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
|
/////////////////////////////////////////////////////////////////////////////
// Name: dc.h
// Purpose: topic overview
// Author: wxWidgets team
// Licence: wxWindows licence
/////////////////////////////////////////////////////////////////////////////
/**
@page overview_dc Device Contexts
A wxDC is a @e device context onto which graphics and text can be drawn.
The device context is intended to represent a number of output devices in a
generic way, with the same API being used throughout.
Some device contexts are created temporarily in order to draw on a window.
This is @true of wxScreenDC, wxClientDC, wxPaintDC, and wxWindowDC.
The following describes the differences between these device contexts and
when you should use them.
@li @b wxScreenDC. Use this to paint on the screen, as opposed to an individual window.
@li @b wxClientDC. Use this to paint on the client area of window (the part without
borders and other decorations), but do not use it from within an wxPaintEvent.
@li @b wxPaintDC. Use this to paint on the client area of a window, but @e only from
within a wxPaintEvent.
@li @b wxWindowDC. Use this to paint on the whole area of a window, including decorations.
This may not be available on non-Windows platforms.
To use a client, paint or window device context, create an object on the stack with
the window as argument, for example:
@code
void MyWindow::OnMyCmd(wxCommandEvent& event)
{
wxClientDC dc(window);
DrawMyPicture(dc);
}
@endcode
Try to write code so it is parameterised by wxDC - if you do this, the same piece of code may
write to a number of different devices, by passing a different device context. This doesn't
work for everything (for example not all device contexts support bitmap drawing) but
will work most of the time.
@see @ref group_class_dc
*/
|
