1// Copyright (c) 2011 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// Handles the visible notification (or balloons).
6
7#ifndef CHROME_BROWSER_NOTIFICATIONS_BALLOON_COLLECTION_IMPL_H_
8#define CHROME_BROWSER_NOTIFICATIONS_BALLOON_COLLECTION_IMPL_H_
9#pragma once
10
11#include <deque>
12
13#include "base/basictypes.h"
14#include "base/message_loop.h"
15#include "chrome/browser/notifications/balloon_collection.h"
16#include "chrome/browser/notifications/balloon_collection_base.h"
17#include "ui/gfx/point.h"
18#include "ui/gfx/rect.h"
19
20// Mac balloons grow from the top down and have close buttons on top, so
21// offsetting is not necessary for easy multiple-closing.  Other platforms grow
22// from the bottom up and have close buttons on top, so it is necessary.
23#if defined(OS_MACOSX)
24#define USE_OFFSETS 0
25#else
26#define USE_OFFSETS 1
27#endif
28
29// A balloon collection represents a set of notification balloons being
30// shown on the screen.  It positions new notifications according to
31// a layout, and monitors for balloons being closed, which it reports
32// up to its parent, the notification UI manager.
33class BalloonCollectionImpl : public BalloonCollection
34#if USE_OFFSETS
35                            , public MessageLoopForUI::Observer
36#endif
37{
38 public:
39  BalloonCollectionImpl();
40  virtual ~BalloonCollectionImpl();
41
42  // BalloonCollection interface.
43  virtual void Add(const Notification& notification,
44                   Profile* profile);
45  virtual bool RemoveById(const std::string& id);
46  virtual bool RemoveBySourceOrigin(const GURL& source_origin);
47  virtual void RemoveAll();
48  virtual bool HasSpace() const;
49  virtual void ResizeBalloon(Balloon* balloon, const gfx::Size& size);
50  virtual void SetPositionPreference(PositionPreference position);
51  virtual void DisplayChanged();
52  virtual void OnBalloonClosed(Balloon* source);
53  virtual const Balloons& GetActiveBalloons();
54
55  // MessageLoopForUI::Observer interface.
56#if defined(OS_WIN)
57  virtual void WillProcessMessage(const MSG& event) {}
58  virtual void DidProcessMessage(const MSG& event);
59#endif
60#if defined(OS_LINUX)
61  virtual void WillProcessEvent(GdkEvent* event) {}
62  virtual void DidProcessEvent(GdkEvent* event);
63#endif
64
65 protected:
66  // Calculates layout values for the balloons including
67  // the scaling, the max/min sizes, and the upper left corner of each.
68  class Layout {
69   public:
70    Layout();
71
72    // These enumerations all are based on a screen orientation where
73    // the origin is the top-left.
74    enum Placement {
75      INVALID,
76      VERTICALLY_FROM_TOP_LEFT,
77      VERTICALLY_FROM_TOP_RIGHT,
78      VERTICALLY_FROM_BOTTOM_LEFT,
79      VERTICALLY_FROM_BOTTOM_RIGHT
80    };
81
82    // Refresh the work area and balloon placement.
83    void OnDisplaySettingsChanged();
84
85    // TODO(johnnyg): Scale the size to account for the system font factor.
86    static int min_balloon_width() { return kBalloonMinWidth; }
87    static int max_balloon_width() { return kBalloonMaxWidth; }
88    static int min_balloon_height() { return kBalloonMinHeight; }
89    static int max_balloon_height() { return kBalloonMaxHeight; }
90
91    // Utility function constrains the input rectangle to the min and max sizes.
92    static gfx::Size ConstrainToSizeLimits(const gfx::Size& rect);
93
94    void set_placement(Placement placement) { placement_ = placement; }
95
96    // Returns both the total space available and the maximum
97    // allowed per balloon.
98    //
99    // The size may be a height or length depending on the way that
100    // balloons are laid out.
101    void GetMaxLinearSize(int* max_balloon_size, int* total_size) const;
102
103    // Refresh the cached values for work area and drawing metrics.
104    // The application should call this method to re-acquire metrics after
105    // any resolution or settings change.
106    // Returns true if and only if a metric changed.
107    bool RefreshSystemMetrics();
108
109    // Returns the origin for the sequence of balloons depending on layout.
110    // Should not be used to place a balloon -- only to call NextPosition().
111    gfx::Point GetLayoutOrigin() const;
112
113    // Compute the position for the next balloon.
114    // Start with *position_iterator = GetLayoutOrigin() and call repeatedly
115    // to get a sequence of positions. Return value is the upper-left coordinate
116    // for each next balloon.
117    gfx::Point NextPosition(const gfx::Size& balloon_size,
118                            gfx::Point* position_iterator) const;
119
120    // Return a offscreen location which is offscreen for this layout,
121    // to be used as the initial position for an animation into view.
122    gfx::Point OffScreenLocation() const;
123
124    // Returns true if the layout requires offsetting for keeping the close
125    // buttons under the cursor during rapid-close interaction.
126    bool RequiresOffsets() const;
127
128   private:
129    // Layout parameters
130    int VerticalEdgeMargin() const;
131    int HorizontalEdgeMargin() const;
132    int InterBalloonMargin() const;
133
134    // Minimum and maximum size of balloon content.
135    static const int kBalloonMinWidth = 300;
136    static const int kBalloonMaxWidth = 300;
137    static const int kBalloonMinHeight = 24;
138    static const int kBalloonMaxHeight = 160;
139
140    Placement placement_;
141    gfx::Rect work_area_;
142    DISALLOW_COPY_AND_ASSIGN(Layout);
143  };
144
145  // Creates a new balloon. Overridable by unit tests.  The caller is
146  // responsible for freeing the pointer returned.
147  virtual Balloon* MakeBalloon(const Notification& notification,
148                               Profile* profile);
149
150  // Gets a bounding box for all the current balloons in screen coordinates.
151  gfx::Rect GetBalloonsBoundingBox() const;
152
153 private:
154  // Adjusts the positions of the balloons (e.g., when one is closed).
155  // Implemented by each platform for specific UI requirements.
156  void PositionBalloons(bool is_reposition);
157
158  // Cross-platform internal implementation for PositionBalloons.
159  void PositionBalloonsInternal(bool is_reposition);
160
161#if defined(OS_MACOSX)
162  // Get the work area on Mac OS, without inverting the coordinates.
163  static gfx::Rect GetMacWorkArea();
164#endif
165
166  // Base implementation for the collection of active balloons.
167  BalloonCollectionBase base_;
168
169  // The layout parameters for balloons in this collection.
170  Layout layout_;
171
172#if USE_OFFSETS
173  // Start and stop observing all UI events.
174  void AddMessageLoopObserver();
175  void RemoveMessageLoopObserver();
176
177  // Cancel all offset and reposition the balloons normally.
178  void CancelOffsets();
179
180  // Handles a mouse motion while the balloons are temporarily offset.
181  void HandleMouseMoveEvent();
182
183  // Is the current cursor in the balloon area?
184  bool IsCursorInBalloonCollection() const;
185
186  // Factory for generating delayed reposition tasks on mouse motion.
187  ScopedRunnableMethodFactory<BalloonCollectionImpl> reposition_factory_;
188
189  // Is the balloon collection currently listening for UI events?
190  bool added_as_message_loop_observer_;
191#endif
192
193  DISALLOW_COPY_AND_ASSIGN(BalloonCollectionImpl);
194};
195
196#endif  // CHROME_BROWSER_NOTIFICATIONS_BALLOON_COLLECTION_IMPL_H_
197