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