src/os2/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 // array/list types
  41 // ----------------------------------------------------------------------------
  42
  43 struct WXDLLEXPORT wxPaintDCInfo
  44 {
  45     wxPaintDCInfo(wxWindow *win, wxDC *dc)
  46     {
  47         hwnd = win->GetHWND();
  48         hdc = dc->GetHDC();
  49         count = 1;
  50     }
  51
  52     WXHWND    hwnd;       // window for this DC
  53     WXHDC     hdc;        // the DC handle
  54     size_t    count;      // usage count
  55 };
  56
  57 #include "wx/arrimpl.cpp"
  58
  59 WX_DEFINE_OBJARRAY(wxArrayDCInfo);
  60
  61 // ----------------------------------------------------------------------------
  62 // macros
  63 // ----------------------------------------------------------------------------
  64
  65 #if !USE_SHARED_LIBRARY
  66     IMPLEMENT_DYNAMIC_CLASS(wxWindowDC, wxDC)
  67     IMPLEMENT_DYNAMIC_CLASS(wxClientDC, wxWindowDC)
  68     IMPLEMENT_DYNAMIC_CLASS(wxPaintDC, wxWindowDC)
  69 #endif
  70
  71 // ----------------------------------------------------------------------------
  72 // global variables
  73 // ----------------------------------------------------------------------------
  74
  75 static PAINTSTRUCT g_paintStruct;
  76
  77 #ifdef __WXDEBUG__
  78     // a global variable which we check to verify that wxPaintDC are only
  79     // created in resopnse to WM_PAINT message - doing this from elsewhere is a
  80     // common programming error among wxWindows programmers and might lead to
  81     // very subtle and difficult to debug refresh/repaint bugs.
  82     int g_isPainting = 0;
  83 #endif // __WXDEBUG__
  84
  85 // ===========================================================================
  86 // implementation
  87 // ===========================================================================
  88
  89 // ----------------------------------------------------------------------------
  90 // wxWindowDC
  91 // ----------------------------------------------------------------------------
  92
  93 wxWindowDC::wxWindowDC()
  94 {
  95   m_canvas = NULL;
  96 }
  97
  98 wxWindowDC::wxWindowDC(wxWindow *the_canvas)
  99 {
 100   m_canvas = the_canvas;
 101   m_hDC = (WXHDC) ::WinOpenWindowDC(GetWinHwnd(the_canvas) );
 102   m_hDCCount++;
 103
 104   SetBackground(wxBrush(m_canvas->GetBackgroundColour(), wxSOLID));
 105 }
 106
 107 wxWindowDC::~wxWindowDC()
 108 {
 109   if (m_canvas && m_hDC)
 110   {
 111     SelectOldObjects(m_hDC);
 112
 113     //
 114     // In PM one does not explicitly close or release an open WindowDC
 115     // They automatically close with the window, unless explicitly detached
 116     //
 117     m_hDC = 0;
 118   }
 119
 120   m_hDCCount--;
 121 }
 122
 123 // ----------------------------------------------------------------------------
 124 // wxClientDC
 125 // ----------------------------------------------------------------------------
 126
 127 wxClientDC::wxClientDC()
 128 {
 129   m_canvas = NULL;
 130 }
 131
 132 wxClientDC::wxClientDC(wxWindow *the_canvas)
 133 {
 134   m_canvas = the_canvas;
 135   m_hDC = (WXHDC) ::GetDC(GetWinHwnd(the_canvas));
 136
 137   // the background mode is only used for text background
 138   // and is set in DrawText() to OPAQUE as required, other-
 139   // wise always TRANSPARENT, RR
 140   ::SetBkMode( GetHdc(), TRANSPARENT );
 141
 142   SetBackground(wxBrush(m_canvas->GetBackgroundColour(), wxSOLID));
 143 }
 144
 145 wxClientDC::~wxClientDC()
 146 {
 147   if ( m_canvas && GetHdc() )
 148   {
 149     SelectOldObjects(m_hDC);
 150
 151     ::ReleaseDC(GetWinHwnd(m_canvas), GetHdc());
 152     m_hDC = 0;
 153   }
 154 }
 155
 156 // ----------------------------------------------------------------------------
 157 // wxPaintDC
 158 // ----------------------------------------------------------------------------
 159
 160 // VZ: initial implementation (by JACS) only remembered the last wxPaintDC
 161 //     created and tried to reuse - this was supposed to take care of a
 162 //     situation when a derived class OnPaint() calls base class OnPaint()
 163 //     because in this case ::BeginPaint() shouldn't be called second time.
