chrome/browser/ui/panels/panel_drag_controller.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 CHROME_BROWSER_UI_PANELS_PANEL_DRAG_CONTROLLER_H_
   6 #define CHROME_BROWSER_UI_PANELS_PANEL_DRAG_CONTROLLER_H_
   7
   8 #include "base/memory/scoped_ptr.h"
   9 #include "chrome/browser/ui/panels/panel_collection.h"
  10 #include "ui/gfx/vector2d.h"
  11
  12 class Panel;
  13 class PanelCollection;
  14 class PanelManager;
  15 namespace gfx {
  16 class Point;
  17 class Rect;
  18 }
  19
  20 // Controls all the drags initiated for all panels, including detaching,
  21 // docking, stacking, snapping and intra-collection dragging.
  22 class PanelDragController {
  23  public:
  24   explicit PanelDragController(PanelManager* panel_manager);
  25   ~PanelDragController();
  26
  27   // Drags the given panel.
  28   // |mouse_location| is in screen coordinate system.
  29   void StartDragging(Panel* panel, const gfx::Point& mouse_location);
  30   void Drag(const gfx::Point& mouse_location);
  31   void EndDragging(bool cancelled);
  32
  33   // Asynchronous confirmation of panel having been closed.
  34   void OnPanelClosed(Panel* panel);
  35
  36   bool is_dragging() const { return dragging_panel_ != NULL; }
  37   Panel* dragging_panel() const { return dragging_panel_; }
  38
  39   // For testing.
  40   static int GetDetachDockedPanelThresholdForTesting();
  41   static int GetDockDetachedPanelThresholdForTesting();
  42   static int GetGluePanelDistanceThresholdForTesting();
  43   static int GetGluePanelOverlapThresholdForTesting();
  44   static int GetSnapPanelToScreenEdgeThresholdForTesting();
  45
  46  private:
  47   enum GlueAction {
  48     STACK,
  49     SNAP
  50   };
  51
  52   enum GlueEdge {
  53     TOP_EDGE,
  54     BOTTOM_EDGE,
  55     LEFT_EDGE,
  56     RIGHT_EDGE
  57   };
  58
  59   gfx::Point GetPanelPositionForMouseLocation(
  60       const gfx::Point& mouse_location) const;
  61
  62   // |target_position| is in screen coordinate systems. It contains the proposed
  63   //  panel origin to move to. Returns true if the request has been performed.
  64   void TryDetach(const gfx::Point& target_position);
  65   void TryDock(const gfx::Point& target_position);
  66   void TryStack(const gfx::Point& target_position);
  67   bool TryUnstackFromTop(const gfx::Point& target_position);
  68   bool TryUnstackFromBottom(const gfx::Point& target_position);
  69   void TrySnap(gfx::Point* target_position);
  70
  71   // Finds the panel that the dragging panel with |potential_position| could
  72   // snap to or stack with. If such panel is found, |target_bounds| contains the
  73   // new bounds for the dragging panel and |target_edge| contains the matched
  74   // edge.
  75   Panel* FindPanelToGlue(const gfx::Point& potential_position,
  76                          GlueAction action,
  77                          gfx::Rect* target_bounds,
  78                          GlueEdge* target_edge) const;
  79
  80   // Moves the |panel| (and all panels below if it is in a stack) to a different
  81   // collection.
  82   void MovePanelAndBelowToCollection(
  83       Panel* panel,
  84       PanelCollection* target_collection,
  85       PanelCollection::PositioningMask positioning_mask) const;
  86
  87   PanelManager* panel_manager_;  // Weak, owns us.
  88   bool panel_stacking_enabled_;
  89
  90   // Panel currently being dragged.
  91   Panel* dragging_panel_;
  92
  93   // The original panel collection when the drag is started.
  94   PanelCollection* dragging_panel_original_collection_;
  95
  96   // The offset from mouse location to the panel position when the drag
  97   // starts.
  98   gfx::Vector2d offset_from_mouse_location_on_drag_start_;
  99
 100   DISALLOW_COPY_AND_ASSIGN(PanelDragController);
 101 };
 102
 103 #endif  // CHROME_BROWSER_UI_PANELS_PANEL_DRAG_CONTROLLER_H_