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96c51ba2e7
This implements the rest of the bulk of float support. Now inline element flow around floats and floats can be pushed down by inline elements before them. Co-authored-by: Oriol Brufau <obrufau@igalia.com>
1722 lines
70 KiB
Rust
1722 lines
70 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 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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FontMetrics, Fragment, HoistedSharedFragment, TextFragment,
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};
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use crate::geom::flow_relative::{Rect, Vec2};
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use crate::geom::LengthOrAuto;
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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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use app_units::Au;
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use atomic_refcell::AtomicRef;
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use gfx::text::glyph::GlyphStore;
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use gfx::text::text_run::GlyphRun;
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use servo_arc::Arc;
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use std::cell::OnceCell;
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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;
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use style::values::specified::text::TextDecorationLine;
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use style::Zero;
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use webrender_api::FontInstanceKey;
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use xi_unicode::LineBreakLeafIter;
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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 first_fragment: bool,
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pub 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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struct InlineNestingLevelState<'box_tree> {
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remaining_boxes: InlineBoxChildIter<'box_tree>,
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line_items_so_far: Vec<LineItem>,
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white_space: WhiteSpace,
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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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}
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struct PartialInlineBoxFragment<'box_tree> {
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base_fragment_info: BaseFragmentInfo,
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style: Arc<ComputedValues>,
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pbm: PaddingBorderMargin,
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/// Whether or not this inline box has already been part of a previous line.
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/// We need to create at least one Fragment for every inline box, but on following
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/// lines, if the inline box is totally empty (such as after a preserved line
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/// break), then we don't want to create empty Fragments for it.
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was_part_of_previous_line: bool,
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parent_nesting_level: InlineNestingLevelState<'box_tree>,
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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: Vec2<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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/// If the current line ends with whitespace, this tracks the advance width of that
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/// whitespace. This is used to find the "real" width of a line if trailing whitespace
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/// is trimmed from the end.
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trailing_whitespace_advance: Length,
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/// The currently calculated block size of this line, taking into account all inline
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/// content already laid out into [`LineItem`]s. Later content may increase the block
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/// size.
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block_size: Length,
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/// Whether any active linebox has added a glyph, border, margin, or padding
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/// to this line, which indicates that the next run that exceeds the line length
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/// 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<Rect<Length>>,
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}
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impl LineUnderConstruction {
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fn new(start_position: Vec2<Length>) -> Self {
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Self {
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inline_position: start_position.inline.clone(),
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trailing_whitespace_advance: Length::zero(),
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start_position: start_position,
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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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}
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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: Rect<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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struct InlineFormattingContextState<'box_tree, '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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/// 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. The
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/// [`LineItem`]s themselves are stored in the nesting state.
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current_line: LineUnderConstruction,
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/// The line breaking state for this inline formatting context.
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linebreaker: Option<LineBreakLeafIter>,
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partial_inline_boxes_stack: Vec<PartialInlineBoxFragment<'box_tree>>,
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current_nesting_level: InlineNestingLevelState<'box_tree>,
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}
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impl<'box_tree, 'a, 'b> InlineFormattingContextState<'box_tree, 'a, 'b> {
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/// Push a completed [LineItem] to the current nesteding level of this
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/// [InlineFormattingContext].
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fn push_line_item(
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&mut self,
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inline_size: Length,
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line_item: LineItem,
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last_whitespace_advance: Length,
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) {
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self.current_line.has_content = true;
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self.current_line.inline_position += inline_size;
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self.current_line.trailing_whitespace_advance = last_whitespace_advance;
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self.current_line
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.block_size
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.max_assign(line_item.block_size());
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self.current_nesting_level.line_items_so_far.push(line_item);
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}
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/// Finish layout of all the partial inline boxes in the current line,
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/// finish current line and start a new one.
