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Functions
void | gtk_im_context_set_client_window () |
void | gtk_im_context_get_preedit_string () |
gboolean | gtk_im_context_filter_keypress () |
void | gtk_im_context_focus_in () |
void | gtk_im_context_focus_out () |
void | gtk_im_context_reset () |
void | gtk_im_context_set_cursor_location () |
void | gtk_im_context_set_use_preedit () |
void | gtk_im_context_set_surrounding () |
gboolean | gtk_im_context_get_surrounding () |
gboolean | gtk_im_context_delete_surrounding () |
Signals
void | commit | Run Last |
gboolean | delete-surrounding | Run Last |
void | preedit-changed | Run Last |
void | preedit-end | Run Last |
void | preedit-start | Run Last |
gboolean | retrieve-surrounding | Run Last |
Description
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 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 Running GTK+ Applications.
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:
1 |
void im_module_init(GTypeModule *module); |
This function should register the GType of the GtkIMContext subclass which
implements the input method by means of g_type_module_register_type()
. Note
that g_type_register_static()
cannot be used as the type needs to be
registered dynamically.
1 |
void im_module_exit(void); |
Here goes any cleanup code your input method might require on module unload.
1 2 3 4 5 |
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 array of GtkIMContextInfo items for each provided input method.
1 |
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 array returned by im_module_list()
.
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-3.0,
in order for the new input method to become available to GTK+ applications.
Functions
gtk_im_context_set_client_window ()
void gtk_im_context_set_client_window (GtkIMContext *context
,GdkWindow *window
);
Set the client window for the input context; this is the GdkWindow in which the input appears. This window is used in order to correctly position status windows, and may also be used for purposes internal to the input method.
gtk_im_context_get_preedit_string ()
void gtk_im_context_get_preedit_string (GtkIMContext *context
,gchar **str
,PangoAttrList **attrs
,gint *cursor_pos
);
Retrieve the current preedit string for the input context, and a list of attributes to apply to the string. This string should be displayed inserted at the insertion point.
Parameters
context |
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str |
location to store the retrieved
string. The string retrieved must be freed with |
[out][transfer full] |
attrs |
location to store the retrieved
attribute list. When you are done with this list, you
must unreference it with |
[out][transfer full] |
cursor_pos |
location to store position of cursor (in characters) within the preedit string. |
[out] |
gtk_im_context_filter_keypress ()
gboolean gtk_im_context_filter_keypress (GtkIMContext *context
,GdkEventKey *event
);
Allow an input method to internally handle key press and release
events. If this function returns TRUE
, then no further processing
should be done for this key event.
gtk_im_context_focus_in ()
void
gtk_im_context_focus_in (GtkIMContext *context
);
Notify the input method that the widget to which this input context corresponds has gained focus. The input method may, for example, change the displayed feedback to reflect this change.
gtk_im_context_focus_out ()
void
gtk_im_context_focus_out (GtkIMContext *context
);
Notify the input method that the widget to which this input context corresponds has lost focus. The input method may, for example, change the displayed feedback or reset the contexts state to reflect this change.
gtk_im_context_reset ()
void
gtk_im_context_reset (GtkIMContext *context
);
Notify the input method that a change such as a change in cursor position has been made. This will typically cause the input method to clear the preedit state.
gtk_im_context_set_cursor_location ()
void gtk_im_context_set_cursor_location (GtkIMContext *context
,const GdkRectangle *area
);
Notify the input method that a change in cursor position has been made. The location is relative to the client window.
gtk_im_context_set_use_preedit ()
void gtk_im_context_set_use_preedit (GtkIMContext *context
,gboolean use_preedit
);
Sets whether the IM context should use the preedit string
to display feedback. If use_preedit
is FALSE (default
is TRUE), then the IM context may use some other method to display
feedback, such as displaying it in a child of the root window.
gtk_im_context_set_surrounding ()
void gtk_im_context_set_surrounding (GtkIMContext *context
,const gchar *text
,gint len
,gint cursor_index
);
Sets surrounding context around the insertion point and preedit string. This function is expected to be called in response to the GtkIMContext::retrieve_surrounding signal, and will likely have no effect if called at other times.
gtk_im_context_get_surrounding ()
gboolean gtk_im_context_get_surrounding (GtkIMContext *context
,gchar **text
,gint *cursor_index
);
Retrieves context around the insertion point. Input methods typically want context in order to constrain input text based on existing text; this is important for languages such as Thai where only some sequences of characters are allowed.
This function is implemented by emitting the
GtkIMContext::retrieve_surrounding signal on the input method; in
response to this signal, a widget should provide as much context as
is available, up to an entire paragraph, by calling
gtk_im_context_set_surrounding()
. Note that there is no obligation
for a widget to respond to the ::retrieve_surrounding signal, so input
methods must be prepared to function without context.
Parameters
context |
||
text |
location to store a UTF-8 encoded
string of text holding context around the insertion point.
