wxWidgets/include/wx/dcbuffer.h

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/////////////////////////////////////////////////////////////////////////////
// Name: wx/dcbuffer.h
// Purpose: wxBufferedDC class
// Author: Ron Lee <ron@debian.org>
// Modified by: Vadim Zeitlin (refactored, added bg preservation)
// Created: 16/03/02
// RCS-ID: $Id$
// Copyright: (c) Ron Lee
// Licence: wxWindows licence
/////////////////////////////////////////////////////////////////////////////
#ifndef _WX_DCBUFFER_H_
#define _WX_DCBUFFER_H_
#include "wx/dcmemory.h"
#include "wx/dcclient.h"
#include "wx/window.h"
// Split platforms into two groups - those which have well-working
// double-buffering by default, and those which do not.
#if defined(__WXMAC__) || defined(__WXGTK20__) || defined(__WXDFB__)
#define wxALWAYS_NATIVE_DOUBLE_BUFFER 1
#else
#define wxALWAYS_NATIVE_DOUBLE_BUFFER 0
#endif
// ----------------------------------------------------------------------------
// Double buffering helper.
// ----------------------------------------------------------------------------
// Assumes the buffer bitmap covers the entire scrolled window,
// and prepares the window DC accordingly
#define wxBUFFER_VIRTUAL_AREA 0x01
// Assumes the buffer bitmap only covers the client area;
// does not prepare the window DC
#define wxBUFFER_CLIENT_AREA 0x02
// Set when not using specific buffer bitmap. Note that this
// is private style and not returned by GetStyle.
#define wxBUFFER_USES_SHARED_BUFFER 0x04
class WXDLLIMPEXP_CORE wxBufferedDC : public wxMemoryDC
{
public:
// Default ctor, must subsequently call Init for two stage construction.
wxBufferedDC()
: m_dc(NULL),
m_buffer(NULL),
m_style(0)
{
}
// Construct a wxBufferedDC using a user supplied buffer.
wxBufferedDC(wxDC *dc,
wxBitmap& buffer = wxNullBitmap,
int style = wxBUFFER_CLIENT_AREA)
: m_dc(NULL), m_buffer(NULL)
{
Init(dc, buffer, style);
}
// Construct a wxBufferedDC with an internal buffer of 'area'
// (where area is usually something like the size of the window
// being buffered)
wxBufferedDC(wxDC *dc, const wxSize& area, int style = wxBUFFER_CLIENT_AREA)
: m_dc(NULL), m_buffer(NULL)
{
Init(dc, area, style);
}
// The usually desired action in the dtor is to blit the buffer.
virtual ~wxBufferedDC()
{
if ( m_dc )
UnMask();
}
// These reimplement the actions of the ctors for two stage creation
void Init(wxDC *dc,
wxBitmap& buffer = wxNullBitmap,
int style = wxBUFFER_CLIENT_AREA)
{
InitCommon(dc, style);
m_buffer = &buffer;
UseBuffer();
}
void Init(wxDC *dc, const wxSize &area, int style = wxBUFFER_CLIENT_AREA)
{
InitCommon(dc, style);
UseBuffer(area.x, area.y);
}
// Blits the buffer to the dc, and detaches the dc from the buffer (so it
// can be effectively used once only).
//
// Usually called in the dtor or by the dtor of derived classes if the
// BufferedDC must blit before the derived class (which may own the dc it's
// blitting to) is destroyed.
void UnMask();
// Set and get the style
void SetStyle(int style) { m_style = style; }
int GetStyle() const { return m_style & ~wxBUFFER_USES_SHARED_BUFFER; }
private:
// common part of Init()s
void InitCommon(wxDC *dc, int style)
{
wxASSERT_MSG( !m_dc, _T("wxBufferedDC already initialised") );
m_dc = dc;
m_style = style;
}
// check that the bitmap is valid and use it
void UseBuffer(wxCoord w = -1, wxCoord h = -1);
// the underlying DC to which we copy everything drawn on this one in
// UnMask()
//
// NB: Without the existence of a wxNullDC, this must be a pointer, else it
// could probably be a reference.
wxDC *m_dc;
// the buffer (selected in this DC), initially invalid
wxBitmap *m_buffer;
// the buffering style
int m_style;
DECLARE_DYNAMIC_CLASS(wxBufferedDC)
wxDECLARE_NO_COPY_CLASS(wxBufferedDC);
};
// ----------------------------------------------------------------------------
// Double buffered PaintDC.
