82b016ed19
Use compositor hit-test commands in the display list to rebuild async wheel targets, and serialize the async scroll metadata needed to reconstruct AsyncScrollingState from the same display-list snapshot. Driving the async scroll tree off the display list rather than a separately collected tree has a few benefits: - No additional full paintable tree traversal is required, since the information needed by the compositor is gathered while recording the display list. - The display list is already serializable, so the async scroll tree no longer needs its own serialization path. - It is more debuggable, as the existing display list dump now also covers the data used to reconstruct the async scroll tree. - In the future we will want to include other areas that can interfere with hit-testing; recording them during display list construction makes it straightforward to preserve a hit-testing order that matches painting order.
439 lines
22 KiB
C++
439 lines
22 KiB
C++
/*
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* Copyright (c) 2026-present, the Ladybird developers.
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*
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* SPDX-License-Identifier: BSD-2-Clause
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*/
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#include <LibWeb/CSS/ComputedValues.h>
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#include <LibWeb/Compositor/AsyncScrollTree.h>
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#include <LibWeb/Compositor/AsyncScrollingState.h>
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#include <LibWeb/DOM/DOMEventListener.h>
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#include <LibWeb/DOM/Document.h>
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#include <LibWeb/DOM/EventTarget.h>
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#include <LibWeb/HTML/Navigable.h>
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#include <LibWeb/HTML/NavigableContainer.h>
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#include <LibWeb/HTML/Window.h>
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#include <LibWeb/Page/Page.h>
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#include <LibWeb/Painting/DisplayList.h>
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#include <LibWeb/Painting/DisplayListRecorder.h>
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#include <LibWeb/Painting/DisplayListRecordingContext.h>
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#include <LibWeb/Painting/PaintableBox.h>
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#include <LibWeb/Painting/ScrollState.h>
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#include <LibWeb/Painting/ViewportPaintable.h>
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#include <LibWeb/PixelUnits.h>
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namespace Web::Compositor {
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static Gfx::FloatPoint css_point_to_device_point(CSSPixelPoint point, double device_pixels_per_css_pixel)
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{
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auto scale = static_cast<float>(device_pixels_per_css_pixel);
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return { point.x().to_float() * scale, point.y().to_float() * scale };
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}
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static Gfx::FloatSize css_size_to_device_size(CSSPixelSize size, double device_pixels_per_css_pixel)
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{
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auto scale = static_cast<float>(device_pixels_per_css_pixel);
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return { size.width().to_float() * scale, size.height().to_float() * scale };
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}
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static Gfx::FloatRect css_rect_to_device_rect(CSSPixelRect rect, double device_pixels_per_css_pixel)
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{
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return { css_point_to_device_point(rect.location(), device_pixels_per_css_pixel), css_size_to_device_size(rect.size(), device_pixels_per_css_pixel) };
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}
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static Optional<float> css_inset_to_device_inset(Optional<CSSPixels> inset, double device_pixels_per_css_pixel)
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{
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if (!inset.has_value())
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return {};
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return inset->to_float() * static_cast<float>(device_pixels_per_css_pixel);
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}
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static AsyncScrollNodeID scroll_node_id_for(UniqueNodeID document_id, Painting::ScrollFrameIndex scroll_frame_index)
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{
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return { .document_id = document_id, .scroll_frame_index = scroll_frame_index };
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}
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static bool is_nested_navigable_container(Painting::PaintableBox const& paintable_box)
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{
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auto node = paintable_box.dom_node();
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return node && node->is_navigable_container() && as<HTML::NavigableContainer const>(*node).content_navigable();
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}
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static CSSPixelPoint maximum_scroll_offset_for(Painting::PaintableBox const& paintable_box)
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{
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CSSPixelPoint max_scroll_offset;
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auto scrollable_overflow_rect = paintable_box.scrollable_overflow_rect();
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if (!scrollable_overflow_rect.has_value())
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return max_scroll_offset;
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auto scrollport_rect = paintable_box.absolute_padding_box_rect();
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max_scroll_offset.set_x(max(CSSPixels(0), scrollable_overflow_rect->width() - scrollport_rect.width()));
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max_scroll_offset.set_y(max(CSSPixels(0), scrollable_overflow_rect->height() - scrollport_rect.height()));
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return max_scroll_offset;
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}
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static void record_scroll_node(Painting::PaintableBox const& paintable_box, DisplayListRecordingContext& context)
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{
