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More doxygen topic overview cleanup.

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git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@52211 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775
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Bryan Petty
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docs/doxygen/mainpages/topics.h
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@@ -38,7 +38,7 @@ The following is a basic categorization of them:
@li @subpage overview_refcount
@li @subpage overview_app
@li @subpage overview_unicode
@li @subpage overview_mbconvclasses
@li @subpage overview_mbconv
@li @subpage overview_i18n
@li @subpage overview_nonenglish
@li @subpage overview_debugging

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docs/doxygen/overviews/log.h
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@@ -1,5 +1,5 @@
/////////////////////////////////////////////////////////////////////////////
// Name: log
// Name: log.h
// Purpose: topic overview
// Author: wxWidgets team
// RCS-ID: $Id$
@@ -8,183 +8,167 @@
/*!
@page log_overview wxLog classes overview
@page overview_log wxLog Classes Overview
Classes: #wxLog,
Classes:
@li wxLog
@li wxLogStderr
@li wxLogStream
@li wxLogTextCtrl
@li wxLogWindow
@li wxLogGui
@li wxLogNull
@li wxLogBuffer
@li wxLogChain
@li wxLogInterposer
@li wxLogInterposerTemp
@li wxStreamToTextRedirector
#wxLogStderr,
This is a general overview of logging classes provided by wxWidgets. The word
logging here has a broad sense, including all of the program output, not only
non-interactive messages. The logging facilities included in wxWidgets provide
the base wxLog class which defines the standard interface for a @e log target
as well as several standard implementations of it and a family of functions to
use with them.
#wxLogStream,
First of all, no knowledge of wxLog classes is needed to use them. For this,
you should only know about @e wxLogXXX() functions. All of them have the same
syntax as @e printf() or @e vprintf() , i.e. they take the format string as the
first argument and respectively a variable number of arguments or a variable
argument list pointer. Here are all of them:
#wxLogTextCtrl,
@li wxLogFatalError which is like wxLogError, but also terminates the program
with the exit code 3 (using @e abort() standard function). Unlike for all
the other logging functions, this function can't be overridden by a log
target.
@li wxLogError is the function to use for error messages, i.e. the messages
that must be shown to the user. The default processing is to pop up a
message box to inform the user about it.
@li wxLogWarning for warnings. They are also normally shown to the user, but
don't interrupt the program work.
@li wxLogMessage is for all normal, informational messages. They also appear in
a message box by default (but it can be changed, see below).
@li wxLogVerbose is for verbose output. Normally, it is suppressed, but might
be activated if the user wishes to know more details about the program
progress (another, but possibly confusing name for the same function is
wxLogInfo).
@li wxLogStatus is for status messages. They will go into the status bar of the
active or specified (as the first argument) wxFrame if it has one.
@li wxLogSysError is mostly used by wxWidgets itself, but might be handy for
logging errors after system call (API function) failure. It logs the
specified message text as well as the last system error code (@e errno or
::GetLastError() depending on the platform) and the corresponding error
message. The second form of this function takes the error code explicitly
as the first argument.
@li wxLogDebug is @b the right function for debug output. It only does anything
at all in the debug mode (when the preprocessor symbol __WXDEBUG__ is
defined) and expands to nothing in release mode (otherwise). @b Tip: under
Windows, you must either run the program under debugger or use a 3rd party
program such as DebugView to actually see the debug output.
- DebugView: http://www.microsoft.com/technet/sysinternals/Miscellaneous/DebugView.mspx
@li wxLogTrace as wxLogDebug only does something in debug build. The reason for
making it a separate function from it is that usually there are a lot of
trace messages, so it might make sense to separate them from other debug
messages which would be flooded in them. Moreover, the second version of
this function takes a trace mask as the first argument which allows to
further restrict the amount of messages generated.
#wxLogWindow,
The usage of these functions should be fairly straightforward, however it may
be asked why not use the other logging facilities, such as C standard stdio
functions or C++ streams. The short answer is that they're all very good
generic mechanisms, but are not really adapted for wxWidgets, while the log
classes are. Some of advantages in using wxWidgets log functions are:
#wxLogGui,
@li @b Portability: It is a common practice to use @e printf() statements or
cout/cerr C++ streams for writing out some (debug or otherwise)
information. Although it works just fine under Unix, these messages go
strictly nowhere under Windows where the stdout of GUI programs is not
assigned to anything. Thus, you might view wxLogMessage() as a simple
substitute for @e printf().
You can also redirect the @e wxLogXXX calls to @e cout by just writing:
@code
wxLog* logger = new wxLogStream(&cout);
wxLog::SetActiveTarget(logger);
@endcode
Finally, there is also a possibility to redirect the output sent to @e cout
to a wxTextCtrl by using the wxStreamToTextRedirector class.
@li @b Flexibility: The output of wxLog functions can be redirected or
suppressed entirely based on their importance, which is either impossible
or difficult to do with traditional methods. For example, only error
messages, or only error messages and warnings might be logged, filtering
out all informational messages.
