summaryrefslogtreecommitdiffstats
path: root/gfx/layers/apz/src/DragTracker.h
blob: 9f7ff1222bff2efaf79d756af89f0eb32e067e73 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#ifndef mozilla_layers_DragTracker_h
#define mozilla_layers_DragTracker_h

#include "mozilla/EventForwards.h"
#include "mozilla/Maybe.h"

namespace mozilla {

class MouseInput;

namespace layers {

// DragTracker simply tracks a sequence of mouse inputs and allows us to tell
// if we are in a drag or not (i.e. the left mouse button went down and hasn't
// gone up yet).
class DragTracker
{
public:
  DragTracker();
  static bool StartsDrag(const MouseInput& aInput);
  static bool EndsDrag(const MouseInput& aInput);
  void Update(const MouseInput& aInput);
  bool InDrag() const;
  bool IsOnScrollbar(bool aOnScrollbar);

private:
  Maybe<bool> mOnScrollbar;
  bool mInDrag;
};

} // namespace layers
} // namespace mozilla

#endif /* mozilla_layers_DragTracker_h */