// Created: 01/02/97
// RCS-ID: $Id$
// Copyright: (c) Julian Smart and Markus Holzem
-// Licence: wxWindows license
+// Licence: wxWindows license
/////////////////////////////////////////////////////////////////////////////
#ifndef _WX_DCCLIENT_H_
#define _WX_DCCLIENT_H_
+// ----------------------------------------------------------------------------
+// headers
+// ----------------------------------------------------------------------------
+
#ifdef __GNUG__
-#pragma interface "dcclient.h"
+ #pragma interface "dcclient.h"
#endif
#include "wx/dc.h"
-class WXDLLEXPORT wxWindowDC: public wxDC
+// ----------------------------------------------------------------------------
+// array types
+// ----------------------------------------------------------------------------
+
+// this one if used by wxPaintDC only
+struct WXDLLEXPORT wxPaintDCInfo;
+WX_DECLARE_OBJARRAY(wxPaintDCInfo, wxArrayDCInfo);
+
+// ----------------------------------------------------------------------------
+// DC classes
+// ----------------------------------------------------------------------------
+
+class WXDLLEXPORT wxWindowDC : public wxDC
{
- DECLARE_DYNAMIC_CLASS(wxWindowDC)
+ DECLARE_DYNAMIC_CLASS(wxWindowDC)
- public:
- wxWindowDC(void);
+public:
+ wxWindowDC();
- // Create a DC corresponding to a canvas
- wxWindowDC(wxWindow *win);
+ // Create a DC corresponding to the whole window
+ wxWindowDC(wxWindow *win);
- ~wxWindowDC(void);
+ virtual ~wxWindowDC();
};
-class WXDLLEXPORT wxClientDC: public wxWindowDC
+class WXDLLEXPORT wxClientDC : public wxWindowDC
{
- DECLARE_DYNAMIC_CLASS(wxClientDC)
+ DECLARE_DYNAMIC_CLASS(wxClientDC)
- public:
- wxClientDC(void);
+public:
+ wxClientDC();
- // Create a DC corresponding to a canvas
- wxClientDC(wxWindow *win);
+ // Create a DC corresponding to the client area of the window
+ wxClientDC(wxWindow *win);
- ~wxClientDC(void);
+ virtual ~wxClientDC();
};
-class WXDLLEXPORT wxPaintDC: public wxWindowDC
+class WXDLLEXPORT wxPaintDC : public wxWindowDC
{
- DECLARE_DYNAMIC_CLASS(wxPaintDC)
+ DECLARE_DYNAMIC_CLASS(wxPaintDC)
+
+public:
+ wxPaintDC();
- public:
- wxPaintDC(void);
+ // Create a DC corresponding for painting the window in OnPaint()
+ wxPaintDC(wxWindow *win);
- // Create a DC corresponding to a canvas
- wxPaintDC(wxWindow *win);
+ virtual ~wxPaintDC();
- ~wxPaintDC(void);
+protected:
+ static wxArrayDCInfo ms_cache;
- protected:
- static WXHDC ms_PaintHDC;
- static size_t ms_PaintCount;
+ // find the entry for this DC in the cache (keyed by the window)
+ wxPaintDCInfo *FindInCache(size_t *index = NULL) const;
};
#endif
#include "wx/dcclient.h"
+// ----------------------------------------------------------------------------
+// array/list types
+// ----------------------------------------------------------------------------
+
+struct WXDLLEXPORT wxPaintDCInfo
+{
+ wxPaintDCInfo(wxWindow *win, wxDC *dc)
+ {
+ hwnd = win->GetHWND();
+ hdc = dc->GetHDC();
+ count = 1;
+ }
+
+ WXHWND hwnd; // window for this DC
+ WXHDC hdc; // the DC handle
+ size_t count; // usage count
+};
+
+#include "wx/arrimpl.cpp"
+
+WX_DEFINE_OBJARRAY(wxArrayDCInfo);
+
// ----------------------------------------------------------------------------
// macros
// ----------------------------------------------------------------------------
// wxPaintDC
// ----------------------------------------------------------------------------
-// TODO (VZ) I have still some doubts about this hack and I still think that we
-// should store pairs of (hwnd, hdc) and not just the DC - what if
-// BeginPaint() was called on other window? It seems to work like
-// this, but to be sure about it we'd need to store hwnd too...