@li @b Completeness: Usually, an error message should be presented to the user
when some operation fails. Let's take a quite simple but common case of a
file error: suppose that you're writing your data file on disk and there is
not enough space. The actual error might have been detected inside
wxWidgets code (say, in wxFile::Write), so the calling function doesn't
really know the exact reason of the failure, it only knows that the data
file couldn't be written to the disk. However, as wxWidgets uses
wxLogError() in this situation, the exact error code (and the corresponding
error message) will be given to the user together with "high level" message
about data file writing error.
#wxLogNull,
After having enumerated all the functions which are normally used to log the
messages, and why would you want to use them we now describe how all this
works.
#wxLogBuffer,
wxWidgets has the notion of a <em>log target</em>: it is just a class deriving
from wxLog. As such, it implements the virtual functions of the base class
which are called when a message is logged. Only one log target is @e active at
any moment, this is the one used by @e wxLogXXX() functions. The normal usage
of a log object (i.e. object of a class derived from wxLog) is to install it as
the active target with a call to @e SetActiveTarget() and it will be used
automatically by all subsequent calls to @e wxLogXXX() functions.
#wxLogChain,
To create a new log target class you only need to derive it from wxLog and
implement one (or both) of @e DoLog() and @e DoLogString() in it. The second
one is enough if you're happy with the standard wxLog message formatting
(prepending "Error:" or "Warning:", timestamping @&c) but just want to send
the messages somewhere else. The first one may be overridden to do whatever
you want but you have to distinguish between the different message types
yourself.
#wxLogInterposer,
There are some predefined classes deriving from wxLog and which might be
helpful to see how you can create a new log target class and, of course, may
also be used without any change. There are:
#wxLogInterposerTemp,
@li wxLogStderr: This class logs messages to a <tt>FILE *</tt>, using stderr by
default as its name suggests.
@li wxLogStream: This class has the same functionality as wxLogStderr, but uses
@e ostream and cerr instead of <tt>FILE *</tt> and stderr.
@li wxLogGui: This is the standard log target for wxWidgets applications (it is
used by default if you don't do anything) and provides the most reasonable
handling of all types of messages for given platform.
@li wxLogWindow: This log target provides a "log console" which collects all
messages generated by the application and also passes them to the previous
active log target. The log window frame has a menu allowing user to clear
the log, close it completely or save all messages to file.
@li wxLogBuffer: This target collects all the logged messages in an internal
buffer allowing to show them later to the user all at once.
@li wxLogNull: The last log class is quite particular: it doesn't do anything.
The objects of this class may be instantiated to (temporarily) suppress
output of @e wxLogXXX() functions. As an example, trying to open a
non-existing file will usually provoke an error message, but if for some
reasons it is unwanted, just use this construction:
@code
wxFile file;
#wxStreamToTextRedirector
This is a general overview of logging classes provided by wxWidgets. The word
logging here has a broad sense, including all of the program output, not only
non-interactive messages. The logging facilities included in wxWidgets provide
the base @e wxLog class which defines the standard interface for a @e log
target as well as several standard implementations of it and a family of
functions to use with them.
First of all, no knowledge of @e wxLog classes is needed to use them. For
this, you should only know about @e wxLogXXX() functions. All of them have
the same syntax as @e printf() or @e vprintf() , i.e. they take the
format string as the first argument and respectively a variable number of
arguments or a variable argument list pointer. Here are all of them:
// wxFile.Open() normally complains if file can't be opened, we don't want it
{
wxLogNull logNo;
if ( !file.Open("bar") )
{
// ... process error ourselves ...
}
} // ~wxLogNull called, old log sink restored
wxLogMessage("..."); // ok
@endcode
@b wxLogFatalError which is like @e wxLogError, but also
terminates the program with the exit code 3 (using @e abort() standard
function). Unlike for all the other logging functions, this function can't be
overridden by a log target.
@b wxLogError is the function to use for error messages, i.e. the
messages that must be shown to the user. The default processing is to pop up a
message box to inform the user about it.
@b wxLogWarning for warnings - they are also normally shown to the
user, but don't interrupt the program work.
@b wxLogMessage is for all normal, informational messages. They also
appear in a message box by default (but it can be changed, see below).
@b wxLogVerbose is for verbose output. Normally, it is suppressed, but
might be activated if the user wishes to know more details about the program
progress (another, but possibly confusing name for the same function is @b wxLogInfo).
@b wxLogStatus is for status messages - they will go into the status
bar of the active or specified (as the first argument) #wxFrame if it has one.
@b wxLogSysError is mostly used by wxWidgets itself, but might be
handy for logging errors after system call (API function) failure. It logs the
specified message text as well as the last system error
code (@e errno or @e ::GetLastError() depending on the platform) and
the corresponding error message. The second form of this function takes the
error code explicitly as the first argument.
