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/* 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 base::print_tree::PrintTree;
use compositing_traits::display_list::AxesScrollSensitivity;
use euclid::default::Size2D;
use fxhash::FxHashSet;
use malloc_size_of_derive::MallocSizeOf;
use style::animation::AnimationSetKey;
use webrender_api::units;
use super::{BoxFragment, ContainingBlockManager, Fragment};
use crate::ArcRefCell;
use crate::context::LayoutContext;
use crate::display_list::StackingContext;
use crate::geom::PhysicalRect;
#[derive(MallocSizeOf)]
pub struct FragmentTree {
/// Fragments at the top-level of the tree.
///
/// If the root element has `display: none`, there are zero fragments.
/// Otherwise, there is at least one:
///
/// * The first fragment is generated by the root element.
/// * There may be additional fragments generated by positioned boxes
/// that have the initial containing block.
pub(crate) root_fragments: Vec<Fragment>,
/// The scrollable overflow rectangle for the entire tree
/// <https://drafts.csswg.org/css-overflow/#scrollable>
pub(crate) scrollable_overflow: PhysicalRect<Au>,
/// The containing block used in the layout of this fragment tree.
pub(crate) initial_containing_block: PhysicalRect<Au>,
/// Whether or not the viewport is sensitive to scroll input events.
pub viewport_scroll_sensitivity: AxesScrollSensitivity,
}
impl FragmentTree {
pub(crate) fn new(
layout_context: &LayoutContext,
root_fragments: Vec<Fragment>,
scrollable_overflow: PhysicalRect<Au>,
initial_containing_block: PhysicalRect<Au>,
viewport_scroll_sensitivity: AxesScrollSensitivity,
) -> Self {
let fragment_tree = Self {
root_fragments,
scrollable_overflow,
initial_containing_block,
viewport_scroll_sensitivity,
};
// As part of building the fragment tree, we want to stop animating elements and
// pseudo-elements that used to be animating or had animating images attached to
// them. Create a set of all elements that used to be animating.
let mut animations = layout_context.style_context.animations.sets.write();
let mut invalid_animating_nodes: FxHashSet<_> = animations.keys().cloned().collect();
let mut image_animations = layout_context.node_image_animation_map.write().to_owned();
let mut invalid_image_animating_nodes: FxHashSet<_> = image_animations
.keys()
.cloned()
.map(|node| AnimationSetKey::new(node, None))
.collect();
fragment_tree.find(|fragment, _level, containing_block| {
if let Some(tag) = fragment.tag() {
invalid_animating_nodes.remove(&AnimationSetKey::new(tag.node, tag.pseudo));
invalid_image_animating_nodes.remove(&AnimationSetKey::new(tag.node, tag.pseudo));
}
fragment.set_containing_block(containing_block);
None::<()>
});
// Cancel animations for any elements and pseudo-elements that are no longer found
// in the fragment tree.
for node in &invalid_animating_nodes {
if let Some(state) = animations.get_mut(node) {
state.cancel_all_animations();
}
}
for node in &invalid_image_animating_nodes {
image_animations.remove(&node.node);
}
fragment_tree
}
pub(crate) fn build_display_list(
&self,
builder: &mut crate::display_list::DisplayListBuilder,
root_stacking_context: &StackingContext,
) {
// Paint the canvas’ background (if any) before/under everything else
root_stacking_context.build_canvas_background_display_list(builder, self);
root_stacking_context.build_display_list(builder);
}
pub fn print(&self) {
let mut print_tree = PrintTree::new("Fragment Tree".to_string());
for fragment in &self.root_fragments {
fragment.print(&mut print_tree);
}
}
pub fn scrollable_overflow(&self) -> units::LayoutSize {
units::LayoutSize::from_untyped(Size2D::new(
self.scrollable_overflow.size.width.to_f32_px(),
self.scrollable_overflow.size.height.to_f32_px(),
))
}
pub(crate) fn find<T>(
&self,
mut process_func: impl FnMut(&Fragment, usize, &PhysicalRect<Au>) -> Option<T>,
) -> Option<T> {
let info = ContainingBlockManager {
for_non_absolute_descendants: &self.initial_containing_block,
for_absolute_descendants: None,
for_absolute_and_fixed_descendants: &self.initial_containing_block,
};
self.root_fragments
.iter()
.find_map(|child| child.find(&info, 0, &mut process_func))
}
/// <https://drafts.csswg.org/cssom-view/#scrolling-area>
///
/// Scrolling area for a viewport that is clipped according to overflow direction of root element.
pub fn get_scrolling_area_for_viewport(&self) -> PhysicalRect<Au> {
let mut scroll_area = self.initial_containing_block;
if let Some(root_fragment) = self.root_fragments.first() {
for fragment in self.root_fragments.iter() {
scroll_area = fragment.unclipped_scrolling_area().union(&scroll_area);
}
match root_fragment {
Fragment::Box(fragment) | Fragment::Float(fragment) => fragment
.borrow()
.clip_unreachable_scrollable_overflow_region(
scroll_area,
self.initial_containing_block,
),
_ => scroll_area,
}
} else {
scroll_area
}
}
/// Find the `<body>` element's [`Fragment`], if it exists in this [`FragmentTree`].
pub(crate) fn body_fragment(&self) -> Option<ArcRefCell<BoxFragment>> {
fn find_body(children: &[Fragment]) -> Option<ArcRefCell<BoxFragment>> {
children.iter().find_map(|fragment| {
match fragment {
Fragment::Box(box_fragment) | Fragment::Float(box_fragment) => {
let borrowed_box_fragment = box_fragment.borrow();
if borrowed_box_fragment.is_body_element_of_html_element_root() {
return Some(box_fragment.clone());
}
// The fragment for the `<body>` element is typically a child of the root (though,
// not if it's absolutely positioned), so we need to recurse into the children of
// the root to find it.
//
// Additionally, recurse into any anonymous fragments, as the `<body>` fragment may
// have created anonymous parents (for instance by creating an inline formatting context).
if borrowed_box_fragment.is_root_element() ||
borrowed_box_fragment.base.is_anonymous()
{
find_body(&borrowed_box_fragment.children)
} else {
None
}
},
Fragment::Positioning(positioning_context)
if positioning_context.borrow().base.is_anonymous() =>
{
// If the `<body>` element is a `display: inline` then it might be nested inside of a
// `PositioningFragment` for the purposes of putting it on the first line of the implied
// inline formatting context.
find_body(&positioning_context.borrow().children)
},
_ => None,
}
})
}
find_body(&self.root_fragments)
}
}
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