/* 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 #include "gtkimcontext.h" #include "gtkmainprivate.h" #include "gtkmarshalers.h" #include "gtkintl.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: * * * 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. * * * 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 array 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 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. */ 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_out() 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: location to store the retrieved string. The * string retrieved must be freed with g_free (). * @attrs: 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: 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: 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: 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; }