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