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1 | ///////////////////////////////////////////////////////////////////////////// |
2 | // Name: dcbuffer.h | |
e54c96f1 | 3 | // Purpose: interface of wxBufferedDC |
23324ae1 FM |
4 | // Author: wxWidgets team |
5 | // RCS-ID: $Id$ | |
6 | // Licence: wxWindows license | |
7 | ///////////////////////////////////////////////////////////////////////////// | |
8 | ||
9 | /** | |
10 | @class wxBufferedDC | |
7c913512 | 11 | |
23324ae1 | 12 | This class provides a simple way to avoid flicker: when drawing on it, |
001f1f56 | 13 | everything is infact first drawn on an in-memory buffer (a wxBitmap) and |
f09b5681 BP |
14 | then copied to the screen, using the associated wxDC, only once, when this |
15 | object is destroyed. wxBufferedDC itself is typically associated with | |
16 | wxClientDC, if you want to use it in your @c EVT_PAINT handler, you should | |
17 | look at wxBufferedPaintDC instead. | |
18 | ||
19 | When used like this, a valid @e DC must be specified in the constructor | |
23324ae1 | 20 | while the @e buffer bitmap doesn't have to be explicitly provided, by |
f09b5681 BP |
21 | default this class will allocate the bitmap of required size itself. |
22 | However using a dedicated bitmap can speed up the redrawing process by | |
23 | eliminating the repeated creation and destruction of a possibly big bitmap. | |
24 | Otherwise, wxBufferedDC can be used in the same way as any other device | |
25 | context. | |
7c913512 | 26 | |
23324ae1 | 27 | There is another possible use for wxBufferedDC is to use it to maintain a |
f09b5681 | 28 | backing store for the window contents. In this case, the associated @e DC |
23324ae1 | 29 | may be @NULL but a valid backing store bitmap should be specified. |
7c913512 | 30 | |
23324ae1 | 31 | Finally, please note that GTK+ 2.0 as well as OS X provide double buffering |
f09b5681 BP |
32 | themselves natively. You can either use wxWindow::IsDoubleBuffered() to |
33 | determine whether you need to use buffering or not, or use | |
34 | wxAutoBufferedPaintDC to avoid needless double buffering on the systems | |
35 | which already do it automatically. | |
7c913512 | 36 | |
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37 | @library{wxcore} |
38 | @category{dc} | |
7c913512 | 39 | |
e54c96f1 | 40 | @see wxDC, wxMemoryDC, wxBufferedPaintDC, wxAutoBufferedPaintDC |
23324ae1 FM |
41 | */ |
42 | class wxBufferedDC : public wxMemoryDC | |
43 | { | |
44 | public: | |
f09b5681 BP |
45 | /** |
46 | Default constructor. You must call one of the Init() methods later in | |
47 | order to use the device context. | |
48 | */ | |
49 | wxBufferedDC(); | |
50 | ||
23324ae1 | 51 | /** |
4050e98d | 52 | Creates a buffer for the provided @a dc. Init() must not be called when |
f09b5681 | 53 | using this constructor. |
3c4f71cc | 54 | |
7c913512 | 55 | @param dc |
f09b5681 BP |
56 | The underlying DC: everything drawn to this object will be flushed |
57 | to this DC when this object is destroyed. You may pass @NULL in | |
58 | order to just initialize the buffer, and not flush it. | |
7c913512 | 59 | @param area |
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60 | The size of the bitmap to be used for buffering (this bitmap is |
61 | created internally when it is not given explicitly). | |
4050e98d BP |
62 | @param style |
63 | wxBUFFER_CLIENT_AREA to indicate that just the client area of the | |
64 | window is buffered, or wxBUFFER_VIRTUAL_AREA to indicate that the | |
65 | buffer bitmap covers the virtual area. | |
66 | */ | |
67 | wxBufferedDC(wxDC* dc, const wxSize& area, | |
68 | int style = wxBUFFER_CLIENT_AREA); | |
98ccd545 | 69 | |
4050e98d BP |
70 | /** |
71 | Creates a buffer for the provided dc. Init() must not be called when | |
72 | using this constructor. | |
73 | ||
74 | @param dc | |
75 | The underlying DC: everything drawn to this object will be flushed | |
76 | to this DC when this object is destroyed. You may pass @NULL in | |
77 | order to just initialize the buffer, and not flush it. | |
7c913512 | 78 | @param buffer |
f09b5681 BP |
79 | Explicitly provided bitmap to be used for buffering: this is the |
80 | most efficient solution as the bitmap doesn't have to be recreated | |
81 | each time but it also requires more memory as the bitmap is never | |
82 | freed. The bitmap should have appropriate size, anything drawn | |
83 | outside of its bounds is clipped. | |
4cc4bfaf | 84 | @param style |
f09b5681 BP |
85 | wxBUFFER_CLIENT_AREA to indicate that just the client area of the |
86 | window is buffered, or wxBUFFER_VIRTUAL_AREA to indicate that the | |
87 | buffer bitmap covers the virtual area. | |
