||
self.fragment.content_rect.start_corner +=
|
||
&relative_adjustement(&self.fragment.style, state.ifc_containing_block);
|
||
}
|
||
|
||
state.inline_position += self.size.inline;
|
||
|
||
if let Some(mut positioning_context) = self.positioning_context {
|
||
positioning_context.adjust_static_position_of_hoisted_fragments_with_offset(
|
||
&self.fragment.content_rect.start_corner,
|
||
PositioningContextLength::zero(),
|
||
);
|
||
state.positioning_context.append(positioning_context);
|
||
}
|
||
|
||
self.fragment
|
||
}
|
||
}
|
||
|
||
struct AbsolutelyPositionedLineItem {
|
||
absolutely_positioned_box: ArcRefCell<AbsolutelyPositionedBox>,
|
||
}
|
||
|
||
impl AbsolutelyPositionedLineItem {
|
||
fn layout(self, state: &mut LineItemLayoutState) -> ArcRefCell<HoistedSharedFragment> {
|
||
let box_ = self.absolutely_positioned_box;
|
||
let style = AtomicRef::map(box_.borrow(), |box_| box_.context.style());
|
||
let initial_start_corner = match Display::from(style.get_box().original_display) {
|
||
Display::GeneratingBox(DisplayGeneratingBox::OutsideInside { outside, inside: _ }) => {
|
||
LogicalVec2 {
|
||
inline: match outside {
|
||
DisplayOutside::Inline => {
|
||
state.inline_position - state.inline_start_of_parent
|
||
},
|
||
DisplayOutside::Block => Length::zero(),
|
||
},
|
||
block: Length::zero(),
|
||
}
|
||
},
|
||
Display::GeneratingBox(DisplayGeneratingBox::LayoutInternal(_)) => {
|
||
unreachable!(
|
||
"The result of blockification should never be a layout-internal value."
|
||
);
|
||
},
|
||
Display::Contents => {
|
||
panic!("display:contents does not generate an abspos box")
|
||
},
|
||
Display::None => {
|
||
panic!("display:none does not generate an abspos box")
|
||
},
|
||
};
|
||
let hoisted_box = AbsolutelyPositionedBox::to_hoisted(
|
||
box_.clone(),
|
||
initial_start_corner,
|
||
state.ifc_containing_block,
|
||
);
|
||
let hoisted_fragment = hoisted_box.fragment.clone();
|
||
state.positioning_context.push(hoisted_box);
|
||
hoisted_fragment
|
||
}
|
||
}
|
||
|
||
struct FloatLineItem {
|
||
fragment: BoxFragment,
|
||
/// Whether or not this float Fragment has been placed yet. Fragments that
|
||
/// do not fit on a line need to be placed after the hypothetical block start
|
||
/// of the next line.
|
||
needs_placement: bool,
|
||
}
|
||
|
||
impl FloatLineItem {
|
||
fn layout(mut self, state: &mut LineItemLayoutState<'_>) -> BoxFragment {
|
||
// The `BoxFragment` for this float is positioned relative to the IFC, so we need
|
||
// to move it to be positioned relative to our parent InlineBox line item. Floats
|
||
// fragments are children of these InlineBoxes and not children of the inline
|
||
// formatting context, so that they are parented properly for StackingContext
|
||
// properties such as opacity & filters.
|
||
let distance_from_parent_to_ifc = LogicalVec2 {
|
||
inline: state.inline_start_of_parent,
|
||
block: state.line_block_start,
|
||
};
|
||
self.fragment.content_rect.start_corner =
|
||
&self.fragment.content_rect.start_corner - &distance_from_parent_to_ifc;
|
||
self.fragment
|
||
}
|
||
}
|
||
|
||
/// Whether or not this character prevents a soft line wrap opportunity when it
|
||
/// comes before or after an atomic inline element.
|
||
///
|
||
/// From https://www.w3.org/TR/css-text-3/#line-break-details:
|
||
///
|
||
/// > For Web-compatibility there is a soft wrap opportunity before and after each
|
||
/// > replaced element or other atomic inline, even when adjacent to a character that
|
||
/// > would normally suppress them, including U+00A0 NO-BREAK SPACE. However, with
|
||
/// > the exception of U+00A0 NO-BREAK SPACE, there must be no soft wrap opportunity
|
||
/// > between atomic inlines and adjacent characters belonging to the Unicode GL, WJ,
|
||
/// > or ZWJ line breaking classes.
|
||
fn char_prevents_soft_wrap_opportunity_when_before_or_after_atomic(character: char) -> bool {
|
||
if character == '\u{00A0}' {
|
||
return false;
|
||
}
|
||
let class = linebreak_property(character);
|
||
class == XI_LINE_BREAKING_CLASS_GL ||
|
||
class == XI_LINE_BREAKING_CLASS_WJ ||
|
||
class == XI_LINE_BREAKING_CLASS_ZWJ
|
||
}
|