chromium/cc/input/scrollbar.h

// 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 = …;
static constexpr base::TimeDelta kInitialAutoscrollTimerDelay = …;

// 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 = …;
static constexpr int kDefaultWinScrollbarThickness = …;

namespace cc {

enum class ScrollbarOrientation { … };

enum class ScrollbarPart { … };

class Scrollbar : public base::RefCounted<Scrollbar> { … };

}  // namespace cc

#endif  // CC_INPUT_SCROLLBAR_H_