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1 | ///////////////////////////////////////////////////////////////////////////// | |
2 | // Name: dragimag.h | |
3 | // Purpose: interface of wxDragImage | |
4 | // Author: wxWidgets team | |
5 | // RCS-ID: $Id$ | |
6 | // Licence: wxWindows licence | |
7 | ///////////////////////////////////////////////////////////////////////////// | |
8 | ||
9 | /** | |
10 | @class wxDragImage | |
11 | ||
12 | This class is used when you wish to drag an object on the screen, and a | |
13 | simple cursor is not enough. | |
14 | ||
15 | On Windows, the Win32 API is used to achieve smooth dragging. On other | |
16 | platforms, wxGenericDragImage is used. Applications may also prefer to use | |
17 | wxGenericDragImage on Windows, too. | |
18 | ||
19 | @beginWxPythonOnly | |
20 | wxPython uses wxGenericDragImage on all platforms, but uses the wxDragImage | |
21 | name. | |
22 | @endWxPythonOnly | |
23 | ||
24 | To use this class, when you wish to start dragging an image, create a | |
25 | wxDragImage object and store it somewhere you can access it as the drag | |
26 | progresses. Call BeginDrag() to start, and EndDrag() to stop the drag. To | |
27 | move the image, initially call Show() and then Move(). If you wish to | |
28 | update the screen contents during the drag (for example, highlight an item | |
29 | as in the dragimag sample), first call Hide(), update the screen, call | |
30 | Move(), and then call Show(). | |
31 | ||
32 | You can drag within one window, or you can use full-screen dragging either | |
33 | across the whole screen, or just restricted to one area of the screen to | |
34 | save resources. If you want the user to drag between two windows, then you | |
35 | will need to use full-screen dragging. | |
36 | ||
37 | If you wish to draw the image yourself, use wxGenericDragImage and override | |
38 | DoDrawImage() and GetImageRect(). | |
39 | ||
40 | @library{wxcore} | |
41 | @category{dnd} | |
42 | ||
43 | @see @ref page_samples_dragimag | |
44 | */ | |
45 | class wxDragImage : public wxObject | |
46 | { | |
47 | public: | |
48 | /** | |
49 | Default constructor. | |
50 | */ | |
51 | wxDragImage(); | |
52 | /** | |
53 | Constructs a drag image from a bitmap and optional cursor. | |
54 | ||
55 | @param image | |
56 | Bitmap to be used as the drag image. The bitmap can have a mask. | |
57 | @param cursor | |
58 | Optional cursor to combine with the image. | |
59 | @param cursorHotspot | |
60 | This parameter is deprecated. | |
61 | */ | |
62 | wxDragImage(const wxBitmap& image, const wxCursor& cursor = wxNullCursor, | |
63 | const wxPoint& cursorHotspot = wxPoint(0, 0)); | |
64 | /** | |
65 | Constructs a drag image from an icon and optional cursor. | |
66 | ||
67 | @param image | |
68 | Icon to be used as the drag image. | |
69 | @param cursor | |
70 | Optional cursor to combine with the image. | |
71 | @param cursorHotspot | |
72 | This parameter is deprecated. | |
73 | ||
74 | @beginWxPythonOnly | |
75 | This constructor is called wxDragIcon in wxPython. | |
76 | @endWxPythonOnly | |
77 | */ | |
78 | wxDragImage(const wxIcon& image, const wxCursor& cursor = wxNullCursor, | |
79 | const wxPoint& cursorHotspot = wxPoint(0, 0)); | |
80 | /** | |
81 | Constructs a drag image from a text string and optional cursor. | |
82 | ||
83 | @param text | |
84 | Text used to construct a drag image. | |
85 | @param cursor | |
86 | Optional cursor to combine with the image. | |
87 | @param cursorHotspot | |
88 | This parameter is deprecated. | |
89 | ||
90 | @beginWxPythonOnly | |
91 | This constructor is called wxDragString in wxPython. | |
92 | @endWxPythonOnly | |
93 | */ | |
94 | wxDragImage(const wxString& text, const wxCursor& cursor = wxNullCursor, | |
95 | const wxPoint& cursorHotspot = wxPoint(0, 0)); | |
96 | /** | |
97 | Constructs a drag image from the text in the given tree control item, | |
98 | and optional cursor. | |
99 | ||
100 | @param treeCtrl | |
101 | Tree control for constructing a tree drag image. | |
102 | @param id | |
103 | Tree control item id. | |
104 | ||
105 | @beginWxPythonOnly | |
106 | This constructor is called wxDragTreeItem in wxPython. | |
107 | @endWxPythonOnly | |
108 | */ | |
109 | wxDragImage(const wxTreeCtrl& treeCtrl, wxTreeItemId& id); | |
110 | /** | |
111 | Constructs a drag image from the text in the given list control item, | |
112 | and optional cursor. | |
113 | ||
114 | @param listCtrl | |
115 | List control for constructing a list drag image. | |
116 | @param id | |
117 | List control item id. | |
118 | ||
119 | @beginWxPythonOnly | |
120 | This constructor is called wxDragListItem in wxPython. | |
121 | @endWxPythonOnly | |
122 | */ | |
123 | wxDragImage(const wxListCtrl& listCtrl, long id); | |
124 | /** | |
125 | Constructs a drag image an optional cursor. This constructor is only | |
126 | available for wxGenericDragImage, and can be used when the application | |
127 | supplies DoDrawImage() and GetImageRect(). | |
128 | ||
129 | @param cursor | |
130 | Optional cursor to combine with the image. | |
131 | @param cursorHotspot | |
132 | This parameter is deprecated. | |
133 | */ | |
134 | wxDragImage(const wxCursor& cursor = wxNullCursor, | |
135 | const wxPoint& cursorHotspot = wxPoint(0, 0)); | |
136 | ||
137 | /** | |
138 | Start dragging the image, in a window or full screen. | |