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fn finish_line_and_reset(&mut self, layout_context: &LayoutContext) {
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let mut nesting_level = &mut self.current_nesting_level;
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for partial in self.partial_inline_boxes_stack.iter_mut().rev() {
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partial.finish_layout(
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nesting_level,
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&mut self.current_line.inline_position,
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false, /* at_end_of_inline_element */
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);
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nesting_level = &mut partial.parent_nesting_level;
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}
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let line_items = std::mem::take(&mut nesting_level.line_items_so_far);
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self.finish_current_line(layout_context, line_items, self.containing_block);
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}
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fn finish_current_line(
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&mut self,
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layout_context: &LayoutContext,
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mut line_items: Vec<LineItem>,
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containing_block: &ContainingBlock,
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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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// > 3. A sequence of collapsible spaces at the end of a line is removed,
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// > as well as any trailing U+1680 OGHAM SPACE MARK whose white-space
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// > property is normal, nowrap, or pre-line.
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let mut whitespace_trimmed = Length::zero();
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for item in line_items.iter_mut().rev() {
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if !item.trim_whitespace_at_end(&mut whitespace_trimmed) {
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break;
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}
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}
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let inline_start_position =
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self.calculate_inline_start_for_current_line(containing_block, whitespace_trimmed);
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let block_start_position = self
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.current_line
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.line_block_start_considering_placement_among_floats();
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let block_end_position = block_start_position + self.current_line.block_size;
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if let Some(sequential_layout_state) = self.sequential_layout_state.as_mut() {
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// This amount includes both the block size of the line and any extra space
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// added to move the line down in order to avoid overlapping floats.
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let increment = block_end_position - self.current_line.start_position.block;
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sequential_layout_state.advance_block_position(increment);
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}
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if self.current_line.has_floats_waiting_to_be_placed {
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place_pending_floats(self, &mut line_items);
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}
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let mut state = LineItemLayoutState {
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inline_position: inline_start_position,
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max_block_size: Length::zero(),
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inline_start_of_parent: Length::zero(),
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ifc_containing_block: containing_block,
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positioning_context: &mut self.positioning_context,
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line_block_start: block_start_position,
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};
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let positioning_context_length = state.positioning_context.len();
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let fragments = layout_line_items(line_items, layout_context, &mut state);
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let size = Vec2 {
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inline: containing_block.inline_size,
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block: state.max_block_size,
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};
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// The inline part of this start offset was taken into account when determining
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// the inline start of the line in `calculate_inline_start_for_current_line` so
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// we do not need to include it in the `start_corner` of the line's main Fragment.
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let start_corner = Vec2 {
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inline: Length::zero(),
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block: block_start_position,
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};
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let line_had_content =
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!fragments.is_empty() || state.positioning_context.len() != positioning_context_length;
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if line_had_content {
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state
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.positioning_context
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.adjust_static_position_of_hoisted_fragments_with_offset(
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&start_corner,
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positioning_context_length,
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);
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self.fragments
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.push(Fragment::Anonymous(AnonymousFragment::new(
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Rect { start_corner, size },
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fragments,
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containing_block.style.writing_mode,
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)));
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}
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self.current_line = LineUnderConstruction::new(Vec2 {
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inline: Length::zero(),
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block: block_end_position,
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});
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}
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/// Given the amount of whitespace trimmed from the line and taking into consideration
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/// the `text-align` property, calculate where the line under construction starts in
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/// the inline axis.
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fn calculate_inline_start_for_current_line(
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&self,
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containing_block: &ContainingBlock,
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whitespace_trimmed: Length,
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) -> Length {
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enum TextAlign {
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Start,
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Center,
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End,
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}
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let line_left_is_inline_start = containing_block
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.style
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.writing_mode
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.line_left_is_inline_start();
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let text_align = match containing_block.style.clone_text_align() {
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TextAlignKeyword::Start => TextAlign::Start,
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TextAlignKeyword::Center => TextAlign::Center,
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TextAlignKeyword::End => TextAlign::End,
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TextAlignKeyword::Left => {
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if line_left_is_inline_start {
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TextAlign::Start
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} else {
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TextAlign::End
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}
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},
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TextAlignKeyword::Right => {
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if line_left_is_inline_start {
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TextAlign::End
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} else {
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TextAlign::Start
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}
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},
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TextAlignKeyword::Justify => {
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// TODO: Add support for justfied text.
