src/msw/dcclient.cpp

   1 /////////////////////////////////////////////////////////////////////////////
   2 // Name:        dcclient.cpp
   3 // Purpose:     wxClientDC class
   4 // Author:      Julian Smart
   5 // Modified by:
   6 // Created:     01/02/97
   7 // RCS-ID:      $Id$
   8 // Copyright:   (c) Julian Smart and Markus Holzem
   9 // Licence:     wxWindows licence
  10 /////////////////////////////////////////////////////////////////////////////
  11
  12 // ===========================================================================
  13 // declarations
  14 // ===========================================================================
  15
  16 // ----------------------------------------------------------------------------
  17 // headers
  18 // ----------------------------------------------------------------------------
  19
  20 #ifdef __GNUG__
  21     #pragma implementation "dcclient.h"
  22 #endif
  23
  24 // For compilers that support precompilation, includes "wx.h".
  25 #include "wx/wxprec.h"
  26
  27 #ifdef __BORLANDC__
  28     #pragma hdrstop
  29 #endif
  30
  31 #include "wx/dcclient.h"
  32 #include "wx/log.h"
  33
  34 #include "wx/msw/private.h"
  35
  36 // ----------------------------------------------------------------------------
  37 // macros
  38 // ----------------------------------------------------------------------------
  39
  40 #if !USE_SHARED_LIBRARY
  41     IMPLEMENT_DYNAMIC_CLASS(wxWindowDC, wxDC)
  42     IMPLEMENT_DYNAMIC_CLASS(wxClientDC, wxWindowDC)
  43     IMPLEMENT_DYNAMIC_CLASS(wxPaintDC, wxWindowDC)
  44 #endif
  45
  46 // ----------------------------------------------------------------------------
  47 // global variables
  48 // ----------------------------------------------------------------------------
  49
  50 static PAINTSTRUCT g_paintStruct;
  51
  52 #ifdef __WXDEBUG__
  53     // a global variable which we check to verify that wxPaintDC are only
  54     // created in resopnse to WM_PAINT message - doing this from elsewhere is a
  55     // common programming error among wxWindows programmers and might lead to
  56     // very subtle and difficult to debug refresh/repaint bugs.
  57     extern bool g_isPainting = FALSE;
  58 #endif // __WXDEBUG__
  59
  60 // ===========================================================================
  61 // implementation
  62 // ===========================================================================
  63
  64 // ----------------------------------------------------------------------------
  65 // wxWindowDC
  66 // ----------------------------------------------------------------------------
  67
  68 wxWindowDC::wxWindowDC()
  69 {
  70   m_canvas = NULL;
  71 }
  72
  73 wxWindowDC::wxWindowDC(wxWindow *the_canvas)
  74 {
  75   m_canvas = the_canvas;
  76   m_hDC = (WXHDC) ::GetWindowDC(GetWinHwnd(the_canvas) );
  77   m_hDCCount++;
  78
  79   SetBackground(wxBrush(m_canvas->GetBackgroundColour(), wxSOLID));
  80 }
  81
  82 wxWindowDC::~wxWindowDC()
  83 {
  84   if (m_canvas && m_hDC)
  85   {
  86     SelectOldObjects(m_hDC);
  87
  88     ::ReleaseDC(GetWinHwnd(m_canvas), GetHdc());
  89     m_hDC = 0;
  90   }
  91
  92   m_hDCCount--;
  93 }
  94
  95 // ----------------------------------------------------------------------------
  96 // wxClientDC
  97 // ----------------------------------------------------------------------------
  98
  99 wxClientDC::wxClientDC()
 100 {
 101   m_canvas = NULL;
 102 }
 103
 104 wxClientDC::wxClientDC(wxWindow *the_canvas)
 105 {
 106   m_canvas = the_canvas;
 107   m_hDC = (WXHDC) ::GetDC(GetWinHwnd(the_canvas));
 108
 109   SetBackground(wxBrush(m_canvas->GetBackgroundColour(), wxSOLID));
 110 }
 111
 112 wxClientDC::~wxClientDC()
 113 {
 114   if ( m_canvas && GetHdc() )
 115   {
 116     SelectOldObjects(m_hDC);
 117
 118     ::ReleaseDC(GetWinHwnd(m_canvas), GetHdc());
 119     m_hDC = 0;
 120   }
 121 }
 122
 123 // ----------------------------------------------------------------------------
 124 // wxPaintDC
 125 // ----------------------------------------------------------------------------
 126
 127 // TODO (VZ) I have still some doubts about this hack and I still think that we
 128 //           should store pairs of (hwnd, hdc) and not just the DC - what if
 129 //           BeginPaint() was called on other window? It seems to work like
 130 //           this, but to be sure about it we'd need to store hwnd too...
 131
 132 WXHDC  wxPaintDC::ms_PaintHDC = 0;
 133 size_t wxPaintDC::ms_PaintCount = 0; // count of ms_PaintHDC usage
 134
 135 wxPaintDC::wxPaintDC()
 136 {
 137   m_canvas = NULL;
 138 }
 139
 140 wxPaintDC::wxPaintDC(wxWindow *canvas)
 141 {
 142   wxCHECK_RET( canvas, "NULL canvas in wxPaintDC ctor" );
 143   wxCHECK_RET( g_isPainting,
 144                _T("wxPaintDC may be created only in EVT_PAINT handler!") );
 145
 146   m_canvas = canvas;
 147
 148   // Don't call Begin/EndPaint if it's already been called: for example, if
 149   // calling a base class OnPaint.
 150   if ( ms_PaintCount > 0 ) {
 151     // it means that we've already called BeginPaint and so we must just
 152     // reuse the same HDC (BeginPaint shouldn't be called more than once)
 153     wxASSERT( ms_PaintHDC );
 154
 155     m_hDC = ms_PaintHDC;
 156     ms_PaintCount++;
 157   }
 158   else {
 159     ms_PaintHDC =
 160     m_hDC = (WXHDC)::BeginPaint((HWND)m_canvas->GetHWND(), &g_paintStruct);
 161     ms_PaintCount = 1;
 162     m_hDCCount++;
 163   }
 164
 165   SetBackground(wxBrush(m_canvas->GetBackgroundColour(), wxSOLID));
 166 }
 167
 168 wxPaintDC::~wxPaintDC()
 169 {
 170   if ( m_hDC ) {
 171     if ( !--ms_PaintCount ) {
 172       ::EndPaint((HWND)m_canvas->GetHWND(), &g_paintStruct);
 173       m_hDCCount--;
 174       m_hDC = (WXHDC) NULL;
 175       ms_PaintHDC = (WXHDC) NULL;
 176     }
 177     //else: ms_PaintHDC still in use
 178   }
 179 }
 180