139 | ||
140 | You need to then call Show() and Move() to show the image on the | |
141 | screen. Call EndDrag() when the drag has finished. | |
142 | ||
143 | Note that this call automatically calls CaptureMouse(). | |
144 | ||
145 | @param hotspot | |
146 | The location of the drag position relative to the upper-left corner | |
147 | of the image. | |
148 | @param window | |
149 | The window that captures the mouse, and within which the dragging | |
150 | is limited unless fullScreen is @true. | |
151 | @param fullScreen | |
152 | If @true, specifies that the drag will be visible over the full | |
153 | screen, or over as much of the screen as is specified by rect. Note | |
154 | that the mouse will still be captured in window. | |
155 | @param rect | |
156 | If non-@NULL, specifies the rectangle (in screen coordinates) that | |
157 | bounds the dragging operation. Specifying this can make the | |
158 | operation more efficient by cutting down on the area under | |
159 | consideration, and it can also make a visual difference since the | |
160 | drag is clipped to this area. | |
161 | */ | |
162 | bool BeginDrag(const wxPoint& hotspot, wxWindow* window, | |
163 | bool fullScreen = false, wxRect* rect = NULL); | |
164 | /** | |
165 | Start dragging the image, using the first window to capture the mouse | |
166 | and the second to specify the bounding area. This form is equivalent to | |
167 | using the first form, but more convenient than working out the bounding | |
168 | rectangle explicitly. | |
169 | ||
170 | You need to then call Show() and Move() to show the image on the | |
171 | screen. Call EndDrag() when the drag has finished. | |
172 | ||
173 | Note that this call automatically calls CaptureMouse(). | |
174 | ||
175 | @param hotspot | |
176 | The location of the drag position relative to the upper-left corner | |
177 | of the image. | |
178 | @param window | |
179 | The window that captures the mouse, and within which the dragging | |
180 | is limited. | |
181 | @param boundingWindow | |
182 | Specifies the area within which the drag occurs. | |
183 | */ | |
184 | bool BeginDrag(const wxPoint& hotspot, wxWindow* window, | |
185 | wxWindow* boundingWindow); | |
186 | ||
187 | /** | |
188 | Draws the image on the device context with top-left corner at the given | |
189 | position. | |
190 | ||
191 | This function is only available with wxGenericDragImage, to allow | |
192 | applications to draw their own image instead of using an actual bitmap. | |
193 | If you override this function, you must also override GetImageRect(). | |
194 | */ | |
195 | virtual bool DoDrawImage(wxDC& dc, const wxPoint& pos) const; | |
196 | ||
197 | /** | |
198 | Call this when the drag has finished. | |
199 | ||
200 | @note This function automatically releases mouse capture. | |
201 | */ | |
202 | bool EndDrag(); | |
203 | ||
204 | /** | |
205 | Returns the rectangle enclosing the image, assuming that the image is | |
206 | drawn with its top-left corner at the given point. | |
207 | ||
208 | This function is available in wxGenericDragImage only, and may be | |
209 | overridden (together with DoDrawImage()) to provide a virtual drawing | |
210 | capability. | |
211 | */ | |
212 | virtual wxRect GetImageRect(const wxPoint& pos) const; | |
213 | ||
214 | /** | |
215 | Hides the image. You may wish to call this before updating the window | |
216 | contents (perhaps highlighting an item). Then call Move() and Show(). | |
217 | */ | |
218 | bool Hide(); | |
219 | ||
220 | /** | |
221 | Call this to move the image to a new position. The image will only be | |
222 | shown if Show() has been called previously (for example at the start of | |
223 | the drag). | |
224 | ||
225 | @param pt | |
226 | The position in client coordinates (relative to the window | |
227 | specified in BeginDrag()). | |
228 | ||
229 | You can move the image either when the image is hidden or shown, but in | |
230 | general dragging will be smoother if you move the image when it is | |
231 | shown. | |
232 | */ | |
233 | bool Move(const wxPoint& pt); | |
234 | ||
235 | /** | |
236 | Shows the image. Call this at least once when dragging. | |
237 | */ | |
238 | bool Show(); | |
239 | ||
240 | /** | |
241 | Override this if you wish to draw the window contents to the backing | |
242 | bitmap yourself. This can be desirable if you wish to avoid flicker by | |
243 | not having to redraw the updated window itself just before dragging, | |
244 | which can cause a flicker just as the drag starts. Instead, paint the | |
245 | drag image's backing bitmap to show the appropriate graphic @e minus | |
246 | the objects to be dragged, and leave the window itself to be updated by | |
247 | the drag image. This can provide eerily smooth, flicker-free drag | |
248 | behaviour. | |
249 | ||
250 | The default implementation copies the window contents to the backing | |
251 | bitmap. A new implementation will normally copy information from | |
252 | another source, such as from its own backing bitmap if it has one, or | |
253 | directly from internal data structures. | |
254 | ||
255 | This function is available in wxGenericDragImage only. | |
256 | */ | |
257 | virtual bool UpdateBackingFromWindow(wxDC& windowDC, wxMemoryDC& destDC, | |
258 | const wxRect& sourceRect, | |
259 | const wxRect& destRect) const; | |
260 | }; | |
261 |