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TextAlign::Start
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},
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TextAlignKeyword::ServoCenter |
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TextAlignKeyword::ServoLeft |
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TextAlignKeyword::ServoRight => {
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// TODO: Implement these modes which seem to be used by quirks mode.
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TextAlign::Start
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},
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};
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let (line_start, available_space) = match self.current_line.placement_among_floats.get() {
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Some(placement_among_floats) => (
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placement_among_floats.start_corner.inline,
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placement_among_floats.size.inline,
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),
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None => (Length::zero(), self.containing_block.inline_size),
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};
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// Properly handling text-indent requires that we do not align the text
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// into the text-indent.
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// See <https://drafts.csswg.org/css-text/#text-indent-property>
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// "This property specifies the indentation applied to lines of inline content in
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// a block. The indent is treated as a margin applied to the start edge of the
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// line box."
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let text_indent = self.current_line.start_position.inline;
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let line_length = self.current_line.inline_position - whitespace_trimmed - text_indent;
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line_start +
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match text_align {
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TextAlign::Start => text_indent,
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TextAlign::End => (available_space - line_length).max(text_indent),
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TextAlign::Center => (available_space - line_length + text_indent) / 2.,
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}
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}
|
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fn place_float_fragment(&mut self, fragment: &mut BoxFragment) {
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let state = self
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.sequential_layout_state
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.as_mut()
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.expect("Tried to lay out a float with no sequential placement state!");
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|
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let block_offset_from_containining_block_top = state
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.current_block_position_including_margins() -
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state.current_containing_block_offset();
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state.place_float_fragment(
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fragment,
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CollapsedMargin::zero(),
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block_offset_from_containining_block_top,
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);
|
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}
|
||
|
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/// 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
|
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/// of the line if it's used as the final placement among floats.
|
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fn place_line_among_floats(&self, potential_line_size: &Vec2<Length>) -> Rect<Length> {
|
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let sequential_layout_state = self
|
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.sequential_layout_state
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||
.as_ref()
|
||
.expect("Should not have called this function without having floats.");
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|
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let ifc_offset_in_float_container = Vec2 {
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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(),
|
||
);
|
||
|
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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: &Vec2<Length>,
|
||
) -> bool {
|
||
// 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 !self.current_line.has_content && self.sequential_layout_state.is_some() {
|
||
let new_placement = self.place_line_among_floats(potential_line_size);
|
||
self.current_line
|
||
.replace_placement_among_floats(new_placement);
|
||
}
|
||
|
||
if potential_line_size.inline > self.containing_block.inline_size {
|
||
return true;
|
||
}
|
||
|
||
// If we already have a placement among floats for this line, and the new potential
|
||
// line size causes a change in the block position, then we will need a line
|
||
// break. This block of code also takes the opportunity to update the placement
|
||
// among floats in the case that line does fit at the same block position (because
|
||
// its inline start may change).
|
||
let old_placement = self.current_line.placement_among_floats.get().cloned();
|
||
if let Some(old_placement) = old_placement {
|
||
if potential_line_size.block > old_placement.size.block {
|
||
let new_placement = self.place_line_among_floats(potential_line_size);
|
||
if new_placement.start_corner.block != old_placement.start_corner.block {
|
||
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.
|
||
let available_inline_space = if self.sequential_layout_state.is_some() {
|
||
let placement_among_floats = self
|
||
.current_line
|
||
.placement_among_floats
|
||
.get_or_init(|| self.place_line_among_floats(potential_line_size));
|
||
placement_among_floats.size.inline
|
||
} else {
|
||
self.containing_block.inline_size
|
||
};
|
||
|
||
potential_line_size.inline > available_inline_space
|
||
}
|
||
}
|
||
|
||
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!(first_fragment, inline_start);
|
||
self.traverse(&inline_box.children);
|
||
add!(last_fragment, inline_end);
|
||
},
|
||
InlineLevelBox::TextRun(text_run) => {
|
||
let BreakAndShapeResult {
|
||
runs,
|
||
break_at_start,
|
||
..
