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 and Markus Holzem
   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/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
  69 // ----------------------------------------------------------------------------
  70 // global variables
  71 // ----------------------------------------------------------------------------
  72
  73 static PAINTSTRUCT g_paintStruct;
  74
  75 #ifdef __WXDEBUG__
  76     // a global variable which we check to verify that wxPaintDC are only
  77     // created in resopnse to WM_PAINT message - doing this from elsewhere is a
  78     // common programming error among wxWindows programmers and might lead to
  79     // very subtle and difficult to debug refresh/repaint bugs.
  80     int g_isPainting = 0;
  81 #endif // __WXDEBUG__
  82
  83 // ===========================================================================
  84 // implementation
  85 // ===========================================================================
  86
  87 // ----------------------------------------------------------------------------
  88 // wxWindowDC
  89 // ----------------------------------------------------------------------------
  90
  91 wxWindowDC::wxWindowDC()
  92 {
  93     m_canvas = NULL;
  94 }
  95
  96 wxWindowDC::wxWindowDC(wxWindow *canvas)
  97 {
  98     wxCHECK_RET( canvas, _T("invalid window in wxWindowDC") );
  99
 100     m_canvas = canvas;
 101     m_hDC = (WXHDC) ::GetWindowDC(GetHwndOf(m_canvas));
 102
 103     // m_bOwnsDC was already set to false in the base class ctor, so the DC
 104     // will be released (and not deleted) in ~wxDC
 105     InitDC();
 106 }
 107
 108 void wxWindowDC::InitDC()
 109 {
 110     // the background mode is only used for text background and is set in
 111     // DrawText() to OPAQUE as required, otherwise always TRANSPARENT,
 112     ::SetBkMode(GetHdc(), TRANSPARENT);
 113
 114     // default bg colour is pne of the window
 115     SetBackground(wxBrush(m_canvas->GetBackgroundColour(), wxSOLID));
 116
 117     // since we are a window dc we need to grab the palette from the window
 118 #if wxUSE_PALETTE
 119     InitializePalette();
 120 #endif
 121 }
 122
 123 // ----------------------------------------------------------------------------
 124 // wxClientDC
 125 // ----------------------------------------------------------------------------
 126
 127 wxClientDC::wxClientDC()
 128 {
 129     m_canvas = NULL;
 130 }
 131
 132 wxClientDC::wxClientDC(wxWindow *canvas)
 133 {
 134     wxCHECK_RET( canvas, _T("invalid window in wxClientDC") );
 135
 136     m_canvas = canvas;
 137     m_hDC = (WXHDC)::GetDC(GetHwndOf(m_canvas));
 138
 139     // m_bOwnsDC was already set to false in the base class ctor, so the DC
 140     // will be released (and not deleted) in ~wxDC
 141
 142     InitDC();
 143 }
 144
 145 void wxClientDC::InitDC()
 146 {
 147     wxWindowDC::InitDC();
 148
 149     // in wxUniv build we must manually do some DC adjustments usually
 150     // performed by Windows for us
 151 #ifdef __WXUNIVERSAL__
 152     wxPoint ptOrigin = m_canvas->GetClientAreaOrigin();
 153     if ( ptOrigin.x || ptOrigin.y )
 154     {
 155         // no need to shift DC origin if shift is null
 156         SetDeviceOrigin(ptOrigin.x, ptOrigin.y);
 157     }
 158
 159     // clip the DC to avoid overwriting the non client area
 160     SetClippingRegion(wxPoint(0, 0), m_canvas->GetClientSize());
 161 #endif // __WXUNIVERSAL__
 162 }
 163
 164 wxClientDC::~wxClientDC()
 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 it - 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 }
 194
 195 wxPaintDC::wxPaintDC(wxWindow *canvas)
 196 {
 197     wxCHECK_RET( canvas, wxT("NULL canvas in wxPaintDC ctor") );
 198
 199 #ifdef __WXDEBUG__
 200     if ( g_isPainting <= 0 )
 201     {
 202         wxFAIL_MSG( wxT("wxPaintDC may be created only in EVT_PAINT handler!") );
 203
 204         return;
 205     }
 206 #endif // __WXDEBUG__
 207
 208     m_canvas = canvas;
 209
 210     // do we have a DC for this window in the cache?
 211     wxPaintDCInfo *info = FindInCache();
 212     if ( info )
 213     {
 214         m_hDC = info->hdc;
 215         info->count++;
 216     }
 217     else // not in cache, create a new one
 218     {
 219         m_hDC = (WXHDC)::BeginPaint(GetHwndOf(m_canvas), &g_paintStruct);
 220         if (m_hDC)
 221             ms_cache.Add(new wxPaintDCInfo(m_canvas, this));
 222     }
 223
 224     // (re)set the DC parameters.
 225     // Note: at this point m_hDC can be NULL under MicroWindows, when dragging.
 226     if (GetHDC())
 227         InitDC();
 228 }
 229
 230 wxPaintDC::~wxPaintDC()
 231 {
 232     if ( m_hDC )
 233     {
 234         SelectOldObjects(m_hDC);
 235
 236         size_t index;
 237         wxPaintDCInfo *info = FindInCache(&index);
 238
 239         wxCHECK_RET( info, wxT("existing DC should have a cache entry") );
 240
 241         if ( !--info->count )
 242         {
 243             ::EndPaint(GetHwndOf(m_canvas), &g_paintStruct);
 244
 245             ms_cache.RemoveAt(index);
 246
 247             // Reduce the number of bogus reports of non-freed memory
 248             // at app exit
 249             if (ms_cache.IsEmpty())
 250                 ms_cache.Clear();
 251         }
 252         //else: cached DC entry is still in use
 253
 254         // prevent the base class dtor from ReleaseDC()ing it again
 255         m_hDC = 0;
 256     }
 257 }
 258
 259 wxPaintDCInfo *wxPaintDC::FindInCache(size_t *index) const
 260 {
 261     wxPaintDCInfo *info = NULL;
 262     size_t nCache = ms_cache.GetCount();
 263     for ( size_t n = 0; n < nCache; n++ )
 264     {
 265         info = &ms_cache[n];
 266         if ( info->hwnd == m_canvas->GetHWND() )
 267         {
 268             if ( index )
 269                 *index = n;
 270             break;
 271         }
 272     }
 273
 274     return info;
 275 }
 276
 277 // find the entry for this DC in the cache (keyed by the window)
 278 WXHDC wxPaintDC::FindDCInCache(wxWindow* win)
 279 {
 280     wxPaintDCInfo *info = NULL;
 281     size_t nCache = ms_cache.GetCount();
 282     for ( size_t n = 0; n < nCache; n++ )
 283     {
 284         info = &ms_cache[n];
 285         if ( info->hwnd == win->GetHWND() )
 286         {
 287             return info->hdc;
 288         }
 289     }
 290     return 0;
 291 }
 292