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1\section{Bitmaps and icons overview}\label{wxbitmapoverview}
2
3Classes: \helpref{wxBitmap}{wxbitmap}, \helpref{wxBitmapHandler}{wxbitmaphandler}, \helpref{wxIcon}{wxicon}, \helpref{wxCursor}{wxcursor}.
4
5The wxBitmap class encapsulates the concept of a platform-dependent bitmap,
6either monochrome or colour. Platform-specific methods for creating a
7wxBitmap object from an existing file are catered for, and
8this is an occasion where conditional compilation will sometimes be
9required.
10
11A bitmap created dynamically or loaded from a file can be selected
12into a memory device context (instance of \helpref{wxMemoryDC}{wxmemorydc}). This
13enables the bitmap to be copied to a window or memory device context
14using \helpref{wxDC::Blit}{wxdcblit}, or to be used as a drawing surface.
15
16See \helpref{wxMemoryDC}{wxmemorydc} for an example of drawing onto a bitmap.
17
18All wxWidgets platforms support XPMs for small bitmaps and icons.
19You may include the XPM inline as below, since it's C code, or you
20can load it at run-time.
21
22\begin{verbatim}
23#include "mondrian.xpm"
24\end{verbatim}
25
26Sometimes you wish to use a .ico resource on Windows, and XPMs on
27other platforms (for example to take advantage of Windows' support for multiple icon resolutions).
28A macro, \helpref{wxICON}{wxiconmacro}, is available which creates an icon using an XPM
29on the appropriate platform, or an icon resource on Windows.
30
31\begin{verbatim}
32wxIcon icon(wxICON(mondrian));
33
34// Equivalent to:
35
36#if defined(__WXGTK__) || defined(__WXMOTIF__)
37wxIcon icon(mondrian_xpm);
38#endif
39
40#if defined(__WXMSW__)
41wxIcon icon("mondrian");
42#endif
43\end{verbatim}
44
45There is also a corresponding \helpref{wxBITMAP}{wxbitmapmacro} macro which allows
46to create the bitmaps in much the same way as \helpref{wxICON}{wxiconmacro} creates
47icons. It assumes that bitmaps live in resources under Windows or OS2 and XPM
48files under all other platforms (for XPMs, the corresponding file must be
49included before this macro is used, of course, and the name of the bitmap
50should be the same as the resource name under Windows with {\tt \_xpm}
51suffix). For example:
52
53\begin{verbatim}
54// an easy and portable way to create a bitmap
55wxBitmap bmp(wxBITMAP(bmpname));
56
57// which is roughly equivalent to the following
58#if defined(__WXMSW__) || defined(__WXPM__)
59 wxBitmap bmp("bmpname", wxBITMAP_TYPE_RESOURCE);
60#else // Unix
61 wxBitmap bmp(bmpname_xpm, wxBITMAP_TYPE_XPM);
62#endif
63\end{verbatim}
64
65You should always use wxICON and wxBITMAP macros because they work for any
66platform (unlike the code above which doesn't deal with wxMac, wxX11, ...) and
67are more short and clear than versions with {\tt \#ifdef}s. Even better,
68use the same XPMs on all platforms.
69
70\subsection{Supported bitmap file formats}\label{supportedbitmapformats}
71
72The following lists the formats handled on different platforms. Note
73that missing or partially-implemented formats are automatically supplemented
74by the \helpref{wxImage}{wximage} to load the data, and then converting
75it to wxBitmap form. Note that using wxImage is the preferred way to
76load images in wxWidgets, with the exception of resources (XPM-files or
77native Windows resources). Writing an image format handler for wxImage
78is also far easier than writing one for wxBitmap, because wxImage has
79exactly one format on all platforms whereas wxBitmap can store pixel data
80very differently, depending on colour depths and platform.