|
||
} = text_run
|
||
.break_and_shape(self.layout_context, &mut self.linebreaker);
|
||
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 {
|
||
// 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,
|
||
fragments: Vec::new(),
|
||
current_line: LineUnderConstruction::new(Vec2 {
|
||
inline: first_line_inline_start,
|
||
block: Length::zero(),
|
||
}),
|
||
linebreaker: None,
|
||
partial_inline_boxes_stack: Vec::new(),
|
||
current_nesting_level: InlineNestingLevelState {
|
||
remaining_boxes: InlineBoxChildIter::from_formatting_context(self),
|
||
line_items_so_far: Vec::with_capacity(self.inline_level_boxes.len()),
|
||
white_space: containing_block.style.clone_inherited_text().white_space,
|
||
text_decoration_line: self.text_decoration_line,
|
||
},
|
||
};
|
||
|
||
// 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??
|
||
}
|
||
|
||
loop {
|
||
if let Some(child) = ifc.current_nesting_level.remaining_boxes.next() {
|
||
match &mut *child.borrow_mut() {
|
||
InlineLevelBox::InlineBox(inline) => {
|
||
let partial =
|
||
PartialInlineBoxFragment::new(inline, child.clone(), &mut ifc);
|
||
ifc.partial_inline_boxes_stack.push(partial);
|
||
},
|
||
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.current_nesting_level.line_items_so_far.push(
|
||
LineItem::AbsolutelyPositioned(AbsolutelyPositionedLineItem {
|
||
absolutely_positioned_box: box_.clone(),
|
||
}),
|
||
);
|
||
},
|
||
InlineLevelBox::OutOfFlowFloatBox(float_box) => {
|
||
float_box.layout_into_line_items(layout_context, &mut ifc);
|
||
},
|
||
}
|
||
} else if let Some(mut partial) = ifc.partial_inline_boxes_stack.pop() {
|
||
// We reached the end of the remaining boxes in this nesting level, so we finish it and
|
||
// start working on the parent nesting level again.
|
||
partial.finish_layout(
|
||
&mut ifc.current_nesting_level,
|
||
&mut ifc.current_line.inline_position,
|
||
true, /* at_end_of_inline_element */
|
||
);
|
||
ifc.current_nesting_level = partial.parent_nesting_level
|
||
} else {
|
||
// We reached the end of the entire IFC.
|
||
break;
|
||
}
|
||
}
|
||
|
||
let line_items = std::mem::take(&mut ifc.current_nesting_level.line_items_so_far);
|
||
ifc.finish_current_line(layout_context, line_items, containing_block);
|
||
|
||
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<'box_tree> PartialInlineBoxFragment<'box_tree> {
|
||
fn new(
|
||
inline_box: &InlineBox,
|
||
this_inline_level_box: ArcRefCell<InlineLevelBox>,
|
||
ifc: &mut InlineFormattingContextState<'box_tree, '_, '_>,
|
||
) -> PartialInlineBoxFragment<'box_tree> {
|
||
let style = inline_box.style.clone();
|
||
let mut pbm = style.padding_border_margin(&ifc.containing_block);
|
||
|
||
if inline_box.first_fragment {
|
||
ifc.current_line.inline_position += pbm.padding.inline_start +
|
||
pbm.border.inline_start +
|
||
pbm.margin.inline_start.auto_is(Length::zero)
|
||
} else {
|
||
pbm.padding.inline_start = Length::zero();
|
||
pbm.border.inline_start = Length::zero();
|
||
pbm.margin.inline_start = LengthOrAuto::zero();
|
||
}
|
||
|
||
let text_decoration_line =
|
||
ifc.current_nesting_level.text_decoration_line | style.clone_text_decoration_line();
|
||
let white_space = style.clone_inherited_text().white_space;
|
||
|
||
PartialInlineBoxFragment {
|
||
base_fragment_info: inline_box.base_fragment_info,
|
||
style,
|
||
pbm,
|
||
was_part_of_previous_line: false,
|
||
parent_nesting_level: std::mem::replace(
|
||
&mut ifc.current_nesting_level,
|
||
InlineNestingLevelState {
|
||
remaining_boxes: InlineBoxChildIter::from_inline_level_box(
|
||
this_inline_level_box,
|
||
),
|
||
line_items_so_far: Vec::with_capacity(inline_box.children.len()),
|
||
white_space,
|
||
text_decoration_line: text_decoration_line,
|
||
},
|
||
),
|
||
}
|
||
}
|
||
|
||
fn finish_layout(
|
||
&mut self,
|
||
nesting_level: &mut InlineNestingLevelState,
|
||
inline_position: &mut Length,
|
||
at_end_of_inline_element: bool,
|
||
) {
|
||
// If we are finishing in order to fragment this InlineBox into multiple lines, do
|
||
// not add end margins, borders, and padding.
