X-Git-Url: https://git.saurik.com/wxWidgets.git/blobdiff_plain/aeb500e64cfc83781e462b68feae19118b9cb105..42bbdbff319e194d4a201021ed4930bf9cba300d:/include/wx/dcbuffer.h

diff --git a/include/wx/dcbuffer.h b/include/wx/dcbuffer.h
index 431dd95cfc..1b5d728020 100644
--- a/include/wx/dcbuffer.h
+++ b/include/wx/dcbuffer.h
@@ -2,7 +2,7 @@
 // Name:        wx/dcbuffer.h
 // Purpose:     wxBufferedDC class
 // Author:      Ron Lee <ron@debian.org>
-// Modified by:
+// Modified by: Vadim Zeitlin (refactored, added bg preservation)
 // Created:     16/03/02
 // RCS-ID:      $Id$
 // Copyright:   (c) Ron Lee
@@ -12,94 +12,139 @@
 #ifndef _WX_DCBUFFER_H_
 #define _WX_DCBUFFER_H_
 
-#if defined(__GNUG__) && !defined(__APPLE__)
-#pragma interface "dcbuffer.h"
-#endif
-
 #include "wx/dcmemory.h"
 #include "wx/dcclient.h"
 
 
-// ==============================================================
-//   Double buffering helper.
-// --------------------------------------------------------------
+// ----------------------------------------------------------------------------
+// Double buffering helper.
+// ----------------------------------------------------------------------------
 
-class WXDLLEXPORT wxBufferedDC : public wxMemoryDC
+class wxBufferedDC : public wxMemoryDC
 {
-private:
-
-        // Without the existence of a wxNullDC, this must be
-        // a pointer, else it could probably be a reference.
-
-    wxDC        *m_dc;
-    wxBitmap    m_buffer;
-
 public:
-
-        // Default ctor, must subsequently call Init for
-        // two stage construction.
-
-    wxBufferedDC()
-        : m_dc( 0 )
-    {}
-
-        // Construct a wxBufferedDC using a user supplied buffer.
-
-    wxBufferedDC( wxDC *dc, const wxBitmap &buffer );
-
-        // 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 );
+    // Default ctor, must subsequently call Init for two stage construction.
+    wxBufferedDC() : m_dc( 0 )
+    {
+    }
+
+    // Construct a wxBufferedDC using a user supplied buffer.
+    wxBufferedDC(wxDC *dc, const wxBitmap &buffer)
+        : m_dc( dc ),
+          m_buffer( buffer )
+    {
+        UseBuffer();
+    }
+
+    // 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)
+        : m_dc( dc ),
+          m_buffer( area.GetWidth(), area.GetHeight() )
+    {
+        UseBuffer();
+    }
 
     // default copy ctor ok.
 
-        // The usually desired  action in the dtor is to blit the buffer.
+    // 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, but
+    // are not used by the ctors themselves to save a few cpu cycles.
+    void Init(wxDC *dc, const wxBitmap &buffer)
+    {
+        wxASSERT_MSG( m_dc == 0 && m_buffer == wxNullBitmap,
+                      _T("wxBufferedDC already initialised") );
+        m_dc = dc;
+        m_buffer = buffer;
+        UseBuffer();
+    }
+
+    void Init(wxDC *dc, const wxSize &area)
+    {
+        Init(dc, wxBitmap(area.GetWidth(), area.GetHeight()));
+    }
+
+    // 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()
+    {
+        wxASSERT_MSG( m_dc != 0,
+                      _T("No underlying DC associated with wxBufferedDC (anymore)") );
+
+        m_dc->Blit( 0, 0,
+                    m_buffer.GetWidth(), m_buffer.GetHeight(), this,
+                    0, 0 );
+        m_dc = NULL;
+    }
 
-    ~wxBufferedDC();
-
-        // These reimplement the actions of the ctors for
-        // two stage creation, but are not used by the ctors
-        // themselves to save a few cpu cycles.
+private:
+    // check that the bitmap is valid and use it
+    void UseBuffer()
+    {
+        wxASSERT_MSG( m_buffer.Ok(), _T("invalid bitmap in wxBufferedDC") );
 
-    void Init( wxDC *dc, const wxBitmap &bitmap );
-    void Init( wxDC *dc, const wxSize &area );
+        SelectObject(m_buffer);
+    }
 
-        // Blits the buffer to the dc, and detaches the dc from
-        // the buffer.  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.
+    // 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;
 
-    void UnMask();
+    // the buffer (selected in this DC)
+    wxBitmap m_buffer;
 
     DECLARE_NO_COPY_CLASS(wxBufferedDC)
 };
 
 
-// ==============================================================
-//   Double buffered PaintDC.
-// --------------------------------------------------------------
+// ----------------------------------------------------------------------------
+// Double buffered PaintDC.
+// ----------------------------------------------------------------------------
 
 // Creates a double buffered wxPaintDC, optionally allowing the
 // user to specify their own buffer to use.
-
-class WXDLLEXPORT wxBufferedPaintDC : public wxBufferedDC
+class wxBufferedPaintDC : public wxBufferedDC
 {
-private:
-
-    wxPaintDC    m_paintdc;
-
 public:
-
-    wxBufferedPaintDC( wxWindow *window, const wxBitmap &buffer = wxNullBitmap );
+    // If no bitmap is supplied by the user, a temporary one wil; be created.
+    wxBufferedPaintDC(wxWindow *window, const wxBitmap& buffer = wxNullBitmap)
+        : m_paintdc(window)
+    {
+        window->PrepareDC( m_paintdc );
+        
+        if( buffer != wxNullBitmap )
+            Init(&m_paintdc, buffer);
+        else
+            Init(&m_paintdc, window->GetClientSize());
+    }
 
     // default copy ctor ok.
 
-    ~wxBufferedPaintDC();
-};
+    virtual ~wxBufferedPaintDC()
+    {
+        // We must UnMask here, else by the time the base class
+        // does it, the PaintDC will have already been destroyed.
+        UnMask();
+    }
 
+private:
+    wxPaintDC m_paintdc;
+
+    DECLARE_NO_COPY_CLASS(wxBufferedPaintDC)
+};
 
 #endif  // _WX_DCBUFFER_H_