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https://github.com/servo/servo.git
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29876d2703
Collect scroll roots during the collect_stacking_context phase instead of during display list construction. This will be useful in order to collect containing block scroll roots as well as to give scroll roots sequential ids in the future. This change also pulls stacking context children out of the StackingContext struct itself, which should reduce very slightly the memory used by the finished display list. This also simplifies the DisplayListBuilder because it no longer has to maintain a stack of ScrollRootIds and StackingContextIds and can instead just rely on the program stack.
313 lines
12 KiB
Rust
313 lines
12 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 http://mozilla.org/MPL/2.0/. */
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//! CSS Multi-column layout http://dev.w3.org/csswg/css-multicol/
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#![deny(unsafe_code)]
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use app_units::Au;
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use block::BlockFlow;
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use context::{LayoutContext, SharedLayoutContext};
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use display_list_builder::DisplayListBuildState;
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use euclid::Point2D;
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use euclid::Size2D;
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use floats::FloatKind;
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use flow::{Flow, FlowClass, OpaqueFlow, mut_base, FragmentationContext};
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use fragment::{Fragment, FragmentBorderBoxIterator, Overflow};
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use gfx_traits::print_tree::PrintTree;
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use std::cmp::{min, max};
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use std::fmt;
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use std::sync::Arc;
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use style::context::SharedStyleContext;
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use style::logical_geometry::LogicalSize;
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use style::properties::ServoComputedValues;
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use style::values::Either;
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use style::values::computed::{LengthOrPercentageOrAuto, LengthOrPercentageOrNone};
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pub struct MulticolFlow {
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pub block_flow: BlockFlow,
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/// Length between the inline-start edge of a column and that of the next.
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/// That is, the used column-width + used column-gap.
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pub column_pitch: Au,
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}
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pub struct MulticolColumnFlow {
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pub block_flow: BlockFlow,
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}
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impl MulticolFlow {
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pub fn from_fragment(fragment: Fragment, float_kind: Option<FloatKind>) -> MulticolFlow {
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MulticolFlow {
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block_flow: BlockFlow::from_fragment_and_float_kind(fragment, float_kind),
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column_pitch: Au(0),
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}
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}
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}
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impl MulticolColumnFlow {
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pub fn from_fragment(fragment: Fragment) -> MulticolColumnFlow {
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MulticolColumnFlow {
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block_flow: BlockFlow::from_fragment(fragment),
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}
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}
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}
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impl Flow for MulticolFlow {
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fn class(&self) -> FlowClass {
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FlowClass::Multicol
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}
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fn as_mut_block(&mut self) -> &mut BlockFlow {
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&mut self.block_flow
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}
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fn as_block(&self) -> &BlockFlow {
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&self.block_flow
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}
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fn as_mut_multicol(&mut self) -> &mut MulticolFlow {
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self
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}
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fn bubble_inline_sizes(&mut self) {
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// FIXME(SimonSapin) http://dev.w3.org/csswg/css-sizing/#multicol-intrinsic
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self.block_flow.bubble_inline_sizes();
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}
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fn assign_inline_sizes(&mut self, shared_context: &SharedStyleContext) {
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debug!("assign_inline_sizes({}): assigning inline_size for flow", "multicol");
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self.block_flow.compute_inline_sizes(shared_context);
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// Move in from the inline-start border edge.
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let inline_start_content_edge = self.block_flow.fragment.border_box.start.i +
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self.block_flow.fragment.border_padding.inline_start;
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// Distance from the inline-end margin edge to the inline-end content edge.