@b wxLogDebug is @b the right function for debug output. It only
does anything at all in the debug mode (when the preprocessor symbol
__WXDEBUG__ is defined) and expands to nothing in release mode (otherwise).
@b Tip: under Windows, you must either run the program under debugger or
use a 3rd party program such as #DbgView
to actually see the debug output.
@b wxLogTrace as @b wxLogDebug only does something in debug
build. The reason for making it a separate function from it is that usually
there are a lot of trace messages, so it might make sense to separate them
from other debug messages which would be flooded in them. Moreover, the second
version of this function takes a trace mask as the first argument which allows
to further restrict the amount of messages generated.
The usage of these functions should be fairly straightforward, however it may
be asked why not use the other logging facilities, such as C standard stdio
functions or C++ streams. The short answer is that they're all very good
generic mechanisms, but are not really adapted for wxWidgets, while the log
classes are. Some of advantages in using wxWidgets log functions are:
@b Portability It is a common practice to use @e printf()
statements or cout/cerr C++ streams for writing out some (debug or otherwise)
information.
Although it works just fine under Unix, these messages go strictly nowhere
under Windows where the stdout of GUI programs is not assigned to anything.
Thus, you might view @e wxLogMessage() as a simple substitute for @e printf().
You can also redirect the @e wxLogXXX calls to @e cout by just writing:
@code
wxLog *logger=new wxLogStream();
wxLog::SetActiveTarget(logger);
@endcode
Finally, there is also a possibility to redirect the output sent to @e cout
to a #wxTextCtrl by using the
#wxStreamToTextRedirector class.
@b Flexibility The output of wxLog functions can be redirected or
suppressed entirely based on their importance, which is either impossible or
difficult to do with traditional methods. For example, only error messages, or
only error messages and warnings might be logged, filtering out all
informational messages.
@b Completeness Usually, an error message should be presented to the user
when some operation fails. Let's take a quite simple but common case of a file
error: suppose that you're writing your data file on disk and there is not
enough space. The actual error might have been detected inside wxWidgets code
(say, in @e wxFile::Write), so the calling function doesn't really know the
exact reason of the failure, it only knows that the data file couldn't be
written to the disk. However, as wxWidgets uses @e wxLogError() in this
situation, the exact error code (and the corresponding error message) will be
given to the user together with "high level" message about data file writing
error.
After having enumerated all the functions which are normally used to log the
messages, and why would you want to use them we now describe how all this
works.
wxWidgets has the notion of a @e log target: it is just a class deriving
from #wxLog. As such, it implements the virtual functions of
the base class which are called when a message is logged. Only one log target
is @e active at any moment, this is the one used by @e wxLogXXX()
functions. The normal usage of a log object (i.e. object of a class derived
from wxLog) is to install it as the active target with a call to @e SetActiveTarget() and it will be used automatically by all subsequent calls
to @e wxLogXXX() functions.
To create a new log target class you only need to derive it from wxLog and
implement one (or both) of @e DoLog() and @e DoLogString() in it. The
second one is enough if you're happy with the standard wxLog message
formatting (prepending "Error:" or "Warning:", timestamping c) but just want
to send the messages somewhere else. The first one may be overridden to do
whatever you want but you have to distinguish between the different message
types yourself.
There are some predefined classes deriving from wxLog and which might be
helpful to see how you can create a new log target class and, of course, may
also be used without any change. There are:
@b wxLogStderr This class logs messages to a @e FILE *, using
stderr by default as its name suggests.
@b wxLogStream This class has the same functionality as wxLogStderr,
but uses @e ostream and cerr instead of @e FILE * and stderr.
@b wxLogGui This is the standard log target for wxWidgets
applications (it is used by default if you don't do anything) and provides the
most reasonable handling of all types of messages for given platform.
@b wxLogWindow This log target provides a "log console" which
collects all messages generated by the application and also passes them to the
previous active log target. The log window frame has a menu allowing user to
clear the log, close it completely or save all messages to file.
@b wxLogBuffer This target collects all the logged messages in an
internal buffer allowing to show them later to the user all at once.
@b wxLogNull The last log class is quite particular: it doesn't do
anything. The objects of this class may be instantiated to (temporarily)
suppress output of @e wxLogXXX() functions. As an example, trying to open a
non-existing file will usually provoke an error message, but if for some
reasons it is unwanted, just use this construction:
@code
wxFile file;
// wxFile.Open() normally complains if file can't be opened, we don't want it
{
wxLogNull logNo;
if ( !file.Open("bar") )
... process error ourselves ...
} // ~wxLogNull called, old log sink restored
wxLogMessage("..."); // ok
@endcode
The log targets can also be combined: for example you may wish to redirect the
messages somewhere else (for example, to a log file) but also process them as
normally. For this the #wxLogChain, #wxLogInterposer and
#wxLogInterposerTemp can be used.
