include/wx/generic/dragimgg.h

   1 /////////////////////////////////////////////////////////////////////////////
   2 // Name:        wx/generic/dragimgg.h
   3 // Purpose:     wxDragImage class: a kind of a cursor, that can cope
   4 //              with more sophisticated images
   5 // Author:      Julian Smart
   6 // Modified by:
   7 // Created:     29/2/2000
   8 // RCS-ID:      $Id$
   9 // Copyright:   (c) Julian Smart
  10 // Licence:     wxWindows licence
  11 /////////////////////////////////////////////////////////////////////////////
  12
  13 #ifndef _WX_DRAGIMGG_H_
  14 #define _WX_DRAGIMGG_H_
  15
  16 #ifdef __GNUG__
  17 #pragma interface "dragimgg.h"
  18 #endif
  19
  20 #include "wx/bitmap.h"
  21 #include "wx/icon.h"
  22 #include "wx/cursor.h"
  23 #include "wx/treectrl.h"
  24 #include "wx/listctrl.h"
  25
  26 /*
  27   To use this class, create a wxDragImage when you start dragging, for example:
  28
  29   void MyTreeCtrl::OnBeginDrag(wxTreeEvent& event)
  30   {
  31 #ifdef __WXMSW__
  32     ::UpdateWindow((HWND) GetHWND()); // We need to implement this in wxWindows
  33 #endif
  34
  35     CaptureMouse();
  36
  37     m_dragImage = new wxDragImage(* this, itemId);
  38     m_dragImage->BeginDrag(wxPoint(0, 0), this);
  39     m_dragImage->Move(pt, this);
  40     m_dragImage->Show(this);
  41     ...
  42   }
  43
  44   In your OnMouseMove function, hide the image, do any display updating required,
  45   then move and show the image again:
  46
  47   void MyTreeCtrl::OnMouseMove(wxMouseEvent& event)
  48   {
  49     if (m_dragMode == MY_TREE_DRAG_NONE)
  50     {
  51         event.Skip();
  52         return;
  53     }
  54
  55     // Prevent screen corruption by hiding the image
  56     if (m_dragImage)
  57         m_dragImage->Hide(this);
  58
  59     // Do some updating of the window, such as highlighting the drop target
  60     ...
  61
  62 #ifdef __WXMSW__
  63     if (updateWindow)
  64         ::UpdateWindow((HWND) GetHWND());
  65 #endif
  66
  67     // Move and show the image again
  68     m_dragImage->Move(event.GetPosition(), this);
  69     m_dragImage->Show(this);
  70  }
  71
  72  Eventually we end the drag and delete the drag image.
  73
  74  void MyTreeCtrl::OnLeftUp(wxMouseEvent& event)
  75  {
  76     ...
  77
  78     // End the drag and delete the drag image
  79     if (m_dragImage)
  80     {
  81         m_dragImage->EndDrag(this);
  82         delete m_dragImage;
  83         m_dragImage = NULL;
  84     }
  85     ReleaseMouse();
  86  }
  87 */
  88
  89 /*
  90  * wxGenericDragImage
  91  */
  92
  93 class WXDLLEXPORT wxGenericDragImage: public wxObject
  94 {
  95 public:
  96
  97     // Ctors & dtor
  98     ////////////////////////////////////////////////////////////////////////////
  99
 100     wxGenericDragImage(const wxCursor& cursor = wxNullCursor, const wxPoint& hotspot = wxPoint(0, 0))
 101     {
 102         Init();
 103         Create(cursor, hotspot);
 104     }
 105     wxGenericDragImage(const wxBitmap& image, const wxCursor& cursor = wxNullCursor, const wxPoint& hotspot = wxPoint(0, 0))
 106     {
 107         Init();
 108
 109         Create(image, cursor, hotspot);
 110     }
 111     wxGenericDragImage(const wxIcon& image, const wxCursor& cursor = wxNullCursor, const wxPoint& hotspot = wxPoint(0, 0))
 112     {
 113         Init();
 114
 115         Create(image, cursor, hotspot);
 116     }
 117     wxGenericDragImage(const wxString& str, const wxCursor& cursor = wxNullCursor, const wxPoint& hotspot = wxPoint(0, 0))
 118     {
 119         Init();
 120
 121         Create(str, cursor, hotspot);
 122     }
 123     wxGenericDragImage(const wxTreeCtrl& treeCtrl, wxTreeItemId& id)
 124     {
 125         Init();
 126
 127         Create(treeCtrl, id);
 128     }
 129     wxGenericDragImage(const wxListCtrl& listCtrl, long id)
 130     {
 131         Init();
 132
 133         Create(listCtrl, id);
 134     }
 135     ~wxGenericDragImage();
 136
 137     // Attributes
 138     ////////////////////////////////////////////////////////////////////////////
 139
 140     // For efficiency, tell wxGenericDragImage to use a bitmap that's already
 141     // created (e.g. from last drag)
 142     void SetBackingBitmap(wxBitmap* bitmap) { m_pBackingBitmap = bitmap; }
 143
 144     // Operations