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let inline_end_content_edge =
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self.block_flow.fragment.margin.inline_end +
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self.block_flow.fragment.border_padding.inline_end;
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self.block_flow.assign_inline_sizes(shared_context);
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let padding_and_borders = self.block_flow.fragment.border_padding.inline_start_end();
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let content_inline_size =
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self.block_flow.fragment.border_box.size.inline - padding_and_borders;
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let column_width;
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{
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let column_style = self.block_flow.fragment.style.get_column();
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let column_gap = match column_style.column_gap {
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Either::First(len) => len,
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Either::Second(_normal) => self.block_flow.fragment.style.get_font().font_size,
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};
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let mut column_count;
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if let Either::First(column_width) = column_style.column_width {
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column_count =
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max(1, (content_inline_size + column_gap).0 / (column_width + column_gap).0);
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if let Some(specified_column_count) = column_style.column_count.0 {
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column_count = min(column_count, specified_column_count as i32);
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}
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} else {
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column_count = column_style.column_count.0.unwrap() as i32;
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}
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column_width =
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max(Au(0), (content_inline_size + column_gap) / column_count - column_gap);
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self.column_pitch = column_width + column_gap;
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}
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self.block_flow.fragment.border_box.size.inline = content_inline_size + padding_and_borders;
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self.block_flow.propagate_assigned_inline_size_to_children(
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shared_context, inline_start_content_edge, inline_end_content_edge, column_width,
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|_, _, _, _, _, _| {});
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}
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fn assign_block_size<'a>(&mut self, ctx: &'a LayoutContext<'a>) {
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debug!("assign_block_size: assigning block_size for multicol");
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let fragmentation_context = Some(FragmentationContext {
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this_fragment_is_empty: true,
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available_block_size: {
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let style = &self.block_flow.fragment.style;
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if let LengthOrPercentageOrAuto::Length(length) = style.content_block_size() {
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length
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} else if let LengthOrPercentageOrNone::Length(length) = style.max_block_size() {
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length
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} else {
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// FIXME: do column balancing instead
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// FIXME: (until column balancing) substract margins/borders/padding
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LogicalSize::from_physical(
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self.block_flow.base.writing_mode,
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ctx.shared_context().viewport_size,
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).block
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}
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}
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});
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// Before layout, everything is in a single "column"
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assert!(self.block_flow.base.children.len() == 1);
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let mut column = self.block_flow.base.children.pop_front_arc().unwrap();
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// Pretend there is no children for this:
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self.block_flow.assign_block_size(ctx);
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loop {
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let remaining = Arc::get_mut(&mut column).unwrap().fragment(ctx, fragmentation_context);
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self.block_flow.base.children.push_back_arc(column);
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column = match remaining {
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Some(remaining) => remaining,
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None => break
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};
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}
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}
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fn compute_absolute_position(&mut self, layout_context: &SharedLayoutContext) {
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self.block_flow.compute_absolute_position(layout_context);
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let pitch = LogicalSize::new(self.block_flow.base.writing_mode, self.column_pitch, Au(0));
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let pitch = pitch.to_physical(self.block_flow.base.writing_mode);
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for (i, child) in self.block_flow.base.children.iter_mut().enumerate() {
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let point = &mut mut_base(child).stacking_relative_position;
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*point = *point + Size2D::new(pitch.width * i as i32, pitch.height * i as i32);
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}
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}
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fn update_late_computed_inline_position_if_necessary(&mut self, inline_position: Au) {
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self.block_flow.update_late_computed_inline_position_if_necessary(inline_position)
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}
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fn update_late_computed_block_position_if_necessary(&mut self, block_position: Au) {
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self.block_flow.update_late_computed_block_position_if_necessary(block_position)
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}
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fn build_display_list(&mut self, state: &mut DisplayListBuildState) {
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debug!("build_display_list_multicol");
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self.block_flow.build_display_list(state);
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}
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fn collect_stacking_contexts(&mut self, state: &mut DisplayListBuildState) {
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self.block_flow.collect_stacking_contexts(state);
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}
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fn repair_style(&mut self, new_style: &Arc<ServoComputedValues>) {
