IMContext

Object Hierarchy:

Description:

[ CCode ( type_id = "gtk_im_context_get_type ()" ) ]
public abstract class IMContext : Object

`GtkIMContext` defines the interface for GTK input methods.

`GtkIMContext` is used by GTK text input widgets like `GtkText` 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 `GtkIMContext` will emit [signal@Gtk.IMContext:GtkIMContext:preedit-start], [signal@Gtk.IMContext:GtkIMContext:preedit-changed] and [signal@Gtk.IMContext:GtkIMContext:preedit-end] signals.

For instance, the built-in GTK input method [class@Gtk.IMContextSimple] implements the input of arbitrary Unicode code points by holding down the <kbd>Control</kbd> and <kbd>Shift</kbd> keys and then typing <kbd>u</kbd> followed by the hexadecimal digits of the code point. When releasing the <kbd>Control</kbd> and <kbd>Shift</kbd> 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 [class@Gtk.IMMulticontext].

All known sub-classes:

IMContextSimple

IMMulticontext

Namespace: Gtk

Package: gtk4

Content:

Properties:

public InputHints input_hints { get; set; }
Additional hints that allow input methods to fine-tune their behaviour.
public InputPurpose input_purpose { get; set; }
The purpose of the text field that the `GtkIMContext is connected to.

Creation methods:

protected IMContext ()

Methods:

public virtual void activate_osk ()
public bool filter_key (bool press, Surface surface, Device device, uint32 time, uint keycode, ModifierType state, int group)
Allow an input method to forward key press and release events to another input method without necessarily having a `GdkEvent` available.
public virtual bool filter_keypress (Event event)
Allow an input method to internally handle key press and release events.
public virtual void focus_in ()
Notify the input method that the widget to which this input context corresponds has gained focus.
public virtual void focus_out ()
Notify the input method that the widget to which this input context corresponds has lost focus.
public virtual void get_preedit_string (out string str, out AttrList attrs, out int cursor_pos)
Retrieve the current preedit string for the input context, and a list of attributes to apply to the string.
public virtual bool get_surrounding (out string text, out int cursor_index)
Retrieves context around the insertion point.
public virtual bool get_surrounding_with_selection (out string text, out int cursor_index, out int anchor_index)
Retrieves context around the insertion point.
public virtual void reset ()
Notify the input method that a change such as a change in cursor position has been made.
public virtual void set_client_widget (Widget? widget)
Set the client widget for the input context.
public virtual void set_cursor_location (Rectangle area)
Notify the input method that a change in cursor position has been made.
public virtual void set_surrounding (string text, int len, int cursor_index)
Sets surrounding context around the insertion point and preedit string.
public virtual void set_surrounding_with_selection (string text, int len, int cursor_index, int anchor_index)
Sets surrounding context around the insertion point and preedit string.
public virtual void set_use_preedit (bool use_preedit)
Sets whether the IM context should use the preedit string to display feedback.

Signals:

public virtual signal void commit (string str)
The commit signal is emitted when a complete input sequence has been entered by the user.
public virtual signal bool delete_surrounding (int offset, int n_chars)
The delete_surrounding signal is emitted when the input method needs to delete all or part of the context surrounding the cursor.
public virtual signal void preedit_changed ()
The preedit_changed signal is emitted whenever the preedit sequence currently being entered has changed.
public virtual signal void preedit_end ()
The preedit_end signal is emitted when a preediting sequence has been completed or canceled.
public virtual signal void preedit_start ()
The preedit_start signal is emitted when a new preediting sequence starts.
public virtual signal bool retrieve_surrounding ()
The retrieve_surrounding signal is emitted when the input method requires the context surrounding the cursor.

Inherited Members:

All known members inherited from class GLib.Object