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      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.
     33 class 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