23324ae1 | 88 | */ |
882678eb | 89 | wxBufferedDC(wxDC* dc, wxBitmap& buffer = wxNullBitmap, |
7c913512 | 90 | int style = wxBUFFER_CLIENT_AREA); |
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91 | |
92 | /** | |
f09b5681 BP |
93 | Copies everything drawn on the DC so far to the underlying DC |
94 | associated with this object, if any. | |
23324ae1 | 95 | */ |
98ccd545 | 96 | virtual ~wxBufferedDC(); |
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97 | |
98 | //@{ | |
99 | /** | |
f09b5681 BP |
100 | Initializes the object created using the default constructor. Please |
101 | see the constructors for parameter details. | |
23324ae1 | 102 | */ |
4cc4bfaf | 103 | void Init(wxDC* dc, const wxSize& area, |
23324ae1 | 104 | int style = wxBUFFER_CLIENT_AREA); |
882678eb | 105 | void Init(wxDC* dc, wxBitmap& buffer = wxNullBitmap, |
7c913512 | 106 | int style = wxBUFFER_CLIENT_AREA); |
23324ae1 FM |
107 | //@} |
108 | }; | |
109 | ||
110 | ||
e54c96f1 | 111 | |
23324ae1 FM |
112 | /** |
113 | @class wxAutoBufferedPaintDC | |
7c913512 | 114 | |
f09b5681 BP |
115 | This wxDC derivative can be used inside of an @c EVT_PAINT() event handler |
116 | to achieve double-buffered drawing. Just use this class instead of | |
117 | wxPaintDC and make sure wxWindow::SetBackgroundStyle() is called with | |
118 | wxBG_STYLE_CUSTOM somewhere in the class initialization code, and that's | |
119 | all you have to do to (mostly) avoid flicker. | |
120 | ||
121 | The difference between wxBufferedPaintDC and this class is that this class | |
122 | won't double-buffer on platforms which have native double-buffering | |
123 | already, avoiding any unneccessary buffering to avoid flicker. | |
7c913512 | 124 | |
f09b5681 BP |
125 | wxAutoBufferedPaintDC is simply a typedef of wxPaintDC on platforms that |
126 | have native double-buffering, otherwise, it is a typedef of | |
127 | wxBufferedPaintDC. | |
7c913512 | 128 | |
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129 | @library{wxbase} |
130 | @category{dc} | |
7c913512 | 131 | |
f09b5681 | 132 | @see wxDC, wxBufferedPaintDC, wxPaintDC |
23324ae1 FM |
133 | */ |
134 | class wxAutoBufferedPaintDC : public wxBufferedPaintDC | |
135 | { | |
136 | public: | |
137 | /** | |
138 | Constructor. Pass a pointer to the window on which you wish to paint. | |
139 | */ | |
4cc4bfaf | 140 | wxAutoBufferedPaintDC(wxWindow* window); |
23324ae1 FM |
141 | }; |
142 | ||
143 | ||
e54c96f1 | 144 | |
23324ae1 FM |
145 | /** |
146 | @class wxBufferedPaintDC | |
7c913512 | 147 | |
f09b5681 BP |
148 | This is a subclass of wxBufferedDC which can be used inside of an |
149 | @c EVT_PAINT() event handler to achieve double-buffered drawing. Just use | |
150 | this class instead of wxPaintDC and make sure | |
151 | wxWindow::SetBackgroundStyle() is called with wxBG_STYLE_CUSTOM somewhere | |
152 | in the class initialization code, and that's all you have to do to (mostly) | |
153 | avoid flicker. The only thing to watch out for is that if you are using | |
154 | this class together with wxScrolled, you probably do @b not want to call | |
155 | wxScrolled::PrepareDC() on it as it already does this internally for the | |
156 | real underlying wxPaintDC. | |
7c913512 | 157 | |
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158 | @library{wxcore} |
159 | @category{dc} | |
7c913512 | 160 | |
f09b5681 | 161 | @see wxDC, wxBufferedDC, wxAutoBufferedPaintDC, wxPaintDC |
23324ae1 FM |
162 | */ |
163 | class wxBufferedPaintDC : public wxBufferedDC | |
164 | { | |
165 | public: | |
166 | //@{ | |
167 | /** | |
f09b5681 BP |
168 | As with wxBufferedDC, you may either provide the bitmap to be used for |
169 | buffering or let this object create one internally (in the latter case, | |
170 | the size of the client part of the window is used). | |
171 | ||
172 | Pass wxBUFFER_CLIENT_AREA for the @a style parameter to indicate that | |
173 | just the client area of the window is buffered, or | |
174 | wxBUFFER_VIRTUAL_AREA to indicate that the buffer bitmap covers the | |
175 | virtual area. | |
23324ae1 | 176 | */ |
4cc4bfaf | 177 | wxBufferedPaintDC(wxWindow* window, wxBitmap& buffer, |
23324ae1 | 178 | int style = wxBUFFER_CLIENT_AREA); |
4cc4bfaf | 179 | wxBufferedPaintDC(wxWindow* window, |
7c913512 | 180 | int style = wxBUFFER_CLIENT_AREA); |
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181 | //@} |
182 | ||
183 | /** | |
f09b5681 BP |
184 | Copies everything drawn on the DC so far to the window associated with |
185 | this object, using a wxPaintDC. | |
23324ae1 | 186 | */ |
98ccd545 | 187 | virtual ~wxBufferedPaintDC(); |
23324ae1 | 188 | }; |
e54c96f1 | 189 |