If the function returns |
[out][transfer full] |
cursor_index |
location to store byte index of the insertion
cursor within |
[out] |
gtk_im_context_delete_surrounding ()
gboolean gtk_im_context_delete_surrounding (GtkIMContext *context
,gint offset
,gint n_chars
);
Asks the widget that the input context is attached to to delete
characters around the cursor position by emitting the
GtkIMContext::delete_surrounding signal. Note that offset
and n_chars
are in characters not in bytes which differs from the usage other
places in GtkIMContext.
In order to use this function, you should first call
gtk_im_context_get_surrounding()
to get the current context, and
call this function immediately afterwards to make sure that you
know what you are deleting. You should also account for the fact
that even if the signal was handled, the input context might not
have deleted all the characters that were requested to be deleted.
This function is used by an input method that wants to make subsitutions in the existing text in response to new input. It is not useful for applications.
Types and Values
struct GtkIMContextClass
struct GtkIMContextClass { /* Signals */ void (*preedit_start) (GtkIMContext *context); void (*preedit_end) (GtkIMContext *context); void (*preedit_changed) (GtkIMContext *context); void (*commit) (GtkIMContext *context, const gchar *str); gboolean (*retrieve_surrounding) (GtkIMContext *context); gboolean (*delete_surrounding) (GtkIMContext *context, gint offset, gint n_chars); /* Virtual functions */ void (*set_client_window) (GtkIMContext *context, GdkWindow *window); void (*get_preedit_string) (GtkIMContext *context, gchar **str, PangoAttrList **attrs, gint *cursor_pos); gboolean (*filter_keypress) (GtkIMContext *context, GdkEventKey *event); void (*focus_in) (GtkIMContext *context); void (*focus_out) (GtkIMContext *context); void (*reset) (GtkIMContext *context); void (*set_cursor_location) (GtkIMContext *context, GdkRectangle *area); void (*set_use_preedit) (GtkIMContext *context, gboolean use_preedit); void (*set_surrounding) (GtkIMContext *context, const gchar *text, gint len, gint cursor_index); gboolean (*get_surrounding) (GtkIMContext *context, gchar **text, gint *cursor_index); };
Members
Default handler of the “preedit-start” signal. |
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Default handler of the “preedit-end” signal. |
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Default handler of the “preedit-changed” signal. |
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Default handler of the “commit” signal. |
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Default handler of the “retrieve-surrounding” signal. |
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Default handler of the “delete-surrounding” signal. |
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Called via |
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struct GtkIMContextInfo
struct GtkIMContextInfo { const gchar *context_id; const gchar *context_name; const gchar *domain; const gchar *domain_dirname; const gchar *default_locales; };
Bookkeeping information about a loadable input method.
Members
The unique identification string of the input method. |
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The human-readable name of the input method. |
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Translation domain to be used with |
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Name of locale directory for use with |
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A colon-separated list of locales where this input method should be the default. The asterisk “*” sets the default for all locales. |
Property Details
The “input-hints”
property
“input-hints” GtkInputHints
Hints for the text field behaviour.
Owner: GtkIMContext
Flags: Read / Write
The “input-purpose”
property
“input-purpose” GtkInputPurpose
Purpose of the text field.
Owner: GtkIMContext
Flags: Read / Write
Default value: GTK_INPUT_PURPOSE_FREE_FORM
Signal Details
The “commit”
signal
void user_function (GtkIMContext *context, char *str, gpointer user_data)
The ::commit 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.
Parameters
context |
the object on which the signal is emitted |
|
str |
the completed character(s) entered by the user |
|
user_data |
user data set when the signal handler was connected. |
Flags: Run Last
The “delete-surrounding”
signal
gboolean user_function (GtkIMContext *context, int offset, int n_chars, gpointer user_data)
The ::delete-surrounding signal is emitted when the input method needs to delete all or part of the context surrounding the cursor.
Parameters
context |
the object on which the signal is emitted |
|
offset |
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 number of characters to be deleted |
|
user_data |
user data set when the signal handler was connected. |
Flags: Run Last
The “preedit-changed”
signal
void user_function (GtkIMContext *context, gpointer user_data)
The ::preedit-changed 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
gtk_im_context_get_preedit_string()
returns the empty string.
Parameters
context |
the object on which the signal is emitted |
|
user_data |
user data set when the signal handler was connected. |
Flags: Run Last
The “preedit-end”
signal
void user_function (GtkIMContext *context, gpointer user_data)
The ::preedit-end signal is emitted when a preediting sequence has been completed or canceled.
Parameters
context |
the object on which the signal is emitted |
|
user_data |
user data set when the signal handler was connected. |
Flags: Run Last
The “preedit-start”
signal
void user_function (GtkIMContext *context, gpointer user_data)
The ::preedit-start signal is emitted when a new preediting sequence starts.
Parameters
context |
the object on which the signal is emitted |
|
user_data |
user data set when the signal handler was connected. |
Flags: Run Last
The “retrieve-surrounding”
signal
gboolean user_function (GtkIMContext *context, gpointer user_data)
The ::retrieve-surrounding 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_set_surrounding()
method.
Parameters
context |
the object on which the signal is emitted |
|
user_data |
user data set when the signal handler was connected. |
Flags: Run Last