wxBufferedDC

This simple class provides a simple way to avoid flicker: when drawing on it, everything is in fact first drawn on an in-memory buffer (a wxBitmap) and then copied to the screen only once, when this object is destroyed.

It can be used in the same way as any other device context. wxBufferedDC itself typically replaces wxClientDC, if you want to use it in your OnPaint() handler, you should look at wxBufferedPaintDC.

Derived from

wxMemoryDC
wxDC
wxObject

Include files

<wx/dcbuffer.h>

See also

wxDC



wxBufferedDC::wxBufferedDC



wxBufferedDC(void)



wxBufferedDC(wxDC * dc, const wxSize& area, int style = wxBUFFER_CLIENT_AREA)



wxBufferedDC(wxDC * dc, const wxBitmap& buffer, int style = wxBUFFER_CLIENT_AREA)

If you use the first, default, constructor, you must call one of the Init methods later in order to use the object.

The other constructors initialize the object immediately and Init() must not be called after using them.

Parameters

dc
The underlying DC: everything drawn to this object will be flushed to this DC when this object is destroyed. You may pass NULL in order to just initialize the buffer, and not flush it.

area
The size of the bitmap to be used for buffering (this bitmap is created internally when it is not given explicitly).

buffer
Explicitly provided bitmap to be used for buffering: this is the most efficient solution as the bitmap doesn't have to be recreated each time but it also requires more memory as the bitmap is never freed. The bitmap should have appropriate size, anything drawn outside of its bounds is clipped.

style
wxBUFFER_CLIENT_AREA to indicate that just the client area of the window is buffered, or wxBUFFER_VIRTUAL_AREA to indicate that the buffer bitmap covers the virtual area (in which case PrepareDC is automatically called for the actual window device context).



wxBufferedDC::Init



void Init(wxDC * dc, const wxSize& area, int style = wxBUFFER_CLIENT_AREA)



void Init(wxDC * dc, const wxBitmap& buffer, int style = wxBUFFER_CLIENT_AREA)

These functions initialize the object created using the default constructor. Please see constructors documentation for details.



wxBufferedDC::~wxBufferedDC

Copies everything drawn on the DC so far to the underlying DC associated with this object, if any.

ymasuda 平成17年11月19日