|
||
if !at_end_of_inline_element {
|
||
self.pbm.padding.inline_end = Length::zero();
|
||
self.pbm.border.inline_end = Length::zero();
|
||
self.pbm.margin.inline_end = LengthOrAuto::zero();
|
||
} else {
|
||
*inline_position += self.pbm.padding.inline_end +
|
||
self.pbm.border.inline_end +
|
||
self.pbm.margin.inline_end.auto_is(Length::zero)
|
||
}
|
||
|
||
self.parent_nesting_level
|
||
.line_items_so_far
|
||
.push(LineItem::InlineBox(InlineBoxLineItem {
|
||
base_fragment_info: self.base_fragment_info,
|
||
style: self.style.clone(),
|
||
pbm: self.pbm.clone(),
|
||
children: std::mem::take(&mut nesting_level.line_items_so_far),
|
||
always_make_fragment: !self.was_part_of_previous_line,
|
||
}));
|
||
|
||
// This InlineBox now has at least one Fragment that corresponds to it, so
|
||
// if subsequent lines can ignore it if it is empty on those lines.
|
||
self.was_part_of_previous_line = true;
|
||
|
||
// If this partial / inline box appears on any subsequent lines, it should not
|
||
// have any start margin, border, or padding.
|
||
self.pbm.padding.inline_start = Length::zero();
|
||
self.pbm.border.inline_start = Length::zero();
|
||
self.pbm.margin.inline_start = LengthOrAuto::zero();
|
||
}
|
||
}
|
||
|
||
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 = Rect {
|
||
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 = Rect {
|
||
start_corner: pbm_sums.start_offset(),
|
||
size: Vec2 {
|
||
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 size = &pbm_sums.sum() + &fragment.content_rect.size;
|
||
let new_potential_line_size = Vec2 {
|
||
inline: ifc.current_line.inline_position + size.inline,
|
||
block: ifc.current_line.block_size.max(size.block),
|
||
};
|
||
|
||
let can_break = ifc.current_nesting_level.white_space.allow_wrap() &&
|
||
ifc.current_nesting_level.line_items_so_far.len() != 0;
|
||
if ifc.new_potential_line_size_causes_line_break(&new_potential_line_size) && can_break {
|
||
ifc.finish_line_and_reset(layout_context);
|
||
}
|
||
|
||
ifc.push_line_item(
|
||
size.inline,
|
||
LineItem::Atomic(AtomicLineItem {
|
||
fragment,
|
||
size,
|
||
positioning_context: child_positioning_context,
|
||
}),
|
||
Length::zero(),
|
||
);
|
||
|
||
// After every atomic, we need to create a line breaking opportunity for the next TextRun.
