GtkIMContext defines the interface for GTK+ input methods. An input method
is used by GTK+ text input widgets like GtkEntry to map from key events to
Unicode character strings. The user may change the current input method via a context menu, unless the
"gtk-show-input-method-menu" GtkSettings property is set to FALSE.
The default input method can be set programmatically via the
"gtk-im-module" GtkSettings property. Alternatively, you may set
the GTK_IM_MODULE environment variable as documented in gtk-running. The GtkEntry "im-module" and GtkTextView "im-module"
properties may also be used to set input methods for specific widget
instances. For instance, a certain entry widget might be expected to contain
certain characters which would be easier to input with a certain input
method. An input method may consume multiple key events in sequence and finally
output the composed result. This is called preediting, and an input method
may provide feedback about this process by displaying the intermediate
composition states as preedit text. For instance, the default GTK+ input
method implements the input of arbitrary Unicode code points by holding down
the Control and Shift keys and then typing "U" followed by the hexadecimal
digits of the code point. When releasing the Control and Shift keys,
preediting ends and the character is inserted as text. Ctrl+Shift+u20AC for
example results in the € sign. Additional input methods can be made available for use by GTK+ widgets as
loadable modules. An input method module is a small shared library which
implements a subclass of GtkIMContext or GtkIMContextSimple and exports
these four functions:
void im_module_init( GTypeModule *module);
This function should register the GType of the GtkIMContext subclass which
implements the input method by means of gTypeModuleRegisterType(). Note
that gTypeRegisterStatic() cannot be used as the type needs to be
registered dynamically.
void im_module_exit(void);
Here goes any cleanup code your input method might require on module unload.
void im_module_list(const GtkIMContextInfo ***contexts, int *n_contexts)
{
*contexts = info_list;
*n_contexts = G_N_ELEMENTS (info_list);
}
This function returns the list of input methods provided by the module. The
example implementation above shows a common solution and simply returns a
pointer to statically defined list of GtkIMContextInfo items for each
provided input method.
GtkIMContext * im_module_create(const gchar *context_id);
This function should return a pointer to a newly created instance of the
GtkIMContext subclass identified by context.id. The context ID is the same
as specified in the GtkIMContextInfo list returned by imModuleList(). After a new loadable input method module has been installed on the system,
the configuration file ‘gtk.immodules’ needs to be
regenerated by gtk-query-immodules-2.0,
in order for the new input method to become available to GTK+ applications.