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self.block_flow.repair_style(new_style)
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}
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fn compute_overflow(&self) -> Overflow {
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self.block_flow.compute_overflow()
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}
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fn generated_containing_block_size(&self, flow: OpaqueFlow) -> LogicalSize<Au> {
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self.block_flow.generated_containing_block_size(flow)
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}
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fn iterate_through_fragment_border_boxes(&self,
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iterator: &mut FragmentBorderBoxIterator,
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level: i32,
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stacking_context_position: &Point2D<Au>) {
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self.block_flow.iterate_through_fragment_border_boxes(iterator, level, stacking_context_position);
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}
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fn mutate_fragments(&mut self, mutator: &mut FnMut(&mut Fragment)) {
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self.block_flow.mutate_fragments(mutator);
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}
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fn print_extra_flow_children(&self, print_tree: &mut PrintTree) {
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self.block_flow.print_extra_flow_children(print_tree);
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}
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}
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impl Flow for MulticolColumnFlow {
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fn class(&self) -> FlowClass {
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FlowClass::MulticolColumn
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}
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fn as_mut_block(&mut self) -> &mut BlockFlow {
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&mut self.block_flow
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}
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fn as_block(&self) -> &BlockFlow {
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&self.block_flow
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}
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fn bubble_inline_sizes(&mut self) {
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self.block_flow.bubble_inline_sizes();
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}
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fn assign_inline_sizes(&mut self, shared_context: &SharedStyleContext) {
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debug!("assign_inline_sizes({}): assigning inline_size for flow", "multicol column");
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self.block_flow.assign_inline_sizes(shared_context);
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}
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fn assign_block_size<'a>(&mut self, ctx: &'a LayoutContext<'a>) {
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debug!("assign_block_size: assigning block_size for multicol column");
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self.block_flow.assign_block_size(ctx);
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}
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fn fragment(&mut self, layout_context: &LayoutContext,
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fragmentation_context: Option<FragmentationContext>)
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-> Option<Arc<Flow>> {
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Flow::fragment(&mut self.block_flow, layout_context, fragmentation_context)
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}
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fn compute_absolute_position(&mut self, layout_context: &SharedLayoutContext) {
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self.block_flow.compute_absolute_position(layout_context)
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}
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fn update_late_computed_inline_position_if_necessary(&mut self, inline_position: Au) {
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self.block_flow.update_late_computed_inline_position_if_necessary(inline_position)
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}
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fn update_late_computed_block_position_if_necessary(&mut self, block_position: Au) {
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self.block_flow.update_late_computed_block_position_if_necessary(block_position)
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}
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fn build_display_list(&mut self, state: &mut DisplayListBuildState) {
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debug!("build_display_list_multicol column");
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self.block_flow.build_display_list(state);
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}
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fn collect_stacking_contexts(&mut self, state: &mut DisplayListBuildState) {
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self.block_flow.collect_stacking_contexts(state);
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}
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fn repair_style(&mut self, new_style: &Arc<ServoComputedValues>) {
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self.block_flow.repair_style(new_style)
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}
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fn compute_overflow(&self) -> Overflow {
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self.block_flow.compute_overflow()
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}
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fn generated_containing_block_size(&self, flow: OpaqueFlow) -> LogicalSize<Au> {
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self.block_flow.generated_containing_block_size(flow)
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}
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fn iterate_through_fragment_border_boxes(&self,
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iterator: &mut FragmentBorderBoxIterator,
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level: i32,
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stacking_context_position: &Point2D<Au>) {
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self.block_flow.iterate_through_fragment_border_boxes(iterator, level, stacking_context_position);
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}
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fn mutate_fragments(&mut self, mutator: &mut FnMut(&mut Fragment)) {
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self.block_flow.mutate_fragments(mutator);
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}
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fn print_extra_flow_children(&self, print_tree: &mut PrintTree) {
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self.block_flow.print_extra_flow_children(print_tree);
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}
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}
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impl fmt::Debug for MulticolFlow {
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fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
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write!(f, "MulticolFlow: {:?}", self.block_flow)
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}
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}
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impl fmt::Debug for MulticolColumnFlow {
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fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
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write!(f, "MulticolColumnFlow: {:?}", self.block_flow)
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}
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}
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