interface/wx/dnd.h

   1 /////////////////////////////////////////////////////////////////////////////
   2 // Name:        dnd.h
   3 // Purpose:     interface of wxDropSource and wx*DropTarget
   4 // Author:      wxWidgets team
   5 // RCS-ID:      $Id$
   6 // Licence:     wxWindows license
   7 /////////////////////////////////////////////////////////////////////////////
   8
   9 /**
  10     @class wxTextDropTarget
  11
  12     A predefined drop target for dealing with text data.
  13
  14     @library{wxcore}
  15     @category{dnd}
  16
  17     @see @ref overview_dnd, wxDropSource, wxDropTarget, wxFileDropTarget
  18 */
  19 class wxTextDropTarget : public wxDropTarget
  20 {
  21 public:
  22     /**
  23         Constructor.
  24     */
  25     wxTextDropTarget();
  26
  27     /**
  28         See wxDropTarget::OnDrop(). This function is implemented appropriately
  29         for text, and calls OnDropText().
  30     */
  31     virtual bool OnDrop(long x, long y, const void data, size_t size);
  32
  33     /**
  34         Override this function to receive dropped text.
  35
  36         @param x
  37             The x coordinate of the mouse.
  38         @param y
  39             The y coordinate of the mouse.
  40         @param data
  41             The data being dropped: a wxString.
  42
  43         Return @true to accept the data, or @false to veto the operation.
  44     */
  45     virtual bool OnDropText(wxCoord x, wxCoord y, const wxString& data) = 0;
  46 };
  47
  48
  49
  50 /**
  51     Result returned from a wxDropSource::DoDragDrop() call.
  52 */
  53 enum wxDragResult
  54 {
  55     wxDragError,    ///< Error prevented the D&D operation from completing.
  56     wxDragNone,     ///< Drag target didn't accept the data.
  57     wxDragCopy,     ///< The data was successfully copied.
  58     wxDragMove,     ///< The data was successfully moved (MSW only).
  59     wxDragLink,     ///< Operation is a drag-link.
  60     wxDragCancel    ///< The operation was cancelled by user (not an error).
  61 };
  62
  63 /**
  64     @class wxDropTarget
  65
  66     This class represents a target for a drag and drop operation. A
  67     wxDataObject can be associated with it and by default, this object will be
  68     filled with the data from the drag source, if the data formats supported by
  69     the data object match the drag source data format.
  70
  71     There are various virtual handler functions defined in this class which may
  72     be overridden to give visual feedback or react in a more fine-tuned way,
  73     e.g. by not accepting data on the whole window area, but only a small
  74     portion of it. The normal sequence of calls is OnEnter(), OnDragOver()
  75     possibly many times, OnDrop() and finally OnData().
  76
  77     @library{wxcore}
  78     @category{dnd}
  79
  80     @see @ref overview_dnd, @ref overview_dataobject, wxDropSource,
  81          wxTextDropTarget, wxFileDropTarget, wxDataFormat, wxDataObject
  82 */
  83 class wxDropTarget
  84 {
  85 public:
  86     /**
  87         Constructor. @a data is the data to be associated with the drop target.
  88     */
  89     wxDropTarget(wxDataObject* data = NULL);
  90
  91     /**
  92         Destructor. Deletes the associated data object, if any.
  93     */
  94     virtual ~wxDropTarget();
  95
  96     /**
  97         This method may only be called from within OnData(). By default, this
  98         method copies the data from the drop source to the wxDataObject
  99         associated with this drop target, calling its wxDataObject::SetData()
 100         method.
 101     */
 102     virtual void GetData();
 103
 104     /**
 105         Called after OnDrop() returns @true. By default this will usually
 106         GetData() and will return the suggested default value @a def.
 107     */
 108     virtual wxDragResult OnData(wxCoord x, wxCoord y, wxDragResult def);
 109
 110     /**
 111         Called when the mouse is being dragged over the drop target. By
 112         default, this calls functions return the suggested return value @a def.
