src/msw/dcclient.cpp

   1 /////////////////////////////////////////////////////////////////////////////
   2 // Name:        src/msw/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 // For compilers that support precompilation, includes "wx.h".
  21 #include "wx/wxprec.h"
  22
  23 #ifdef __BORLANDC__
  24     #pragma hdrstop
  25 #endif
  26
  27 #include "wx/dcclient.h"
  28
  29 #ifndef WX_PRECOMP
  30     #include "wx/string.h"
  31     #include "wx/log.h"
  32     #include "wx/window.h"
  33 #endif
  34
  35 #include "wx/msw/private.h"
  36
  37 // ----------------------------------------------------------------------------
  38 // array/list types
  39 // ----------------------------------------------------------------------------
  40
  41 struct WXDLLEXPORT wxPaintDCInfo
  42 {
  43     wxPaintDCInfo(wxWindow *win, wxDC *dc)
  44     {
  45         hwnd = win->GetHWND();
  46         hdc = dc->GetHDC();
  47         count = 1;
  48     }
  49
  50     WXHWND    hwnd;       // window for this DC
  51     WXHDC     hdc;        // the DC handle
  52     size_t    count;      // usage count
  53 };
  54
  55 #include "wx/arrimpl.cpp"
  56
  57 WX_DEFINE_OBJARRAY(wxArrayDCInfo)
  58
  59 // ----------------------------------------------------------------------------
  60 // macros
  61 // ----------------------------------------------------------------------------
  62
  63 IMPLEMENT_DYNAMIC_CLASS(wxWindowDC, wxDC)
  64 IMPLEMENT_DYNAMIC_CLASS(wxClientDC, wxWindowDC)
  65 IMPLEMENT_DYNAMIC_CLASS(wxPaintDC, wxClientDC)
  66 IMPLEMENT_CLASS(wxPaintDCEx, wxPaintDC)
  67
  68 // ----------------------------------------------------------------------------
  69 // global variables
  70 // ----------------------------------------------------------------------------
  71
  72 static PAINTSTRUCT g_paintStruct;
  73
  74 #ifdef __WXDEBUG__
  75     // a global variable which we check to verify that wxPaintDC are only
  76     // created in response to WM_PAINT message - doing this from elsewhere is a
  77     // common programming error among wxWidgets programmers and might lead to
  78     // very subtle and difficult to debug refresh/repaint bugs.
  79     int g_isPainting = 0;
  80 #endif // __WXDEBUG__
  81
  82 // ===========================================================================
  83 // implementation
  84 // ===========================================================================
  85
  86 // ----------------------------------------------------------------------------
  87 // wxWindowDC
  88 // ----------------------------------------------------------------------------
  89
  90 wxWindowDC::wxWindowDC()
  91 {
  92     m_canvas = NULL;
  93 }
  94
  95 wxWindowDC::wxWindowDC(wxWindow *canvas)
  96 {
  97     wxCHECK_RET( canvas, _T("invalid window in wxWindowDC") );
  98
  99     m_canvas = canvas;
 100     m_hDC = (WXHDC) ::GetWindowDC(GetHwndOf(m_canvas));
 101
 102     // m_bOwnsDC was already set to false in the base class ctor, so the DC
 103     // will be released (and not deleted) in ~wxDC
 104     InitDC();
 105 }
 106
 107 void wxWindowDC::InitDC()
 108 {
 109     // the background mode is only used for text background and is set in
 110     // DrawText() to OPAQUE as required, otherwise always TRANSPARENT,
 111     ::SetBkMode(GetHdc(), TRANSPARENT);
 112
 113     // default bg colour is pne of the window
 114     SetBackground(wxBrush(m_canvas->GetBackgroundColour(), wxSOLID));
 115
 116     // since we are a window dc we need to grab the palette from the window
 117 #if wxUSE_PALETTE
 118     InitializePalette();
 119 #endif
 120 }
 121
 122 void wxWindowDC::DoGetSize(int *width, int *height) const
 123 {
 124     wxCHECK_RET( m_canvas, _T("wxWindowDC without a window?") );
 125
 126     m_canvas->GetSize(width, height);
 127 }
 128
 129 // ----------------------------------------------------------------------------
 130 // wxClientDC
