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Diffstat (limited to 'components/layout/fragment_tree/box_fragment.rs')
| -rw-r--r-- | components/layout/fragment_tree/box_fragment.rs | 397 |
1 files changed, 397 insertions, 0 deletions
diff --git a/components/layout/fragment_tree/box_fragment.rs b/components/layout/fragment_tree/box_fragment.rs new file mode 100644 index 00000000000..30be154caf1 --- /dev/null +++ b/components/layout/fragment_tree/box_fragment.rs @@ -0,0 +1,397 @@ +/* This Source Code Form is subject to the terms of the Mozilla Public + * License, v. 2.0. If a copy of the MPL was not distributed with this + * file, You can obtain one at https://mozilla.org/MPL/2.0/. */ + +use app_units::Au; +use atomic_refcell::AtomicRefCell; +use base::print_tree::PrintTree; +use malloc_size_of_derive::MallocSizeOf; +use servo_arc::Arc as ServoArc; +use style::Zero; +use style::computed_values::border_collapse::T as BorderCollapse; +use style::computed_values::overflow_x::T as ComputedOverflow; +use style::computed_values::position::T as ComputedPosition; +use style::logical_geometry::WritingMode; +use style::properties::ComputedValues; +use style::values::specified::box_::DisplayOutside; + +use super::{BaseFragment, BaseFragmentInfo, CollapsedBlockMargins, Fragment}; +use crate::formatting_contexts::Baselines; +use crate::geom::{ + AuOrAuto, LengthPercentageOrAuto, PhysicalPoint, PhysicalRect, PhysicalSides, ToLogical, +}; +use crate::style_ext::ComputedValuesExt; +use crate::table::SpecificTableGridInfo; +use crate::taffy::SpecificTaffyGridInfo; + +/// Describes how a [`BoxFragment`] paints its background. +#[derive(MallocSizeOf)] +pub(crate) enum BackgroundMode { + /// Draw the normal [`BoxFragment`] background as well as the extra backgrounds + /// based on the style and positioning rectangles in this data structure. + Extra(Vec<ExtraBackground>), + /// Do not draw a background for this Fragment. This is used for elements like + /// table tracks and table track groups, which rely on cells to paint their + /// backgrounds. + None, + /// Draw the background normally, getting information from the Fragment style. + Normal, +} + +#[derive(MallocSizeOf)] +pub(crate) struct ExtraBackground { + #[conditional_malloc_size_of] + pub style: ServoArc<ComputedValues>, + pub rect: PhysicalRect<Au>, +} + +#[derive(Clone, Debug, MallocSizeOf)] +pub(crate) enum SpecificLayoutInfo { + Grid(Box<SpecificTaffyGridInfo>), + TableCellWithCollapsedBorders, + TableGridWithCollapsedBorders(Box<SpecificTableGridInfo>), + TableWrapper, +} + +#[derive(MallocSizeOf)] +pub(crate) struct BoxFragment { + pub base: BaseFragment, + + #[conditional_malloc_size_of] + pub style: ServoArc<ComputedValues>, + pub children: Vec<Fragment>, + + /// The content rect of this fragment in the parent fragment's content rectangle. This + /// does not include padding, border, or margin -- it only includes content. + pub content_rect: PhysicalRect<Au>, + + pub padding: PhysicalSides<Au>, + pub border: PhysicalSides<Au>, + pub margin: PhysicalSides<Au>, + + /// When the `clear` property is not set to `none`, it may introduce clearance. + /// Clearance is some extra spacing that is added above the top margin, + /// so that the element doesn't overlap earlier floats in the same BFC. + /// The presence of clearance prevents the top margin from collapsing with + /// earlier margins or with the bottom margin of the parent block. + /// <https://drafts.csswg.org/css2/#clearance> + pub clearance: Option<Au>, + + /// When this [`BoxFragment`] is for content that has a baseline, this tracks + /// the first and last baselines of that content. This is used to propagate baselines + /// to things such as tables and inline formatting contexts. + baselines: Baselines, + + block_margins_collapsed_with_children: Option<Box<CollapsedBlockMargins>>, + + /// The scrollable overflow of this box fragment. + pub scrollable_overflow_from_children: PhysicalRect<Au>, + + /// The resolved box insets if this box is `position: sticky`. These are calculated + /// during stacking context tree construction because they rely on the size of the + /// scroll container. + pub(crate) resolved_sticky_insets: AtomicRefCell<Option<PhysicalSides<AuOrAuto>>>, + + pub background_mode: BackgroundMode, + + /// Additional information of from layout that could be used by Javascripts and devtools. + pub specific_layout_info: Option<SpecificLayoutInfo>, +} + +impl BoxFragment { + #[allow(clippy::too_many_arguments)] + pub fn new( + base_fragment_info: BaseFragmentInfo, + style: ServoArc<ComputedValues>, + children: Vec<Fragment>, + content_rect: PhysicalRect<Au>, + padding: PhysicalSides<Au>, + border: PhysicalSides<Au>, + margin: PhysicalSides<Au>, + clearance: Option<Au>, + ) -> BoxFragment { + let