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auto parent_scroll_frame_index = Painting::ScrollFrameIndex {};
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if (auto scrollable_ancestor = paintable_box.nearest_scrollable_ancestor())
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parent_scroll_frame_index = scrollable_ancestor->own_scroll_frame_index();
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auto scrollport_rect = paintable_box.is_viewport_paintable()
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? Gfx::IntRect { {}, context.device_viewport_rect().size().to_type<int>() }
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: context.rounded_device_rect(paintable_box.absolute_padding_box_rect()).to_type<int>();
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auto& recorder = context.display_list_recorder();
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recorder.compositor_scroll_node({
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.document_id = paintable_box.document().unique_id(),
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.scroll_frame_index = paintable_box.own_scroll_frame_index(),
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.parent_scroll_frame_index = parent_scroll_frame_index,
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.scrollport_rect = scrollport_rect,
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.max_scroll_offset = css_point_to_device_point(maximum_scroll_offset_for(paintable_box), context.device_pixels_per_css_pixel()),
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.is_viewport = paintable_box.is_viewport_paintable(),
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});
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}
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static void record_main_thread_wheel_event_region(Painting::PaintableBox const& paintable_box, DisplayListRecordingContext& context)
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{
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auto rect = css_rect_to_device_rect(paintable_box.absolute_united_border_box_rect(), context.device_pixels_per_css_pixel());
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if (rect.is_empty())
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return;
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context.display_list_recorder().compositor_main_thread_wheel_event_region({
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.rect = rect,
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});
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}
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static void record_viewport_scrollbar_state(Painting::PaintableBox const& paintable_box, DisplayListRecordingContext& context)
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{
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if (!paintable_box.is_viewport_paintable())
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return;
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if (!paintable_box.document().page().async_scrolling_enabled())
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return;
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if (!Painting::should_paint_viewport_scrollbars())
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return;
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if (paintable_box.computed_values().scrollbar_width() == CSS::ScrollbarWidth::None)
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return;
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auto scrollbar_colors = paintable_box.computed_values().scrollbar_color();
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auto const& metrics = context.chrome_metrics();
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for (auto direction : { Painting::PaintableBox::ScrollDirection::Vertical, Painting::PaintableBox::ScrollDirection::Horizontal }) {
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auto scrollbar_data = paintable_box.compute_scrollbar_data(direction, metrics, nullptr, Painting::PaintableBox::ScrollbarSizing::Regular);
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if (!scrollbar_data.has_value())
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continue;
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auto expanded_scrollbar_data = paintable_box.compute_scrollbar_data(direction, metrics, nullptr, Painting::PaintableBox::ScrollbarSizing::Enlarged);
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VERIFY(expanded_scrollbar_data.has_value());
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auto gutter_rect = context.rounded_device_rect(scrollbar_data->gutter_rect).to_type<int>();
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auto max_scroll_offset = css_point_to_device_point(maximum_scroll_offset_for(paintable_box), context.device_pixels_per_css_pixel());
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auto orientation = direction == Painting::PaintableBox::ScrollDirection::Horizontal ? Gfx::Orientation::Horizontal : Gfx::Orientation::Vertical;
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auto thumb_color = scrollbar_colors.thumb_color;
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if (gutter_rect.is_empty() && thumb_color == CSS::InitialValues::scrollbar_color().thumb_color)
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thumb_color = thumb_color.with_alpha(128);
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context.display_list_recorder().compositor_viewport_scrollbar({
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.document_id = paintable_box.document().unique_id(),
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.scroll_frame_index = paintable_box.own_scroll_frame_index(),
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.gutter_rect = gutter_rect,
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.thumb_rect = context.rounded_device_rect(scrollbar_data->thumb_rect).to_type<int>(),
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.expanded_gutter_rect = context.rounded_device_rect(expanded_scrollbar_data->gutter_rect).to_type<int>(),
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.expanded_thumb_rect = context.rounded_device_rect(expanded_scrollbar_data->thumb_rect).to_type<int>(),
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.scroll_size = scrollbar_data->thumb_travel_to_scroll_ratio.to_double(),
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.expanded_scroll_size = expanded_scrollbar_data->thumb_travel_to_scroll_ratio.to_double(),
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.max_scroll_offset = max_scroll_offset.primary_offset_for_orientation(orientation),
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.thumb_color = thumb_color,
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.track_color = scrollbar_colors.track_color,
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.vertical = direction == Painting::PaintableBox::ScrollDirection::Vertical,
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});
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}
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}
