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docs for C++ meta

This commit is contained in:
John Cupitt 2008-08-09 18:45:26 +00:00
parent 5d8309b5fc
commit 263397cce3
2 changed files with 39 additions and 15 deletions
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6
TODO
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@ -1,9 +1,3 @@
- wrap meta() stuff in C++, we need it in py as well
need fred.get_int ("poop"); I think
add notes to docs on this
- merge loadable format stuff, postpone new object parameter API to next
version

48
doc/src/vimage.tex
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@ -172,7 +172,45 @@ int Yoffset();
\noindent
Where \verb+TBandFmt+, \verb+TCoding+, \verb+TType+ and \verb+TCompression+
are \verb+enum+s for the types in the VIPS file header. See section~\pref{sec:header} for an explanation of all of these fields.
are \verb+enum+s for the types in the VIPS file header. See
section~\pref{sec:header} for an explanation of all of these fields.
Two functions give access to the filename and history
fields maintained by the VIPS IO system.
\begin{verbatim}
char *filename();
char *Hist();
\end{verbatim}
You can get and set extra metadata fields with \verb+meta_get()+ and
\verb+meta_set()+. They read and write \verb+GValue+ objects, see
\pref{sec:meta}.
\begin{verbatim}
void meta_set( const char *field, GValue *value );
void meta_get( const char *field, GValue *value_copy );
GType meta_get_type( const char *field );
\end{verbatim}
A set of convenience functions build on these two to provide accessors for
common types.
\begin{verbatim}
int meta_get_int( const char *field )
double meta_get_double( const char *field )
const char *meta_get_string( const char *field )
void *meta_get_area( const char *field )
void *meta_get_blob( const char *field, size_t *length )
void meta_set( const char *field, int value )
void meta_set( const char *field, double value )
void meta_set( const char *field, const char *value )
void meta_set( const char *field,
VCallback free_fn, void *value )
void meta_set( const char *field,
VCallback free_fn, void *value, size_t length )
\end{verbatim}
The \verb+image()+ member function provides access to the \verb+IMAGE+
descriptor underlying the C++ API. See the \pref{sec:appl} for details.
@ -211,14 +249,6 @@ VImage.PIL_mode_from_vips (vips-image) ->
See also \verb+frombuffer+ and \verb+fromstring+ above.
Finally, two projection functions give access to the filename and history
fields maintained by the VIPS IO system.
\begin{verbatim}
char *filename();
char *Hist();
\end{verbatim}
\subsection{Assignment}
\verb+VImage+ defines copy and assignment, with reference-counted