 113
 114         @param x
 115             The x coordinate of the mouse.
 116         @param y
 117             The y coordinate of the mouse.
 118         @param def
 119             Suggested value for return value. Determined by SHIFT or CONTROL
 120             key states.
 121
 122         @return The desired operation or wxDragNone. This is used for optical
 123                  feedback from the side of the drop source, typically in form
 124                  of changing the icon.
 125     */
 126     virtual wxDragResult OnDragOver(wxCoord x, wxCoord y, wxDragResult def);
 127
 128     /**
 129         Called when the user drops a data object on the target. Return @false
 130         to veto the operation.
 131
 132         @param x
 133             The x coordinate of the mouse.
 134         @param y
 135             The y coordinate of the mouse.
 136
 137         @return @true to accept the data, or @false to veto the operation.
 138     */
 139     virtual bool OnDrop(wxCoord x, wxCoord y);
 140
 141     /**
 142         Called when the mouse enters the drop target. By default, this calls
 143         OnDragOver().
 144
 145         @param x
 146             The x coordinate of the mouse.
 147         @param y
 148             The y coordinate of the mouse.
 149         @param def
 150             Suggested default for return value. Determined by SHIFT or CONTROL
 151             key states.
 152
 153         @return The desired operation or wxDragNone. This is used for optical
 154                  feedback from the side of the drop source, typically in form
 155                  of changing the icon.
 156     */
 157     virtual wxDragResult OnEnter(wxCoord x, wxCoord y, wxDragResult def);
 158
 159     /**
 160         Called when the mouse leaves the drop target.
 161     */
 162     virtual void OnLeave();
 163
 164     /**
 165         Sets the data wxDataObject associated with the drop target and deletes
 166         any previously associated data object.
 167     */
 168     void SetDataObject(wxDataObject* data);
 169 };
 170
 171
 172
 173 /**
 174     @class wxDropSource
 175
 176     This class represents a source for a drag and drop operation.
 177
 178     @library{wxcore}
 179     @category{dnd}
 180
 181     @see @ref overview_dnd, @ref overview_dataobject, wxDropTarget,
 182          wxTextDropTarget, wxFileDropTarget
 183 */
 184 class wxDropSource
 185 {
 186 public:
 187     /**
 188         This constructor requires that you must call SetData() later.
 189
 190         Note that the exact type of @a iconCopy and subsequent parameters
 191         differs between wxMSW and wxGTK: these are cursors under Windows but
 192         icons for GTK. You should use the macro wxDROP_ICON() in portable
 193         programs instead of directly using either of these types.
 194
 195         @param win
 196             The window which initiates the drag and drop operation.
 197         @param iconCopy
 198             The icon or cursor used for feedback for copy operation.
 199         @param iconMove
 200             The icon or cursor used for feedback for move operation.
 201         @param iconNone
 202             The icon or cursor used for feedback when operation can't be done.
 203     */
 204     wxDropSource(wxWindow* win = NULL,
 205                  const wxIconOrCursor& iconCopy = wxNullIconOrCursor,
 206                  const wxIconOrCursor& iconMove = wxNullIconOrCursor,
 207                  const wxIconOrCursor& iconNone = wxNullIconOrCursor);
 208     /**
 209         Note that the exact type of @a iconCopy and subsequent parameters
 210         differs between wxMSW and wxGTK: these are cursors under Windows but
 211         icons for GTK. You should use the macro wxDROP_ICON() in portable
 212         programs instead of directly using either of these types.
 213
 214         @param win
 215             The window which initiates the drag and drop operation.
 216         @param iconCopy
 217             The icon or cursor used for feedback for copy operation.
 218         @param iconMove
 219             The icon or cursor used for feedback for move operation.
 220         @param iconNone
 221             The icon or cursor used for feedback when operation can't be done.
 222     */
 223     wxDropSource(wxDataObject& data, wxWindow* win = NULL,
 224                  const wxIconOrCursor& iconCopy = wxNullIconOrCursor,
 225                  const wxIconOrCursor& iconMove = wxNullIconOrCursor,
 226                  const wxIconOrCursor& iconNone = wxNullIconOrCursor);
 227
 228     /**
 229         Default constructor.
 230     */
 231     virtual ~wxDropSource();
 232
 233     /**
 234         Starts the drag-and-drop operation which will terminate when the user
 235         releases the mouse. Call this in response to a mouse button press, for
 236         example.
