src/os2/dcclient.cpp

   1 /////////////////////////////////////////////////////////////////////////////
   2 // Name:        dcclient.cpp
   3 // Purpose:     wxClientDC class
   4 // Author:      David Webster
   5 // Modified by:
   6 // Created:     09/21/99
   7 // RCS-ID:      $Id$
   8 // Copyright:   (c) David Webster
   9 // Licence:     wxWindows licence
  10 /////////////////////////////////////////////////////////////////////////////
  11
  12 // ===========================================================================
  13 // declarations
  14 // ===========================================================================
  15
  16 // ----------------------------------------------------------------------------
  17 // headers
  18 // ----------------------------------------------------------------------------
  19
  20 // For compilers that support precompilation, includes "wx.h".
  21 #include "wx/wxprec.h"
  22
  23 #include "wx/string.h"
  24 #include "wx/log.h"
  25 #include "wx/window.h"
  26
  27 #include "wx/os2/private.h"
  28
  29 #include "wx/dcclient.h"
  30
  31 // ----------------------------------------------------------------------------
  32 // array/list types
  33 // ----------------------------------------------------------------------------
  34
  35 struct WXDLLEXPORT wxPaintDCInfo
  36 {
  37     wxPaintDCInfo(wxWindow *win, wxDC *dc)
  38     {
  39         hwnd = win->GetHWND();
  40         hdc = dc->GetHDC();
  41         count = 1;
  42     }
  43
  44     WXHWND    hwnd;       // window for this DC
  45     WXHDC     hdc;        // the DC handle
  46     size_t    count;      // usage count
  47 };
  48
  49 #include "wx/arrimpl.cpp"
  50
  51 WX_DEFINE_OBJARRAY(wxArrayDCInfo);
  52
  53 // ----------------------------------------------------------------------------
  54 // macros
  55 // ----------------------------------------------------------------------------
  56
  57 #if !USE_SHARED_LIBRARY
  58     IMPLEMENT_DYNAMIC_CLASS(wxWindowDC, wxDC)
  59     IMPLEMENT_DYNAMIC_CLASS(wxClientDC, wxWindowDC)
  60     IMPLEMENT_DYNAMIC_CLASS(wxPaintDC, wxWindowDC)
  61 #endif
  62
  63 // ----------------------------------------------------------------------------
  64 // global variables
  65 // ----------------------------------------------------------------------------
  66
  67 static RECT        g_paintStruct;
  68
  69 #ifdef __WXDEBUG__
  70     // a global variable which we check to verify that wxPaintDC are only
  71     // created in resopnse to WM_PAINT message - doing this from elsewhere is a
  72     // common programming error among wxWindows programmers and might lead to
  73     // very subtle and difficult to debug refresh/repaint bugs.
  74     int g_isPainting = 0;
  75 #endif // __WXDEBUG__
  76
  77 // ===========================================================================
  78 // implementation
  79 // ===========================================================================
  80
  81 // ----------------------------------------------------------------------------
  82 // wxWindowDC
  83 // ----------------------------------------------------------------------------
  84
  85 wxWindowDC::wxWindowDC()
  86 {
  87   m_canvas = NULL;
  88 }
  89
  90 wxWindowDC::wxWindowDC(wxWindow *the_canvas)
  91 {
  92   m_canvas = the_canvas;
  93   m_hDC = (WXHDC) ::WinOpenWindowDC(GetWinHwnd(the_canvas) );
  94   m_hDCCount++;
  95   //
  96   // default under PM is that Window and Client DC's are the same
  97   // so we offer a separate Presentation Space to use for the
  98   // entire window.  Otherwise, calling BeginPaint will just create
  99   // chached-micro client presentation space
 100   //
 101    m_hPS = GpiCreatePS( m_hab
 102                        ,m_hDC
 103                        ,&m_PageSize
 104                        ,PU_PELS | GPIF_LONG | GPIA_ASSOC
 105                       );
 106   ::GpiAssociate(m_hPS, NULLHANDLE);
 107   ::GpiAssociate(m_hPS, m_hDC);
 108   SetBackground(wxBrush(m_canvas->GetBackgroundColour(), wxSOLID));
 109 }
 110
 111 wxWindowDC::~wxWindowDC()
 112 {
 113   if (m_canvas && m_hDC)
 114   {
 115     SelectOldObjects(m_hDC);
 116
 117     //
 118     // In PM one does not explicitly close or release an open WindowDC
 119     // They automatically close with the window, unless explicitly detached
 120     // but we need to destroy our PS
 121     //
 122     ::GpiAssociate(m_hPS, NULLHANDLE);
