/* GTK - The GIMP Toolkit
* Copyright (C) 2000 Red Hat, Inc.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the
* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
* Boston, MA 02111-1307, USA.
*/
#include "config.h"
#include <string.h>
#include "gtkimcontext.h"
#include "gtkmain.h" /* For _gtk_boolean_handled_accumulator */
#include "gtkmarshalers.h"
#include "gtkintl.h"
#include "gtkalias.h"
/**
* SECTION:gtkimcontext
* @title: GtkIMContext
* @short_description: Base class for input method contexts
* @include: gtk/gtk.h,gtk/gtkimmodule.h
*
* #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
* #GtkSettings:gtk-show-input-method-menu GtkSettings property is set to FALSE.
* The default input method can be set programmatically via the
* #GtkSettings:gtk-im-module GtkSettings property. Alternatively, you may set
* the GTK_IM_MODULE environment variable as documented in #gtk-running.
*
* The #GtkEntry #GtkEntry:im-module and #GtkTextView #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:
*
* <informalexample><programlisting>
* void im_module_init(#GTypeModule *module);
* </programlisting></informalexample>
* 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.
*
* <informalexample><programlisting>
* void im_module_exit(void);
* </programlisting></informalexample>
* Here goes any cleanup code your input method might require on module unload.
*
* <informalexample><programlisting>
* void im_module_list(const #GtkIMContextInfo ***contexts, int *n_contexts)
* {
* *contexts = info_list;
* *n_contexts = G_N_ELEMENTS (info_list);
* }
* </programlisting></informalexample>
* 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.
*
* <informalexample><programlisting>
* #GtkIMContext * im_module_create(const #gchar *context_id);
* </programlisting></informalexample>
* 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 <filename>immodules.cache</filename> needs to be
* regenerated by <link linkend="gtk-query-immodules-2.0">gtk-query-immodules-2.0</link>,
* in order for the new input method to become available to GTK+ applications.
*/
enum {
PREEDIT_START,
PREEDIT_END,
PREEDIT_CHANGED,
COMMIT,
RETRIEVE_SURROUNDING,
DELETE_SURROUNDING,
LAST_SIGNAL
};
static guint im_context_signals[LAST_SIGNAL] = { 0 };
static void gtk_im_context_real_get_preedit_string (GtkIMContext *context,
gchar **str,
PangoAttrList **attrs,
gint *cursor_pos);
static gboolean gtk_im_context_real_filter_keypress (GtkIMContext *context,
GdkEventKey *event);
static gboolean gtk_im_context_real_get_surrounding (GtkIMContext *context,
gchar **text,
gint *cursor_index);
static void gtk_im_context_real_set_surrounding (GtkIMContext *context,
const char *text,
gint len,
gint cursor_index);
G_DEFINE_ABSTRACT_TYPE (GtkIMContext, gtk_im_context, G_TYPE_OBJECT)
/**
* GtkIMContextClass:
* @preedit_start: Default handler of the #GtkIMContext::preedit-start signal.
* @preedit_end: Default handler of the #GtkIMContext::preedit-end signal.
* @preedit_changed: Default handler of the #GtkIMContext::preedit-changed
* signal.
* @commit: Default handler of the #GtkIMContext::commit signal.
* @retrieve_surrounding: Default handler of the
* #GtkIMContext::retrieve-surrounding signal.
* @delete_surrounding: Default handler of the
* #GtkIMContext::delete-surrounding signal.
* @set_client_window: Called via gtk_im_context_set_client_window() when the
* input window where the entered text will appear changes. Override this to
* keep track of the current input window, for instance for the purpose of
* positioning a status display of your input method.
* @get_preedit_string: Called via gtk_im_context_get_preedit_string() to
* retrieve the text currently being preedited for display at the cursor
* position. Any input method which composes complex characters or any
* other compositions from multiple sequential key presses should override
* this method to provide feedback.
* @filter_keypress: Called via gtk_im_context_filter_keypress() on every
* key press or release event. Every non-trivial input method needs to
* override this in order to implement the mapping from key events to text.
* A return value of %TRUE indicates to the caller that the event was
* consumed by the input method. In that case, the #GtkIMContext::commit
* signal should be emitted upon completion of a key sequence to pass the
* resulting text back to the input widget. Alternatively, %FALSE may be
* returned to indicate that the event wasn't handled by the input method.
* If a builtin mapping exists for the key, it is used to produce a
* character.
* @focus_in: Called via gtk_im_context_focus_in() when the input widget
* has gained focus. May be overridden to keep track of the current focus.
* @focus_out: Called via gtk_im_context_focus_in() when the input widget
* has lost focus. May be overridden to keep track of the current focus.
