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15b6757b | 1 | ///////////////////////////////////////////////////////////////////////////// |
d54cf7ff | 2 | // Name: dc.h |
15b6757b FM |
3 | // Purpose: topic overview |
4 | // Author: wxWidgets team | |
5 | // RCS-ID: $Id$ | |
526954c5 | 6 | // Licence: wxWindows licence |
15b6757b FM |
7 | ///////////////////////////////////////////////////////////////////////////// |
8 | ||
880efa2a | 9 | /** |
36c9828f | 10 | |
928f1a07 FM |
11 | @page overview_dc Device Contexts |
12 | ||
13 | Classes: wxBufferedDC, wxBufferedPaintDC, wxDC, wxPostScriptDC, | |
14 | wxMetafileDC, wxMemoryDC, wxPrinterDC, wxScreenDC, wxClientDC, | |
15 | wxPaintDC, wxWindowDC. | |
16 | ||
17 | A wxDC is a @e device context onto which graphics and text can be drawn. | |
18 | The device context is intended to represent a number of output devices in a | |
19 | generic way, with the same API being used throughout. | |
20 | ||
21 | Some device contexts are created temporarily in order to draw on a window. | |
22 | This is @true of wxScreenDC, wxClientDC, wxPaintDC, and wxWindowDC. | |
23 | The following describes the differences between these device contexts and | |
24 | when you should use them. | |
25 | ||
26 | @li @b wxScreenDC. Use this to paint on the screen, as opposed to an individual window. | |
27 | @li @b wxClientDC. Use this to paint on the client area of window (the part without | |
28 | borders and other decorations), but do not use it from within an wxPaintEvent. | |
29 | @li @b wxPaintDC. Use this to paint on the client area of a window, but @e only from | |
30 | within a wxPaintEvent. | |
31 | @li @b wxWindowDC. Use this to paint on the whole area of a window, including decorations. | |
32 | This may not be available on non-Windows platforms. | |
33 | ||
34 | To use a client, paint or window device context, create an object on the stack with | |
35 | the window as argument, for example: | |
36 | ||
37 | @code | |
38 | void MyWindow::OnMyCmd(wxCommandEvent& event) | |
39 | { | |
40 | wxClientDC dc(window); | |
41 | DrawMyPicture(dc); | |
42 | } | |
43 | @endcode | |
44 | ||
45 | Try to write code so it is parameterised by wxDC - if you do this, the same piece of code may | |
46 | write to a number of different devices, by passing a different device context. This doesn't | |
47 | work for everything (for example not all device contexts support bitmap drawing) but | |
48 | will work most of the time. | |
36c9828f | 49 | |
d54cf7ff | 50 | */ |
36c9828f | 51 |