include/wx/dnd.h

   1 ///////////////////////////////////////////////////////////////////////////////
   2 // Name:        wx/dnd.h
   3 // Purpose:     Drag and drop classes declarations
   4 // Author:      Vadim Zeitlin, Robert Roebling
   5 // Modified by:
   6 // Created:     26.05.99
   7 // RCS-ID:      $Id$
   8 // Copyright:   (c) wxWindows Team
   9 // Licence:     wxWindows license
  10 ///////////////////////////////////////////////////////////////////////////////
  11
  12 #ifndef _WX_DND_H_BASE_
  13 #define _WX_DND_H_BASE_
  14
  15 #include "wx/defs.h"
  16
  17 #if wxUSE_DRAG_AND_DROP
  18
  19 #include "wx/dataobj.h"
  20
  21 // ----------------------------------------------------------------------------
  22 // constants
  23 // ----------------------------------------------------------------------------
  24
  25 // result of wxDropSource::DoDragDrop() call
  26 enum wxDragResult
  27 {
  28     wxDragError,    // error prevented the d&d operation from completing
  29     wxDragNone,     // drag target didn't accept the data
  30     wxDragCopy,     // the data was successfully copied
  31     wxDragMove,     // the data was successfully moved (MSW only)
  32     wxDragCancel    // the operation was cancelled by user (not an error)
  33 };
  34
  35 // ----------------------------------------------------------------------------
  36 // wxDropSource is the object you need to create (and call DoDragDrop on it)
  37 // to initiate a drag-and-drop operation
  38 // ----------------------------------------------------------------------------
  39
  40 class WXDLLEXPORT wxDropSourceBase
  41 {
  42 public:
  43     wxDropSourceBase() { m_data = (wxDataObject *)NULL; }
  44     virtual ~wxDropSourceBase() { }
  45
  46     // set the data which is transfered by drag and drop
  47     void SetData(wxDataObject& data)
  48       { m_data = &data; }
  49
  50     wxDataObject *GetDataObject()
  51       { return m_data; }
  52
  53     // start drag action, see enum wxDragResult for return value description
  54     //
  55     // if bAllowMove is TRUE, data can be moved, if not - only copied
  56     virtual wxDragResult DoDragDrop(bool bAllowMove = FALSE) = 0;
  57
  58     // override to give feedback depending on the current operation result
  59     // "effect"
  60     virtual bool GiveFeedback( wxDragResult WXUNUSED(effect),
  61                                bool WXUNUSED(bScrolling) )
  62     {
  63         return TRUE;
  64     }
  65
  66 protected:
  67     wxDataObject *m_data;
  68 };
  69
  70 // ----------------------------------------------------------------------------
  71 // wxDropTarget should be associated with a window if it wants to be able to
  72 // receive data via drag and drop.
  73 //
  74 // To use this class, you should derive from wxDropTarget and implement
  75 // OnData() pure virtual method. You may also wish to override OnDrop() if you
  76 // want to accept the data only inside some region of the window (this may
  77 // avoid having to copy the data to this application which happens only when
  78 // OnData() is called)
  79 // ----------------------------------------------------------------------------
  80
  81 class WXDLLEXPORT wxDropTargetBase
  82 {
  83 public:
  84     // ctor takes a pointer to heap-allocated wxDataObject which will be owned
  85     // by wxDropTarget and deleted by it automatically. If you don't give it
  86     // here, you can use SetDataObject() later.
  87     wxDropTargetBase(wxDataObject *dataObject = (wxDataObject*)NULL)
  88         { m_dataObject = dataObject; }
  89     // dtor deletes our data object
  90     virtual ~wxDropTargetBase()
  91         { delete m_dataObject; }
  92
  93     // get/set the associated wxDataObject
  94     wxDataObject *GetDataObject() const
  95         { return m_dataObject; }
  96     void SetDataObject(wxDataObject *dataObject)
  97         { if (m_dataObject) delete m_dataObject;
  98     m_dataObject = dataObject; }
  99
 100     // these functions are called when data is moved over position (x, y) and
 101     // may return either wxDragCopy, wxDragMove or wxDragNone depending on
 102     // what would happen if the data were dropped here.
 103     //
 104     // the last parameter is what would happen by default and is determined by
 105     // the platform-specific logic (for example, under Windows it's wxDragCopy
 106     // if Ctrl key is pressed and wxDragMove otherwise) except that it will
 107     // always be wxDragNone if the carried data is in an unsupported format.
 108
 109     // called when the mouse enters the window (only once until OnLeave())
 110     virtual wxDragResult OnEnter(wxCoord x, wxCoord y, wxDragResult def)
 111         { return OnDragOver(x, y, def); }
 112
 113     // called when the mouse moves in the window - shouldn't take long to
 114     // execute or otherwise mouse movement would be too slow
 115     virtual wxDragResult OnDragOver(wxCoord WXUNUSED(x), wxCoord WXUNUSED(y),
 116                                     wxDragResult def)
 117         { return def; }
 118
 119     // called when mouse leaves the window: might be used to remove the
 120     // feedback which was given in OnEnter()
 121     virtual void OnLeave() { }
 122
 123     // this function is called when data is dropped at position (x, y) - if it
 124     // returns TRUE, OnData() will be called immediately afterwards which will
 125     // allow to retrieve the data dropped.
 126     virtual bool OnDrop(wxCoord x, wxCoord y) = 0;
 127
 128     // called after OnDrop() returns TRUE: you will usually just call
 129     // GetData() from here and, probably, also refresh something to update the
 130     // new data
 131     virtual bool OnData(wxCoord x, wxCoord y) = 0;
 132
 133     // may be called *only* from inside OnData() and will fill m_dataObject
 134     // with the data from the drop source if it returns TRUE
 135     virtual bool GetData() = 0;
 136
 137 protected:
 138     wxDataObject *m_dataObject;
 139 };
 140
 141 // ----------------------------------------------------------------------------
 142 // the platform-specific headers also define standard wxDropTarget
 143 // implementations wxTextDropTarget and wxFileDropTarget
 144 // ----------------------------------------------------------------------------
 145
 146 // ----------------------------------------------------------------------------
 147 // include platform dependent class declarations
 148 // ----------------------------------------------------------------------------
 149
 150 #if defined(__WXMSW__)
 151     #include "wx/msw/ole/dropsrc.h"
 152     #include "wx/msw/ole/droptgt.h"
 153 #elif defined(__WXMOTIF__)
 154     #include "wx/motif/dnd.h"
 155 #elif defined(__WXGTK__)
 156     #include "wx/gtk/dnd.h"
 157 #elif defined(__WXQT__)
 158     #include "wx/qt/dnd.h"
 159 #elif defined(__WXMAC__)
 160     #include "wx/mac/dnd.h"
 161 #elif defined(__WXPM__)
 162     #include "wx/os2/dnd.h"
 163 #elif defined(__WXSTUBS__)
 164     #include "wx/stubs/dnd.h"
 165 #endif
 166
 167 #endif // wxUSE_DRAG_AND_DROP
 168
 169 #endif // _WX_DND_H_BASE_