*/
The log targets can also be combined: for example you may wish to redirect the
messages somewhere else (for example, to a log file) but also process them as
normally. For this the wxLogChain, wxLogInterposer, and wxLogInterposerTemp can
be used.
*/

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@@ -1,5 +1,5 @@
/////////////////////////////////////////////////////////////////////////////
// Name: mbconvclasses
// Name: mbconvclasses.h
// Purpose: topic overview
// Author: wxWidgets team
// RCS-ID: $Id$
@@ -8,171 +8,184 @@
/*!
@page mbconvclasses_overview wxMBConv classes overview
@page overview_mbconv wxMBConv Classes Overview
Classes: #wxMBConv, wxMBConvLibc,
#wxMBConvUTF7, #wxMBConvUTF8,
#wxCSConv,
#wxMBConvUTF16, #wxMBConvUTF32
The wxMBConv classes in wxWidgets enable an Unicode-aware application to
easily convert between Unicode and the variety of 8-bit encoding systems still
in use.
@ref needforconversion_overview
@ref conversionandwxstring_overview
@ref mbconvclasses_overview
@ref mbconvobjects_overview
#wxCSConv
@ref convertingstrings_overview
@ref convertingbuffers_overview
Classes: wxMBConv, wxMBConvLibc, wxMBConvUTF7, wxMBConvUTF8, wxCSConv,
wxMBConvUTF16, wxMBConvUTF32
The wxMBConv classes in wxWidgets enable an Unicode-aware application to easily
convert between Unicode and the variety of 8-bit encoding systems still in use.
@li @ref overview_mbconv_need
@li @ref overview_mbconv_string
@li @ref overview_mbconv_classes
@li @ref overview_mbconv_objects
@li @ref overview_mbconv_csconv
@li @ref overview_mbconv_converting
@li @ref overview_mbconv_buffers
@section needforconversion Background: The need for conversion
As programs are becoming more and more globalized, and users exchange documents
across country boundaries as never before, applications increasingly need to
take into account all the different character sets in use around the world. It
is no longer enough to just depend on the default byte-sized character set that
computers have traditionally used.
A few years ago, a solution was proposed: the Unicode standard. Able to contain
the complete set of characters in use in one unified global coding system,
it would resolve the character set problems once and for all.
But it hasn't happened yet, and the migration towards Unicode has created new
challenges, resulting in "compatibility encodings" such as UTF-8. A large
number of systems out there still depends on the old 8-bit encodings, hampered
by the huge amounts of legacy code still widely deployed. Even sending
Unicode data from one Unicode-aware system to another may need encoding to an
8-bit multibyte encoding (UTF-7 or UTF-8 is typically used for this purpose), to
pass unhindered through any traditional transport channels.
@section conversionandwxstring Background: The wxString class
If you have compiled wxWidgets in Unicode mode, the wxChar type will become
identical to wchar_t rather than char, and a wxString stores wxChars. Hence,
all wxString manipulation in your application will then operate on Unicode
strings, and almost as easily as working with ordinary char strings (you
just need to remember to use the wxT() macro to encapsulate any string
literals).
But often, your environment doesn't want Unicode strings. You could be sending
data over a network, or processing a text file for some other application. You
need a way to quickly convert your easily-handled Unicode data to and from a
traditional 8-bit encoding. And this is what the wxMBConv classes do.
@section wxmbconvclasses wxMBConv classes
The base class for all these conversions is the wxMBConv class (which itself
implements standard libc locale conversion). Derived classes include
wxMBConvLibc, several different wxMBConvUTFxxx classes, and wxCSConv, which
implement different kinds of conversions. You can also derive your own class
for your own custom encoding and use it, should you need it. All you need to do
is override the MB2WC and WC2MB methods.
@section wxmbconvobjects wxMBConv objects
Several of the wxWidgets-provided wxMBConv classes have predefined instances
(wxConvLibc, wxConvFileName, wxConvUTF7, wxConvUTF8, wxConvLocal). You can use
these predefined objects directly, or you can instantiate your own objects.
A variable, wxConvCurrent, points to the conversion object that the user
interface is supposed to use, in the case that the user interface is not
Unicode-based (like with GTK+ 1.2). By default, it points to wxConvLibc or
wxConvLocal, depending on which works best on the current platform.
@section wxcsconvclass wxCSConv
The wxCSConv class is special because when it is instantiated, you can tell it
which character set it should use, which makes it meaningful to keep many
instances of them around, each with a different character set (or you can
create a wxCSConv instance on the fly).
The predefined wxCSConv instance, wxConvLocal, is preset to use the
default user character set, but you should rarely need to use it directly,
it is better to go through wxConvCurrent.
@section convertingstrings Converting strings
Once you have chosen which object you want to use to convert your text,
here is how you would use them with wxString. These examples all assume
that you are using a Unicode build of wxWidgets, although they will still
compile in a non-Unicode build (they just won't convert anything).
Example 1: Constructing a wxString from input in current encoding.
