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 licence
   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(wxCoord x, wxCoord y);
  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 bool 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 type of @a iconCopy and subsequent parameters
 191         differs between different ports: these are cursors under Windows and OS
 192         X but icons for GTK. You should use the macro wxDROP_ICON() in portable
 193         programs instead of directly using either of these types.
 194
 195         @onlyfor{wxmsw,wxosx}
 196
 197         @param win
 198             The window which initiates the drag and drop operation.
 199         @param iconCopy
 200             The icon or cursor used for feedback for copy operation.
 201         @param iconMove
 202             The icon or cursor used for feedback for move operation.
 203         @param iconNone
 204             The icon or cursor used for feedback when operation can't be done.
 205     */
 206     wxDropSource(wxWindow* win = NULL,
 207                  const wxCursor& iconCopy = wxNullIcon,
 208                  const wxCursor& iconMove = wxNullIcon,
 209                  const wxCursor& iconNone = wxNullIcon);
 210
 211     /**
 212         The constructor taking a wxDataObject.
 213
 214         Note that the type of @a iconCopy and subsequent parameters
 215         differs between different ports: these are cursors under Windows and OS
 216         X but icons for GTK. You should use the macro wxDROP_ICON() in portable
 217         programs instead of directly using either of these types.
 218
 219         @onlyfor{wxmsw,wxosx}
 220
 221         @param data
 222             The data associated with the drop source.
 223         @param win
 224             The window which initiates the drag and drop operation.
 225         @param iconCopy
 226             The icon or cursor used for feedback for copy operation.
 227         @param iconMove
 228             The icon or cursor used for feedback for move operation.
 229         @param iconNone
 230             The icon or cursor used for feedback when operation can't be done.
 231     */
 232     wxDropSource(wxDataObject& data, wxWindow* win = NULL,
 233                  const wxCursor& iconCopy = wxNullIcon,
 234                  const wxCursor& iconMove = wxNullIcon,
 235                  const wxCursor& iconNone = wxNullIcon);
 236
 237     /**
 238         This constructor requires that you must call SetData() later.
 239
 240         This is the wxGTK-specific version of the constructor taking wxIcon
 241         instead of wxCursor as the other ports.
 242
 243         @onlyfor{wxgtk}
 244
 245         @param win
 246             The window which initiates the drag and drop operation.
 247         @param iconCopy
 248             The icon or cursor used for feedback for copy operation.
 249         @param iconMove
 250             The icon or cursor used for feedback for move operation.
 251         @param iconNone
 252             The icon or cursor used for feedback when operation can't be done.
 253     */
 254     wxDropSource(wxWindow* win = NULL,
 255                  const wxIcon& iconCopy = wxNullCursor,
 256                  const wxIcon& iconMove = wxNullCursor,
 257                  const wxIcon& iconNone = wxNullCursor);
 258
 259     /**
 260         The constructor taking a wxDataObject.
 261
 262         This is the wxGTK-specific version of the constructor taking wxIcon
 263         instead of wxCursor as the other ports.
 264
 265         @onlyfor{wxgtk}
 266
 267         @param data
 268             The data associated with the drop source.
 269         @param win
 270             The window which initiates the drag and drop operation.
 271         @param iconCopy
 272             The icon or cursor used for feedback for copy operation.
 273         @param iconMove
 274             The icon or cursor used for feedback for move operation.
 275         @param iconNone
 276             The icon or cursor used for feedback when operation can't be done.
 277     */
 278     wxDropSource(wxDataObject& data, wxWindow* win = NULL,
 279                  const wxIcon& iconCopy = wxNullCursor,
 280                  const wxIcon& iconMove = wxNullCursor,
 281                  const wxIcon& iconNone = wxNullCursor);
 282
 283     /**
 284         Starts the drag-and-drop operation which will terminate when the user
 285         releases the mouse. Call this in response to a mouse button press, for
 286         example.
 287
 288         @param flags
 289             If wxDrag_AllowMove is included in the flags, data may be moved and
 290             not only copied (default). If wxDrag_DefaultMove is specified
 291             (which includes the previous flag), this is even the default
 292             operation.
 293
 294         @return The operation requested by the user, may be ::wxDragCopy,
 295                  ::wxDragMove, ::wxDragLink, ::wxDragCancel or ::wxDragNone if
 296                  an error occurred.
 297     */
 298     virtual wxDragResult DoDragDrop(int flags = wxDrag_CopyOnly);
 299
 300     /**
 301         Returns the wxDataObject object that has been assigned previously.
 302     */
 303     wxDataObject* GetDataObject();
 304
 305     /**
 306         You may give some custom UI feedback during the drag and drop operation
 307         by overriding this function. It is called on each mouse move, so your
 308         implementation must not be too slow.
 309
 310         @param effect
 311             The effect to implement. One of ::wxDragCopy, ::wxDragMove,
 312             ::wxDragLink and ::wxDragNone.
 313
 314         @return @false if you want default feedback, or @true if you implement
 315                 your own feedback. The return value is ignored under GTK.
 316     */
 317     virtual bool GiveFeedback(wxDragResult effect);
 318
 319     /**
 320         Set the icon to use for a certain drag result.
 321
 322         @param res
 323             The drag result to set the icon for.
 324         @param cursor
 325             The ion to show when this drag result occurs.
 326     */
 327     void SetCursor(wxDragResult res, const wxCursor& cursor);
 328
 329     /**
 330         Sets the data wxDataObject associated with the drop source. This will
 331         not delete any previously associated data.
 332     */
 333     void SetData(wxDataObject& data);
 334 };
 335
 336
 337
 338 /**
 339     @class wxFileDropTarget
 340
 341     This is a drop target which accepts files (dragged from File Manager or
 342     Explorer).
 343
 344     @library{wxcore}
 345     @category{dnd}
 346
 347     @see @ref overview_dnd, wxDropSource, wxDropTarget, wxTextDropTarget
 348 */
 349 class wxFileDropTarget : public wxDropTarget
 350 {
 351 public:
 352     /**
 353         Constructor.
 354     */
 355     wxFileDropTarget();
 356
 357     /**
 358         See wxDropTarget::OnDrop(). This function is implemented appropriately
 359         for files, and calls OnDropFiles().
 360     */
 361     virtual bool OnDrop(wxCoord x, wxCoord y);
 362
 363     /**
 364         Override this function to receive dropped files.
 365
 366         @param x
 367             The x coordinate of the mouse.
 368         @param y
 369             The y coordinate of the mouse.
 370         @param filenames
 371             An array of filenames.
 372
 373         Return @true to accept the data, or @false to veto the operation.
 374     */
 375     virtual bool OnDropFiles(wxCoord x, wxCoord y,
 376                              const wxArrayString& filenames) = 0;
 377 };
 378
 379
 380
 381 // ============================================================================
 382 // Global functions/macros
 383 // ============================================================================
 384
 385 /** @addtogroup group_funcmacro_gdi */
 386 //@{
 387
 388 /**
 389     This macro creates either a cursor (MSW) or an icon (elsewhere) with the
 390     given @a name (of type <tt>const char*</tt>). Under MSW, the cursor is
 391     loaded from the resource file and the icon is loaded from XPM file under
 392     other platforms.
 393
 394     This macro should be used with wxDropSource::wxDropSource().
 395
 396     @return wxCursor on MSW, otherwise returns a wxIcon
 397
 398     @header{wx/dnd.h}
 399 */
 400 #define wxDROP_ICON(name)
 401
 402 //@}
 403