|
||
if let Some(linebreaker) = ifc.linebreaker.as_mut() {
|
||
linebreaker.next(" ");
|
||
}
|
||
}
|
||
}
|
||
|
||
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>,
|
||
) -> BreakAndShapeResult {
|
||
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 = font_group
|
||
.borrow_mut()
|
||
.first(font_context)
|
||
.expect("could not find font");
|
||
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,
|
||
);
|
||
|
||
BreakAndShapeResult {
|
||
font_metrics: (&font.metrics).into(),
|
||
font_key: font.font_key,
|
||
runs,
|
||
break_at_start,
|
||
}
|
||
})
|
||
}
|
||
|
||
fn layout_into_line_items(
|
||
&self,
|
||
layout_context: &LayoutContext,
|
||
ifc: &mut InlineFormattingContextState,
|
||
) {
|
||
let BreakAndShapeResult {
|
||
font_metrics,
|
||
font_key,
|
||
runs,
|
||
break_at_start,
|
||
} = self.break_and_shape(layout_context, &mut ifc.linebreaker);
|
||
|
||
let white_space = self.parent_style.get_inherited_text().white_space;
|
||
let add_glyphs_to_current_line =
|
||
|ifc: &mut InlineFormattingContextState,
|
||
glyphs: Vec<std::sync::Arc<GlyphStore>>,
|
||
inline_advance,
|
||
force_text_run_creation: bool| {
|
||
if !force_text_run_creation && glyphs.is_empty() {
|
||
return;
|
||
}
|
||
|
||
let last_whitespace_advance = match (white_space.preserve_spaces(), glyphs.last()) {
|
||
(false, Some(last_glyph)) if last_glyph.is_whitespace() => {
|
||
last_glyph.total_advance()
|
||
},
|
||
_ => Au::zero(),
|
||
};
|
||
|
||
ifc.push_line_item(
|
||
inline_advance,
|
||
LineItem::TextRun(TextRunLineItem {
|
||
text: glyphs,
|
||
base_fragment_info: self.base_fragment_info.into(),
|
||
parent_style: self.parent_style.clone(),
|
||
font_metrics,
|
||
font_key,
|
||
text_decoration_line: ifc.current_nesting_level.text_decoration_line,
|
||
}),
|
||
Length::from(last_whitespace_advance),
|
||
);
|
||
};
|
||
|
||
let line_height = line_height(&self.parent_style, &font_metrics);
|
||
let new_max_height_of_line = ifc.current_line.block_size.max(line_height);
|
||
|
||
let mut glyphs = vec![];
|
||
let mut advance_from_text_run = Length::zero();
|
||
let mut iterator = runs.iter().enumerate();
|
||
while let Some((run_index, run)) = iterator.next() {
|
||
// If this whitespace forces a line break, finish the line and reset everything.
|
||
if run.glyph_store.is_whitespace() && white_space.preserve_newlines() {
|
||
let last_byte = self.text.as_bytes().get(run.range.end().to_usize() - 1);
|
||
if last_byte == Some(&b'\n') {
|
||
// TODO: We shouldn't need to force the creation of a TextRun here, but only TextRuns are
|
||
// influencing line height calculation of lineboxes (and not all inline boxes on a line).
|
||
// Once that is fixed, we can avoid adding an empty TextRun here.
|
||
add_glyphs_to_current_line(
|
||
ifc,
|
||
glyphs.drain(..).collect(),
|
||
advance_from_text_run,
|
||
true,
|
||
);
|
||
ifc.finish_line_and_reset(layout_context);
|
||
advance_from_text_run = Length::zero();
|
||
continue;
|
||
}
|
||
}
|
||
|
||
let new_advance_from_glyph_run = Length::from(run.glyph_store.total_advance());
|
||
let new_total_advance = new_advance_from_glyph_run +
|
||
advance_from_text_run +
|
||
ifc.current_line.inline_position;
|
||
|
||
let new_potential_line_size = Vec2 {
|
||
inline: new_total_advance,
|
||
block: new_max_height_of_line,
|
||
};
|
||
|
||
// We can only break the line, if this isn't the first actual content (non-whitespace or
|
||
// preserved whitespace) on the line and this isn't the unbreakable run of this text run
|
||
// (or we can break at the start according to the text breaker).
|
||
let can_break = ifc.current_line.has_content && (break_at_start || run_index != 0);
|
||
if ifc.new_potential_line_size_causes_line_break(&new_potential_line_size) && can_break
|
||
{
|
||
add_glyphs_to_current_line(
|
||
ifc,
|
||
glyphs.drain(..).collect(),
|
||
advance_from_text_run,
|
||
true,
|
||
);
|
||
ifc.finish_line_and_reset(layout_context);
|
||
advance_from_text_run = Length::zero();
|
||
}
|
||
|
||
// From <https://www.w3.org/TR/css-text-3/#white-space-phase-2>:
|
||
// "Then, the entire block is rendered. Inlines are laid out, taking bidi
|
||
// reordering into account, and wrapping as specified by the text-wrap
|
||
// property. As each line is laid out,
|
||
//
|
||
// > 1. A sequence of collapsible spaces at the beginning of a line is removed."
