ash/wm/workspace/workspace_cycler.h

   1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef ASH_WM_WORKSPACE_WORKSPACE_CYCLER_H_
   6 #define ASH_WM_WORKSPACE_WORKSPACE_CYCLER_H_
   7
   8 #include "ash/ash_export.h"
   9 #include "ash/wm/workspace/workspace_cycler_animator.h"
  10 #include "base/basictypes.h"
  11 #include "base/compiler_specific.h"
  12 #include "base/memory/scoped_ptr.h"
  13 #include "ui/base/events/event_handler.h"
  14
  15 namespace ash {
  16 namespace internal {
  17
  18 class WorkspaceManager;
  19
  20 // Class to enable quick workspace switching (cycling) via 3 finger vertical
  21 // scroll.
  22 // During cycling, the workspaces are arranged in a card stack as shown below:
  23 //  ____________________________________________
  24 // |          ________________________          |
  25 // |         |                        |         |
  26 // |        _|________________________|_        |
  27 // |       |                            |       |
  28 // |      _|____________________________|_      |
  29 // |     |                                |     |
  30 // |     |                                |     |
  31 // |     |     workspace to activate      |     |
  32 // |     |                                |     |
  33 // |     |                                |     |
  34 // |    _|________________________________|_    |
  35 // |   |                                    |   |
  36 // |  _|____________________________________|_  |
  37 // | |                                        | |
  38 // |_|________________________________________|_|
  39 // The user selects a workspace to activate by moving the workspace they want
  40 // to activate to the most prominent position in the card stack.
  41
  42 class ASH_EXPORT WorkspaceCycler : public ui::EventHandler,
  43                                    public WorkspaceCyclerAnimator::Delegate {
  44  public:
  45   explicit WorkspaceCycler(WorkspaceManager* workspace_manager);
  46   virtual ~WorkspaceCycler();
  47
  48   // Abort any animations that the cycler is doing. The active workspace is set
  49   // to the active workspace before cycling was initiated.
  50   // Cycling should be aborted:
  51   // - Before a workspace is added or destroyed.
  52   // - Before a workspace is activated.
  53   // - When the workspace bounds or the shelf bounds change.
  54   void AbortCycling();
  55
  56  private:
  57   // The cycler state.
  58   enum State {
  59     NOT_CYCLING,
  60
  61     // The cycler is waiting for the user to scroll far enough vertically to
  62     // trigger cycling workspaces.
  63     NOT_CYCLING_TRACKING_SCROLL,
  64
  65     // The workspaces are animating into a card stack configuration. The cycler
  66     // is in this state for the duration of the animation.
  67     STARTING_CYCLING,
  68
  69     // The user is moving workspaces around in the card stack.
  70     CYCLING,
  71
  72     // The workspace that the user selected to be active is being animated to
  73     // take up the entire screen. The cycler is in this state for the duration
  74     // of the animation.
  75     STOPPING_CYCLING,
  76   };
  77
  78   // Set the cycler state to |new_state|.
  79   // The state is not changed if transitioning from the current state to
  80   // |new_state| is not valid.
  81   void SetState(State new_state);
  82
  83   // Returns true if transitioning from |state_| to |next_state| is valid.
  84   bool IsValidNextState(State next_state) const;
  85
  86   // ui::EventHandler overrides:
  87   virtual void OnEvent(ui::Event* event) OVERRIDE;
  88   virtual void OnScrollEvent(ui::ScrollEvent* event) OVERRIDE;
  89
  90   // WorkspaceCyclerAnimator::Delegate overrides:
  91   virtual void StartWorkspaceCyclerAnimationFinished() OVERRIDE;
  92   virtual void StopWorkspaceCyclerAnimationFinished() OVERRIDE;
  93
  94   WorkspaceManager* workspace_manager_;
  95
  96   scoped_ptr<WorkspaceCyclerAnimator> animator_;
  97
  98   // The cycler's state.
  99   State state_;
 100
 101   // The amount of scrolling which has occurred.
 102   float scroll_x_;
 103   float scroll_y_;
 104
 105   DISALLOW_COPY_AND_ASSIGN(WorkspaceCycler);
 106 };
 107
 108 }  // namespace internal
 109 }  // namespace ash
 110
 111 #endif  // ASH_WM_WORKSPACE_WORKSPACE_CYCLER_H_