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1 | ///////////////////////////////////////////////////////////////////////////// |
2 | // Name: bitmap | |
3 | // Purpose: topic overview | |
4 | // Author: wxWidgets team | |
5 | // RCS-ID: $Id$ | |
6 | // Licence: wxWindows license | |
7 | ///////////////////////////////////////////////////////////////////////////// | |
8 | ||
9 | /*! | |
10 | ||
11 | @page bitmap_overview Bitmaps and icons overview | |
12 | ||
13 | Classes: #wxBitmap, #wxBitmapHandler, #wxIcon, #wxCursor. | |
14 | The wxBitmap class encapsulates the concept of a platform-dependent bitmap, | |
15 | either monochrome or colour. Platform-specific methods for creating a | |
16 | wxBitmap object from an existing file are catered for, and | |
17 | this is an occasion where conditional compilation will sometimes be | |
18 | required. | |
19 | A bitmap created dynamically or loaded from a file can be selected | |
20 | into a memory device context (instance of #wxMemoryDC). This | |
21 | enables the bitmap to be copied to a window or memory device context | |
22 | using wxDC::Blit, or to be used as a drawing surface. | |
23 | See #wxMemoryDC for an example of drawing onto a bitmap. | |
24 | All wxWidgets platforms support XPMs for small bitmaps and icons. | |
25 | You may include the XPM inline as below, since it's C code, or you | |
26 | can load it at run-time. | |
27 | ||
28 | @code | |
29 | #include "mondrian.xpm" | |
30 | @endcode | |
31 | ||
32 | Sometimes you wish to use a .ico resource on Windows, and XPMs on | |
33 | other platforms (for example to take advantage of Windows' support for multiple icon resolutions). | |
34 | A macro, #wxICON, is available which creates an icon using an XPM | |
35 | on the appropriate platform, or an icon resource on Windows. | |
36 | ||
37 | @code | |
38 | wxIcon icon(wxICON(mondrian)); | |
39 | ||
40 | // Equivalent to: | |
41 | ||
42 | #if defined(__WXGTK__) || defined(__WXMOTIF__) | |
43 | wxIcon icon(mondrian_xpm); | |
44 | #endif | |
45 | ||
46 | #if defined(__WXMSW__) | |
47 | wxIcon icon("mondrian"); | |
48 | #endif | |
49 | @endcode | |
50 | ||
51 | There is also a corresponding #wxBITMAP macro which allows | |
52 | to create the bitmaps in much the same way as #wxICON creates | |
53 | icons. It assumes that bitmaps live in resources under Windows or OS2 and XPM | |
54 | files under all other platforms (for XPMs, the corresponding file must be | |
55 | included before this macro is used, of course, and the name of the bitmap | |
56 | should be the same as the resource name under Windows with @c _xpm | |
57 | suffix). For example: | |
58 | ||
59 | @code | |
60 | // an easy and portable way to create a bitmap | |
61 | wxBitmap bmp(wxBITMAP(bmpname)); | |
62 | ||
63 | // which is roughly equivalent to the following | |
64 | #if defined(__WXMSW__) || defined(__WXPM__) | |
65 | wxBitmap bmp("bmpname", wxBITMAP_TYPE_RESOURCE); | |
66 | #else // Unix | |
67 | wxBitmap bmp(bmpname_xpm, wxBITMAP_TYPE_XPM); | |
68 | #endif | |
69 | @endcode | |
70 | ||
71 | You should always use wxICON and wxBITMAP macros because they work for any | |
72 | platform (unlike the code above which doesn't deal with wxMac, wxX11, ...) and | |
73 | are more short and clear than versions with @c #ifdefs. Even better, | |
74 | use the same XPMs on all platforms. | |
75 | @ref supportedbitmapformats_overview | |
76 | @ref bitmaphandlers_overview | |
77 | ||
78 | ||
79 | @section supportedbitmapformats Supported bitmap file formats | |
80 | ||
81 | The following lists the formats handled on different platforms. Note | |
82 | that missing or partially-implemented formats are automatically supplemented | |
83 | by the #wxImage to load the data, and then converting | |