 145     ////////////////////////////////////////////////////////////////////////////
 146
 147     // Create a drag image with a virtual image (need to override DoDrawImage, GetImageRect)
 148     bool Create(const wxCursor& cursor = wxNullCursor, const wxPoint& hotspot = wxPoint(0, 0));
 149
 150     // Create a drag image from a bitmap and optional cursor
 151     bool Create(const wxBitmap& image, const wxCursor& cursor = wxNullCursor, const wxPoint& hotspot = wxPoint(0, 0));
 152
 153     // Create a drag image from an icon and optional cursor
 154     bool Create(const wxIcon& image, const wxCursor& cursor = wxNullCursor, const wxPoint& hotspot = wxPoint(0, 0));
 155
 156     // Create a drag image from a string and optional cursor
 157     bool Create(const wxString& str, const wxCursor& cursor = wxNullCursor, const wxPoint& hotspot = wxPoint(0, 0));
 158
 159     // Create a drag image for the given tree control item
 160     bool Create(const wxTreeCtrl& treeCtrl, wxTreeItemId& id);
 161
 162     // Create a drag image for the given list control item
 163     bool Create(const wxListCtrl& listCtrl, long id);
 164
 165     // Begin drag. hotspot is the location of the drag position relative to the upper-left
 166     // corner of the image.
 167     bool BeginDrag(const wxPoint& hotspot, wxWindow* window, bool fullScreen = FALSE, wxRect* rect = (wxRect*) NULL);
 168
 169     // Begin drag. hotspot is the location of the drag position relative to the upper-left
 170     // corner of the image. This is full screen only. fullScreenRect gives the
 171     // position of the window on the screen, to restrict the drag to.
 172     bool BeginDrag(const wxPoint& hotspot, wxWindow* window, wxWindow* fullScreenRect);
 173
 174     // End drag
 175     bool EndDrag();
 176
 177     // Move the image: call from OnMouseMove. Pt is in window client coordinates if window
 178     // is non-NULL, or in screen coordinates if NULL.
 179     bool Move(const wxPoint& pt);
 180
 181     // Show the image
 182     bool Show();
 183
 184     // Hide the image
 185     bool Hide();
 186
 187     // Implementation
 188     ////////////////////////////////////////////////////////////////////////////
 189
 190     void Init();
 191
 192     // Override this if you are using a virtual image (drawing your own image)
 193     virtual wxRect GetImageRect(const wxPoint& pos) const;
 194
 195     // Override this if you are using a virtual image (drawing your own image)
 196     virtual bool DoDrawImage(wxDC& dc, const wxPoint& pos) const;
 197
 198     // Override this if you wish to draw the window contents to the backing bitmap
 199     // yourself. This can be desirable if you wish to avoid flicker by not having to
 200     // redraw the window itself before dragging in order to be graphic-minus-dragged-objects.
 201     // Instead, paint the drag image's backing bitmap to be correct, and leave the window
 202     // to be updated only when dragging the objects away (thus giving a smoother appearance).
 203     virtual bool UpdateBackingFromWindow(wxDC& windowDC, wxMemoryDC& destDC,
 204         const wxRect& sourceRect, const wxRect& destRect) const;
 205
 206     // Erase and redraw simultaneously if possible
 207     virtual bool RedrawImage(const wxPoint& oldPos, const wxPoint& newPos, bool eraseOld, bool drawNew);
 208
 209 protected:
 210     wxBitmap        m_bitmap;
 211     wxIcon          m_icon;
 212     wxCursor        m_cursor;
 213     wxCursor        m_oldCursor;
 214     wxPoint         m_hotspot;
 215     wxPoint         m_offset; // The hostpot value passed to BeginDrag
 216     wxPoint         m_position;
 217     bool            m_isDirty;
 218     bool            m_isShown;
 219     wxWindow*       m_window;
 220     wxDC*           m_windowDC;
 221
 222     // Stores the window contents while we're dragging the image around
 223     wxBitmap        m_backingBitmap;
 224     wxBitmap*       m_pBackingBitmap; // Pointer to existing backing bitmap
 225                                       // (pass to wxGenericDragImage as an efficiency measure)
 226     // A temporary bitmap for repairing/redrawing
 227     wxBitmap        m_repairBitmap;
 228
 229     wxRect          m_boundingRect;
 230     bool            m_fullScreen;
 231
 232 private:
 233     DECLARE_DYNAMIC_CLASS(wxGenericDragImage)
 234 };
 235
 236 #endif
 237     // _WX_DRAGIMGG_H_