scrollable_overflow_from_children = + children.iter().fold(PhysicalRect::zero(), |acc, child| { + acc.union(&child.scrollable_overflow()) + }); + + BoxFragment { + base: base_fragment_info.into(), + style, + children, + content_rect, + padding, + border, + margin, + clearance, + baselines: Baselines::default(), + block_margins_collapsed_with_children: None, + scrollable_overflow_from_children, + resolved_sticky_insets: AtomicRefCell::default(), + background_mode: BackgroundMode::Normal, + specific_layout_info: None, + } + } + + pub fn with_baselines(mut self, baselines: Baselines) -> Self { + self.baselines = baselines; + self + } + + /// Get the baselines for this [`BoxFragment`] if they are compatible with the given [`WritingMode`]. + /// If they are not compatible, [`Baselines::default()`] is returned. + pub fn baselines(&self, writing_mode: WritingMode) -> Baselines { + let mut baselines = + if writing_mode.is_horizontal() == self.style.writing_mode.is_horizontal() { + self.baselines + } else { + // If the writing mode of the container requesting baselines is not + // compatible, ensure that the baselines established by this fragment are + // not used. + Baselines::default() + }; + + // From the https://drafts.csswg.org/css-align-3/#baseline-export section on "block containers": + // > However, for legacy reasons if its baseline-source is auto (the initial + // > value) a block-level or inline-level block container that is a scroll container + // > always has a last baseline set, whose baselines all correspond to its block-end + // > margin edge. + // + // This applies even if there is no baseline set, so we unconditionally set the value here + // and ignore anything that is set via [`Self::with_baselines`]. + if self.style.establishes_scroll_container(self.base.flags) { + let content_rect_size = self.content_rect.size.to_logical(writing_mode); + let padding = self.padding.to_logical(writing_mode); + let border = self.border.to_logical(writing_mode); + let margin = self.margin.to_logical(writing_mode); + baselines.last = Some( + content_rect_size.block + padding.block_end + border.block_end + margin.block_end, + ) + } + baselines + } + + pub fn add_extra_background(&mut self, extra_background: ExtraBackground) { + match self.background_mode { + BackgroundMode::Extra(ref mut backgrounds) => backgrounds.push(extra_background), + _ => self.background_mode = BackgroundMode::Extra(vec![extra_background]), + } + } + + pub fn set_does_not_paint_background(&mut self) { + self.background_mode = BackgroundMode::None; + } + + pub fn with_specific_layout_info(mut self, info: Option<SpecificLayoutInfo>) -> Self { + self.specific_layout_info = info; + self + } + + pub fn with_block_margins_collapsed_with_children( + mut self, + collapsed_margins: CollapsedBlockMargins, + ) -> Self { + self.block_margins_collapsed_with_children = Some(collapsed_margins.into()); + self + } + + pub fn scrollable_overflow(&self) -> PhysicalRect<Au> { + let physical_padding_rect = self.padding_rect(); + let content_origin = self.content_rect.origin.to_vector(); + physical_padding_rect.union( + &self + .scrollable_overflow_from_children + .translate(content_origin), + ) + } + + pub(crate) fn padding_rect(&self) -> PhysicalRect<Au> { + self.content_rect.outer_rect(self.padding) + } + + pub(crate) fn border_rect(&self) -> PhysicalRect<Au> { + self.padding_rect().outer_rect(self.border) + } + + pub(crate) fn margin_rect(&self) -> PhysicalRect<Au> { + self.border_rect().outer_rect(self.margin) + } + + pub(crate) fn padding_border_margin(&self) -> PhysicalSides<Au> { + self.margin + self.border + self.padding + } + + pub fn print(&self, tree: &mut PrintTree) { + tree.new_level(format!( + "Box\ + \nbase={:?}\ + \ncontent={:?}\ + \npadding rect={:?}\ + \nborder rect={:?}\ + \nmargin={:?}\ + \nclearance={:?}\ + \nscrollable_overflow={:?}\ + \nbaselines={:?}\ + \noverflow={:?}", + self.base, + self.content_rect, + self.padding_rect(), + self.border_rect(), + self.margin, + self.clearance, + self.scrollable_overflow(), + self.baselines, + self.style.effective_overflow(self.base.flags), + )); + + for child in &self.children { + child.print(tree); + } + tree.end_level(); + } + + pub fn scrollable_overflow_for_parent(&self) -> PhysicalRect<Au> { + let mut overflow = self.border_rect(); + if self.style.establishes_scroll_container(self.base.flags) { + return overflow; + } + + // https://www.w3.org/TR/css-overflow-3/#scrollable + // Only include the scrollable overflow of a child box if it has overflow: visible. + let scrollable_overflow = self.scrollable_overflow(); + let bottom_right = PhysicalPoint::new( + overflow.max_x().max(scrollable_overflow.max_x()), + overflow.max_y().max(scrollable_overflow.max_y()), + ); + + let overflow_style = self.style.effective_overflow(self.base.flags); + if overflow_style.y == ComputedOverflow::Visible { + overflow.origin.y = overflow.origin.y.min(scrollable_overflow.origin.y); + overflow.size.height = bottom_right.y - overflow.origin.y; + } + + if overflow_style.x == ComputedOverflow::Visible { + overflow.origin.x = overflow.origin.x.min(scrollable_overflow.origin.x); + overflow.size.width = bottom_right.x - overflow.origin.x; + } + + overflow + } + + pub(crate) fn calculate_resolved_insets_if_positioned( + &self, + containing_block: &PhysicalRect<Au>, + ) -> PhysicalSides<AuOrAuto> { + let position = self.style.get_box().position; + debug_assert_ne!