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// Copyright 2014 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "third_party/blink/renderer/core/scroll/scrollbar_layer_delegate.h"
#include "cc/paint/paint_canvas.h"
#include "third_party/blink/renderer/core/scroll/scroll_types.h"
#include "third_party/blink/renderer/core/scroll/scrollable_area.h"
#include "third_party/blink/renderer/core/scroll/scrollbar.h"
#include "third_party/blink/renderer/core/scroll/scrollbar_theme.h"
#include "third_party/blink/renderer/platform/graphics/graphics_context.h"
#include "third_party/blink/renderer/platform/graphics/paint/paint_canvas.h"
#include "third_party/blink/renderer/platform/graphics/paint/paint_record_builder.h"
#include "ui/gfx/skia_util.h"
namespace blink {
namespace {
class ScopedScrollbarPainter {
public:
ScopedScrollbarPainter(cc::PaintCanvas& canvas, float device_scale_factor)
: canvas_(canvas) {
builder_.Context().SetDeviceScaleFactor(device_scale_factor);
}
~ScopedScrollbarPainter() { canvas_.drawPicture(builder_.EndRecording()); }
GraphicsContext& Context() { return builder_.Context(); }
private:
cc::PaintCanvas& canvas_;
PaintRecordBuilder builder_;
};
} // namespace
ScrollbarLayerDelegate::ScrollbarLayerDelegate(blink::Scrollbar& scrollbar,
float device_scale_factor)
: scrollbar_(&scrollbar), device_scale_factor_(device_scale_factor) {
// Custom scrollbars are either non-composited or use cc::PictureLayers
// which don't need ScrollbarLayerDelegate.
DCHECK(!scrollbar.IsCustomScrollbar());
}
ScrollbarLayerDelegate::~ScrollbarLayerDelegate() = default;
cc::ScrollbarOrientation ScrollbarLayerDelegate::Orientation() const {
if (scrollbar_->Orientation() == kHorizontalScrollbar)
return cc::HORIZONTAL;
return cc::VERTICAL;
}
bool ScrollbarLayerDelegate::IsLeftSideVerticalScrollbar() const {
return scrollbar_->IsLeftSideVerticalScrollbar();
}
bool ScrollbarLayerDelegate::HasThumb() const {
return scrollbar_->GetTheme().HasThumb(*scrollbar_);
}
bool ScrollbarLayerDelegate::IsSolidColor() const {
return scrollbar_->GetTheme().IsSolidColor();
}
bool ScrollbarLayerDelegate::IsOverlay() const {
return scrollbar_->IsOverlayScrollbar();
}
gfx::Rect ScrollbarLayerDelegate::ThumbRect() const {
IntRect track_rect = scrollbar_->GetTheme().ThumbRect(*scrollbar_);
track_rect.MoveBy(-scrollbar_->Location());
return track_rect;
}
gfx::Rect ScrollbarLayerDelegate::TrackRect() const {
IntRect track_rect = scrollbar_->GetTheme().TrackRect(*scrollbar_);
track_rect.MoveBy(-scrollbar_->Location());
return track_rect;
}
bool ScrollbarLayerDelegate::SupportsDragSnapBack() const {
return scrollbar_->GetTheme().SupportsDragSnapBack();
}
gfx::Rect ScrollbarLayerDelegate::BackButtonRect() const {
IntRect back_button_rect = scrollbar_->GetTheme().BackButtonRect(*scrollbar_);
if (!back_button_rect.IsEmpty())
back_button_rect.MoveBy(-scrollbar_->Location());
return back_button_rect;
}
gfx::Rect ScrollbarLayerDelegate::ForwardButtonRect() const {
IntRect forward_button_rect =
scrollbar_->GetTheme().ForwardButtonRect(*scrollbar_);
if (!forward_button_rect.IsEmpty())
forward_button_rect.MoveBy(-scrollbar_->Location());
return forward_button_rect;
}
float ScrollbarLayerDelegate::Opacity() const {
return scrollbar_->GetTheme().Opacity(*scrollbar_);
}
bool ScrollbarLayerDelegate::NeedsRepaintPart(cc::ScrollbarPart part) const {
if (part == cc::THUMB)
return scrollbar_->ThumbNeedsRepaint();
return scrollbar_->TrackNeedsRepaint();
}
bool ScrollbarLayerDelegate::UsesNinePatchThumbResource() const {
return scrollbar_->GetTheme().UsesNinePatchThumbResource();
}
gfx::Size ScrollbarLayerDelegate::NinePatchThumbCanvasSize() const {
DCHECK(scrollbar_->GetTheme().UsesNinePatchThumbResource());
return static_cast<gfx::Size>(
scrollbar_->GetTheme().NinePatchThumbCanvasSize(*scrollbar_));
}
gfx::Rect ScrollbarLayerDelegate::NinePatchThumbAperture() const {
DCHECK(scrollbar_->GetTheme().UsesNinePatchThumbResource());
return scrollbar_->GetTheme().NinePatchThumbAperture(*scrollbar_);
}
bool ScrollbarLayerDelegate::ShouldPaint() const {
// TODO(crbug.com/860499): Remove this condition, it should not occur.
// Layers may exist and be painted for a |scrollbar_| that has had its
// ScrollableArea detached. This seems weird because if the area is detached
// the layer should be destroyed but here we are. https://crbug.com/860499.
if (!scrollbar_->GetScrollableArea())
return false;
// When the frame is throttled, the scrollbar will not be painted because
// the frame has not had its lifecycle updated. Thus the actual value of
// HasTickmarks can't be known and may change once the frame is unthrottled.
if (scrollbar_->GetScrollableArea()->IsThrottled())
return false;
return true;
}
bool ScrollbarLayerDelegate::HasTickmarks() const {
return ShouldPaint() && scrollbar_->HasTickmarks();
}
void ScrollbarLayerDelegate::PaintPart(cc::PaintCanvas* canvas,
cc::ScrollbarPart part,
const gfx::Rect& rect) {
if (!ShouldPaint())
return;
auto& theme = scrollbar_->GetTheme();
ScopedScrollbarPainter painter(*canvas, device_scale_factor_);
// The canvas coordinate space is relative to the part's origin.
switch (part) {
case cc::THUMB:
theme.PaintThumb(painter.Context(), *scrollbar_, IntRect(rect));
scrollbar_->ClearThumbNeedsRepaint();
break;
case cc::TRACK_BUTTONS_TICKMARKS: {
DCHECK_EQ(IntSize(rect.size()), scrollbar_->FrameRect().Size());
IntPoint offset(IntPoint(rect.origin()) -
scrollbar_->FrameRect().Location());
theme.PaintTrackButtonsTickmarks(painter.Context(), *scrollbar_, offset);
scrollbar_->ClearTrackNeedsRepaint();
break;
}
default:
NOTREACHED();
}
}
} // namespace blink
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