gobject:object, common-lisp:standard-object, common-lisp:t

gtk:im-context-simple, gtk:im-multicontext

The gtk:im-context class defines the interface for GTK input methods. An input method is used by GTK text input widgets like the gtk:entry widget to map from key events to Unicode character strings.

An input method may consume multiple key events in sequence before finally outputting 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. To do so, the gtk:im-context object will emit the "preedit-start", "preedit-changed" and "preedit-end" signals.

For instance, the built-in GTK gtk:im-context-simple 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. For example,

Ctrl+Shift+u 2 0 A C  

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 provides a GIOExtension for the extension point named gtk-im-module.

To connect a widget to the users preferred input method, you should use the gtk:im-multicontext class.

The "commit" signal

lambda (context str)    :run-last      

context

The gtk:im-context object on which the signal is emitted.

str

The string with the completed character(s) entered by the user.

The signal is emitted when a complete input sequence has been entered by the user. This can be a single character immediately after a key press or the final result of preediting.

The "delete-surrounding" signal

lambda (context offset n-chars)    :run-last      

context

The gtk:im-context object on which the signal is emitted.

offset

The integer with the character offset from the cursor position of the text to be deleted. A negative value indicates a position before the cursor.

n-chars

The integer with the number of characters to be deleted.

Returns

True if the signal was handled.

The signal is emitted when the input method needs to delete all or part of the context surrounding the cursor.

The "preedit-changed" signal

lambda (context)    :run-last      

context

The gtk:im-context object on which the signal is emitted.

The signal is emitted whenever the preedit sequence currently being entered has changed. It is also emitted at the end of a preedit sequence, in which case the gtk:im-context-preedit-string function returns the empty string.

The "preedit-end" signal

lambda (context)    :run-last      

context

The gtk:im-context object on which the signal is emitted.

The signal is emitted when a preediting sequence has been completed or canceled.

The "preedit-start" signal

lambda (context)    :run-last      

context

The gtk:im-context object on which the signal is emitted.

The signal is emitted when a new preediting sequence starts.

The "retrieve-surrounding" signal

lambda (context)    :run-last      

context

The gtk:im-context object on which the signal is emitted.

Returns

True if the signal was handled.

The signal is emitted when the input method requires the context surrounding the cursor. The callback should set the input method surrounding context by calling the gtk:im-context-surrounding function.