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static bool has_blocking_wheel_event_listener(DOM::EventTarget const& event_target)
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{
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for (auto listener : event_target.event_listener_list()) {
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if (AK::first_is_one_of(listener->type, "wheel"sv, "mousewheel"sv) && listener->passive != true)
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return true;
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}
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return false;
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}
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static bool is_root_wheel_event_target(DOM::Node const& node)
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{
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auto& document = node.document();
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return &node == document.document_element() || &node == document.body();
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}
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static void collect_root_blocking_wheel_event_regions(AsyncScrollingState& async_scrolling_state, DOM::Document& document)
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{
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DOM::EventTarget* roots[] = {
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document.navigable() ? document.navigable()->active_window() : nullptr,
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&document,
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document.document_element(),
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document.body(),
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};
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for (auto* target : roots) {
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if (target && has_blocking_wheel_event_listener(*target)) {
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async_scrolling_state.has_blocking_wheel_event_listeners = true;
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async_scrolling_state.has_blocking_wheel_event_region_covering_viewport = true;
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return;
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}
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}
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}
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void initialize_async_scrolling_metadata_recording(DisplayListRecordingContext& context, Painting::ViewportPaintable& document_paintable)
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{
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AsyncScrollingState async_scrolling_state;
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collect_root_blocking_wheel_event_regions(async_scrolling_state, document_paintable.document());
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context.set_async_scrolling_metadata_context(
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document_paintable.document().unique_id(),
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document_paintable.scroll_state(),
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async_scrolling_state.has_blocking_wheel_event_listeners,
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async_scrolling_state.has_blocking_wheel_event_region_covering_viewport);
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}
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void record_async_scrolling_metadata_for_paintable(Painting::PaintableBox const& paintable_box, DisplayListRecordingContext& context)
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{
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if (!context.is_recording_async_scrolling_metadata())
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return;
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auto device_pixels_per_css_pixel = context.device_pixels_per_css_pixel();
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auto& recorder = context.display_list_recorder();
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if (!context.has_blocking_wheel_event_region_covering_viewport()) {
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if (auto node = paintable_box.dom_node(); node && !is_root_wheel_event_target(*node) && has_blocking_wheel_event_listener(*node)) {
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context.set_has_blocking_wheel_event_listeners(true);
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recorder.compositor_blocking_wheel_event_region({
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.rect = css_rect_to_device_rect(paintable_box.absolute_united_border_box_rect(), device_pixels_per_css_pixel),
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});
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}
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}
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if (is_nested_navigable_container(paintable_box)) {
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record_main_thread_wheel_event_region(paintable_box, context);
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} else if (paintable_box.own_scroll_frame_index().value() && paintable_box.could_be_scrolled_by_wheel_event()) {
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record_scroll_node(paintable_box, context);
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}
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record_viewport_scrollbar_state(paintable_box, context);
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auto const& scroll_state = context.async_scrolling_scroll_state();
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auto sticky_frame_index = paintable_box.enclosing_scroll_frame_index();
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if (paintable_box.is_sticky_position() && sticky_frame_index.value()) {
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auto const& frame = scroll_state.frame_at(sticky_frame_index);
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if (frame.is_sticky() && frame.has_sticky_constraints()) {
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auto const& constraints = frame.sticky_constraints();
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auto const& insets = constraints.insets;
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recorder.compositor_sticky_area({
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.document_id = context.async_scrolling_document_id(),
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.scroll_frame_index = sticky_frame_index,
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.parent_scroll_frame_index = frame.parent_index(),
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.nearest_scrolling_ancestor_index = scroll_state.nearest_scrolling_ancestor(sticky_frame_index),
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.position_relative_to_scroll_ancestor = css_point_to_device_point(constraints.position_relative_to_scroll_ancestor, device_pixels_per_css_pixel),