@code
wxString str(input_data, *wxConvCurrent);
@endcode
Example 2: Input in UTF-8 encoding.
@code
wxString str(input_data, wxConvUTF8);
@endcode
Example 3: Input in KOI8-R. Construction of wxCSConv instance on the fly.
@code
wxString str(input_data, wxCSConv(wxT("koi8-r")));
@endcode
Example 4: Printing a wxString to stdout in UTF-8 encoding.
@code
puts(str.mb_str(wxConvUTF8));
@endcode
Example 5: Printing a wxString to stdout in custom encoding.
Using preconstructed wxCSConv instance.
@code
wxCSConv cust(user_encoding);
printf("Data: %s\n", (const char*) str.mb_str(cust));
@endcode
Note: Since mb_str() returns a temporary wxCharBuffer to hold the result
of the conversion, you need to explicitly cast it to const char* if you use
it in a vararg context (like with printf).
@section convertingbuffers Converting buffers
If you have specialized needs, or just don't want to use wxString, you
can also use the conversion methods of the conversion objects directly.
This can even be useful if you need to do conversion in a non-Unicode
build of wxWidgets; converting a string from UTF-8 to the current
encoding should be possible by doing this:
@code
wxString str(wxConvUTF8.cMB2WC(input_data), *wxConvCurrent);
@endcode
Here, cMB2WC of the UTF8 object returns a wxWCharBuffer containing a Unicode
string. The wxString constructor then converts it back to an 8-bit character
set using the passed conversion object, *wxConvCurrent. (In a Unicode build
of wxWidgets, the constructor ignores the passed conversion object and
retains the Unicode data.)
This could also be done by first making a wxString of the original data:
@code
wxString input_str(input_data);
wxString str(input_str.wc_str(wxConvUTF8), *wxConvCurrent);
@endcode
To print a wxChar buffer to a non-Unicode stdout:
@code
printf("Data: %s\n", (const char*) wxConvCurrent-cWX2MB(unicode_data));
@endcode
If you need to do more complex processing on the converted data, you
may want to store the temporary buffer in a local variable:
@code
const wxWX2MBbuf tmp_buf = wxConvCurrent-cWX2MB(unicode_data);
const char *tmp_str = (const char*) tmp_buf;
printf("Data: %s\n", tmp_str);
process_data(tmp_str);
@endcode
If a conversion had taken place in cWX2MB (i.e. in a Unicode build),
the buffer will be deallocated as soon as tmp_buf goes out of scope.
(The macro wxWX2MBbuf reflects the correct return value of cWX2MB
(either char* or wxCharBuffer), except for the const.)
*/
<hr>
@section overview_mbconv_need Background: The Need for Conversion
As programs are becoming more and more globalized, and users exchange documents
across country boundaries as never before, applications increasingly need to
take into account all the different character sets in use around the world. It
is no longer enough to just depend on the default byte-sized character set that
computers have traditionally used.
A few years ago, a solution was proposed: the Unicode standard. Able to contain
the complete set of characters in use in one unified global coding system, it
would resolve the character set problems once and for all.
But it hasn't happened yet, and the migration towards Unicode has created new
challenges, resulting in "compatibility encodings" such as UTF-8. A large
number of systems out there still depends on the old 8-bit encodings, hampered
by the huge amounts of legacy code still widely deployed. Even sending Unicode
data from one Unicode-aware system to another may need encoding to an 8-bit
multibyte encoding (UTF-7 or UTF-8 is typically used for this purpose), to pass
unhindered through any traditional transport channels.
@section overview_mbconv_string Background: The wxString Class
If you have compiled wxWidgets in Unicode mode, the wxChar type will become
identical to wchar_t rather than char, and a wxString stores wxChars. Hence,
all wxString manipulation in your application will then operate on Unicode
strings, and almost as easily as working with ordinary char strings (you just
need to remember to use the wxT() macro to encapsulate any string literals).
But often, your environment doesn't want Unicode strings. You could be sending
data over a network, or processing a text file for some other application. You
need a way to quickly convert your easily-handled Unicode data to and from a
traditional 8-bit encoding. And this is what the wxMBConv classes do.
@section overview_mbconv_classes wxMBConv Classes
The base class for all these conversions is the wxMBConv class (which itself
implements standard libc locale conversion). Derived classes include
wxMBConvLibc, several different wxMBConvUTFxxx classes, and wxCSConv, which
implement different kinds of conversions. You can also derive your own class
for your own custom encoding and use it, should you need it. All you need to do
is override the MB2WC and WC2MB methods.
@section overview_mbconv_objects wxMBConv Objects
Several of the wxWidgets-provided wxMBConv classes have predefined instances
(wxConvLibc, wxConvFileName, wxConvUTF7, wxConvUTF8, wxConvLocal). You can use
these predefined objects directly, or you can instantiate your own objects.