84 | it to wxBitmap form. Note that using wxImage is the preferred way to | |
85 | load images in wxWidgets, with the exception of resources (XPM-files or | |
86 | native Windows resources). Writing an image format handler for wxImage | |
87 | is also far easier than writing one for wxBitmap, because wxImage has | |
88 | exactly one format on all platforms whereas wxBitmap can store pixel data | |
89 | very differently, depending on colour depths and platform. | |
90 | @b wxBitmap | |
91 | Under Windows, wxBitmap may load the following formats: | |
92 | ||
93 | ||
94 | Windows bitmap resource (wxBITMAP_TYPE_BMP_RESOURCE) | |
95 | Windows bitmap file (wxBITMAP_TYPE_BMP) | |
96 | XPM data and file (wxBITMAP_TYPE_XPM) | |
97 | All formats that are supported by the #wxImage class. | |
98 | ||
99 | ||
100 | Under wxGTK, wxBitmap may load the following formats: | |
101 | ||
102 | ||
103 | XPM data and file (wxBITMAP_TYPE_XPM) | |
104 | All formats that are supported by the #wxImage class. | |
105 | ||
106 | ||
107 | Under wxMotif and wxX11, wxBitmap may load the following formats: | |
108 | ||
109 | ||
110 | XBM data and file (wxBITMAP_TYPE_XBM) | |
111 | XPM data and file (wxBITMAP_TYPE_XPM) | |
112 | All formats that are supported by the #wxImage class. | |
113 | ||
114 | ||
115 | @b wxIcon | |
116 | Under Windows, wxIcon may load the following formats: | |
117 | ||
118 | ||
119 | Windows icon resource (wxBITMAP_TYPE_ICO_RESOURCE) | |
120 | Windows icon file (wxBITMAP_TYPE_ICO) | |
121 | XPM data and file (wxBITMAP_TYPE_XPM) | |
122 | ||
123 | ||
124 | Under wxGTK, wxIcon may load the following formats: | |
125 | ||
126 | ||
127 | XPM data and file (wxBITMAP_TYPE_XPM) | |
128 | All formats that are supported by the #wxImage class. | |
129 | ||
130 | ||
131 | Under wxMotif and wxX11, wxIcon may load the following formats: | |
132 | ||
133 | ||
134 | XBM data and file (wxBITMAP_TYPE_XBM) | |
135 | XPM data and file (wxBITMAP_TYPE_XPM) | |
136 | All formats that are supported by the #wxImage class. | |
137 | ||
138 | ||
139 | @b wxCursor | |
140 | Under Windows, wxCursor may load the following formats: | |
141 | ||
142 | ||
143 | Windows cursor resource (wxBITMAP_TYPE_CUR_RESOURCE) | |
144 | Windows cursor file (wxBITMAP_TYPE_CUR) | |
145 | Windows icon file (wxBITMAP_TYPE_ICO) | |
146 | Windows bitmap file (wxBITMAP_TYPE_BMP) | |
147 | ||
148 | ||
149 | Under wxGTK, wxCursor may load the following formats (in additional | |
150 | to stock cursors): | |
151 | ||
152 | ||
153 | None (stock cursors only). | |
154 | ||
155 | ||
156 | Under wxMotif and wxX11, wxCursor may load the following formats: | |
157 | ||
158 | ||
159 | XBM data and file (wxBITMAP_TYPE_XBM) | |
160 | ||
161 | ||
162 | ||
163 | @section bitmaphandlers Bitmap format handlers | |
164 | ||
165 | To provide extensibility, the functionality for loading and saving bitmap formats | |
166 | is not implemented in the wxBitmap class, but in a number of handler classes, | |
167 | derived from wxBitmapHandler. There is a static list of handlers which wxBitmap | |
168 | examines when a file load/save operation is requested. Some handlers are provided as standard, but if you | |
169 | have special requirements, you may wish to initialise the wxBitmap class with | |
170 | some extra handlers which you write yourself or receive from a third party. | |
171 | To add a handler object to wxBitmap, your application needs to include the header which implements it, and | |
172 | then call the static function wxBitmap::AddHandler. | |
173 | @b Note: bitmap handlers are not implemented on all platforms, and new ones rarely need | |
174 | to be implemented since wxImage can be used for loading most formats, as noted earlier. | |
175 | ||
176 | */ | |
177 | ||
178 |