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
   9 // Licence:     wxWindows licence
  10 /////////////////////////////////////////////////////////////////////////////
  11
  12 // ===========================================================================
  13 // declarations
  14 // ===========================================================================
  15
  16 // ----------------------------------------------------------------------------
  17 // headers
  18 // ----------------------------------------------------------------------------
  19
  20 #if defined(__GNUG__) && !defined(NO_GCC_PRAGMA)
  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 IMPLEMENT_DYNAMIC_CLASS(wxWindowDC, wxDC)
  66 IMPLEMENT_DYNAMIC_CLASS(wxClientDC, wxWindowDC)
  67 IMPLEMENT_DYNAMIC_CLASS(wxPaintDC, wxClientDC)
  68 IMPLEMENT_CLASS(wxPaintDCEx, wxPaintDC)
  69
  70 // ----------------------------------------------------------------------------
  71 // global variables
  72 // ----------------------------------------------------------------------------
  73
  74 static PAINTSTRUCT g_paintStruct;
  75
  76 #ifdef __WXDEBUG__
  77     // a global variable which we check to verify that wxPaintDC are only
  78     // created in resopnse to WM_PAINT message - doing this from elsewhere is a
  79     // common programming error among wxWindows programmers and might lead to
  80     // very subtle and difficult to debug refresh/repaint bugs.
  81     int g_isPainting = 0;
  82 #endif // __WXDEBUG__
  83
  84 // ===========================================================================
  85 // implementation
  86 // ===========================================================================
  87
  88 // ----------------------------------------------------------------------------
  89 // wxWindowDC
  90 // ----------------------------------------------------------------------------
  91
  92 wxWindowDC::wxWindowDC()
  93 {
  94     m_canvas = NULL;
  95 }
  96
  97 wxWindowDC::wxWindowDC(wxWindow *canvas)
  98 {
  99     wxCHECK_RET( canvas, _T("invalid window in wxWindowDC") );
 100
 101     m_canvas = canvas;
 102     m_hDC = (WXHDC) ::GetWindowDC(GetHwndOf(m_canvas));
 103
 104     // m_bOwnsDC was already set to false in the base class ctor, so the DC
 105     // will be released (and not deleted) in ~wxDC
 106     InitDC();
 107 }
 108
 109 void wxWindowDC::InitDC()
 110 {
 111     // the background mode is only used for text background and is set in
 112     // DrawText() to OPAQUE as required, otherwise always TRANSPARENT,
 113     ::SetBkMode(GetHdc(), TRANSPARENT);
 114
 115     // default bg colour is pne of the window
 116     SetBackground(wxBrush(m_canvas->GetBackgroundColour(), wxSOLID));
 117
 118     // since we are a window dc we need to grab the palette from the window
 119 #if wxUSE_PALETTE
 120     InitializePalette();
 121 #endif
 122 }
 123
 124 void wxWindowDC::DoGetSize(int *width, int *height) const
 125 {
 126     wxCHECK_RET( m_canvas, _T("wxWindowDC without a window?") );
 127
 128     m_canvas->GetSize(width, height);
 129 }
 130
 131 // ----------------------------------------------------------------------------
 132 // wxClientDC
 133 // ----------------------------------------------------------------------------
 134
 135 wxClientDC::wxClientDC()
 136 {
 137     m_canvas = NULL;
 138 }
 139
 140 wxClientDC::wxClientDC(wxWindow *canvas)
 141 {
 142     wxCHECK_RET( canvas, _T("invalid window in wxClientDC") );
 143
 144     m_canvas = canvas;
 145     m_hDC = (WXHDC)::GetDC(GetHwndOf(m_canvas));
 146
 147     // m_bOwnsDC was already set to false in the base class ctor, so the DC
 148     // will be released (and not deleted) in ~wxDC
 149
 150     InitDC();
 151 }
 152
 153 void wxClientDC::InitDC()
 154 {
 155     wxWindowDC::InitDC();
 156
 157     // in wxUniv build we must manually do some DC adjustments usually
 158     // performed by Windows for us
 159 #ifdef __WXUNIVERSAL__
 160     wxPoint ptOrigin = m_canvas->GetClientAreaOrigin();
 161     if ( ptOrigin.x || ptOrigin.y )
 162     {
 163         // no need to shift DC origin if shift is null
 164         SetDeviceOrigin(ptOrigin.x, ptOrigin.y);
 165     }
 166
 167     // clip the DC to avoid overwriting the non client area
 168     SetClippingRegion(wxPoint(0, 0), m_canvas->GetClientSize());
 169 #endif // __WXUNIVERSAL__
 170 }
 171
 172 wxClientDC::~wxClientDC()
 173 {
 174 }
 175
 176 void wxClientDC::DoGetSize(int *width, int *height) const
 177 {
 178     wxCHECK_RET( m_canvas, _T("wxClientDC without a window?") );
 179
 180     m_canvas->GetClientSize(width, height);
 181 }
 182
 183 // ----------------------------------------------------------------------------
 184 // wxPaintDC
 185 // ----------------------------------------------------------------------------
 186
 187 // VZ: initial implementation (by JACS) only remembered the last wxPaintDC
 188 //     created and tried to reuse it - this was supposed to take care of a
 189 //     situation when a derived class OnPaint() calls base class OnPaint()
 190 //     because in this case ::BeginPaint() shouldn't be called second time.
 191 //
 192 //     I'm not sure how useful this is, however we must remember the HWND
 193 //     associated with the last HDC as well - otherwise we may (and will!) try
 194 //     to reuse the HDC for another HWND which is a nice recipe for disaster.
