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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_SNAP_SIZER_H_
6 #define ASH_WM_WORKSPACE_SNAP_SIZER_H_
7 
8 #include <vector>
9 
10 #include "ash/ash_export.h"
11 #include "base/basictypes.h"
12 #include "base/time/time.h"
13 #include "ui/gfx/rect.h"
14 
15 namespace ash {
16 namespace wm {
17 class WindowState;
18 }
19 
20 namespace internal {
21 
22 // SnapSizer is responsible for determining the resulting bounds of a window
23 // that is being snapped to the left or right side of the screen.
24 // The bounds used in this class are in the container's coordinates.
25 class ASH_EXPORT SnapSizer {
26  public:
27   enum Edge {
28     LEFT_EDGE,
29     RIGHT_EDGE
30   };
31 
32   enum InputType {
33     TOUCH_MAXIMIZE_BUTTON_INPUT,
34     OTHER_INPUT
35   };
36 
37   // Set |input_type| to |TOUCH_MAXIMIZE_BUTTON_INPUT| when called by a touch
38   // operation by the maximize button. This will allow the user to snap resize
39   // the window beginning close to the border.
40   SnapSizer(wm::WindowState* window_state,
41             const gfx::Point& start,
42             Edge edge,
43             InputType input_type);
44   virtual ~SnapSizer();
45 
46   // Snaps a window left or right.
47   static void SnapWindow(wm::WindowState* window_state, Edge edge);
48 
49   // Snaps |window_| to the target bounds.
50   void SnapWindowToTargetBounds();
51 
52   // Updates the target bounds based on a mouse move.
53   void Update(const gfx::Point& location);
54 
55   // Bounds to position the window at.
target_bounds()56   const gfx::Rect& target_bounds() const { return target_bounds_; }
57 
58   // Returns the appropriate snap bounds (e.g. if a window is already snapped,
59   // then it returns the next snap-bounds).
60   gfx::Rect GetSnapBounds(const gfx::Rect& bounds);
61 
62   // Set the snap sizer to the button press default size and prevent resizing.
63   void SelectDefaultSizeAndDisableResize();
64 
65   // Returns the target bounds based on the edge and the provided |size_index|.
66   // For unit test purposes this function is not private.
67   gfx::Rect GetTargetBoundsForSize(size_t size_index) const;
68 
69   // Returns true when snapping sequence is at its last (docking) step.
end_of_sequence()70   bool end_of_sequence() const { return end_of_sequence_; }
71 
72  private:
73   // Calculates the amount to increment by. This returns one of -1, 0 or 1 and
74   // is intended to by applied to |size_index_|. |x| is the current
75   // x-coordinate, and |reference_x| is used to determine whether to increase
76   // or decrease the position. It's one of |last_adjust_x_| or |last_update_x_|.
77   int CalculateIncrement(int x, int reference_x) const;
78 
79   // Changes the bounds. |x| is the current x-coordinate and |delta| the amount
80   // to increase by. |delta| comes from CalculateIncrement() and is applied
81   // to |size_index_|.
82   void ChangeBounds(int x, int delta);
83 
84   // Returns the target bounds based on the edge and |size_index_|.
85   gfx::Rect GetTargetBounds() const;
86 
87   // Returns true if the specified point is along the edge of the screen.
88   bool AlongEdge(int x) const;
89 
90   // WindowState of the window being snapped.
91   wm::WindowState* window_state_;
92 
93   const Edge edge_;
94 
95   // Current target bounds for the snap.
96   gfx::Rect target_bounds_;
97 
98   // Time Update() was last invoked.
99   base::TimeTicks time_last_update_;
100 
101   // Index into |kSizes| that dictates the width of the screen the target
102   // bounds should get.
103   int size_index_;
104 
105   // Set to true when an attempt is made to increment |size_index_| past
106   // the size of |usable_width_|.
107   bool end_of_sequence_;
108 
109   // If set, |size_index_| will get ignored and the single button default
110   // setting will be used instead.
111   bool resize_disabled_;
112 
113   // Number of times Update() has been invoked since last ChangeBounds().
114   int num_moves_since_adjust_;
115 
116   // X-coordinate the last time ChangeBounds() was invoked.
117   int last_adjust_x_;
118 
119   // X-coordinate last supplied to Update().
120   int last_update_x_;
121 
122   // Initial x-coordinate.
123   const int start_x_;
124 
125   // |TOUCH_MAXIMIZE_BUTTON_INPUT| if the snap sizer was created through a
126   // touch & drag operation of the maximizer button. It changes the behavior of
127   // the drag / resize behavior when the dragging starts close to the border.
128   const InputType input_type_;
129 
130   // A list of usable window widths for size. This gets created when the
131   // sizer gets created.
132   const std::vector<int> usable_width_;
133 
134   DISALLOW_COPY_AND_ASSIGN(SnapSizer);
135 };
136 
137 }  // namespace internal
138 }  // namespace ash
139 
140 #endif  // ASH_WM_WORKSPACE_SNAP_SIZER_H_
141