81
82\wxheading{wxBitmap}
83
84Under Windows, wxBitmap may load the following formats:
85
86\begin{itemize}\itemsep=0pt
87\item Windows bitmap resource (wxBITMAP\_TYPE\_BMP\_RESOURCE)
88\item Windows bitmap file (wxBITMAP\_TYPE\_BMP)
89\item XPM data and file (wxBITMAP\_TYPE\_XPM)
90\item All formats that are supported by the \helpref{wxImage}{wximage} class.
91\end{itemize}
92
93Under wxGTK, wxBitmap may load the following formats:
94
95\begin{itemize}\itemsep=0pt
96\item XPM data and file (wxBITMAP\_TYPE\_XPM)
97\item All formats that are supported by the \helpref{wxImage}{wximage} class.
98\end{itemize}
99
100Under wxMotif and wxX11, wxBitmap may load the following formats:
101
102\begin{itemize}\itemsep=0pt
103\item XBM data and file (wxBITMAP\_TYPE\_XBM)
104\item XPM data and file (wxBITMAP\_TYPE\_XPM)
105\item All formats that are supported by the \helpref{wxImage}{wximage} class.
106\end{itemize}
107
108\wxheading{wxIcon}
109
110Under Windows, wxIcon may load the following formats:
111
112\begin{itemize}\itemsep=0pt
113\item Windows icon resource (wxBITMAP\_TYPE\_ICO\_RESOURCE)
114\item Windows icon file (wxBITMAP\_TYPE\_ICO)
115\item XPM data and file (wxBITMAP\_TYPE\_XPM)
116\end{itemize}
117
118Under wxGTK, wxIcon may load the following formats:
119
120\begin{itemize}\itemsep=0pt
121\item XPM data and file (wxBITMAP\_TYPE\_XPM)
122\item All formats that are supported by the \helpref{wxImage}{wximage} class.
123\end{itemize}
124
125Under wxMotif and wxX11, wxIcon may load the following formats:
126
127\begin{itemize}\itemsep=0pt
128\item XBM data and file (wxBITMAP\_TYPE\_XBM)
129\item XPM data and file (wxBITMAP\_TYPE\_XPM)
130\item All formats that are supported by the \helpref{wxImage}{wximage} class.
131\end{itemize}
132
133\wxheading{wxCursor}
134
135Under Windows, wxCursor may load the following formats:
136
137\begin{itemize}\itemsep=0pt
138\item Windows cursor resource (wxBITMAP\_TYPE\_CUR\_RESOURCE)
139\item Windows cursor file (wxBITMAP\_TYPE\_CUR)
140\item Windows icon file (wxBITMAP\_TYPE\_ICO)
141\item Windows bitmap file (wxBITMAP\_TYPE\_BMP)
142\end{itemize}
143
144Under wxGTK, wxCursor may load the following formats (in additional
145to stock cursors):
146
147\begin{itemize}\itemsep=0pt
148\item None (stock cursors only).
149\end{itemize}
150
151Under wxMotif and wxX11, wxCursor may load the following formats:
152
153\begin{itemize}\itemsep=0pt
154\item XBM data and file (wxBITMAP\_TYPE\_XBM)
155\end{itemize}
156
157\subsection{Bitmap format handlers}\label{bitmaphandlers}
158
159To provide extensibility, the functionality for loading and saving bitmap formats
160is not implemented in the wxBitmap class, but in a number of handler classes,
161derived from wxBitmapHandler. There is a static list of handlers which wxBitmap
162examines when a file load/save operation is requested. Some handlers are provided as standard, but if you
163have special requirements, you may wish to initialise the wxBitmap class with
164some extra handlers which you write yourself or receive from a third party.
165
166To add a handler object to wxBitmap, your application needs to include the header which implements it, and
167then call the static function \helpref{wxBitmap::AddHandler}{wxbitmapaddhandler}.
168
169{\bf Note:} bitmap handlers are not implemented on all platforms, and new ones rarely need
170to be implemented since wxImage can be used for loading most formats, as noted earlier.
171