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