clarified the parameters of MB2WC and WC2MB a little in the docs/headers

[wxWidgets.git] / docs / latex / wx / encconv.tex

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% encconv.h at 30/Dec/99 18:45:16
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\section{\class{wxEncodingConverter}}\label{wxencodingconverter}

This class is capable of converting strings between two
8-bit encodings/charsets. It can also convert from/to Unicode (but only
if you compiled wxWidgets with wxUSE\_WCHAR\_T set to 1). Only limited subset
of encodings in supported by wxEncodingConverter:
{\tt wxFONTENCODING\_ISO8859\_1..15}, {\tt wxFONTENCODING\_CP1250..1257} and 
{\tt wxFONTENCODING\_KOI8}.

\wxheading{Note}

Please use \helpref{wxMBConv classes}{mbconvclasses} instead
if possible. \helpref{wxCSConv}{wxcsconv} has much better support for various
encodings than wxEncodingConverter. wxEncodingConverter is useful only
if you rely on {\tt wxCONVERT\_SUBSTITUTE} mode of operation (see 
\helpref{Init}{wxencodingconverterinit}).

\wxheading{Derived from}

\helpref{wxObject}{wxobject}

\wxheading{Include files}

<wx/encconv.h>

\wxheading{See also}

\helpref{wxFontMapper}{wxfontmapper}, 
\helpref{wxMBConv}{wxmbconv}, 
\helpref{Writing non-English applications}{nonenglishoverview}


\latexignore{\rtfignore{\wxheading{Members}}}


\membersection{wxEncodingConverter::wxEncodingConverter}\label{wxencodingconverterwxencodingconverter}

\func{}{wxEncodingConverter}{\void}

Constructor.


\membersection{wxEncodingConverter::Init}\label{wxencodingconverterinit}

\func{bool}{Init}{\param{wxFontEncoding }{input\_enc}, \param{wxFontEncoding }{output\_enc}, \param{int }{method = wxCONVERT\_STRICT}}

Initialize conversion. Both output or input encoding may
be wxFONTENCODING\_UNICODE, but only if wxUSE\_ENCODING is set to 1.
All subsequent calls to \helpref{Convert()}{wxencodingconverterconvert} 
will interpret its argument
as a string in {\it input\_enc} encoding and will output string in 
{\it output\_enc} encoding.
You must call this method before calling Convert. You may call 
it more than once in order to switch to another conversion.
{\it Method} affects behaviour of Convert() in case input character
cannot be converted because it does not exist in output encoding:

\begin{twocollist}\itemsep=0pt
\twocolitem{{\bf wxCONVERT\_STRICT}}{follow behaviour of GNU Recode -
just copy unconvertible  characters to output and don't change them 
(its integer value will stay the same)}
\twocolitem{{\bf wxCONVERT\_SUBSTITUTE}}{try some (lossy) substitutions 
- e.g. replace unconvertible latin capitals with acute by ordinary
capitals, replace en-dash or em-dash by '-' etc.}
\end{twocollist}

Both modes guarantee that output string will have same length
as input string.

\wxheading{Return value} 

false if given conversion is impossible, true otherwise
(conversion may be impossible either if you try to convert
to Unicode with non-Unicode build of wxWidgets or if input
or output encoding is not supported.)


\membersection{wxEncodingConverter::CanConvert}\label{wxencodingconvertercanconvert}

\func{static bool}{CanConvert}{\param{wxFontEncoding}{encIn}, \param{wxFontEncoding }{encOut}}

Return true if (any text in) multibyte encoding \arg{encIn} can be converted to
another one (\it{encOut}) losslessly.

Do not call this method with \texttt{wxFONTENCODING\_UNICODE} as either
parameter, it doesn't make sense (always works in one sense and always depends
on the text to convert in the other).


\membersection{wxEncodingConverter::Convert}\label{wxencodingconverterconvert}

\constfunc{void}{Convert}{\param{const char* }{input}, \param{char* }{output}}

\constfunc{void}{Convert}{\param{const wchar\_t* }{input}, \param{wchar\_t* }{output}}

\constfunc{void}{Convert}{\param{const char* }{input}, \param{wchar\_t* }{output}}

\constfunc{void}{Convert}{\param{const wchar\_t* }{input}, \param{char* }{output}}

Convert input string according to settings passed to
\helpref{Init}{wxencodingconverterinit} and writes the result to {\it output}.

\constfunc{void}{Convert}{\param{char* }{str}}

\constfunc{void}{Convert}{\param{wchar\_t* }{str}}

Convert input string according to settings passed to
\helpref{Init}{wxencodingconverterinit} in-place, i.e. write the result to the
same memory area.

\constfunc{wxString}{Convert}{\param{const wxString\& }{input}}

Convert wxString and return new wxString object.

\wxheading{Notes}

You must call \helpref{Init}{wxencodingconverterinit} before using this method!

{\tt wchar\_t} versions of the method are not available if wxWidgets was compiled
with {\tt wxUSE\_WCHAR\_T} set to 0.


\membersection{wxEncodingConverter::GetPlatformEquivalents}\label{wxencodingconvertergetplatformequivalents}

\func{static wxFontEncodingArray}{GetPlatformEquivalents}{\param{wxFontEncoding }{enc}, \param{int }{platform = wxPLATFORM\_CURRENT}}

Return equivalents for given font that are used
under given platform. Supported platforms:

\begin{itemize}\itemsep=0pt
\item wxPLATFORM\_UNIX
\item wxPLATFORM\_WINDOWS
\item wxPLATFORM\_OS2
\item wxPLATFORM\_MAC
\item wxPLATFORM\_CURRENT
\end{itemize}

wxPLATFORM\_CURRENT means the platform this binary was compiled for.

Examples:

\begin{verbatim}
current platform   enc          returned value
----------------------------------------------
unix            CP1250             {ISO8859_2}
unix         ISO8859_2             {ISO8859_2}
windows      ISO8859_2                {CP1250}
unix            CP1252  {ISO8859_1,ISO8859_15}
\end{verbatim}

Equivalence is defined in terms of convertibility:
two encodings are equivalent if you can convert text between
then without losing information (it may - and will - happen
that you lose special chars like quotation marks or em-dashes
but you shouldn't lose any diacritics and language-specific
characters when converting between equivalent encodings).

Remember that this function does {\bf NOT} check for presence of
fonts in system. It only tells you what are most suitable
encodings. (It usually returns only one encoding.)

\wxheading{Notes}

\begin{itemize}\itemsep=0pt
\item Note that argument {\it enc} itself may be present in the returned array,
so that you can, as a side-effect, detect whether the
encoding is native for this platform or not.
\item \helpref{Convert}{wxencodingconverterconvert} is not limited to 
converting between equivalent encodings, it can convert between two arbitrary
encodings.
\item If {\it enc} is present in the returned array, then it is {\bf always} the first
item of it.
\item Please note that the returned array may contain no items at all.
\end{itemize}


\membersection{wxEncodingConverter::GetAllEquivalents}\label{wxencodingconvertergetallequivalents}

\func{static wxFontEncodingArray}{GetAllEquivalents}{\param{wxFontEncoding }{enc}}

Similar to 
\helpref{GetPlatformEquivalents}{wxencodingconvertergetplatformequivalents}, 
but this one will return ALL 
equivalent encodings, regardless of the platform, and including itself.

This platform's encodings are before others in the array. And again, if {\it enc} is in the array,
it is the very first item in it.