21245e7adb
Async wheel routing used scroll node scrollports as the hit-test surface. That works while the scrollable content is the topmost content under the pointer, but it ignores the rest of the painted scene. A sibling with a higher z-index can visually cover a nested scroller without being part of that scroller's subtree. In that case the compositor could still pick the covered scroller from its scrollport rect and consume the wheel event, even though normal hit testing would target the covering element and let the page or an ancestor handle the scroll. Record wheel hit-test targets as display-list metadata in paint order and resolve each target to the scroll frame that should receive wheel deltas. The compositor can then walk those targets from front to back, preserve non-passive wheel regions as main-thread barriers, and only scroll the node associated with the topmost hit-testable box.
81 lines
3.6 KiB
C++
81 lines
3.6 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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#pragma once
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#include <AK/Optional.h>
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#include <AK/RefPtr.h>
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#include <AK/Vector.h>
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#include <LibGfx/CornerRadii.h>
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#include <LibGfx/Point.h>
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#include <LibGfx/Rect.h>
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#include <LibWeb/Compositor/AsyncScrollingState.h>
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#include <LibWeb/Forward.h>
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#include <LibWeb/Painting/ScrollState.h>
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namespace Web::Compositor {
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struct WheelHitTestResult {
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Optional<AsyncScrollNodeID> node_id;
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bool blocked_by_main_thread_region { false };
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};
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struct CachedWheelHitTestTarget {
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Optional<AsyncScrollNodeID> target_node_id;
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Painting::VisualContextIndex visual_context_index;
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Gfx::FloatRect rect;
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Gfx::CornerRadii corner_radii;
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Gfx::FloatRect viewport_rect;
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};
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struct MainThreadWheelEventTarget {
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Painting::VisualContextIndex visual_context_index;
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Gfx::FloatRect rect;
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Gfx::FloatRect viewport_rect;
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};
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// Mutable compositor-side copy of AsyncScrollingState. Current scroll offsets live in ScrollStateSnapshot; this tree
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// owns scroll node geometry and derived hit-test targets.
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class AsyncScrollTree {
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public:
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void set_state(AsyncScrollingState&&);
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void rebuild_wheel_hit_test_targets(RefPtr<Painting::DisplayList> const&, Painting::ScrollStateSnapshot const&);
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void clear_wheel_hit_test_targets();
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Optional<Gfx::FloatPoint> scroll_offset_for_node(AsyncScrollNodeID, Painting::ScrollStateSnapshot const&) const;
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Optional<AsyncScrollNodeID> viewport_scroll_node_id() const;
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WheelHitTestResult hit_test_scroll_node_for_wheel(Gfx::FloatPoint position, Gfx::FloatPoint delta) const;
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bool scroll_node_is_viewport(AsyncScrollNodeID) const;
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bool apply_scroll_delta(AsyncScrollNodeID, Gfx::FloatPoint delta, Painting::ScrollStateSnapshot&);
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Optional<Gfx::FloatPoint> set_scroll_offset(AsyncScrollNodeID, Gfx::FloatPoint, Painting::ScrollStateSnapshot&);
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private:
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static Gfx::FloatPoint clamp_scroll_offset_to_node(AsyncScrollNode const&, Gfx::FloatPoint);
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static Gfx::FloatPoint scroll_offset_for_node(AsyncScrollNode const&, Painting::ScrollStateSnapshot const&);
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static bool can_scroll_node_by_delta(AsyncScrollNode const&, Painting::ScrollStateSnapshot const&, Gfx::FloatPoint);
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static bool has_non_zero_scroll_delta(Gfx::FloatPoint);
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AsyncScrollNode const* scroll_node_for_id(AsyncScrollNodeID) const;
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WheelHitTestResult hit_test_result_for_scroll_node(AsyncScrollNodeID, Gfx::FloatPoint delta) const;
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AsyncStickyArea const* sticky_area_for_scroll_frame_index(Painting::ScrollFrameIndex) const;
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Optional<AsyncScrollNodeID> scrollable_ancestor_for_node(AsyncScrollNodeID, Painting::ScrollStateSnapshot const&, Gfx::FloatPoint delta) const;
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Optional<Painting::ScrollFrameIndex> parent_scroll_frame_index(Painting::ScrollFrameIndex) const;
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Gfx::FloatPoint cumulative_device_offset_for_frame(Painting::ScrollFrameIndex, Painting::ScrollStateSnapshot const&) const;
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Gfx::FloatPoint apply_scroll_delta_to_node(AsyncScrollNode const&, Gfx::FloatPoint delta, Painting::ScrollStateSnapshot&);
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void update_sticky_offsets(Painting::ScrollStateSnapshot&) const;
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Vector<AsyncScrollNode> m_scroll_nodes;
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Vector<AsyncStickyArea> m_sticky_areas;
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Vector<WheelHitTestTarget> m_wheel_hit_test_regions;
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Vector<MainThreadWheelEventRegion> m_main_thread_wheel_event_regions;
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Vector<CachedWheelHitTestTarget> m_wheel_hit_test_targets;
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Vector<MainThreadWheelEventTarget> m_main_thread_wheel_event_targets;
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RefPtr<Painting::AccumulatedVisualContextTree const> m_visual_context_tree;
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Painting::ScrollStateSnapshot m_scroll_state_snapshot;
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};
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}
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