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1 /////////////////////////////////////////////////////////////////////////////
2 // Name: wx/dcbuffer.h
3 // Purpose: wxBufferedDC class
4 // Author: Ron Lee <ron@debian.org>
5 // Modified by: Vadim Zeitlin (refactored, added bg preservation)
6 // Created: 16/03/02
7 // RCS-ID: $Id$
8 // Copyright: (c) Ron Lee
9 // Licence: wxWindows licence
10 /////////////////////////////////////////////////////////////////////////////
11
12 #ifndef _WX_DCBUFFER_H_
13 #define _WX_DCBUFFER_H_
14
15 #include "wx/dcmemory.h"
16 #include "wx/dcclient.h"
17 #include "wx/window.h"
18
19 // Split platforms into two groups - those which have well-working
20 // double-buffering by default, and those which do not.
21 #if defined(__WXMAC__) || defined(__WXGTK20__) || defined(__WXDFB__)
22 #define wxALWAYS_NATIVE_DOUBLE_BUFFER 1
23 #else
24 #define wxALWAYS_NATIVE_DOUBLE_BUFFER 0
25 #endif
26
27
28 // ----------------------------------------------------------------------------
29 // Double buffering helper.
30 // ----------------------------------------------------------------------------
31
32 // Assumes the buffer bitmap covers the entire scrolled window,
33 // and prepares the window DC accordingly
34 #define wxBUFFER_VIRTUAL_AREA 0x01
35
36 // Assumes the buffer bitmap only covers the client area;
37 // does not prepare the window DC
38 #define wxBUFFER_CLIENT_AREA 0x02
39
40 // Set when not using specific buffer bitmap. Note that this
41 // is private style and not returned by GetStyle.
42 #define wxBUFFER_USES_SHARED_BUFFER 0x04
43
44 class WXDLLEXPORT wxBufferedDC : public wxMemoryDC
45 {
46 public:
47 // Default ctor, must subsequently call Init for two stage construction.
48 wxBufferedDC()
49 : m_dc(NULL),
50 m_buffer(NULL),
51 m_style(0)
52 {
53 }
54
55 // Construct a wxBufferedDC using a user supplied buffer.
56 wxBufferedDC(wxDC *dc,
57 wxBitmap& buffer = wxNullBitmap,
58 int style = wxBUFFER_CLIENT_AREA)
59 : m_dc(NULL), m_buffer(NULL)
60 {
61 Init(dc, buffer, style);
62 }
63
64 // Construct a wxBufferedDC with an internal buffer of 'area'
65 // (where area is usually something like the size of the window
66 // being buffered)
67 wxBufferedDC(wxDC *dc, const wxSize& area, int style = wxBUFFER_CLIENT_AREA)
68 : m_dc(NULL), m_buffer(NULL)
69 {
70 Init(dc, area, style);
71 }
72
73 // The usually desired action in the dtor is to blit the buffer.
74 virtual ~wxBufferedDC()
75 {
76 if ( m_dc )
77 UnMask();
78 }
79
80 // These reimplement the actions of the ctors for two stage creation
81 void Init(wxDC *dc,
82 wxBitmap& buffer = wxNullBitmap,
83 int style = wxBUFFER_CLIENT_AREA)
84 {
85 InitCommon(dc, style);
86
87 m_buffer = &buffer;
88
89 UseBuffer();
90 }
91
92 void Init(wxDC *dc, const wxSize &area, int style = wxBUFFER_CLIENT_AREA)
93 {
94 InitCommon(dc, style);
95
96 UseBuffer(area.x, area.y);
97 }
98
99 // Blits the buffer to the dc, and detaches the dc from the buffer (so it
100 // can be effectively used once only).
101 //
102 // Usually called in the dtor or by the dtor of derived classes if the
103 // BufferedDC must blit before the derived class (which may own the dc it's
104 // blitting to) is destroyed.
105 void UnMask();
106
107 // Set and get the style
108 void SetStyle(int style) { m_style = style; }
109 int GetStyle() const { return m_style & ~wxBUFFER_USES_SHARED_BUFFER; }
110
111 private:
112 // common part of Init()s
113 void InitCommon(wxDC *dc, int style)
114 {
115 wxASSERT_MSG( !m_dc, _T("wxBufferedDC already initialised") );
116
117 m_dc = dc;
118 m_style = style;
119
120 // inherit the same layout direction as the original DC
121 if (dc && dc->IsOk())
122 SetLayoutDirection(dc->GetLayoutDirection());
123 }
124
125 // check that the bitmap is valid and use it
126 void UseBuffer(wxCoord w = -1, wxCoord h = -1);
127
128 // the underlying DC to which we copy everything drawn on this one in
129 // UnMask()
130 //
131 // NB: Without the existence of a wxNullDC, this must be a pointer, else it
132 // could probably be a reference.