|
||
//
|
||
// This prevents whitespace from being added to the beginning of a line. We could
|
||
// trim it later, but we don't want it to come into play when determining line
|
||
// width.
|
||
if run.glyph_store.is_whitespace() &&
|
||
!white_space.preserve_spaces() &&
|
||
!ifc.current_line.has_content
|
||
{
|
||
continue;
|
||
}
|
||
|
||
advance_from_text_run += Length::from(run.glyph_store.total_advance());
|
||
glyphs.push(run.glyph_store.clone());
|
||
ifc.current_line.has_content = true;
|
||
}
|
||
|
||
add_glyphs_to_current_line(
|
||
ifc,
|
||
glyphs.drain(..).collect(),
|
||
advance_from_text_run,
|
||
false,
|
||
);
|
||
}
|
||
}
|
||
|
||
impl FloatBox {
|
||
fn layout_into_line_items(
|
||
&mut self,
|
||
layout_context: &LayoutContext,
|
||
ifc: &mut InlineFormattingContextState,
|
||
) {
|
||
let mut fragment = self.layout(
|
||
layout_context,
|
||
ifc.positioning_context,
|
||
ifc.containing_block,
|
||
);
|
||
|
||
let margin_box = fragment.border_rect().inflate(&fragment.margin);
|
||
let inline_size = margin_box.size.inline.max(Length::zero());
|
||
|
||
let available_inline_size = match ifc.current_line.placement_among_floats.get() {
|
||
Some(placement_among_floats) => placement_among_floats.size.inline,
|
||
None => ifc.containing_block.inline_size,
|
||
} - (ifc.current_line.inline_position -
|
||
ifc.current_line.trailing_whitespace_advance);
|
||
|
||
// 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 fits_on_line = !ifc.current_line.has_content || inline_size <= available_inline_size;
|
||
let needs_placement_later =
|
||
ifc.current_line.has_floats_waiting_to_be_placed || !fits_on_line;
|
||
|
||
if needs_placement_later {
|
||
ifc.current_line.has_floats_waiting_to_be_placed = true;
|
||
} else {
|
||
ifc.place_float_fragment(&mut fragment);
|
||
|
||
// 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 = ifc.place_line_among_floats(&Vec2 {
|
||
inline: ifc.current_line.inline_position,
|
||
block: ifc.current_line.block_size,
|
||
});
|
||
ifc.current_line
|
||
.replace_placement_among_floats(new_placement);
|
||
}
|
||
|
||
ifc.current_nesting_level
|
||
.line_items_so_far
|
||
.push(LineItem::Float(FloatLineItem {
|
||
fragment,
|
||
needs_placement: needs_placement_later,
|
||
}));
|
||
}
|
||
}
|
||
|
||
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,
|
||
max_block_size: 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(
|
||
line_items: Vec<LineItem>,
|
||
layout_context: &LayoutContext,
|
||
state: &mut LineItemLayoutState,
|
||
) -> Vec<Fragment> {
|
||
let mut fragments = vec![];
|
||
for item in line_items.into_iter() {
|
||
match item {
|
||
LineItem::TextRun(text_line_item) => {
|
||
if let Some(fragment) = text_line_item.layout(state) {
|
||
fragments.push(Fragment::Text(fragment));
|
||
}
|
||
},
|
||
LineItem::InlineBox(box_line_item) => {
|
||
if let Some(fragment) = box_line_item.layout(layout_context, state) {
|
||
fragments.push(Fragment::Box(fragment))
|
||
}
|
||
},
|
||
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::InlineBox(box_line_item) => {
|
||
place_pending_floats(ifc, &mut box_line_item.children);
|
||
},
|
||
LineItem::Float(float_line_item) => {
|
||
if float_line_item.needs_placement {
|
||
ifc.place_float_fragment(&mut float_line_item.fragment);
|
||
}
|
||
},
|
||
_ => {},
|
||
}
|
||
}
|
||
}
|
||
|
||
enum LineItem {
|
||
TextRun(TextRunLineItem),
|
||
InlineBox(InlineBoxLineItem),
|
||
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::InlineBox(b) => {
|
||
for child in b.children.iter_mut().rev() {
|
||
if !child.trim_whitespace_at_end(whitespace_trimmed) {
|
||
return false;
|
||
}
|
||
}
|
||
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::InlineBox(_) => {
|
||
// TODO(mrobinson): This should get the line height from the font.
