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 #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/os2/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 RECT        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   // default under PM is that Window and Client DC's are the same
 105   // so we offer a separate Presentation Space to use for the
 106   // entire window.  Otherwise, calling BeginPaint will just create
 107   // chached-micro client presentation space
 108   //
 109    m_hPS = GpiCreatePS( m_hab
 110                        ,m_hDC
 111                        ,&m_PageSize
 112                        ,PU_PELS | GPIF_LONG | GPIA_ASSOC
 113                       );
 114   ::GpiAssociate(m_hPS, NULLHANDLE);
 115   ::GpiAssociate(m_hPS, m_hDC);
 116   SetBackground(wxBrush(m_canvas->GetBackgroundColour(), wxSOLID));
 117 }
 118
 119 wxWindowDC::~wxWindowDC()
 120 {
 121   if (m_canvas && m_hDC)
 122   {
 123     SelectOldObjects(m_hDC);
 124
 125     //
 126     // In PM one does not explicitly close or release an open WindowDC
 127     // They automatically close with the window, unless explicitly detached
 128     // but we need to destroy our PS
 129     //
 130     ::GpiAssociate(m_hPS, NULLHANDLE);
 131     ::GpiDestroyPS(m_hPS);
 132     m_hPS = NULLHANDLE;
 133     m_hDC = NULLHANDLE;
 134   }
 135
 136   m_hDCCount--;
 137 }
 138
 139 // ----------------------------------------------------------------------------
 140 // wxClientDC
 141 // ----------------------------------------------------------------------------
 142
 143 wxClientDC::wxClientDC()
 144 {
 145   m_canvas = NULL;
 146 }
 147
 148 wxClientDC::wxClientDC(wxWindow *the_canvas)
 149 {
 150   m_canvas = the_canvas;
 151
 152   //
 153   // default under PM is that Window and Client DC's are the same
 154   //
 155   m_hDC = (WXHDC) ::WinOpenWindowDC(GetWinHwnd(the_canvas));
 156
 157   //
 158   // Default mode is BM_LEAVEALONE so we make no call Set the mix
 159   //
 160   SetBackground(wxBrush(m_canvas->GetBackgroundColour(), wxSOLID));
 161 }
 162
 163 wxClientDC::~wxClientDC()
 164 {
 165   if ( m_canvas && GetHdc() )
 166   {
 167     SelectOldObjects(m_hDC);
 168
 169     // We don't explicitly release Device contexts in PM and
 170     // the cached micro PS is already gone
 171
 172     m_hDC = 0;
 173   }
 174 }
 175
 176 // ----------------------------------------------------------------------------
 177 // wxPaintDC
 178 // ----------------------------------------------------------------------------
 179
 180 // VZ: initial implementation (by JACS) only remembered the last wxPaintDC
 181 //     created and tried to reuse - this was supposed to take care of a
 182 //     situation when a derived class OnPaint() calls base class OnPaint()
 183 //     because in this case ::BeginPaint() shouldn't be called second time.
 184 //
 185 //     I'm not sure how useful this is, however we must remember the HWND
 186 //     associated with the last HDC as well - otherwise we may (and will!) try
 187 //     to reuse the HDC for another HWND which is a nice recipe for disaster.
 188 //
 189 //     So we store a list of windows for which we already have the DC and not
 190 //     just one single hDC. This seems to work, but I'm really not sure about
 191 //     the usefullness of the whole idea - IMHO it's much better to not call
 192 //     base class OnPaint() at all, or, if we really want to allow it, add a
 193 //     "wxPaintDC *" parameter to wxPaintEvent which should be used if it's
 194 //     !NULL instead of creating a new DC.
 195
 196 wxArrayDCInfo wxPaintDC::ms_cache;
 197
 198 wxPaintDC::wxPaintDC()
 199 {
 200     m_canvas = NULL;
 201     m_hDC = 0;
 202 }
 203
 204 wxPaintDC::wxPaintDC(wxWindow *canvas)
 205 {
 206     wxCHECK_RET( canvas, wxT("NULL canvas in wxPaintDC ctor") );
 207
 208 #ifdef __WXDEBUG__
 209     if ( g_isPainting <= 0 )
 210     {
 211         wxFAIL_MSG( wxT("wxPaintDC may be created only in EVT_PAINT handler!") );
 212
 213         return;
 214     }
 215 #endif // __WXDEBUG__
 216
 217     m_canvas = canvas;
 218
 219     // do we have a DC for this window in the cache?
 220     wxPaintDCInfo *info = FindInCache();
 221     if ( info )
 222     {
 223         m_hDC = info->hdc;
 224         info->count++;
 225     }
 226     else // not in cache, create a new one
 227     {
 228         m_hDC = (WXHDC)::WinBeginPaint(GetWinHwnd(m_canvas), NULLHANDLE, &g_paintStruct);
 229         ms_cache.Add(new wxPaintDCInfo(m_canvas, this));
 230     }
 231     SetBackground(wxBrush(m_canvas->GetBackgroundColour(), wxSOLID));
 232 }
 233
 234 wxPaintDC::~wxPaintDC()
 235 {
 236     if ( m_hDC )
 237     {
 238         SelectOldObjects(m_hDC);
 239
 240         size_t index;
 241         wxPaintDCInfo *info = FindInCache(&index);
 242
 243         wxCHECK_RET( info, wxT("existing DC should have a cache entry") );
 244
 245         if ( !--info->count )
 246         {
 247             ::WinEndPaint(m_hPS);
 248
 249             ms_cache.Remove(index);
 250         }
 251         //else: cached DC entry is still in use
 252
 253         // prevent the base class dtor from ReleaseDC()ing it again
 254         m_hDC = 0;
 255     }
 256 }
 257
 258 wxPaintDCInfo *wxPaintDC::FindInCache(size_t *index) const
 259 {
 260     wxPaintDCInfo *info = NULL;
 261     size_t nCache = ms_cache.GetCount();
 262     for ( size_t n = 0; n < nCache; n++ )
 263     {
 264         info = &ms_cache[n];
 265         if ( info->hwnd == m_canvas->GetHWND() )
 266         {
 267             if ( index )
 268                 *index = n;
 269             break;
 270         }
 271     }
 272
 273     return info;
 274 }