133 wxDC *m_dc;
134
135 // the buffer (selected in this DC), initially invalid
136 wxBitmap *m_buffer;
137
138 // the buffering style
139 int m_style;
140
141 DECLARE_DYNAMIC_CLASS(wxBufferedDC)
142 DECLARE_NO_COPY_CLASS(wxBufferedDC)
143 };
144
145
146 // ----------------------------------------------------------------------------
147 // Double buffered PaintDC.
148 // ----------------------------------------------------------------------------
149
150 // Creates a double buffered wxPaintDC, optionally allowing the
151 // user to specify their own buffer to use.
152 class WXDLLEXPORT wxBufferedPaintDC : public wxBufferedDC
153 {
154 public:
155 // If no bitmap is supplied by the user, a temporary one will be created.
156 wxBufferedPaintDC(wxWindow *window, wxBitmap& buffer, int style = wxBUFFER_CLIENT_AREA)
157 : m_paintdc(window)
158 {
159 // If we're buffering the virtual window, scale the paint DC as well
160 if (style & wxBUFFER_VIRTUAL_AREA)
161 window->PrepareDC( m_paintdc );
162
163 if( buffer.IsOk() )
164 Init(&m_paintdc, buffer, style);
165 else
166 Init(&m_paintdc, GetBufferedSize(window, style), style);
167 }
168
169 // If no bitmap is supplied by the user, a temporary one will be created.
170 wxBufferedPaintDC(wxWindow *window, int style = wxBUFFER_CLIENT_AREA)
171 : m_paintdc(window)
172 {
173 // If we're using the virtual window, scale the paint DC as well
174 if (style & wxBUFFER_VIRTUAL_AREA)
175 window->PrepareDC( m_paintdc );
176
177 Init(&m_paintdc, GetBufferedSize(window, style), style);
178 }
179
180 // default copy ctor ok.
181
182 virtual ~wxBufferedPaintDC()
183 {
184 // We must UnMask here, else by the time the base class
185 // does it, the PaintDC will have already been destroyed.
186 UnMask();
187 }
188
189 protected:
190 // return the size needed by the buffer: this depends on whether we're
191 // buffering just the currently shown part or the total (scrolled) window
192 static wxSize GetBufferedSize(wxWindow *window, int style)
193 {
194 return style & wxBUFFER_VIRTUAL_AREA ? window->GetVirtualSize()
195 : window->GetClientSize();
196 }
197
198 private:
199 wxPaintDC m_paintdc;
200
201 DECLARE_ABSTRACT_CLASS(wxBufferedPaintDC)
202 DECLARE_NO_COPY_CLASS(wxBufferedPaintDC)
203 };
204
205
206
207 //
208 // wxAutoBufferedPaintDC is a wxPaintDC in toolkits which have double-
209 // buffering by default. Otherwise it is a wxBufferedPaintDC. Thus,
210 // you can only expect it work with a simple constructor that
211 // accepts single wxWindow* argument.
212 //
213 #if wxALWAYS_NATIVE_DOUBLE_BUFFER
214 #define wxAutoBufferedPaintDCBase wxPaintDC
215 #else
216 #define wxAutoBufferedPaintDCBase wxBufferedPaintDC
217 #endif
218
219
220 #ifdef __WXDEBUG__
221
222 class wxAutoBufferedPaintDC : public wxAutoBufferedPaintDCBase
223 {
224 public:
225
226 wxAutoBufferedPaintDC(wxWindow* win)
227 : wxAutoBufferedPaintDCBase(win)
228 {
229 TestWinStyle(win);
230 }
231
232 virtual ~wxAutoBufferedPaintDC() { }
233
234 private:
235
236 void TestWinStyle(wxWindow* win)
237 {
238 // Help the user to get the double-buffering working properly.
239 wxASSERT_MSG( win->GetBackgroundStyle() == wxBG_STYLE_CUSTOM,
240 wxT("In constructor, you need to call SetBackgroundStyle(wxBG_STYLE_CUSTOM), ")
241 wxT("and also, if needed, paint the background manually in the paint event handler."));
242 }
243
244 DECLARE_NO_COPY_CLASS(wxAutoBufferedPaintDC)
245 };
246
247 #else // !__WXDEBUG__
248
249 // In release builds, just use typedef
250 typedef wxAutoBufferedPaintDCBase wxAutoBufferedPaintDC;
251
252 #endif
253
254
255 // Check if the window is natively double buffered and will return a wxPaintDC
256 // if it is, a wxBufferedPaintDC otherwise. It is the caller's responsibility
257 // to delete the wxDC pointer when finished with it.
258 inline wxDC* wxAutoBufferedPaintDCFactory(wxWindow* window)
259 {
260 if ( window->IsDoubleBuffered() )
261 return new wxPaintDC(window);
262 else
263 return new wxBufferedPaintDC(window);
264 }
265
266 #endif // _WX_DCBUFFER_H_