 131 // ----------------------------------------------------------------------------
 132
 133 wxClientDC::wxClientDC()
 134 {
 135     m_canvas = NULL;
 136 }
 137
 138 wxClientDC::wxClientDC(wxWindow *canvas)
 139 {
 140     wxCHECK_RET( canvas, _T("invalid window in wxClientDC") );
 141
 142     m_canvas = canvas;
 143     m_hDC = (WXHDC)::GetDC(GetHwndOf(m_canvas));
 144
 145     // m_bOwnsDC was already set to false in the base class ctor, so the DC
 146     // will be released (and not deleted) in ~wxDC
 147
 148     InitDC();
 149 }
 150
 151 void wxClientDC::InitDC()
 152 {
 153     wxWindowDC::InitDC();
 154
 155     // in wxUniv build we must manually do some DC adjustments usually
 156     // performed by Windows for us
 157     //
 158     // we also need to take the menu/toolbar manually into account under
 159     // Windows CE because they're just another control there, not anything
 160     // special as usually under Windows
 161 #if defined(__WXUNIVERSAL__) || defined(__WXWINCE__)
 162     wxPoint ptOrigin = m_canvas->GetClientAreaOrigin();
 163     if ( ptOrigin.x || ptOrigin.y )
 164     {
 165         // no need to shift DC origin if shift is null
 166         SetDeviceOrigin(ptOrigin.x, ptOrigin.y);
 167     }
 168
 169     // clip the DC to avoid overwriting the non client area
 170     SetClippingRegion(wxPoint(0,0), m_canvas->GetClientSize());
 171 #endif // __WXUNIVERSAL__ || __WXWINCE__
 172 }
 173
 174 wxClientDC::~wxClientDC()
 175 {
 176 }
 177
 178 void wxClientDC::DoGetSize(int *width, int *height) const
 179 {
 180     wxCHECK_RET( m_canvas, _T("wxClientDC without a window?") );
 181
 182     m_canvas->GetClientSize(width, height);
 183 }
 184
 185 // ----------------------------------------------------------------------------
 186 // wxPaintDC
 187 // ----------------------------------------------------------------------------
 188
 189 // VZ: initial implementation (by JACS) only remembered the last wxPaintDC
 190 //     created and tried to reuse it - this was supposed to take care of a
 191 //     situation when a derived class OnPaint() calls base class OnPaint()
 192 //     because in this case ::BeginPaint() shouldn't be called second time.
 193 //
 194 //     I'm not sure how useful this is, however we must remember the HWND
 195 //     associated with the last HDC as well - otherwise we may (and will!) try
 196 //     to reuse the HDC for another HWND which is a nice recipe for disaster.
 197 //
 198 //     So we store a list of windows for which we already have the DC and not
 199 //     just one single hDC. This seems to work, but I'm really not sure about
 200 //     the usefullness of the whole idea - IMHO it's much better to not call
 201 //     base class OnPaint() at all, or, if we really want to allow it, add a
 202 //     "wxPaintDC *" parameter to wxPaintEvent which should be used if it's
 203 //     !NULL instead of creating a new DC.
 204
 205 wxArrayDCInfo wxPaintDC::ms_cache;
 206
 207 wxPaintDC::wxPaintDC()
 208 {
 209     m_canvas = NULL;
 210 }
 211
 212 wxPaintDC::wxPaintDC(wxWindow *canvas)
 213 {
 214     wxCHECK_RET( canvas, wxT("NULL canvas in wxPaintDC ctor") );
 215
 216 #ifdef __WXDEBUG__
 217     if ( g_isPainting <= 0 )
 218     {
 219         wxFAIL_MSG( wxT("wxPaintDC may be created only in EVT_PAINT handler!") );
 220
 221         return;
 222     }
 223 #endif // __WXDEBUG__
 224
 225     m_canvas = canvas;
 226
 227     // do we have a DC for this window in the cache?
 228     wxPaintDCInfo *info = FindInCache();
 229     if ( info )
 230     {
 231         m_hDC = info->hdc;
 232         info->count++;
 233     }
 234     else // not in cache, create a new one
 235     {
 236         m_hDC = (WXHDC)::BeginPaint(GetHwndOf(m_canvas), &g_paintStruct);
 237         if (m_hDC)
 238             ms_cache.Add(new wxPaintDCInfo(m_canvas, this));
 239     }
 240
 241     // Note: at this point m_hDC can be NULL under MicroWindows, when dragging.