|
||
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: &Arc<ComputedValues>, font_metrics: &FontMetrics) -> Length {
|
||
let font_size = parent_style.get_font().font_size.size.0;
|
||
match parent_style.get_inherited_text().line_height {
|
||
LineHeight::Normal => font_metrics.line_gap,
|
||
LineHeight::Number(n) => font_size * n.0,
|
||
LineHeight::Length(l) => l.0,
|
||
}
|
||
}
|
||
|
||
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 line_height(&self) -> Length {
|
||
line_height(&self.parent_style, &self.font_metrics)
|
||
}
|
||
|
||
fn layout(self, state: &mut LineItemLayoutState) -> Option<TextFragment> {
|
||
state.max_block_size.max_assign(self.line_height());
|
||
|
||
// This happens after updating the `max_block_size`, because even trimmed newlines
|
||
// should affect the height of the line.
|
||
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 = Rect {
|
||
start_corner: Vec2 {
|
||
block: Length::zero(),
|
||
inline: state.inline_position - state.inline_start_of_parent,
|
||
},
|
||
size: Vec2 {
|
||
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,
|
||
})
|
||
}
|
||
}
|
||
|
||
struct InlineBoxLineItem {
|
||
base_fragment_info: BaseFragmentInfo,
|
||
style: Arc<ComputedValues>,
|
||
pbm: PaddingBorderMargin,
|
||
children: Vec<LineItem>,
|
||
always_make_fragment: bool,
|
||
}
|
||
|
||
impl InlineBoxLineItem {
|
||
fn layout(
|
||
self,
|
||
layout_context: &LayoutContext,
|
||
state: &mut LineItemLayoutState,
|
||
) -> Option<BoxFragment> {
|
||
let style = self.style.clone();
|
||
|
||
let padding = self.pbm.padding.clone();
|
||
let border = self.pbm.border.clone();
|
||
let margin = self.pbm.margin.auto_is(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,
|
||
max_block_size: Length::zero(),
|
||
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 fragments = layout_line_items(self.children, layout_context, &mut nested_state);
|
||
|
||
// 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.always_make_fragment &&
|
||
nested_state.max_block_size.is_zero() &&
|
||
fragments.is_empty() &&
|
||
!box_has_padding_border_or_margin &&
|
||
!box_had_absolutes
|
||
{
|
||
return None;
|
||
}
|
||
|
||
let mut content_rect = Rect {
|
||
start_corner: Vec2 {
|
||
inline: state.inline_position - state.inline_start_of_parent,
|
||
block: Length::zero(),
|
||
},
|
||
size: Vec2 {
|
||
inline: nested_state.inline_position - state.inline_position,
|
||
block: nested_state.max_block_size,
|
||
},
|
||
};
|
||
|
||
state.inline_position = nested_state.inline_position + pbm_sums.inline_end;
|
||
state.max_block_size.max_assign(content_rect.size.block);
|
||
|
||
// 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: Vec2<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;
|
||
state.max_block_size.max_assign(self.size.block);
|
||
|
||
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: _ }) => {
|
||
Vec2 {
|
||
inline: match outside {
|
||
DisplayOutside::Inline => {
|
||
state.inline_position - state.inline_start_of_parent
|
||
},
|
||
DisplayOutside::Block => Length::zero(),
|
||
},
|
||
block: Length::zero(),
|
||
}
|
||
},
|
||
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 = Vec2 {
|
||
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
|
||
}
|
||
}
|