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.border_box_size = css_size_to_device_size(constraints.border_box_size, device_pixels_per_css_pixel),
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.scrollport_size = css_size_to_device_size(constraints.scrollport_size, device_pixels_per_css_pixel),
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.containing_block_region = css_rect_to_device_rect(constraints.containing_block_region, device_pixels_per_css_pixel),
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.needs_parent_offset_adjustment = constraints.needs_parent_offset_adjustment,
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.inset_top = css_inset_to_device_inset(insets.top, device_pixels_per_css_pixel),
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.inset_right = css_inset_to_device_inset(insets.right, device_pixels_per_css_pixel),
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.inset_bottom = css_inset_to_device_inset(insets.bottom, device_pixels_per_css_pixel),
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.inset_left = css_inset_to_device_inset(insets.left, device_pixels_per_css_pixel),
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});
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}
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}
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}
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void finalize_async_scrolling_metadata_recording(DisplayListRecordingContext& context, HTML::Navigable& navigable, Gfx::IntRect viewport_rect)
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{
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if (!context.is_recording_async_scrolling_metadata())
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return;
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context.display_list_recorder().set_async_scrolling_metadata({
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.viewport_rect = viewport_rect,
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.wheel_event_listener_state_generation = navigable.page().wheel_event_listener_state_generation(),
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.has_blocking_wheel_event_listeners = context.has_blocking_wheel_event_listeners(),
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.has_blocking_wheel_event_region_covering_viewport = context.has_blocking_wheel_event_region_covering_viewport(),
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});
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}
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AsyncScrollingState async_scrolling_state_from_display_list(Painting::DisplayList const& display_list)
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{
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AsyncScrollingState async_scrolling_state;
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Vector<Painting::ScrollFrameIndex> parent_scroll_frame_indices;
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if (auto const& metadata = display_list.async_scrolling_metadata(); metadata.has_value()) {
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async_scrolling_state.viewport_rect = metadata->viewport_rect;
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async_scrolling_state.wheel_event_listener_state_generation = metadata->wheel_event_listener_state_generation;
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async_scrolling_state.has_blocking_wheel_event_listeners = metadata->has_blocking_wheel_event_listeners;
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async_scrolling_state.has_blocking_wheel_event_region_covering_viewport = metadata->has_blocking_wheel_event_region_covering_viewport;
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}
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display_list.for_each_command_header([&](Painting::DisplayListCommandHeader const& header, ReadonlyBytes payload) {
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switch (header.type) {
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case Painting::DisplayListCommandType::CompositorBlockingWheelEventRegion: {
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auto command = Painting::read_display_list_command_payload<Painting::CompositorBlockingWheelEventRegion>(payload);
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async_scrolling_state.has_blocking_wheel_event_listeners = true;
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async_scrolling_state.blocking_wheel_event_regions.append({
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.visual_context_index = header.context_index,
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.rect = command.rect,
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});
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break;
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}
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case Painting::DisplayListCommandType::CompositorStickyArea: {
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auto command = Painting::read_display_list_command_payload<Painting::CompositorStickyArea>(payload);
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async_scrolling_state.sticky_areas.append({
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.document_id = command.document_id,
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.scroll_frame_index = command.scroll_frame_index,
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.parent_scroll_frame_index = command.parent_scroll_frame_index,
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.nearest_scrolling_ancestor_index = command.nearest_scrolling_ancestor_index,
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.position_relative_to_scroll_ancestor = command.position_relative_to_scroll_ancestor,
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.border_box_size = command.border_box_size,
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.scrollport_size = command.scrollport_size,
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.containing_block_region = command.containing_block_region,
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.needs_parent_offset_adjustment = command.needs_parent_offset_adjustment,
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.inset_top = command.inset_top,
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.inset_right = command.inset_right,
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.inset_bottom = command.inset_bottom,
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.inset_left = command.inset_left,
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});
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break;
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}
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case Painting::DisplayListCommandType::CompositorScrollNode: {
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auto command = Painting::read_display_list_command_payload<Painting::CompositorScrollNode>(payload);
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async_scrolling_state.scroll_nodes.append({
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.node_id = scroll_node_id_for(command.document_id, command.scroll_frame_index),