 242     if (!GetHDC())
 243         return;
 244
 245     // (re)set the DC parameters.
 246     InitDC();
 247
 248     // the HDC can have a clipping box (which we didn't set), make sure our
 249     // DoGetClippingBox() checks for it
 250     m_clipping = true;
 251 }
 252
 253 wxPaintDC::~wxPaintDC()
 254 {
 255     if ( m_hDC )
 256     {
 257         SelectOldObjects(m_hDC);
 258
 259         size_t index;
 260         wxPaintDCInfo *info = FindInCache(&index);
 261
 262         wxCHECK_RET( info, wxT("existing DC should have a cache entry") );
 263
 264         if ( --info->count == 0 )
 265         {
 266             ::EndPaint(GetHwndOf(m_canvas), &g_paintStruct);
 267
 268             ms_cache.RemoveAt(index);
 269
 270             // Reduce the number of bogus reports of non-freed memory
 271             // at app exit
 272             if (ms_cache.IsEmpty())
 273                 ms_cache.Clear();
 274         }
 275         //else: cached DC entry is still in use
 276
 277         // prevent the base class dtor from ReleaseDC()ing it again
 278         m_hDC = 0;
 279     }
 280 }
 281
 282 wxPaintDCInfo *wxPaintDC::FindInCache(size_t *index) const
 283 {
 284     wxPaintDCInfo *info = NULL;
 285     size_t nCache = ms_cache.GetCount();
 286     for ( size_t n = 0; n < nCache; n++ )
 287     {
 288         wxPaintDCInfo *info1 = &ms_cache[n];
 289         if ( info1->hwnd == m_canvas->GetHWND() )
 290         {
 291             info = info1;
 292             if ( index )
 293                 *index = n;
 294             break;
 295         }
 296     }
 297
 298     return info;
 299 }
 300
 301 // find the entry for this DC in the cache (keyed by the window)
 302 WXHDC wxPaintDC::FindDCInCache(wxWindow* win)
 303 {
 304     size_t nCache = ms_cache.GetCount();
 305     for ( size_t n = 0; n < nCache; n++ )
 306     {
 307         wxPaintDCInfo *info = &ms_cache[n];
 308         if ( info->hwnd == win->GetHWND() )
 309         {
 310             return info->hdc;
 311         }
 312     }
 313     return 0;
 314 }
 315
 316 /*
 317  * wxPaintDCEx
 318  */
 319
 320 // TODO: don't duplicate wxPaintDC code here!!
 321
 322 wxPaintDCEx::wxPaintDCEx(wxWindow *canvas, WXHDC dc) : saveState(0)
 323 {
 324     wxCHECK_RET( dc, wxT("wxPaintDCEx requires an existing device context") );
 325
 326     m_canvas = canvas;
 327
 328     wxPaintDCInfo *info = FindInCache();
 329     if ( info )
 330     {
 331         m_hDC = info->hdc;
 332         info->count++;
 333     }
 334     else // not in cache, create a new one
 335     {
 336         m_hDC = dc;
 337         ms_cache.Add(new wxPaintDCInfo(m_canvas, this));
 338         saveState = SaveDC((HDC) dc);
 339     }
 340 }
 341
 342 wxPaintDCEx::~wxPaintDCEx()
 343 {
 344     size_t index;
 345     wxPaintDCInfo *info = FindInCache(&index);
 346
 347     wxCHECK_RET( info, wxT("existing DC should have a cache entry") );
 348
 349     if ( --info->count == 0 )
 350     {
 351         RestoreDC((HDC) m_hDC, saveState);
 352         ms_cache.RemoveAt(index);
 353
 354         // Reduce the number of bogus reports of non-freed memory
 355         // at app exit
 356         if (ms_cache.IsEmpty())
 357             ms_cache.Clear();
 358     }
 359     //else: cached DC entry is still in use
 360
 361     // prevent the base class dtor from ReleaseDC()ing it again
 362     m_hDC = 0;
 363 }