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1 | ///////////////////////////////////////////////////////////////////////////// | |
2 | // Name: dcmemory.h | |
3 | // Purpose: interface of wxMemoryDC | |
4 | // Author: wxWidgets team | |
5 | // RCS-ID: $Id$ | |
6 | // Licence: wxWindows license | |
7 | ///////////////////////////////////////////////////////////////////////////// | |
8 | ||
9 | /** | |
10 | @class wxMemoryDC | |
11 | @wxheader{dcmemory.h} | |
12 | ||
13 | A memory device context provides a means to draw graphics onto a bitmap. When | |
14 | drawing in to a mono-bitmap, using @c wxWHITE, @c wxWHITE_PEN and | |
15 | @c wxWHITE_BRUSH | |
16 | will draw the background colour (i.e. 0) whereas all other colours will draw the | |
17 | foreground colour (i.e. 1). | |
18 | ||
19 | @library{wxcore} | |
20 | @category{dc} | |
21 | ||
22 | @see wxBitmap, wxDC | |
23 | */ | |
24 | class wxMemoryDC : public wxDC | |
25 | { | |
26 | public: | |
27 | //@{ | |
28 | /** | |
29 | Constructs a new memory device context and calls SelectObject() | |
30 | with the given bitmap. | |
31 | Use the wxDC::IsOk member to test whether the constructor was successful | |
32 | in creating a usable device context. | |
33 | */ | |
34 | wxMemoryDC(); | |
35 | wxMemoryDC(wxBitmap& bitmap); | |
36 | //@} | |
37 | ||
38 | /** | |
39 | Works exactly like SelectObjectAsSource() but | |
40 | this is the function you should use when you select a bitmap because you want | |
41 | to modify | |
42 | it, e.g. drawing on this DC. | |
43 | Using SelectObjectAsSource() when modifying | |
44 | the bitmap may incurr some problems related to wxBitmap being a reference | |
45 | counted object | |
46 | (see @ref overview_trefcount "reference counting overview"). | |
47 | Also, before using the updated bitmap data, make sure to select it out of | |
48 | context first | |
49 | (for example by selecting wxNullBitmap into the device context). | |
50 | ||
51 | @see wxDC::DrawBitmap | |
52 | */ | |
53 | void SelectObject(wxBitmap& bitmap); | |
54 | ||
55 | /** | |
56 | Selects the given bitmap into the device context, to use as the memory | |
57 | bitmap. Selecting the bitmap into a memory DC allows you to draw into | |
58 | the DC (and therefore the bitmap) and also to use wxDC::Blit to copy | |
59 | the bitmap to a window. For this purpose, you may find wxDC::DrawIcon | |
60 | easier to use instead. | |
61 | If the argument is wxNullBitmap (or some other uninitialised wxBitmap) the | |
62 | current bitmap is | |
63 | selected out of the device context, and the original bitmap restored, allowing | |
64 | the current bitmap to | |
65 | be destroyed safely. | |
66 | */ | |
67 | void SelectObjectAsSource(const wxBitmap& bitmap); | |
68 | }; | |
69 |