1 /////////////////////////////////////////////////////////////////////////////
3 // Purpose: wxClientDC class
4 // Author: Julian Smart
8 // Copyright: (c) Julian Smart
9 // Licence: wxWindows licence
10 /////////////////////////////////////////////////////////////////////////////
12 // ===========================================================================
14 // ===========================================================================
16 // ----------------------------------------------------------------------------
18 // ----------------------------------------------------------------------------
21 #pragma implementation "dcclient.h"
24 // For compilers that support precompilation, includes "wx.h".
25 #include "wx/wxprec.h"
31 #include "wx/string.h"
33 #include "wx/window.h"
35 #include "wx/msw/private.h"
37 #include "wx/dcclient.h"
39 // ----------------------------------------------------------------------------
41 // ----------------------------------------------------------------------------
43 struct WXDLLEXPORT wxPaintDCInfo
45 wxPaintDCInfo(wxWindow
*win
, wxDC
*dc
)
47 hwnd
= win
->GetHWND();
52 WXHWND hwnd
; // window for this DC
53 WXHDC hdc
; // the DC handle
54 size_t count
; // usage count
57 #include "wx/arrimpl.cpp"
59 WX_DEFINE_OBJARRAY(wxArrayDCInfo
);
61 // ----------------------------------------------------------------------------
63 // ----------------------------------------------------------------------------
65 IMPLEMENT_DYNAMIC_CLASS(wxWindowDC
, wxDC
)
66 IMPLEMENT_DYNAMIC_CLASS(wxClientDC
, wxWindowDC
)
67 IMPLEMENT_DYNAMIC_CLASS(wxPaintDC
, wxClientDC
)
68 IMPLEMENT_CLASS(wxPaintDCEx
, wxPaintDC
)
70 // ----------------------------------------------------------------------------
72 // ----------------------------------------------------------------------------
74 static PAINTSTRUCT g_paintStruct
;
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.
84 // ===========================================================================
86 // ===========================================================================
88 // ----------------------------------------------------------------------------
90 // ----------------------------------------------------------------------------
92 wxWindowDC::wxWindowDC()
97 wxWindowDC::wxWindowDC(wxWindow
*canvas
)
99 wxCHECK_RET( canvas
, _T("invalid window in wxWindowDC") );
102 m_hDC
= (WXHDC
) ::GetWindowDC(GetHwndOf(m_canvas
));
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
109 void wxWindowDC::InitDC()
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
);
115 // default bg colour is pne of the window
116 SetBackground(wxBrush(m_canvas
->GetBackgroundColour(), wxSOLID
));
118 // since we are a window dc we need to grab the palette from the window
124 void wxWindowDC::DoGetSize(int *width
, int *height
) const
126 wxCHECK_RET( m_canvas
, _T("wxWindowDC without a window?") );
128 m_canvas
->GetSize(width
, height
);
131 // ----------------------------------------------------------------------------
133 // ----------------------------------------------------------------------------
135 wxClientDC::wxClientDC()
140 wxClientDC::wxClientDC(wxWindow
*canvas
)
142 wxCHECK_RET( canvas
, _T("invalid window in wxClientDC") );
145 m_hDC
= (WXHDC
)::GetDC(GetHwndOf(m_canvas
));
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
153 void wxClientDC::InitDC()
155 wxWindowDC::InitDC();
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
)
163 // no need to shift DC origin if shift is null
164 SetDeviceOrigin(ptOrigin
.x
, ptOrigin
.y
);
167 // clip the DC to avoid overwriting the non client area
168 SetClippingRegion(wxPoint(0, 0), m_canvas
->GetClientSize());
169 #endif // __WXUNIVERSAL__
172 wxClientDC::~wxClientDC()
176 void wxClientDC::DoGetSize(int *width
, int *height
) const
178 wxCHECK_RET( m_canvas
, _T("wxClientDC without a window?") );
180 m_canvas
->GetClientSize(width
, height
);
183 // ----------------------------------------------------------------------------
185 // ----------------------------------------------------------------------------
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.
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.
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.
203 wxArrayDCInfo
wxPaintDC::ms_cache
;
205 wxPaintDC::wxPaintDC()
210 wxPaintDC::wxPaintDC(wxWindow
*canvas
)
212 wxCHECK_RET( canvas
, wxT("NULL canvas in wxPaintDC ctor") );
215 if ( g_isPainting
<= 0 )
217 wxFAIL_MSG( wxT("wxPaintDC may be created only in EVT_PAINT handler!") );
221 #endif // __WXDEBUG__
225 // do we have a DC for this window in the cache?
226 wxPaintDCInfo
*info
= FindInCache();
232 else // not in cache, create a new one
234 m_hDC
= (WXHDC
)::BeginPaint(GetHwndOf(m_canvas
), &g_paintStruct
);
236 ms_cache
.Add(new wxPaintDCInfo(m_canvas
, this));
239 // (re)set the DC parameters.
240 // Note: at this point m_hDC can be NULL under MicroWindows, when dragging.
245 wxPaintDC::~wxPaintDC()
249 SelectOldObjects(m_hDC
);
252 wxPaintDCInfo
*info
= FindInCache(&index
);
254 wxCHECK_RET( info
, wxT("existing DC should have a cache entry") );
256 if ( !--info
->count
)
258 ::EndPaint(GetHwndOf(m_canvas
), &g_paintStruct
);
260 ms_cache
.RemoveAt(index
);
262 // Reduce the number of bogus reports of non-freed memory
264 if (ms_cache
.IsEmpty())
267 //else: cached DC entry is still in use
269 // prevent the base class dtor from ReleaseDC()ing it again
274 wxPaintDCInfo
*wxPaintDC::FindInCache(size_t *index
) const
276 wxPaintDCInfo
*info
= NULL
;
277 size_t nCache
= ms_cache
.GetCount();
278 for ( size_t n
= 0; n
< nCache
; n
++ )
280 wxPaintDCInfo
*info1
= &ms_cache
[n
];
281 if ( info1
->hwnd
== m_canvas
->GetHWND() )
293 // find the entry for this DC in the cache (keyed by the window)
294 WXHDC
wxPaintDC::FindDCInCache(wxWindow
* win
)
296 wxPaintDCInfo
*info
= NULL
;
297 size_t nCache
= ms_cache
.GetCount();
298 for ( size_t n
= 0; n
< nCache
; n
++ )
301 if ( info
->hwnd
== win
->GetHWND() )
313 wxPaintDCEx::wxPaintDCEx(wxWindow
*canvas
, WXHDC dc
) : saveState(0)
318 wxFAIL_MSG( wxT("wxPaintDCEx requires an existing device context") );
321 #endif // __WXDEBUG__
325 wxPaintDCInfo
*info
= FindInCache();
331 else // not in cache, create a new one
334 ms_cache
.Add(new wxPaintDCInfo(m_canvas
, this));
335 saveState
= SaveDC((HDC
) dc
);
339 wxPaintDCEx::~wxPaintDCEx()
342 wxPaintDCInfo
*info
= FindInCache(&index
);
344 wxCHECK_RET( info
, wxT("existing DC should have a cache entry") );
346 if ( !--info
->count
)
348 RestoreDC((HDC
) m_hDC
, saveState
);
349 ms_cache
.RemoveAt(index
);
351 // Reduce the number of bogus reports of non-freed memory
353 if (ms_cache
.IsEmpty())
356 //else: cached DC entry is still in use
358 // prevent the base class dtor from ReleaseDC()ing it again