( + position, + ComputedPosition::Static, + "Should not call this method on statically positioned box." + ); + + if let Some(resolved_sticky_insets) = *self.resolved_sticky_insets.borrow() { + return resolved_sticky_insets; + } + + let convert_to_au_or_auto = |sides: PhysicalSides<Au>| { + PhysicalSides::new( + AuOrAuto::LengthPercentage(sides.top), + AuOrAuto::LengthPercentage(sides.right), + AuOrAuto::LengthPercentage(sides.bottom), + AuOrAuto::LengthPercentage(sides.left), + ) + }; + + // "A resolved value special case property like top defined in another + // specification If the property applies to a positioned element and the + // resolved value of the display property is not none or contents, and + // the property is not over-constrained, then the resolved value is the + // used value. Otherwise the resolved value is the computed value." + // https://drafts.csswg.org/cssom/#resolved-values + let insets = self.style.physical_box_offsets(); + let (cb_width, cb_height) = (containing_block.width(), containing_block.height()); + if position == ComputedPosition::Relative { + let get_resolved_axis = |start: &LengthPercentageOrAuto, + end: &LengthPercentageOrAuto, + container_length: Au| { + let start = start.map(|value| value.to_used_value(container_length)); + let end = end.map(|value| value.to_used_value(container_length)); + match (start.non_auto(), end.non_auto()) { + (None, None) => (Au::zero(), Au::zero()), + (None, Some(end)) => (-end, end), + (Some(start), None) => (start, -start), + // This is the overconstrained case, for which the resolved insets will + // simply be the computed insets. + (Some(start), Some(end)) => (start, end), + } + }; + let (left, right) = get_resolved_axis(&insets.left, &insets.right, cb_width); + let (top, bottom) = get_resolved_axis(&insets.top, &insets.bottom, cb_height); + return convert_to_au_or_auto(PhysicalSides::new(top, right, bottom, left)); + } + + debug_assert!( + position == ComputedPosition::Fixed || position == ComputedPosition::Absolute + ); + + let margin_rect = self.margin_rect(); + let (top, bottom) = match (&insets.top, &insets.bottom) { + ( + LengthPercentageOrAuto::LengthPercentage(top), + LengthPercentageOrAuto::LengthPercentage(bottom), + ) => ( + top.to_used_value(cb_height), + bottom.to_used_value(cb_height), + ), + _ => (margin_rect.origin.y, cb_height - margin_rect.max_y()), + }; + let (left, right) = match (&insets.left, &insets.right) { + ( + LengthPercentageOrAuto::LengthPercentage(left), + LengthPercentageOrAuto::LengthPercentage(right), + ) => (left.to_used_value(cb_width), right.to_used_value(cb_width)), + _ => (margin_rect.origin.x, cb_width - margin_rect.max_x()), + }; + + convert_to_au_or_auto(PhysicalSides::new(top, right, bottom, left)) + } + + /// Whether this is a non-replaced inline-level box whose inner display type is `flow`. + /// <https://drafts.csswg.org/css-display-3/#inline-box> + pub(crate) fn is_inline_box(&self) -> bool { + self.style.is_inline_box(self.base.flags) + } + + /// Whether this is an atomic inline-level box. + /// <https://drafts.csswg.org/css-display-3/#atomic-inline> + pub(crate) fn is_atomic_inline_level(&self) -> bool { + self.style.get_box().display.outside() == DisplayOutside::Inline && !self.is_inline_box() + } + + /// Whether this is a table wrapper box. + /// <https://www.w3.org/TR/css-tables-3/#table-wrapper-box> + pub(crate) fn is_table_wrapper(&self) -> bool { + matches!( + self.specific_layout_info, + Some(SpecificLayoutInfo::TableWrapper) + ) + } + + pub(crate) fn has_collapsed_borders(&self) -> bool { + match &self.specific_layout_info { + Some(SpecificLayoutInfo::TableCellWithCollapsedBorders) => true, + Some(SpecificLayoutInfo::TableGridWithCollapsedBorders(_)) => true, + Some(SpecificLayoutInfo::TableWrapper) => { + self.style.get_inherited_table().border_collapse == BorderCollapse::Collapse + }, + _ => false, + } + } + + pub(crate) fn block_margins_collapsed_with_children(&self) -> CollapsedBlockMargins { + match self.block_margins_collapsed_with_children.as_ref() { + Some(collapsed_block_margins) => *(collapsed_block_margins).clone(), + _ => CollapsedBlockMargins::zero(), + } + } +} |