A variable, wxConvCurrent, points to the conversion object that the user
interface is supposed to use, in the case that the user interface is not
Unicode-based (like with GTK+ 1.2). By default, it points to wxConvLibc or
wxConvLocal, depending on which works best on the current platform.
@section overview_mbconv_csconv wxCSConv
The wxCSConv class is special because when it is instantiated, you can tell it
which character set it should use, which makes it meaningful to keep many
instances of them around, each with a different character set (or you can
create a wxCSConv instance on the fly).
The predefined wxCSConv instance, wxConvLocal, is preset to use the default
user character set, but you should rarely need to use it directly, it is better
to go through wxConvCurrent.
@section overview_mbconv_converting Converting Strings
Once you have chosen which object you want to use to convert your text, here is
how you would use them with wxString. These examples all assume that you are
using a Unicode build of wxWidgets, although they will still compile in a
non-Unicode build (they just won't convert anything).
Example 1: Constructing a wxString from input in current encoding.
@code
wxString str(input_data, *wxConvCurrent);
@endcode
Example 2: Input in UTF-8 encoding.
@code
wxString str(input_data, wxConvUTF8);
@endcode
Example 3: Input in KOI8-R. Construction of wxCSConv instance on the fly.
@code
wxString str(input_data, wxCSConv(wxT("koi8-r")));
@endcode
Example 4: Printing a wxString to stdout in UTF-8 encoding.
@code
puts(str.mb_str(wxConvUTF8));
@endcode
Example 5: Printing a wxString to stdout in custom encoding. Using
preconstructed wxCSConv instance.
@code
wxCSConv cust(user_encoding);
printf("Data: %s\n", (const char*) str.mb_str(cust));
@endcode
@note Since mb_str() returns a temporary wxCharBuffer to hold the result of the
conversion, you need to explicitly cast it to const char* if you use it in a
vararg context (like with printf).
@section overview_mbconv_buffers Converting Buffers
If you have specialized needs, or just don't want to use wxString, you can also
use the conversion methods of the conversion objects directly. This can even be
useful if you need to do conversion in a non-Unicode build of wxWidgets;
converting a string from UTF-8 to the current encoding should be possible by
doing this:
@code
wxString str(wxConvUTF8.cMB2WC(input_data), *wxConvCurrent);
@endcode
Here, cMB2WC of the UTF8 object returns a wxWCharBuffer containing a Unicode
string. The wxString constructor then converts it back to an 8-bit character
set using the passed conversion object, *wxConvCurrent. (In a Unicode build of
wxWidgets, the constructor ignores the passed conversion object and retains the
Unicode data.)
This could also be done by first making a wxString of the original data:
@code
wxString input_str(input_data);
wxString str(input_str.wc_str(wxConvUTF8), *wxConvCurrent);
@endcode
To print a wxChar buffer to a non-Unicode stdout:
@code
printf("Data: %s\n", (const char*) wxConvCurrent->cWX2MB(unicode_data));
@endcode
If you need to do more complex processing on the converted data, you may want
to store the temporary buffer in a local variable:
@code
const wxWX2MBbuf tmp_buf = wxConvCurrent->cWX2MB(unicode_data);
const char *tmp_str = (const char*) tmp_buf;
printf("Data: %s\n", tmp_str);
process_data(tmp_str);
@endcode
If a conversion had taken place in cWX2MB (i.e. in a Unicode build), the buffer
will be deallocated as soon as tmp_buf goes out of scope. The macro wxWX2MBbuf
reflects the correct return value of cWX2MB (either char* or wxCharBuffer),
except for the const.
*/

273
docs/doxygen/overviews/nonenglish.h
View File

@@ -1,5 +1,5 @@
/////////////////////////////////////////////////////////////////////////////
// Name: nonenglish
// Name: nonenglish.h
// Purpose: topic overview
// Author: wxWidgets team
// RCS-ID: $Id$
@@ -8,156 +8,161 @@
/*!
@page nonenglish_overview Writing non-English applications
@page overview_nonenglish Writing Non-English Applications
This article describes how to write applications that communicate with
the user in a language other than English. Unfortunately many languages use
different charsets under Unix and Windows (and other platforms, to make
the situation even more complicated). These charsets usually differ in so
many characters that it is impossible to use the same texts under all
platforms.
The wxWidgets library provides a mechanism that helps you avoid distributing many
identical, only differently encoded, packages with your application
(e.g. help files and menu items in iso8859-13 and windows-1257). Thanks
to this mechanism you can, for example, distribute only iso8859-13 data
and it will be handled transparently under all systems.
Please read #Internationalization which
describes the locales concept.
In the following text, wherever @e iso8859-2 and @e windows-1250 are
used, any encodings are meant and any encodings may be substituted there.
@b Locales
The best way to ensure correctly displayed texts in a GUI across platforms
is to use locales. Write your in-code messages in English or without
diacritics and put real messages into the message catalog (see
#Internationalization).