 237
 238         @param flags
 239             If wxDrag_AllowMove is included in the flags, data may be moved and
 240             not only copied (default). If wxDrag_DefaultMove is specified
 241             (which includes the previous flag), this is even the default
 242             operation.
 243
 244         @return The operation requested by the user, may be ::wxDragCopy,
 245                  ::wxDragMove, ::wxDragLink, ::wxDragCancel or ::wxDragNone if
 246                  an error occurred.
 247     */
 248     virtual wxDragResult DoDragDrop(int flags = wxDrag_CopyOnly);
 249
 250     /**
 251         Returns the wxDataObject object that has been assigned previously.
 252     */
 253     wxDataObject* GetDataObject();
 254
 255     /**
 256         You may give some custom UI feedback during the drag and drop operation
 257         by overriding this function. It is called on each mouse move, so your
 258         implementation must not be too slow.
 259
 260         @param effect
 261             The effect to implement. One of ::wxDragCopy, ::wxDragMove,
 262             ::wxDragLink and ::wxDragNone.
 263         @param scrolling
 264             @true if the window is scrolling. MSW only.
 265
 266         @return @false if you want default feedback, or @true if you implement
 267                 your own feedback. The return value is ignored under GTK.
 268     */
 269     virtual bool GiveFeedback(wxDragResult effect);
 270
 271     /**
 272         Set the icon to use for a certain drag result.
 273
 274         @param res
 275             The drag result to set the icon for.
 276         @param cursor
 277             The ion to show when this drag result occurs.
 278     */
 279     void SetCursor(wxDragResult res, const wxCursor& cursor);
 280
 281     /**
 282         Sets the data wxDataObject associated with the drop source. This will
 283         not delete any previously associated data.
 284     */
 285     void SetData(wxDataObject& data);
 286 };
 287
 288
 289
 290 /**
 291     @class wxFileDropTarget
 292
 293     This is a drop target which accepts files (dragged from File Manager or
 294     Explorer).
 295
 296     @library{wxcore}
 297     @category{dnd}
 298
 299     @see @ref overview_dnd, wxDropSource, wxDropTarget, wxTextDropTarget
 300 */
 301 class wxFileDropTarget : public wxDropTarget
 302 {
 303 public:
 304     /**
 305         Constructor.
 306     */
 307     wxFileDropTarget();
 308
 309     /**
 310         See wxDropTarget::OnDrop(). This function is implemented appropriately
 311         for files, and calls OnDropFiles().
 312     */
 313     virtual bool OnDrop(long x, long y, const void data, size_t size);
 314
 315     /**
 316         Override this function to receive dropped files.
 317
 318         @param x
 319             The x coordinate of the mouse.
 320         @param y
 321             The y coordinate of the mouse.
 322         @param filenames
 323             An array of filenames.
 324
 325         Return @true to accept the data, or @false to veto the operation.
 326     */
 327     virtual bool OnDropFiles(wxCoord x, wxCoord y,
 328                              const wxArrayString& filenames);
 329 };
 330
 331
 332
 333 // ============================================================================
 334 // Global functions/macros
 335 // ============================================================================
 336
 337 /** @ingroup group_funcmacro_gdi */
 338 //@{
 339
 340 /**
 341     This macro creates either a cursor (MSW) or an icon (elsewhere) with the
 342     given @a name (of type <tt>const char*</tt>). Under MSW, the cursor is
 343     loaded from the resource file and the icon is loaded from XPM file under
 344     other platforms.
 345
 346     This macro should be used with wxDropSource::wxDropSource().
 347
 348     @return wxCursor on MSW, otherwise returns a wxIcon
 349
 350     @header{wx/dnd.h}
 351 */
 352 #define wxDROP_ICON(name)
 353
 354 //@}
 355