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/string.h"
  32 #include "wx/log.h"
  33 #include "wx/window.h"
  34
  35 #include "wx/msw/private.h"
  36
  37 #include "wx/dcclient.h"
  38
  39 // ----------------------------------------------------------------------------
  40 // macros
  41 // ----------------------------------------------------------------------------
  42
  43 #if !USE_SHARED_LIBRARY
  44     IMPLEMENT_DYNAMIC_CLASS(wxWindowDC, wxDC)
  45     IMPLEMENT_DYNAMIC_CLASS(wxClientDC, wxWindowDC)
  46     IMPLEMENT_DYNAMIC_CLASS(wxPaintDC, wxWindowDC)
  47 #endif
  48
  49 // ----------------------------------------------------------------------------
  50 // global variables
  51 // ----------------------------------------------------------------------------
  52
  53 static PAINTSTRUCT g_paintStruct;
  54
  55 #ifdef __WXDEBUG__
  56     // a global variable which we check to verify that wxPaintDC are only
  57     // created in resopnse to WM_PAINT message - doing this from elsewhere is a
  58     // common programming error among wxWindows programmers and might lead to
  59     // very subtle and difficult to debug refresh/repaint bugs.
  60     extern bool g_isPainting = FALSE;
  61 #endif // __WXDEBUG__
  62
  63 // ===========================================================================
  64 // implementation
  65 // ===========================================================================
  66
  67 // ----------------------------------------------------------------------------
  68 // wxWindowDC
  69 // ----------------------------------------------------------------------------
  70
  71 wxWindowDC::wxWindowDC()
  72 {
  73   m_canvas = NULL;
  74 }
  75
  76 wxWindowDC::wxWindowDC(wxWindow *the_canvas)
  77 {
  78   m_canvas = the_canvas;
  79   m_hDC = (WXHDC) ::GetWindowDC(GetWinHwnd(the_canvas) );
  80   m_hDCCount++;
  81
  82   SetBackground(wxBrush(m_canvas->GetBackgroundColour(), wxSOLID));
  83 }
  84
  85 wxWindowDC::~wxWindowDC()
  86 {
  87   if (m_canvas && m_hDC)
  88   {
  89     SelectOldObjects(m_hDC);
  90
  91     ::ReleaseDC(GetWinHwnd(m_canvas), GetHdc());
  92     m_hDC = 0;
  93   }
  94
  95   m_hDCCount--;
  96 }
  97
  98 // ----------------------------------------------------------------------------
  99 // wxClientDC
 100 // ----------------------------------------------------------------------------
 101
 102 wxClientDC::wxClientDC()
 103 {
 104   m_canvas = NULL;
 105 }
 106
 107 wxClientDC::wxClientDC(wxWindow *the_canvas)
 108 {
 109   m_canvas = the_canvas;
 110   m_hDC = (WXHDC) ::GetDC(GetWinHwnd(the_canvas));
 111
 112   SetBackground(wxBrush(m_canvas->GetBackgroundColour(), wxSOLID));
 113 }
 114
 115 wxClientDC::~wxClientDC()
 116 {
 117   if ( m_canvas && GetHdc() )
 118   {
 119     SelectOldObjects(m_hDC);
 120
 121     ::ReleaseDC(GetWinHwnd(m_canvas), GetHdc());
 122     m_hDC = 0;
 123   }
 124 }
 125
 126 // ----------------------------------------------------------------------------
 127 // wxPaintDC
 128 // ----------------------------------------------------------------------------
 129
 130 // TODO (VZ) I have still some doubts about this hack and I still think that we
 131 //           should store pairs of (hwnd, hdc) and not just the DC - what if
 132 //           BeginPaint() was called on other window? It seems to work like
 133 //           this, but to be sure about it we'd need to store hwnd too...
 134
 135 WXHDC  wxPaintDC::ms_PaintHDC = 0;
 136 size_t wxPaintDC::ms_PaintCount = 0; // count of ms_PaintHDC usage
 137
 138 wxPaintDC::wxPaintDC()
 139 {
 140   m_canvas = NULL;
 141 }
 142
 143 wxPaintDC::wxPaintDC(wxWindow *canvas)
 144 {
 145   wxCHECK_RET( canvas, "NULL canvas in wxPaintDC ctor" );
 146
 147 #ifdef __WXDEBUG__
 148   wxCHECK_RET( g_isPainting, _T("wxPaintDC may be created only in EVT_PAINT handler!") );
 149 #endif
 150
 151   m_canvas = canvas;
 152
 153   // Don't call Begin/EndPaint if it's already been called: for example, if
 154   // calling a base class OnPaint.
 155   if ( ms_PaintCount > 0 ) {
 156     // it means that we've already called BeginPaint and so we must just
 157     // reuse the same HDC (BeginPaint shouldn't be called more than once)
 158     wxASSERT( ms_PaintHDC );
 159
 160     m_hDC = ms_PaintHDC;
 161     ms_PaintCount++;
 162   }
 163   else {
 164     ms_PaintHDC =
 165     m_hDC = (WXHDC)::BeginPaint((HWND)m_canvas->GetHWND(), &g_paintStruct);
 166     ms_PaintCount = 1;
 167     m_hDCCount++;
 168   }
 169
 170   SetBackground(wxBrush(m_canvas->GetBackgroundColour(), wxSOLID));
 171 }
 172
 173 wxPaintDC::~wxPaintDC()
 174 {
 175   if ( m_hDC ) {
 176     if ( !--ms_PaintCount ) {
 177       ::EndPaint((HWND)m_canvas->GetHWND(), &g_paintStruct);
 178       m_hDCCount--;
 179       m_hDC = (WXHDC) NULL;
 180       ms_PaintHDC = (WXHDC) NULL;
 181     }
 182     //else: ms_PaintHDC still in use
 183   }
 184 }
 185