 123     ::GpiDestroyPS(m_hPS);
 124     m_hPS = NULLHANDLE;
 125     m_hDC = NULLHANDLE;
 126   }
 127
 128   m_hDCCount--;
 129 }
 130
 131 // ----------------------------------------------------------------------------
 132 // wxClientDC
 133 // ----------------------------------------------------------------------------
 134
 135 wxClientDC::wxClientDC()
 136 {
 137   m_canvas = NULL;
 138 }
 139
 140 wxClientDC::wxClientDC(wxWindow *the_canvas)
 141 {
 142   m_canvas = the_canvas;
 143
 144   //
 145   // default under PM is that Window and Client DC's are the same
 146   //
 147   m_hDC = (WXHDC) ::WinOpenWindowDC(GetWinHwnd(the_canvas));
 148
 149   //
 150   // Default mode is BM_LEAVEALONE so we make no call Set the mix
 151   //
 152   SetBackground(wxBrush(m_canvas->GetBackgroundColour(), wxSOLID));
 153 }
 154
 155 wxClientDC::~wxClientDC()
 156 {
 157   if ( m_canvas && GetHdc() )
 158   {
 159     SelectOldObjects(m_hDC);
 160
 161     // We don't explicitly release Device contexts in PM and
 162     // the cached micro PS is already gone
 163
 164     m_hDC = 0;
 165   }
 166 }
 167
 168 // ----------------------------------------------------------------------------
 169 // wxPaintDC
 170 // ----------------------------------------------------------------------------
 171
 172 // VZ: initial implementation (by JACS) only remembered the last wxPaintDC
 173 //     created and tried to reuse - this was supposed to take care of a
 174 //     situation when a derived class OnPaint() calls base class OnPaint()
 175 //     because in this case ::BeginPaint() shouldn't be called second time.
 176 //
 177 //     I'm not sure how useful this is, however we must remember the HWND
 178 //     associated with the last HDC as well - otherwise we may (and will!) try
 179 //     to reuse the HDC for another HWND which is a nice recipe for disaster.
 180 //
 181 //     So we store a list of windows for which we already have the DC and not
 182 //     just one single hDC. This seems to work, but I'm really not sure about
 183 //     the usefullness of the whole idea - IMHO it's much better to not call
 184 //     base class OnPaint() at all, or, if we really want to allow it, add a
 185 //     "wxPaintDC *" parameter to wxPaintEvent which should be used if it's
 186 //     !NULL instead of creating a new DC.
 187
 188 wxArrayDCInfo wxPaintDC::ms_cache;
 189
 190 wxPaintDC::wxPaintDC()
 191 {
 192     m_canvas = NULL;
 193     m_hDC = 0;
 194 }
 195
 196 wxPaintDC::wxPaintDC(wxWindow *canvas)
 197 {
 198     wxCHECK_RET( canvas, wxT("NULL canvas in wxPaintDC ctor") );
 199
 200 #ifdef __WXDEBUG__
 201     if ( g_isPainting <= 0 )
 202     {
 203         wxFAIL_MSG( wxT("wxPaintDC may be created only in EVT_PAINT handler!") );
 204
 205         return;
 206     }
 207 #endif // __WXDEBUG__
 208
 209     m_canvas = canvas;
 210
 211     // do we have a DC for this window in the cache?
 212     wxPaintDCInfo *info = FindInCache();
 213     if ( info )
 214     {
 215         m_hDC = info->hdc;
 216         info->count++;
 217     }
 218     else // not in cache, create a new one
 219     {
 220         m_hDC = (WXHDC)::WinBeginPaint(GetWinHwnd(m_canvas), NULLHANDLE, &g_paintStruct);
 221         ms_cache.Add(new wxPaintDCInfo(m_canvas, this));
 222     }
 223     SetBackground(wxBrush(m_canvas->GetBackgroundColour(), wxSOLID));
 224 }
 225
 226 wxPaintDC::~wxPaintDC()
 227 {
 228     if ( m_hDC )
 229     {
 230         SelectOldObjects(m_hDC);
 231
 232         size_t index;
 233         wxPaintDCInfo *info = FindInCache(&index);
 234
 235         wxCHECK_RET( info, wxT("existing DC should have a cache entry") );
 236
 237         if ( !--info->count )
 238         {
 239             ::WinEndPaint(m_hPS);
 240
 241             ms_cache.Remove(index);
 242         }
 243         //else: cached DC entry is still in use
 244
 245         // prevent the base class dtor from ReleaseDC()ing it again
 246         m_hDC = 0;
 247     }
 248 }
 249
 250 wxPaintDCInfo *wxPaintDC::FindInCache(size_t *index) const
 251 {
 252     wxPaintDCInfo *info = NULL;
 253     size_t nCache = ms_cache.GetCount();
 254     for ( size_t n = 0; n < nCache; n++ )
 255     {
 256         info = &ms_cache[n];
 257         if ( info->hwnd == m_canvas->GetHWND() )
 258         {
 259             if ( index )
 260                 *index = n;
 261             break;
 262         }
 263     }
 264
 265     return info;
 266 }