A standard .po file begins with a header like this:
This article describes how to write applications that communicate with the user
in a language other than English. Unfortunately many languages use different
charsets under Unix and Windows (and other platforms, to make the situation
even more complicated). These charsets usually differ in so many characters
that it is impossible to use the same texts under all platforms.
@code
# SOME DESCRIPTIVE TITLE.
# Copyright (C) YEAR Free Software Foundation, Inc.
# FIRST AUTHOR EMAIL@ADDRESS, YEAR.
#
msgid ""
msgstr ""
"Project-Id-Version: PACKAGE VERSION\n"
"POT-Creation-Date: 1999-02-19 16:03+0100\n"
"PO-Revision-Date: YEAR-MO-DA HO:MI+ZONE\n"
"Last-Translator: FULL NAME EMAIL@ADDRESS\n"
"Language-Team: LANGUAGE LL@li.org\n"
"MIME-Version: 1.0\n"
"Content-Type: text/plain; charset=CHARSET\n"
"Content-Transfer-Encoding: ENCODING\n"
@endcode
The wxWidgets library provides a mechanism that helps you avoid distributing
many identical, only differently encoded, packages with your application (e.g.
help files and menu items in iso8859-13 and windows-1257). Thanks to this
mechanism you can, for example, distribute only iso8859-13 data and it will be
handled transparently under all systems.
Note this particular line:
Please read the @ref overview_i18n which describes the locales concept.
@code
"Content-Type: text/plain; charset=CHARSET\n"
@endcode
It specifies the charset used by the catalog. All strings in the catalog
are encoded using this charset.
You have to fill in proper charset information. Your .po file may look like this
after doing so:
@code
# SOME DESCRIPTIVE TITLE.
# Copyright (C) YEAR Free Software Foundation, Inc.
# FIRST AUTHOR EMAIL@ADDRESS, YEAR.
#
msgid ""
msgstr ""
"Project-Id-Version: PACKAGE VERSION\n"
"POT-Creation-Date: 1999-02-19 16:03+0100\n"
"PO-Revision-Date: YEAR-MO-DA HO:MI+ZONE\n"
"Last-Translator: FULL NAME EMAIL@ADDRESS\n"
"Language-Team: LANGUAGE LL@li.org\n"
"MIME-Version: 1.0\n"
"Content-Type: text/plain; charset=iso8859-2\n"
"Content-Transfer-Encoding: 8bit\n"
@endcode
(Make sure that the header is @b not marked as @e fuzzy.)
wxWidgets is able to use this catalog under any supported platform
(although iso8859-2 is a Unix encoding and is normally not understood by
Windows).
How is this done? When you tell the wxLocale class to load a message catalog that
contains a correct header, it checks the charset. The catalog is then converted
to the charset used (see
wxLocale::GetSystemEncoding and
wxLocale::GetSystemEncodingName) by
the user's operating system. This is the default behaviour of the
#wxLocale class; you can disable it by @b not passing
@c wxLOCALE_CONV_ENCODING to wxLocale::Init.
@b Non-English strings or 8-bit characters in the source code
By convention, you should only use characters without diacritics (i.e. 7-bit
ASCII strings) for msgids in the source code and write them in English.
If you port software to wxWindows, you may be confronted with legacy source
code containing non-English string literals. Instead of translating the strings
in the source code to English and putting the original strings into message
catalog, you may configure wxWidgets to use non-English msgids and translate to
English using message catalogs:
In the following text, wherever @e iso8859-2 and @e windows-1250 are used, any
encodings are meant and any encodings may be substituted there.
If you use the program @c xgettext to extract the strings from
the source code, specify the option @c --from-code=source code charset.
Specify the source code language and charset as arguments to
wxLocale::AddCatalog. For example:
@section overview_nonenglish_locales Locales
@code
locale.AddCatalog(_T("myapp"),
wxLANGUAGE_GERMAN, _T("iso-8859-1"));
@endcode
The best way to ensure correctly displayed texts in a GUI across platforms is
to use locales. Write your in-code messages in English or without diacritics
and put real messages into the message catalog (see @ref overview_i18n).
A standard .po file begins with a header like this:
@code
# SOME DESCRIPTIVE TITLE.
# Copyright (C) YEAR Free Software Foundation, Inc.
# FIRST AUTHOR <EMAIL@ADDRESS>, YEAR.
#
msgid ""
msgstr ""
"Project-Id-Version: PACKAGE VERSION\n"
"POT-Creation-Date: 1999-02-19 16:03+0100\n"
"PO-Revision-Date: YEAR-MO-DA HO:MI+ZONE\n"
"Last-Translator: FULL NAME <EMAIL@ADDRESS>\n"
"Language-Team: LANGUAGE <LL@li.org>\n"
"MIME-Version: 1.0\n"
"Content-Type: text/plain; charset=CHARSET\n"
"Content-Transfer-Encoding: ENCODING\n"
@endcode
Note this particular line:
@code
"Content-Type: text/plain; charset=CHARSET\n"
@endcode
It specifies the charset used by the catalog. All strings in the catalog are
encoded using this charset.