 195 //
 196 //     So we store a list of windows for which we already have the DC and not
 197 //     just one single hDC. This seems to work, but I'm really not sure about
 198 //     the usefullness of the whole idea - IMHO it's much better to not call
 199 //     base class OnPaint() at all, or, if we really want to allow it, add a
 200 //     "wxPaintDC *" parameter to wxPaintEvent which should be used if it's
 201 //     !NULL instead of creating a new DC.
 202
 203 wxArrayDCInfo wxPaintDC::ms_cache;
 204
 205 wxPaintDC::wxPaintDC()
 206 {
 207     m_canvas = NULL;
 208 }
 209
 210 wxPaintDC::wxPaintDC(wxWindow *canvas)
 211 {
 212     wxCHECK_RET( canvas, wxT("NULL canvas in wxPaintDC ctor") );
 213
 214 #ifdef __WXDEBUG__
 215     if ( g_isPainting <= 0 )
 216     {
 217         wxFAIL_MSG( wxT("wxPaintDC may be created only in EVT_PAINT handler!") );
 218
 219         return;
 220     }
 221 #endif // __WXDEBUG__
 222
 223     m_canvas = canvas;
 224
 225     // do we have a DC for this window in the cache?
 226     wxPaintDCInfo *info = FindInCache();
 227     if ( info )
 228     {
 229         m_hDC = info->hdc;
 230         info->count++;
 231     }
 232     else // not in cache, create a new one
 233     {
 234         m_hDC = (WXHDC)::BeginPaint(GetHwndOf(m_canvas), &g_paintStruct);
 235         if (m_hDC)
 236             ms_cache.Add(new wxPaintDCInfo(m_canvas, this));
 237     }
 238
 239     // (re)set the DC parameters.
 240     // Note: at this point m_hDC can be NULL under MicroWindows, when dragging.
 241     if (GetHDC())
 242         InitDC();
 243 }
 244
 245 wxPaintDC::~wxPaintDC()
 246 {
 247     if ( m_hDC )
 248     {
 249         SelectOldObjects(m_hDC);
 250
 251         size_t index;
 252         wxPaintDCInfo *info = FindInCache(&index);
 253
 254         wxCHECK_RET( info, wxT("existing DC should have a cache entry") );
 255
 256         if ( !--info->count )
 257         {
 258             ::EndPaint(GetHwndOf(m_canvas), &g_paintStruct);
 259
 260             ms_cache.RemoveAt(index);
 261
 262             // Reduce the number of bogus reports of non-freed memory
 263             // at app exit
 264             if (ms_cache.IsEmpty())
 265                 ms_cache.Clear();
 266         }
 267         //else: cached DC entry is still in use
 268
 269         // prevent the base class dtor from ReleaseDC()ing it again
 270         m_hDC = 0;
 271     }
 272 }
 273
 274 wxPaintDCInfo *wxPaintDC::FindInCache(size_t *index) const
 275 {
 276     wxPaintDCInfo *info = NULL;
 277     size_t nCache = ms_cache.GetCount();
 278     for ( size_t n = 0; n < nCache; n++ )
 279     {
 280         wxPaintDCInfo *info1 = &ms_cache[n];
 281         if ( info1->hwnd == m_canvas->GetHWND() )
 282         {
 283             info = info1;
 284             if ( index )
 285                 *index = n;
 286             break;
 287         }
 288     }
 289
 290     return info;
 291 }
 292
 293 // find the entry for this DC in the cache (keyed by the window)
 294 WXHDC wxPaintDC::FindDCInCache(wxWindow* win)
 295 {
 296     wxPaintDCInfo *info = NULL;
 297     size_t nCache = ms_cache.GetCount();
 298     for ( size_t n = 0; n < nCache; n++ )
 299     {
 300         info = &ms_cache[n];
 301         if ( info->hwnd == win->GetHWND() )
 302         {
 303             return info->hdc;
 304         }
 305     }
 306     return 0;
 307 }
 308
 309 /*
 310  * wxPaintDCEx
 311  */
 312
 313 // TODO: don't duplicate wxPaintDC code here!!
 314
 315 wxPaintDCEx::wxPaintDCEx(wxWindow *canvas, WXHDC dc) : saveState(0)
 316 {
 317     wxCHECK_RET( dc, wxT("wxPaintDCEx requires an existing device context") );
 318
 319     m_canvas = canvas;
 320
 321     wxPaintDCInfo *info = FindInCache();
 322     if ( info )
 323     {
 324         m_hDC = info->hdc;
 325         info->count++;
 326     }
 327     else // not in cache, create a new one
 328     {
 329         m_hDC = dc;
 330         ms_cache.Add(new wxPaintDCInfo(m_canvas, this));
 331         saveState = SaveDC((HDC) dc);
 332     }
 333 }
 334
 335 wxPaintDCEx::~wxPaintDCEx()
 336 {
 337     size_t index;
 338     wxPaintDCInfo *info = FindInCache(&index);
 339
 340     wxCHECK_RET( info, wxT("existing DC should have a cache entry") );
 341
 342     if ( !--info->count )
 343     {
 344         RestoreDC((HDC) m_hDC, saveState);
 345         ms_cache.RemoveAt(index);
 346
 347         // Reduce the number of bogus reports of non-freed memory
 348         // at app exit
 349         if (ms_cache.IsEmpty())
 350             ms_cache.Clear();
 351     }
 352     //else: cached DC entry is still in use
 353
 354     // prevent the base class dtor from ReleaseDC()ing it again
 355     m_hDC = 0;
 356 }
 357