* @reset: Called via gtk_im_context_reset() to signal a change such as a
* change in cursor position. An input method that implements preediting
* should override this method to clear the preedit state on reset.
* @set_cursor_location: Called via gtk_im_context_set_cursor_location()
* to inform the input method of the current cursor location relative to
* the client window. May be overridden to implement the display of popup
* windows at the cursor position.
* @set_use_preedit: Called via gtk_im_context_set_use_preedit() to control
* the use of the preedit string. Override this to display feedback by some
* other means if turned off.
* @set_surrounding: Called via gtk_im_context_set_surrounding() in response
* to signal #GtkIMContext::retrieve-surrounding to update the input
* method's idea of the context around the cursor. It is not necessary to
* override this method even with input methods which implement
* context-dependent behavior. The base implementation is sufficient for
* gtk_im_context_get_surrounding() to work.
* @get_surrounding: Called via gtk_im_context_get_surrounding() to update
* the context around the cursor location. It is not necessary to override
* this method even with input methods which implement context-dependent
* behavior. The base implementation emits
* #GtkIMContext::retrieve-surrounding and records the context received
* by the subsequent invocation of @get_surrounding.
*/
static void
gtk_im_context_class_init (GtkIMContextClass *klass)
{
klass->get_preedit_string = gtk_im_context_real_get_preedit_string;
klass->filter_keypress = gtk_im_context_real_filter_keypress;
klass->get_surrounding = gtk_im_context_real_get_surrounding;
klass->set_surrounding = gtk_im_context_real_set_surrounding;
/**
* GtkIMContext::preedit-start:
* @context: the object on which the signal is emitted
*
* The ::preedit-start signal is emitted when a new preediting sequence
* starts.
*/
im_context_signals[PREEDIT_START] =
g_signal_new (I_("preedit-start"),
G_TYPE_FROM_CLASS (klass),
G_SIGNAL_RUN_LAST,
G_STRUCT_OFFSET (GtkIMContextClass, preedit_start),
NULL, NULL,
_gtk_marshal_VOID__VOID,
G_TYPE_NONE, 0);
/**
* GtkIMContext::preedit-end:
* @context: the object on which the signal is emitted
*
* The ::preedit-end signal is emitted when a preediting sequence
* has been completed or canceled.
*/
im_context_signals[PREEDIT_END] =
g_signal_new (I_("preedit-end"),
G_TYPE_FROM_CLASS (klass),
G_SIGNAL_RUN_LAST,
G_STRUCT_OFFSET (GtkIMContextClass, preedit_end),
NULL, NULL,
_gtk_marshal_VOID__VOID,
G_TYPE_NONE, 0);
/**
* GtkIMContext::preedit-changed:
* @context: the object on which the signal is emitted
*
* 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.
*/
im_context_signals[PREEDIT_CHANGED] =
g_signal_new (I_("preedit-changed"),
G_TYPE_FROM_CLASS (klass),
G_SIGNAL_RUN_LAST,
G_STRUCT_OFFSET (GtkIMContextClass, preedit_changed),
NULL, NULL,
_gtk_marshal_VOID__VOID,
G_TYPE_NONE, 0);
/**
* GtkIMContext::commit:
* @context: the object on which the signal is emitted
* @str: the completed character(s) entered by the user
*
* 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.
*/
im_context_signals[COMMIT] =
g_signal_new (I_("commit"),
G_TYPE_FROM_CLASS (klass),
G_SIGNAL_RUN_LAST,
G_STRUCT_OFFSET (GtkIMContextClass, commit),
NULL, NULL,
_gtk_marshal_VOID__STRING,
G_TYPE_NONE, 1,
G_TYPE_STRING);
/**
* GtkIMContext::retrieve-surrounding:
* @context: the object on which the signal is emitted
*
* 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.
*
* Return value: %TRUE if the signal was handled.
*/
im_context_signals[RETRIEVE_SURROUNDING] =
g_signal_new (I_("retrieve-surrounding"),
G_TYPE_FROM_CLASS (klass),
G_SIGNAL_RUN_LAST,
G_STRUCT_OFFSET (GtkIMContextClass, retrieve_surrounding),
_gtk_boolean_handled_accumulator, NULL,
_gtk_marshal_BOOLEAN__VOID,
G_TYPE_BOOLEAN, 0);
/**
* GtkIMContext::delete-surrounding:
* @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
*
* The ::delete-surrounding signal is emitted when the input method
* needs to delete all or part of the context surrounding the cursor.
*
* Return value: %TRUE if the signal was handled.