-
-WXHDC wxPaintDC::ms_PaintHDC = 0;
-size_t wxPaintDC::ms_PaintCount = 0; // count of ms_PaintHDC usage
+// VZ: initial implementation (by JACS) only remembered the last wxPaintDC
+// created and tried to reuse - this was supposed to take care of a
+// situation when a derived class OnPaint() calls base class OnPaint()
+// because in this case ::BeginPaint() shouldn't be called second time.
+//
+// I'm not sure how useful this is, however we must remember the HWND
+// associated with the last HDC as well - otherwise we may (and will!) try
+// to reuse the HDC for another HWND which is a nice recipe for disaster.
+//
+// So we store a list of windows for which we already have the DC and not
+// just one single hDC. This seems to work, but I'm really not sure about
+// the usefullness of the whole idea - IMHO it's much better to not call
+// base class OnPaint() at all, or, if we realyl want to allow it, add a
+// "wxPaintDC *" parameter to wxPaintEvent which should be used if it's
+// !NULL instead of creating a new DC.
+
+wxArrayDCInfo wxPaintDC::ms_cache;
wxPaintDC::wxPaintDC()
{
- m_canvas = NULL;
+ m_canvas = NULL;
+ m_hDC = 0;
}
wxPaintDC::wxPaintDC(wxWindow *canvas)
{
- wxCHECK_RET( canvas, "NULL canvas in wxPaintDC ctor" );
-
+ wxCHECK_RET( canvas, "NULL canvas in wxPaintDC ctor" );
+
#ifdef __WXDEBUG__
- wxCHECK_RET( g_isPainting, _T("wxPaintDC may be created only in EVT_PAINT handler!") );
-#endif
+ if ( !g_isPainting )
+ {
+ wxFAIL_MSG( _T("wxPaintDC may be created only in EVT_PAINT handler!") );
- m_canvas = canvas;
+ return;
+ }
+#endif // __WXDEBUG__
- // Don't call Begin/EndPaint if it's already been called: for example, if
- // calling a base class OnPaint.
- if ( ms_PaintCount > 0 ) {
- // it means that we've already called BeginPaint and so we must just
- // reuse the same HDC (BeginPaint shouldn't be called more than once)
- wxASSERT( ms_PaintHDC );
+ m_canvas = canvas;
- m_hDC = ms_PaintHDC;
- ms_PaintCount++;
- }
- else {
- ms_PaintHDC =
- m_hDC = (WXHDC)::BeginPaint((HWND)m_canvas->GetHWND(), &g_paintStruct);
- ms_PaintCount = 1;
- m_hDCCount++;
- }
+ // do we have a DC for this window in the cache?
+ wxPaintDCInfo *info = FindInCache();
+ if ( info )
+ {
+ m_hDC = info->hdc;
+ info->count++;
+ }
+ else // not in cache, create a new one
+ {
+ m_hDC = (WXHDC)::BeginPaint(GetWinHwnd(m_canvas), &g_paintStruct);
+ ms_cache.Add(new wxPaintDCInfo(m_canvas, this));
+ }
- SetBackground(wxBrush(m_canvas->GetBackgroundColour(), wxSOLID));
+ SetBackground(wxBrush(m_canvas->GetBackgroundColour(), wxSOLID));
}
wxPaintDC::~wxPaintDC()
{
- if ( m_hDC ) {
- if ( !--ms_PaintCount ) {
- ::EndPaint((HWND)m_canvas->GetHWND(), &g_paintStruct);
- m_hDCCount--;
- m_hDC = (WXHDC) NULL;
- ms_PaintHDC = (WXHDC) NULL;
+ if ( m_hDC )
+ {
+ size_t index;
+ wxPaintDCInfo *info = FindInCache(&index);
+
+ wxCHECK_RET( info, _T("existing DC should have a cache entry") );
+
+ if ( !--info->count )
+ {
+ ::EndPaint(GetWinHwnd(m_canvas), &g_paintStruct);
+
+ ms_cache.Remove(index);
+ }
+ //else: cached DC entry is still in use
}
- //else: ms_PaintHDC still in use
- }
}
+wxPaintDCInfo *wxPaintDC::FindInCache(size_t *index) const
+{
+ wxPaintDCInfo *info = NULL;
+ size_t nCache = ms_cache.GetCount();
+ for ( size_t n = 0; n < nCache; n++ )
+ {
+ info = &ms_cache[n];
+ if ( info->hwnd == m_canvas->GetHWND() )
+ {
+ if ( index )
+ *index = n;
+ break;
+ }
+ }
+
+ return info;
+}
projects / wxWidgets.git / commitdiff
