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cc / input / scrollbar.h [blame]
// Copyright 2013 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef CC_INPUT_SCROLLBAR_H_
#define CC_INPUT_SCROLLBAR_H_
#include "base/memory/ref_counted.h"
#include "cc/cc_export.h"
#include "cc/paint/paint_canvas.h"
#include "ui/gfx/geometry/point.h"
#include "ui/gfx/geometry/rect.h"
// Autoscrolling (on the main thread) happens by applying a delta every 50ms.
// Hence, pixels per second for a autoscroll cc animation can be calculated as:
// autoscroll velocity = delta / 0.05 sec = delta x 20
static constexpr float kAutoscrollMultiplier = 20.f;
static constexpr base::TimeDelta kInitialAutoscrollTimerDelay =
base::Milliseconds(250);
// Constants used to figure the how far out in the non-scrolling direction
// should trigger the thumb to snap back to its origin. These calculations are
// based on observing the behavior of the MSVC8 main window scrollbar + some
// guessing/extrapolation.
static constexpr int kOffSideMultiplier = 8;
static constexpr int kDefaultWinScrollbarThickness = 17;
namespace cc {
enum class ScrollbarOrientation { kHorizontal, kVertical };
enum class ScrollbarPart {
kThumb,
kBackButton,
kForwardButton,
kBackTrack,
kForwardTrack,
kNoPart,
};
class Scrollbar : public base::RefCounted<Scrollbar> {
public:
// Check if this scrollbar and the other scrollbar are backed with the same
// source scrollbar (e.g. blink::Scrollbar).
virtual bool IsSame(const Scrollbar&) const = 0;
virtual ScrollbarOrientation Orientation() const = 0;
virtual bool IsLeftSideVerticalScrollbar() const = 0;
virtual bool IsSolidColor() const = 0;
virtual bool IsOverlay() const = 0;
virtual bool IsRunningWebTest() const = 0;
virtual bool IsFluentOverlayScrollbarMinimalMode() const = 0;
virtual bool HasThumb() const = 0;
virtual bool SupportsDragSnapBack() const = 0;
virtual bool JumpOnTrackClick() const = 0;
virtual bool IsOpaque() const = 0;
// The following rects are all relative to the scrollbar's origin.
// The location of ThumbRect reflects scroll offset, but cc will ignore it
// because the compositor thread will compute thumb location from scroll
// offset.
virtual gfx::Rect ThumbRect() const = 0;
virtual gfx::Rect TrackRect() const = 0;
virtual gfx::Rect BackButtonRect() const = 0;
virtual gfx::Rect ForwardButtonRect() const = 0;
virtual float Opacity() const = 0;
virtual bool HasTickmarks() const = 0;
virtual bool ThumbNeedsRepaint() const = 0;
virtual void ClearThumbNeedsRepaint() = 0;
virtual bool TrackAndButtonsNeedRepaint() const = 0;
// Paints the thumb in the given rect. The implementation should paint
// relative to the rect, and doesn't need to know the current coordinate
// space of `canvas`. When `UsesNinePatchThumbResource()` returns true,
// whether to use nine-patch depends on the size of `rect`. Nine-patch
// will be disabled if the size is the full size of the thumb.
virtual void PaintThumb(PaintCanvas& canvas, const gfx::Rect& rect) = 0;
// Paints the track (including tickmarks if present) and buttons in the
// given rect. See the above function about `rect`.
virtual void PaintTrackAndButtons(PaintCanvas& canvas,
const gfx::Rect& rect) = 0;
// The thumb color for a solid color scrollbar, or a scrollbar using solid
// color thumb. This is meaningful only when IsSolidColor() or
// UsesSolidColorThumb() is true.
virtual SkColor4f ThumbColor() const = 0;
// The following two functions are called from blink only.
// Returns true if either the track or the thumb needs repaint, or the thumb
// moved (which doesn't need to repaint the track or the thumb in many
// scrollbar themes).
virtual bool NeedsUpdateDisplay() const = 0;
virtual void ClearNeedsUpdateDisplay() = 0;
// Whether the thumb can be painted as a nine-patch resource. Cc will stretch
// the resource to fill the full size of the thumb. This should never change
// during the life of the scrollbar.
virtual bool UsesNinePatchThumbResource() const = 0;
virtual gfx::Size NinePatchThumbCanvasSize() const = 0;
virtual gfx::Rect NinePatchThumbAperture() const = 0;
// Whether the thumb can be painted in a single color. This should not never
// change during the life of the scrollbar.
virtual bool UsesSolidColorThumb() const = 0;
// The insets of the solid color thumb from ThumbRect().
virtual gfx::Insets SolidColorThumbInsets() const = 0;
// Whether the track and buttons can be painted together as a nine-patch
// resource. Cc which will stretch the resource to fill the full size of the
// scrollbar. This should never change during the life of the scrollbar.
// Note that tickmarks can't be painted in nine-patch. If there are tickmarks
// (`HasTickmarks()`), this can still return true, but the nine-patch
// implementation in cc will not be used for painting.
virtual bool UsesNinePatchTrackAndButtonsResource() const = 0;
virtual gfx::Size NinePatchTrackAndButtonsCanvasSize(float scale) const = 0;
virtual gfx::Rect NinePatchTrackAndButtonsAperture(float scale) const = 0;
// This is used by blink only, to adjust the painted thumb rect in
// main-thread minimal mode.
virtual gfx::Rect ShrinkMainThreadedMinimalModeThumbRect(
gfx::Rect& rect) const = 0;
protected:
friend class base::RefCounted<Scrollbar>;
virtual ~Scrollbar() {}
};
} // namespace cc
#endif // CC_INPUT_SCROLLBAR_H_