*/
im_context_signals[DELETE_SURROUNDING] =
g_signal_new (I_("delete-surrounding"),
G_TYPE_FROM_CLASS (klass),
G_SIGNAL_RUN_LAST,
G_STRUCT_OFFSET (GtkIMContextClass, delete_surrounding),
_gtk_boolean_handled_accumulator, NULL,
_gtk_marshal_BOOLEAN__INT_INT,
G_TYPE_BOOLEAN, 2,
G_TYPE_INT,
G_TYPE_INT);
}
static void
gtk_im_context_init (GtkIMContext *im_context)
{
}
static void
gtk_im_context_real_get_preedit_string (GtkIMContext *context,
gchar **str,
PangoAttrList **attrs,
gint *cursor_pos)
{
if (str)
*str = g_strdup ("");
if (attrs)
*attrs = pango_attr_list_new ();
if (cursor_pos)
*cursor_pos = 0;
}
static gboolean
gtk_im_context_real_filter_keypress (GtkIMContext *context,
GdkEventKey *event)
{
return FALSE;
}
typedef struct
{
gchar *text;
gint cursor_index;
} SurroundingInfo;
static void
gtk_im_context_real_set_surrounding (GtkIMContext *context,
const gchar *text,
gint len,
gint cursor_index)
{
SurroundingInfo *info = g_object_get_data (G_OBJECT (context),
"gtk-im-surrounding-info");
if (info)
{
g_free (info->text);
info->text = g_strndup (text, len);
info->cursor_index = cursor_index;
}
}
static gboolean
gtk_im_context_real_get_surrounding (GtkIMContext *context,
gchar **text,
gint *cursor_index)
{
gboolean result;
gboolean info_is_local = FALSE;
SurroundingInfo local_info = { NULL, 0 };
SurroundingInfo *info;
info = g_object_get_data (G_OBJECT (context), "gtk-im-surrounding-info");
if (!info)
{
info = &local_info;
g_object_set_data (G_OBJECT (context), I_("gtk-im-surrounding-info"), info);
info_is_local = TRUE;
}
g_signal_emit (context,
im_context_signals[RETRIEVE_SURROUNDING], 0,
&result);
if (result)
{
*text = g_strdup (info->text ? info->text : "");
*cursor_index = info->cursor_index;
}
else
{
*text = NULL;
*cursor_index = 0;
}
if (info_is_local)
{
g_free (info->text);
g_object_set_data (G_OBJECT (context), I_("gtk-im-surrounding-info"), NULL);
}
return result;
}
/**
* gtk_im_context_set_client_window:
* @context: a #GtkIMContext
* @window: (allow-none): the client window. This may be %NULL to indicate
* that the previous client window no longer exists.
*
* 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.
**/
void
gtk_im_context_set_client_window (GtkIMContext *context,
GdkWindow *window)
{
GtkIMContextClass *klass;
g_return_if_fail (GTK_IS_IM_CONTEXT (context));
klass = GTK_IM_CONTEXT_GET_CLASS (context);
if (klass->set_client_window)
klass->set_client_window (context, window);
}
/**
* gtk_im_context_get_preedit_string:
* @context: a #GtkIMContext
* @str: (out) (transfer full): location to store the retrieved
* string. The string retrieved must be freed with g_free().
* @attrs: (out) (transfer full): location to store the retrieved
* attribute list. When you are done with this list, you
* must unreference it with pango_attr_list_unref().
* @cursor_pos: (out): location to store position of cursor (in characters)
* within the preedit string.
*
* 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.
**/
void
gtk_im_context_get_preedit_string (GtkIMContext *context,
gchar **str,
PangoAttrList **attrs,
gint *cursor_pos)
{
GtkIMContextClass *klass;
g_return_if_fail (GTK_IS_IM_CONTEXT (context));
klass = GTK_IM_CONTEXT_GET_CLASS (context);
klass->get_preedit_string (context, str, attrs, cursor_pos);
g_return_if_fail (str == NULL || g_utf8_validate (*str, -1, NULL));
}
/**
* gtk_im_context_filter_keypress:
* @context: a #GtkIMContext
* @event: the key 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.
*
* Return value: %TRUE if the input method handled the key event.
*
**/
gboolean
gtk_im_context_filter_keypress (GtkIMContext *context,
GdkEventKey *key)
{
GtkIMContextClass *klass;
g_return_val_if_fail (GTK_IS_IM_CONTEXT (context), FALSE);
g_return_val_if_fail (key != NULL, FALSE);
klass = GTK_IM_CONTEXT_GET_CLASS (context);
return klass->filter_keypress (context, key);
}
/**
* gtk_im_context_focus_in:
* @context: a #GtkIMContext
*
* 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.
**/
void
gtk_im_context_focus_in (GtkIMContext *context)
{
GtkIMContextClass *klass;
g_return_if_fail (GTK_IS_IM_CONTEXT (context));
klass = GTK_IM_CONTEXT_GET_CLASS (context);
if (klass->focus_in)
klass->focus_in (context);
}
/**
* gtk_im_context_focus_out:
* @context: a #GtkIMContext
*
* 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.