 164 //
 165 //     I'm not sure how useful this is, however we must remember the HWND
 166 //     associated with the last HDC as well - otherwise we may (and will!) try
 167 //     to reuse the HDC for another HWND which is a nice recipe for disaster.
 168 //
 169 //     So we store a list of windows for which we already have the DC and not
 170 //     just one single hDC. This seems to work, but I'm really not sure about
 171 //     the usefullness of the whole idea - IMHO it's much better to not call
 172 //     base class OnPaint() at all, or, if we really want to allow it, add a
 173 //     "wxPaintDC *" parameter to wxPaintEvent which should be used if it's
 174 //     !NULL instead of creating a new DC.
 175
 176 wxArrayDCInfo wxPaintDC::ms_cache;
 177
 178 wxPaintDC::wxPaintDC()
 179 {
 180     m_canvas = NULL;
 181     m_hDC = 0;
 182 }
 183
 184 wxPaintDC::wxPaintDC(wxWindow *canvas)
 185 {
 186     wxCHECK_RET( canvas, _T("NULL canvas in wxPaintDC ctor") );
 187
 188 #ifdef __WXDEBUG__
 189     if ( g_isPainting <= 0 )
 190     {
 191         wxFAIL_MSG( _T("wxPaintDC may be created only in EVT_PAINT handler!") );
 192
 193         return;
 194     }
 195 #endif // __WXDEBUG__
 196
 197     m_canvas = canvas;
 198
 199     // do we have a DC for this window in the cache?
 200     wxPaintDCInfo *info = FindInCache();
 201     if ( info )
 202     {
 203         m_hDC = info->hdc;
 204         info->count++;
 205     }
 206     else // not in cache, create a new one
 207     {
 208         m_hDC = (WXHDC)::BeginPaint(GetWinHwnd(m_canvas), &g_paintStruct);
 209         ms_cache.Add(new wxPaintDCInfo(m_canvas, this));
 210     }
 211
 212     // the background mode is only used for text background
 213     // and is set in DrawText() to OPAQUE as required, other-
 214     // wise always TRANSPARENT, RR
 215     ::SetBkMode( GetHdc(), TRANSPARENT );
 216
 217     SetBackground(wxBrush(m_canvas->GetBackgroundColour(), wxSOLID));
 218 }
 219
 220 wxPaintDC::~wxPaintDC()
 221 {
 222     if ( m_hDC )
 223     {
 224         SelectOldObjects(m_hDC);
 225
 226         size_t index;
 227         wxPaintDCInfo *info = FindInCache(&index);
 228
 229         wxCHECK_RET( info, _T("existing DC should have a cache entry") );
 230
 231         if ( !--info->count )
 232         {
 233             ::EndPaint(GetWinHwnd(m_canvas), &g_paintStruct);
 234
 235             ms_cache.Remove(index);
 236         }
 237         //else: cached DC entry is still in use
 238
 239         // prevent the base class dtor from ReleaseDC()ing it again
 240         m_hDC = 0;
 241     }
 242 }
 243
 244 wxPaintDCInfo *wxPaintDC::FindInCache(size_t *index) const
 245 {
 246     wxPaintDCInfo *info = NULL;
 247     size_t nCache = ms_cache.GetCount();
 248     for ( size_t n = 0; n < nCache; n++ )
 249     {
 250         info = &ms_cache[n];
 251         if ( info->hwnd == m_canvas->GetHWND() )
 252         {
 253             if ( index )
 254                 *index = n;
 255             break;
 256         }
 257     }
 258
 259     return info;
 260 }