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.parent_node_id = {},
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.hit_test_visual_context_index = header.context_index,
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.scrollport_rect = command.scrollport_rect,
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.max_scroll_offset = command.max_scroll_offset,
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.is_viewport = command.is_viewport,
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});
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parent_scroll_frame_indices.append(command.parent_scroll_frame_index);
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break;
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}
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case Painting::DisplayListCommandType::CompositorMainThreadWheelEventRegion: {
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auto command = Painting::read_display_list_command_payload<Painting::CompositorMainThreadWheelEventRegion>(payload);
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async_scrolling_state.main_thread_wheel_event_regions.append({
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.visual_context_index = header.context_index,
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.rect = command.rect,
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});
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break;
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}
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case Painting::DisplayListCommandType::CompositorViewportScrollbar: {
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auto command = Painting::read_display_list_command_payload<Painting::CompositorViewportScrollbar>(payload);
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async_scrolling_state.viewport_scrollbars.append({
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.scroll_node_id = scroll_node_id_for(command.document_id, command.scroll_frame_index),
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.scroll_frame_index = command.scroll_frame_index,
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.gutter_rect = command.gutter_rect,
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.thumb_rect = command.thumb_rect,
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.expanded_gutter_rect = command.expanded_gutter_rect,
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.expanded_thumb_rect = command.expanded_thumb_rect,
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.scroll_size = command.scroll_size,
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.expanded_scroll_size = command.expanded_scroll_size,
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.max_scroll_offset = command.max_scroll_offset,
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.thumb_color = command.thumb_color,
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.track_color = command.track_color,
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.vertical = command.vertical,
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});
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break;
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}
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default:
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break;
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}
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});
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VERIFY(parent_scroll_frame_indices.size() == async_scrolling_state.scroll_nodes.size());
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for (size_t i = 0; i < async_scrolling_state.scroll_nodes.size(); ++i) {
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auto parent_scroll_frame_index = parent_scroll_frame_indices[i];
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if (parent_scroll_frame_index.value())
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async_scrolling_state.scroll_nodes[i].parent_node_id = scroll_node_id_for(async_scrolling_state.scroll_nodes[i].node_id.document_id, parent_scroll_frame_index);
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}
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return async_scrolling_state;
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}
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WheelRoutingAdmission wheel_routing_admission_for(AsyncScrollingState const& state)
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{
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if (state.has_blocking_wheel_event_listeners)
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return WheelRoutingAdmission::BlockingWheelEventListeners;
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bool found_viewport_node = false;
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for (auto const& node : state.scroll_nodes) {
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if (node.is_viewport) {
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found_viewport_node = true;
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break;
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}
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}
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if (!found_viewport_node)
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return WheelRoutingAdmission::NoViewportScrollNode;
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return WheelRoutingAdmission::Accepted;
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}
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StringView wheel_routing_admission_to_string(WheelRoutingAdmission admission)
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{
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switch (admission) {
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case WheelRoutingAdmission::Accepted:
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return "accepted"sv;
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case WheelRoutingAdmission::NoAsyncScrollingState:
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return "no async scrolling state"sv;
|
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case WheelRoutingAdmission::BlockingWheelEventListeners:
|
|
return "blocking wheel event listeners"sv;
|
|
case WheelRoutingAdmission::NoViewportScrollNode:
|
|
return "no viewport scroll node"sv;
|
|
case WheelRoutingAdmission::StaleWheelEventListeners:
|
|
return "stale wheel event listeners"sv;
|
|
}
|
|
VERIFY_NOT_REACHED();
|
|
}
|
|
|
|
bool blocks_wheel_event_at_position(AsyncScrollingState const& async_scrolling_state, RefPtr<Painting::DisplayList> const& display_list, Painting::ScrollStateSnapshot const& scroll_state_snapshot, Gfx::FloatPoint position)
|
|
{
|
|
if (async_scrolling_state.has_blocking_wheel_event_region_covering_viewport)
|
|
return true;
|
|
|
|
// If a caller knows blocking wheel listeners exist but cannot provide a display list for visual-context hit
|
|
// testing, async scrolling must fail closed. Sending the input to the main thread is slower, but it preserves
|
|
// cancelability.