**/
void
gtk_im_context_focus_out (GtkIMContext *context)
{
GtkIMContextClass *klass;
g_return_if_fail (GTK_IS_IM_CONTEXT (context));
klass = GTK_IM_CONTEXT_GET_CLASS (context);
if (klass->focus_out)
klass->focus_out (context);
}
/**
* gtk_im_context_reset:
* @context: a #GtkIMContext
*
* 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.
**/
void
gtk_im_context_reset (GtkIMContext *context)
{
GtkIMContextClass *klass;
g_return_if_fail (GTK_IS_IM_CONTEXT (context));
klass = GTK_IM_CONTEXT_GET_CLASS (context);
if (klass->reset)
klass->reset (context);
}
/**
* gtk_im_context_set_cursor_location:
* @context: a #GtkIMContext
* @area: new location
*
* Notify the input method that a change in cursor
* position has been made. The location is relative to the client
* window.
**/
void
gtk_im_context_set_cursor_location (GtkIMContext *context,
const GdkRectangle *area)
{
GtkIMContextClass *klass;
g_return_if_fail (GTK_IS_IM_CONTEXT (context));
klass = GTK_IM_CONTEXT_GET_CLASS (context);
if (klass->set_cursor_location)
klass->set_cursor_location (context, (GdkRectangle *) area);
}
/**
* gtk_im_context_set_use_preedit:
* @context: a #GtkIMContext
* @use_preedit: whether the IM context should use the preedit string.
*
* 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.
**/
void
gtk_im_context_set_use_preedit (GtkIMContext *context,
gboolean use_preedit)
{
GtkIMContextClass *klass;
g_return_if_fail (GTK_IS_IM_CONTEXT (context));
klass = GTK_IM_CONTEXT_GET_CLASS (context);
if (klass->set_use_preedit)
klass->set_use_preedit (context, use_preedit);
}
/**
* gtk_im_context_set_surrounding:
* @context: a #GtkIMContext
* @text: text surrounding the insertion point, as UTF-8.
* the preedit string should not be included within
* @text.
* @len: the length of @text, or -1 if @text is nul-terminated
* @cursor_index: the byte index of the insertion cursor within @text.
*
* 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.
**/
void
gtk_im_context_set_surrounding (GtkIMContext *context,
const gchar *text,
gint len,
gint cursor_index)
{
GtkIMContextClass *klass;
g_return_if_fail (GTK_IS_IM_CONTEXT (context));
g_return_if_fail (text != NULL || len == 0);
if (text == NULL && len == 0)
text = "";
if (len < 0)
len = strlen (text);
g_return_if_fail (cursor_index >= 0 && cursor_index <= len);
klass = GTK_IM_CONTEXT_GET_CLASS (context);
if (klass->set_surrounding)
klass->set_surrounding (context, text, len, cursor_index);
}
/**
* gtk_im_context_get_surrounding:
* @context: a #GtkIMContext
* @text: (out) (transfer full): location to store a UTF-8 encoded
* string of text holding context around the insertion point.
* If the function returns %TRUE, then you must free the result
* stored in this location with g_free().
* @cursor_index: (out) location to store byte index of the insertion
* cursor within @text.
*
* 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.
*
* Return value: %TRUE if surrounding text was provided; in this case
* you must free the result stored in *text.
**/
gboolean
gtk_im_context_get_surrounding (GtkIMContext *context,
gchar **text,
gint *cursor_index)
{
GtkIMContextClass *klass;
gchar *local_text = NULL;
gint local_index;
gboolean result = FALSE;
g_return_val_if_fail (GTK_IS_IM_CONTEXT (context), FALSE);
klass = GTK_IM_CONTEXT_GET_CLASS (context);
if (klass->get_surrounding)
result = klass->get_surrounding (context,
text ? text : &local_text,
cursor_index ? cursor_index : &local_index);
if (result)
g_free (local_text);
return result;
}
/**
* gtk_im_context_delete_surrounding:
* @context: a #GtkIMContext
* @offset: offset from cursor position in chars;
* a negative value means start before the cursor.
* @n_chars: number of characters to delete.
*
* 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.
*
* Return value: %TRUE if the signal was handled.
**/
gboolean
gtk_im_context_delete_surrounding (GtkIMContext *context,
gint offset,
gint n_chars)
{
gboolean result;
g_return_val_if_fail (GTK_IS_IM_CONTEXT (context), FALSE);
g_signal_emit (context,
im_context_signals[DELETE_SURROUNDING], 0,
offset, n_chars, &result);
return result;
}
#define __GTK_IM_CONTEXT_C__
#include "gtkaliasdef.c"