// ----------------------------------------------------------------------------
// Creates a double buffered wxPaintDC, optionally allowing the
// user to specify their own buffer to use.
class WXDLLIMPEXP_CORE wxBufferedPaintDC : public wxBufferedDC
{
public:
// If no bitmap is supplied by the user, a temporary one will be created.
wxBufferedPaintDC(wxWindow *window, wxBitmap& buffer, int style = wxBUFFER_CLIENT_AREA)
: m_paintdc(window)
{
// If we're buffering the virtual window, scale the paint DC as well
if (style & wxBUFFER_VIRTUAL_AREA)
window->PrepareDC( m_paintdc );
if( buffer.IsOk() )
Init(&m_paintdc, buffer, style);
else
Init(&m_paintdc, GetBufferedSize(window, style), style);
}
// If no bitmap is supplied by the user, a temporary one will be created.
wxBufferedPaintDC(wxWindow *window, int style = wxBUFFER_CLIENT_AREA)
: m_paintdc(window)
{
// If we're using the virtual window, scale the paint DC as well
if (style & wxBUFFER_VIRTUAL_AREA)
window->PrepareDC( m_paintdc );
Init(&m_paintdc, GetBufferedSize(window, style), style);
}
// default copy ctor ok.
virtual ~wxBufferedPaintDC()
{
// We must UnMask here, else by the time the base class
// does it, the PaintDC will have already been destroyed.
UnMask();
}
protected:
// return the size needed by the buffer: this depends on whether we're
// buffering just the currently shown part or the total (scrolled) window
static wxSize GetBufferedSize(wxWindow *window, int style)
{
return style & wxBUFFER_VIRTUAL_AREA ? window->GetVirtualSize()
: window->GetClientSize();
}
private:
wxPaintDC m_paintdc;
DECLARE_ABSTRACT_CLASS(wxBufferedPaintDC)
wxDECLARE_NO_COPY_CLASS(wxBufferedPaintDC);
};
//
// wxAutoBufferedPaintDC is a wxPaintDC in toolkits which have double-
// buffering by default. Otherwise it is a wxBufferedPaintDC. Thus,
// you can only expect it work with a simple constructor that
// accepts single wxWindow* argument.
//
#if wxALWAYS_NATIVE_DOUBLE_BUFFER
#define wxAutoBufferedPaintDCBase wxPaintDC
#else
#define wxAutoBufferedPaintDCBase wxBufferedPaintDC
#endif
class WXDLLIMPEXP_CORE wxAutoBufferedPaintDC : public wxAutoBufferedPaintDCBase
{
public:
wxAutoBufferedPaintDC(wxWindow* win)
: wxAutoBufferedPaintDCBase(win)
{
wxASSERT_MSG( win->GetBackgroundStyle() == wxBG_STYLE_CUSTOM,
"You need to call SetBackgroundStyle(wxBG_STYLE_CUSTOM) in ctor, "
"and also, if needed, paint the background in wxEVT_PAINT handler."
);
}
virtual ~wxAutoBufferedPaintDC() { }
private:
wxDECLARE_NO_COPY_CLASS(wxAutoBufferedPaintDC);
};
// Check if the window is natively double buffered and will return a wxPaintDC
// if it is, a wxBufferedPaintDC otherwise. It is the caller's responsibility
// to delete the wxDC pointer when finished with it.
inline wxDC* wxAutoBufferedPaintDCFactory(wxWindow* window)
{
if ( window->IsDoubleBuffered() )
return new wxPaintDC(window);
else
return new wxBufferedPaintDC(window);
}
#endif // _WX_DCBUFFER_H_