Input_Method_basic(3) API for Input method.

Data Structures


struct MInputDriver
Structure of input method driver.
struct MInputMethod
Structure of input method.
struct MInputContext
Structure of input context.

Typedefs


typedef void(* MInputCallbackFunc )(MInputContext *ic, MSymbol command)
Type of input method callback functions.

Enumerations


enum MInputCandidatesChanged { MINPUT_CANDIDATES_LIST_CHANGED = 1, MINPUT_CANDIDATES_INDEX_CHANGED = 2, MINPUT_CANDIDATES_SHOW_CHANGED = 4, MINPUT_CANDIDATES_CHANGED_MAX }
Bit-masks to specify how candidates of input method is changed.

Variables


MSymbol Minput_method
Symbol whose name is 'input-method'.
MInputDriver minput_default_driver
The default driver for internal input methods.
MInputDriver * minput_driver
The driver for internal input methods.
MSymbol Minput_driver

Variables: Predefined symbols for callback commands.


 These are the predefined symbols that are used as the COMMAND argument of callback functions of an input method driver (see MInputDriver::callback_list).

Most of them do not require extra argument nor return any value; exceptions are these:

Minput_get_surrounding_text: When a callback function assigned for this command is called, the first element of MInputContext::plist has key Minteger and the value specifies which portion of the surrounding text should be retrieved. If the value is positive, it specifies the number of characters following the current cursor position. If the value is negative, the absolute value specifies the number of characters preceding the current cursor position. If the value is zero, it means that the caller just wants to know if the surrounding text is currently supported or not.

If the surrounding text is currently supported, the callback function must set the key of this element to Mtext and the value to the retrieved M-text. The length of the M-text may be shorter than the requested number of characters, if the available text is not that long. The length can be zero in the worst case. Or, the length may be longer if an application thinks it is more efficient to return that length.

If the surrounding text is not currently supported, the callback function should return without changing the first element of MInputContext::plist.

Minput_delete_surrounding_text: When a callback function assigned for this command is called, the first element of MInputContext::plist has key Minteger and the value specifies which portion of the surrounding text should be deleted in the same way as the case of Minput_get_surrounding_text. The callback function must delete the specified text. It should not alter MInputContext::plist.
MSymbol Minput_preedit_start

MSymbol Minput_preedit_done

MSymbol Minput_preedit_draw

MSymbol Minput_status_start

MSymbol Minput_status_done

MSymbol Minput_status_draw

MSymbol Minput_candidates_start

MSymbol Minput_candidates_done

MSymbol Minput_candidates_draw

MSymbol Minput_set_spot

MSymbol Minput_toggle

MSymbol Minput_reset

MSymbol Minput_get_surrounding_text

MSymbol Minput_delete_surrounding_text

Variables: Predefined symbols for special input events.


 These are the predefined symbols that are used as the KEY argument of minput_filter(). 
MSymbol Minput_focus_out

MSymbol Minput_focus_in

MSymbol Minput_focus_move

Variables: Predefined symbols used in input method information.


 
MSymbol Minherited

MSymbol Mcustomized

MSymbol Mconfigured

Functions


 
MInputMethod * minput_open_im (MSymbol language, MSymbol name, void *arg)
Open an input method.
void minput_close_im (MInputMethod *im)
Close an input method.
MInputContext * minput_create_ic (MInputMethod *im, void *arg)
Create an input context.
void minput_destroy_ic (MInputContext *ic)
Destroy an input context.
int minput_filter (MInputContext *ic, MSymbol key, void *arg)
Filter an input key.
int minput_lookup (MInputContext *ic, MSymbol key, void *arg, MText *mt)
Look up a text produced in the input context.
void minput_set_spot (MInputContext *ic, int x, int y, int ascent, int descent, int fontsize, MText *mt, int pos)
Set the spot of the input context.
void minput_toggle (MInputContext *ic)
Toggle input method.
void minput_reset_ic (MInputContext *ic)
Reset an input context.
MPlist * minput_get_title_icon (MSymbol language, MSymbol name)
Get title and icon filename of an input method.
MText * minput_get_description (MSymbol language, MSymbol name)
Get description text of an input method.
MPlist * minput_get_command (MSymbol language, MSymbol name, MSymbol command)
Get information about input method command(s).
int minput_config_command (MSymbol language, MSymbol name, MSymbol command, MPlist *keyseqlist)
Configure the key sequence of an input method command.
MPlist * minput_get_variable (MSymbol language, MSymbol name, MSymbol variable)
Get information about input method variable(s).
int minput_config_variable (MSymbol language, MSymbol name, MSymbol variable, MPlist *value)
Configure the value of an input method variable.
char * minput_config_file ()
Get the name of per-user customization file.
int minput_save_config (void)
Save configurations in per-user customization file.

