A bitmap created dynamically or loaded from a file can be selected
into a memory device context (instance of \helpref{wxMemoryDC}{wxmemorydc}). This
enables the bitmap to be copied to a window or memory device context
-using \helpref{wxDC::Blit}{wxdcblit}, or to be used as a drawing surface. The {\bf
-wxToolBarSimple} class is implemented using bitmaps, and the toolbar demo
-shows one of the toolbar bitmaps being used for drawing a miniature
-version of the graphic which appears on the main window.
+using \helpref{wxDC::Blit}{wxdcblit}, or to be used as a drawing surface.
See \helpref{wxMemoryDC}{wxmemorydc} for an example of drawing onto a bitmap.
-The following shows the conditional compilation required to load a
-bitmap under Unix and in Windows. The alternative is to use the string
-version of the bitmap constructor, which loads a file under Unix and a
-resource or file under Windows, but has the disadvantage of requiring the
-XPM icon file to be available at run-time.
+All wxWidgets platforms support XPMs for small bitmaps and icons.
+You may include the XPM inline as below, since it's C code, or you
+can load it at run-time.
\begin{verbatim}
-#if defined(__WXGTK__) || defined(__WXMOTIF__)
#include "mondrian.xpm"
-#endif
\end{verbatim}
-A macro, \helpref{wxICON}{wxicon}, is available which creates an icon using an XPM
+Sometimes you wish to use a .ico resource on Windows, and XPMs on
+other platforms (for example to take advantage of Windows' support for multiple icon resolutions).
+A macro, \helpref{wxICON}{wxiconmacro}, is available which creates an icon using an XPM
on the appropriate platform, or an icon resource on Windows.
\begin{verbatim}
#endif
\end{verbatim}
-There is also a corresponding \helpref{wxBITMAP}{wxbitmap} macro which allows
-to create the bitmaps in much the same way as \helpref{wxICON}{wxicon} creates
+There is also a corresponding \helpref{wxBITMAP}{wxbitmapmacro} macro which allows
+to create the bitmaps in much the same way as \helpref{wxICON}{wxiconmacro} creates
icons. It assumes that bitmaps live in resources under Windows or OS2 and XPM
files under all other platforms (for XPMs, the corresponding file must be
included before this macro is used, of course, and the name of the bitmap
\end{verbatim}
You should always use wxICON and wxBITMAP macros because they work for any
-platform (unlike the code above which doesn't deal with wxMac, wxBe, ...) and
-are more short and clear than versions with {\tt #ifdef}s.
+platform (unlike the code above which doesn't deal with wxMac, wxX11, ...) and
+are more short and clear than versions with {\tt \#ifdef}s. Even better,
+use the same XPMs on all platforms.
\subsection{Supported bitmap file formats}\label{supportedbitmapformats}
The following lists the formats handled on different platforms. Note
-that missing or partially-implemented formats can be supplemented
-by using \helpref{wxImage}{wximage} to load the data, and then converting
-it to wxBitmap form.
+that missing or partially-implemented formats are automatically supplemented
+by the \helpref{wxImage}{wximage} to load the data, and then converting
+it to wxBitmap form. Note that using wxImage is the preferred way to
+load images in wxWidgets, with the exception of resources (XPM-files or
+native Windows resources). Writing an image format handler for wxImage
+is also far easier than writing one for wxBitmap, because wxImage has
+exactly one format on all platforms whereas wxBitmap can store pixel data
+very differently, depending on colour depths and platform.
\wxheading{wxBitmap}
\begin{itemize}\itemsep=0pt
\item Windows bitmap resource (wxBITMAP\_TYPE\_BMP\_RESOURCE)
\item Windows bitmap file (wxBITMAP\_TYPE\_BMP)
-\item PNG file (wxBITMAP\_TYPE\_PNG). Currently 4-bit (16-colour) PNG files do not load properly.
\item XPM data and file (wxBITMAP\_TYPE\_XPM)
+\item All formats that are supported by the \helpref{wxImage}{wximage} class.
\end{itemize}
Under wxGTK, wxBitmap may load the following formats:
\begin{itemize}\itemsep=0pt
-\item Windows bitmap file (wxBITMAP\_TYPE\_BMP)
-\item PNG (wxBITMAP\_TYPE\_PNG).
\item XPM data and file (wxBITMAP\_TYPE\_XPM)
+\item All formats that are supported by the \helpref{wxImage}{wximage} class.
\end{itemize}
-Under wxMotif, wxBitmap may load the following formats:
+Under wxMotif and wxX11, wxBitmap may load the following formats:
\begin{itemize}\itemsep=0pt
-%\item Windows bitmap file (wxBITMAP\_TYPE\_BMP)
-%\item PNG (wxBITMAP\_TYPE\_PNG).
\item XBM data and file (wxBITMAP\_TYPE\_XBM)
\item XPM data and file (wxBITMAP\_TYPE\_XPM)
+\item All formats that are supported by the \helpref{wxImage}{wximage} class.
\end{itemize}
\wxheading{wxIcon}
Under wxGTK, wxIcon may load the following formats:
\begin{itemize}\itemsep=0pt
-\item PNG (wxBITMAP\_TYPE\_PNG).
\item XPM data and file (wxBITMAP\_TYPE\_XPM)
+\item All formats that are supported by the \helpref{wxImage}{wximage} class.
\end{itemize}
-Under wxMotif, wxIcon may load the following formats:
+Under wxMotif and wxX11, wxIcon may load the following formats:
\begin{itemize}\itemsep=0pt
-%\item Windows bitmap file (wxBITMAP\_TYPE\_BMP)
-%\item PNG (wxBITMAP\_TYPE\_PNG).
\item XBM data and file (wxBITMAP\_TYPE\_XBM)
\item XPM data and file (wxBITMAP\_TYPE\_XPM)
+\item All formats that are supported by the \helpref{wxImage}{wximage} class.
\end{itemize}
\wxheading{wxCursor}
\item None (stock cursors only).
\end{itemize}
-Under wxMotif, wxCursor may load the following formats:
+Under wxMotif and wxX11, wxCursor may load the following formats:
\begin{itemize}\itemsep=0pt
\item XBM data and file (wxBITMAP\_TYPE\_XBM)
some extra handlers which you write yourself or receive from a third party.
To add a handler object to wxBitmap, your application needs to include the header which implements it, and
-then call the static function \helpref{wxBitmap::AddHandler}{wxbitmapaddhandler}. For example:
-
-{\small
-\begin{verbatim}
- #include <wx/pnghand.h>
- #include <wx/xpmhand.h>
- ...
- // Initialisation
- wxBitmap::AddHandler(new wxPNGFileHandler);
- wxBitmap::AddHandler(new wxXPMFileHandler);
- wxBitmap::AddHandler(new wxXPMDataHandler);
- ...
-\end{verbatim}
-}
-
-Assuming the handlers have been written correctly, you should now be able to load and save PNG files
-and XPM files using the usual wxBitmap API.
+then call the static function \helpref{wxBitmap::AddHandler}{wxbitmapaddhandler}.
-{\bf Note:} bitmap handlers are not implemented on all platforms. Currently, the above is only necessary on
-Windows, to save the extra overhead of formats that may not be necessary (if you don't use them, they
-are not linked into the executable). Unix platforms have PNG and XPM capability built-in (where supported).
+{\bf Note:} bitmap handlers are not implemented on all platforms, and new ones rarely need
+to be implemented since wxImage can be used for loading most formats, as noted earlier.
projects / wxWidgets.git / blobdiff