36c9828f70
git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@51911 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775
54 lines
2.0 KiB
C
54 lines
2.0 KiB
C
/////////////////////////////////////////////////////////////////////////////
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// Name: dc
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// Purpose: topic overview
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// Author: wxWidgets team
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// RCS-ID: $Id$
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// Licence: wxWindows license
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/////////////////////////////////////////////////////////////////////////////
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/*!
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@page dc_overview Device context overview
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Classes: #wxBufferedDC, #wxBufferedPaintDC, #wxDC, #wxPostScriptDC,
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#wxMetafileDC, #wxMemoryDC, #wxPrinterDC,
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#wxScreenDC, #wxClientDC, #wxPaintDC,
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#wxWindowDC.
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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 generic way,
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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,
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and #wxWindowDC. The following describes the differences between
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these device contexts and when you should use them.
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@b wxScreenDC. Use this to paint on the screen, as opposed to an individual window.
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@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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@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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@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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*/
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