///////////////////////////////////////////////////////////////////////////// // Name: wx/dcbuffer.h // Purpose: wxBufferedDC class // Author: Ron Lee // Modified by: Vadim Zeitlin (refactored, added bg preservation) // Created: 16/03/02 // RCS-ID: $Id: dcbuffer.h 61872 2009-09-09 22:37:05Z VZ $ // 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 class WXDLLEXPORT 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() { wxCHECK_RET( m_dc, wxT("no underlying wxDC?") ); wxASSERT_MSG( m_buffer && m_buffer->IsOk(), wxT("invalid backing store") ); wxCoord x = 0, y = 0; if ( m_style & wxBUFFER_CLIENT_AREA ) GetDeviceOrigin(&x, &y); m_dc->Blit(0, 0, m_buffer->GetWidth(), m_buffer->GetHeight(), this, -x, -y ); m_dc = NULL; } // Set and get the style void SetStyle(int style) { m_style = style; } int GetStyle() const { return m_style; } private: // common part of Init()s void InitCommon(wxDC *dc, int style) { wxASSERT_MSG( !m_dc, wxT("wxBufferedDC already initialised") ); m_dc = dc; m_style = style; // inherit the same layout direction as the original DC if (dc && dc->IsOk()) SetLayoutDirection(dc->GetLayoutDirection()); } // 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) DECLARE_NO_COPY_CLASS(wxBufferedDC) }; // ---------------------------------------------------------------------------- // Double buffered PaintDC. // ---------------------------------------------------------------------------- // Creates a double buffered wxPaintDC, optionally allowing the // user to specify their own buffer to use. class WXDLLEXPORT 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) DECLARE_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 #ifdef __WXDEBUG__ class wxAutoBufferedPaintDC : public wxAutoBufferedPaintDCBase { public: wxAutoBufferedPaintDC(wxWindow* win) : wxAutoBufferedPaintDCBase(win) { TestWinStyle(win); } virtual ~wxAutoBufferedPaintDC() { } private: void TestWinStyle(wxWindow* win) { // Help the user to get the double-buffering working properly. wxASSERT_MSG( win->GetBackgroundStyle() == wxBG_STYLE_CUSTOM, wxT("In constructor, you need to call SetBackgroundStyle(wxBG_STYLE_CUSTOM), ") wxT("and also, if needed, paint the background manually in the paint event handler.")); } DECLARE_NO_COPY_CLASS(wxAutoBufferedPaintDC) }; #else // !__WXDEBUG__ // In release builds, just use typedef typedef wxAutoBufferedPaintDCBase wxAutoBufferedPaintDC; #endif // 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_