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/*
* Copyright (C) 2008, 2009 Apple Inc. All Rights Reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
* OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#ifndef THIRD_PARTY_BLINK_RENDERER_CORE_LAYOUT_CUSTOM_SCROLLBAR_H_
#define THIRD_PARTY_BLINK_RENDERER_CORE_LAYOUT_CUSTOM_SCROLLBAR_H_
#include "third_party/blink/renderer/core/core_export.h"
#include "third_party/blink/renderer/core/scroll/scrollbar.h"
#include "third_party/blink/renderer/core/style/computed_style_constants.h"
#include "third_party/blink/renderer/platform/geometry/physical_offset.h"
#include "third_party/blink/renderer/platform/heap/collection_support/heap_hash_map.h"
#include "third_party/blink/renderer/platform/heap/garbage_collected.h"
#include "third_party/blink/renderer/platform/wtf/casting.h"
namespace blink {
class ComputedStyle;
class GraphicsContext;
class LayoutObject;
class LayoutCustomScrollbarPart;
// Custom scrollbars are created when a box has -webkit-scrollbar* pseudo
// styles. The parts of a custom scrollbar are layout objects of class
// LayoutCustomScrollbarPart.
class CORE_EXPORT CustomScrollbar final : public Scrollbar {
public:
CustomScrollbar(ScrollableArea*,
ScrollbarOrientation,
const LayoutObject* style_source,
bool suppress_use_counters = false);
~CustomScrollbar() override;
// Return the thickness that a custom scrollbar would have, before actually
// constructing the real scrollbar.
static int HypotheticalScrollbarThickness(const ScrollableArea*,
ScrollbarOrientation,
const LayoutObject* style_source);
gfx::Rect ButtonRect(ScrollbarPart) const;
gfx::Rect TrackRect(int start_length, int end_length) const;
gfx::Rect TrackPieceRectWithMargins(ScrollbarPart, const gfx::Rect&) const;
int MinimumThumbLength() const;
bool IsOverlayScrollbar() const override { return false; }
void OffsetDidChange(mojom::blink::ScrollType) override;
void PositionScrollbarParts();
// Custom scrollbars may be translucent.
bool IsOpaque() const override { return false; }
LayoutCustomScrollbarPart* GetPart(ScrollbarPart part_type) {
auto it = parts_.find(part_type);
return it != parts_.end() ? it->value.Get() : nullptr;
}
const LayoutCustomScrollbarPart* GetPart(ScrollbarPart part_type) const {
auto it = parts_.find(part_type);
return it != parts_.end() ? it->value.Get() : nullptr;
}
// Although this method returns an entire ComputedStyle, it is only used when
// computing a cursor to use.
// This method implements a cursor-specific, inheritance-like fallback for
// ScrollbarParts that aren't used.
// For example: without this fallback, hovering over a scrollbar-track on a
// scrollbar styled only with `::-webkit-scrollbar` and
// `::webkit-scroll-thumb` will surprisingly use the cursor style from the
// originating element (the scroller) since the scrollbar-track will not have
// a corresponding LayoutCustomScrollbarPart. In this case, it'd be
// preferable to use the cursor style set in the `::webkit-scrollbar`
const ComputedStyle* GetScrollbarPartStyleForCursor(
ScrollbarPart part_type) const;
void InvalidateDisplayItemClientsOfScrollbarParts();
void ClearPaintFlags();
void Paint(GraphicsContext&, const PhysicalOffset& paint_offset) const;
void Trace(Visitor*) const override;
private:
friend class Scrollbar;
void SetEnabled(bool) override;
void DisconnectFromScrollableArea() override;
void SetHoveredPart(ScrollbarPart) override;
void SetPressedPart(ScrollbarPart, WebInputEvent::Type) override;
void StyleChanged() override;
bool IsCustomScrollbar() const override { return true; }
void DestroyScrollbarParts();
void UpdateScrollbarParts();
const ComputedStyle* GetScrollbarPseudoElementStyle(ScrollbarPart, PseudoId);
void UpdateScrollbarPart(ScrollbarPart);
HeapHashMap<ScrollbarPart, Member<LayoutCustomScrollbarPart>> parts_;
bool needs_position_scrollbar_parts_ = true;
// When constructing a CustomScrollbar solely for the purpose of computing
// hypothetical thickness, don't record feature usage.
bool suppress_use_counters_ = false;
};
template <>
struct DowncastTraits<CustomScrollbar> {
static bool AllowFrom(const Scrollbar& scrollbar) {
return scrollbar.IsCustomScrollbar();
}
};
} // namespace blink
#endif // THIRD_PARTY_BLINK_RENDERER_CORE_LAYOUT_CUSTOM_SCROLLBAR_H_
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