|
|
if (!display_list)
|
|
return async_scrolling_state.has_blocking_wheel_event_listeners;
|
|
|
|
auto const& visual_context_tree = display_list->visual_context_tree();
|
|
for (auto const& region : async_scrolling_state.blocking_wheel_event_regions) {
|
|
auto position_in_context = visual_context_tree.transform_point_for_hit_test(region.visual_context_index, position, scroll_state_snapshot);
|
|
if (position_in_context.has_value() && region.rect.contains(*position_in_context))
|
|
return true;
|
|
}
|
|
return false;
|
|
}
|
|
|
|
static WheelHitTestResult hit_test_scroll_node_at_position(AsyncScrollingState const& async_scrolling_state, RefPtr<Painting::DisplayList> const& display_list, Painting::ScrollStateSnapshot const& scroll_state_snapshot, Gfx::FloatPoint position, Gfx::FloatPoint delta)
|
|
{
|
|
if (!display_list)
|
|
return {};
|
|
|
|
AsyncScrollTree scroll_tree;
|
|
auto async_scrolling_state_copy = async_scrolling_state;
|
|
scroll_tree.set_state(move(async_scrolling_state_copy));
|
|
scroll_tree.rebuild_wheel_scroll_targets(display_list, scroll_state_snapshot);
|
|
return scroll_tree.hit_test_scroll_node_for_wheel(position, delta);
|
|
}
|
|
|
|
WheelScrollAdmission admit_wheel_scroll(AsyncScrollingState const& async_scrolling_state, RefPtr<Painting::DisplayList> const& display_list, Painting::ScrollStateSnapshot const& scroll_state_snapshot, Gfx::FloatPoint position, Gfx::FloatPoint delta, bool blocking_wheel_event_regions_are_current)
|
|
{
|
|
auto hit_test_result = hit_test_scroll_node_at_position(async_scrolling_state, display_list, scroll_state_snapshot, position, delta);
|
|
if (hit_test_result.blocked_by_main_thread_region)
|
|
return WheelScrollAdmission::BlockedByMainThreadRegion;
|
|
|
|
// Async scrolling may only start when the snapshot can prove that the wheel event cannot be canceled by script
|
|
// at this position. Stale or missing blocker information sends the event back to the main thread.
|
|
if (async_scrolling_state.has_blocking_wheel_event_listeners) {
|
|
if (!blocking_wheel_event_regions_are_current)
|
|
return WheelScrollAdmission::StaleBlockingWheelEventRegions;
|
|
if (blocks_wheel_event_at_position(async_scrolling_state, display_list, scroll_state_snapshot, position))
|
|
return WheelScrollAdmission::BlockedByWheelEventRegion;
|
|
}
|
|
|
|
if (!hit_test_result.node_id.has_value())
|
|
return WheelScrollAdmission::NoScrollableTarget;
|
|
return WheelScrollAdmission::Accepted;
|
|
}
|
|
|
|
}
|