You have to fill in proper charset information. Your .po file may look like
this after doing so:
@code
# SOME DESCRIPTIVE TITLE.
# Copyright (C) YEAR Free Software Foundation, Inc.
# FIRST AUTHOR <EMAIL@ADDRESS>, YEAR.
#
msgid ""
msgstr ""
"Project-Id-Version: PACKAGE VERSION\n"
"POT-Creation-Date: 1999-02-19 16:03+0100\n"
"PO-Revision-Date: YEAR-MO-DA HO:MI+ZONE\n"
"Last-Translator: FULL NAME <EMAIL@ADDRESS>\n"
"Language-Team: LANGUAGE <LL@li.org>\n"
"MIME-Version: 1.0\n"
"Content-Type: text/plain; charset=iso8859-2\n"
"Content-Transfer-Encoding: 8bit\n"
@endcode
(Make sure that the header is @b not marked as @e fuzzy.)
wxWidgets is able to use this catalog under any supported platform
(although iso8859-2 is a Unix encoding and is normally not understood by
Windows).
How is this done? When you tell the wxLocale class to load a message catalog
that contains a correct header, it checks the charset. The catalog is then
converted to the charset used (see wxLocale::GetSystemEncoding and
wxLocale::GetSystemEncodingName) by the user's operating system. This is the
default behaviour of the wxLocale class; you can disable it by @b not passing
@c wxLOCALE_CONV_ENCODING to wxLocale::Init.
@section overview_nonenglish_strings Non-English Strings or 8-bit Characters in Source
By convention, you should only use characters without diacritics (i.e. 7-bit
ASCII strings) for msgids in the source code and write them in English.
If you port software to wxWindows, you may be confronted with legacy source
code containing non-English string literals. Instead of translating the strings
in the source code to English and putting the original strings into message
catalog, you may configure wxWidgets to use non-English msgids and translate to
English using message catalogs:
@li If you use the program @c xgettext to extract the strings from the source
code, specify the option <tt>--from-code=@<source code charset@></tt>.
@li Specify the source code language and charset as arguments to
wxLocale::AddCatalog. For example:
@code
locale.AddCatalog(_T("myapp"), wxLANGUAGE_GERMAN, _T("iso-8859-1"));
@endcode
@b Font mapping
You can use @ref mbconvclasses_overview and
#wxFontMapper to display text:
@section overview_nonenglish_fontmapping Font Mapping
@code
if (!wxFontMapper::Get()-IsEncodingAvailable(enc, facename))
{
You can use @ref overview_mbconv and wxFontMapper to display text:
@code
if (!wxFontMapper::Get()->IsEncodingAvailable(enc, facename))
{
wxFontEncoding alternative;
if (wxFontMapper::Get()-GetAltForEncoding(enc, ,
facename, @false))
if (wxFontMapper::Get()->GetAltForEncoding(enc, &alternative,
facename, false))
{
wxCSConv convFrom(wxFontMapper::Get()-GetEncodingName(enc));
wxCSConv convTo(wxFontMapper::Get()-GetEncodingName(alternative));
wxCSConv convFrom(wxFontMapper::Get()->GetEncodingName(enc));
wxCSConv convTo(wxFontMapper::Get()->GetEncodingName(alternative));
text = wxString(text.mb_str(convFrom), convTo);
}
else
...failure (or we may try iso8859-1/7bit ASCII)...
}
...display text...
@endcode
@b Converting data
You may want to store all program data (created documents etc.) in
the same encoding, let's say @c utf-8. You can use
#wxCSConv class to convert data to the encoding used by the
system your application is running on (see
wxLocale::GetSystemEncoding).
@b Help files
If you're using #wxHtmlHelpController there is
no problem at all. You only need to make sure that all the HTML files contain
the META tag, e.g.
@code
meta http-equiv="Content-Type" content="text/html; charset=iso8859-2"
@endcode
and that the hhp project file contains one additional line in the @c OPTIONS
section:
@code
Charset=iso8859-2
@endcode
This additional entry tells the HTML help controller what encoding is used
in contents and index tables.
*/
}
...display text...
@endcode
@section overview_nonenglish_converting Converting Data
You may want to store all program data (created documents etc.) in the same
encoding, let's say @c utf-8. You can use wxCSConv to convert data to the
encoding used by the system your application is running on (see
wxLocale::GetSystemEncoding).
@section overview_nonenglish_help Help Files
If you're using wxHtmlHelpController there is no problem at all. You only need
to make sure that all the HTML files contain the META tag:
@code
<meta http-equiv="Content-Type" content="text/html; charset=iso8859-2">
@endcode
Also, the hhp project file needs one additional line in the @c OPTIONS section:
@code
Charset=iso8859-2
@endcode
This additional entry tells the HTML help controller what encoding is used in
contents and index tables.
*/