Obsolete functions


 
MPlist * minput_get_variables (MSymbol language, MSymbol name)
Get a list of variables of an input method (obsolete).
int minput_set_variable (MSymbol language, MSymbol name, MSymbol variable, void *value)
Set the initial value of an input method variable.
MPlist * minput_get_commands (MSymbol language, MSymbol name)
Get information about input method commands.
int minput_assign_command_keys (MSymbol language, MSymbol name, MSymbol command, MPlist *keyseq)
Assign a key sequence to an input method command (obsolete).
int minput_callback (MInputContext *ic, MSymbol command)
Call a callback function.

Detailed Description

API for Input method.

An input method is an object to enable inputting various characters. An input method is identified by a pair of symbols, LANGUAGE and NAME. This pair decides an input method driver of the input method. An input method driver is a set of functions for handling the input method. There are two kinds of input methods; internal one and foreign one.

  • Internal Input Method

An internal input method has non Mnil LANGUAGE, and its body is defined in the m17n database by the tag <Minput_method, LANGUAGE, NAME>. For this kind of input methods, the m17n library uses two predefined input method drivers, one for CUI use and the other for GUI use. Those drivers utilize the input processing engine provided by the m17n library itself. The m17n database may provide input methods that are not limited to a specific language. The database uses Mt as LANGUAGE of those input methods.

An internal input method accepts an input key which is a symbol associated with an input event. As there is no way for the m17n library to know how input events are represented in an application program, an application programmer has to convert an input event to an input key by himself. See the documentation of the function minput_event_to_key() for the detail.

  • Foreign Input Method

A foreign input method has Mnil LANGUAGE, and its body is defined in an external resource (e.g. XIM of X Window System). For this kind of input methods, the symbol NAME must have a property of key Minput_driver, and the value must be a pointer to an input method driver. Therefore, by preparing a proper driver, any kind of input method can be treated in the framework of the m17n library.

For convenience, the m17n-X library provides an input method driver that enables the input style of OverTheSpot for XIM, and stores Minput_driver property of the symbol Mxim with a pointer to the driver. See the documentation of m17n GUI API for the detail.

PROCESSING FLOW

The typical processing flow of handling an input method is:

  • open an input method
  • create an input context for the input method
  • filter an input key
  • look up a produced text in the input context

Data Structure Documentation

MInputDriver

FIELD DOCUMENTATION:

int(* MInputDriver::open_im)(MInputMethod *im)

Open an input method. This function opens the input method im. It is called from the function minput_open_im() after all member of im but <info> set. If opening im succeeds, it returns 0. Otherwise, it returns -1. The function can setup im->info to keep various information that is referred by the other driver functions.

void(* MInputDriver::close_im)(MInputMethod *im)

Close an input method. This function closes the input method im. It is called from the function minput_close_im(). It frees all memory allocated for im->info (if any) after finishing all the tasks of closing the input method. But, the other members of im should not be touched.

int(* MInputDriver::create_ic)(MInputContext *ic)

Create an input context. This function creates the input context ic. It is called from the function minput_create_ic() after all members of ic but <info> are set. If creating ic succeeds, it returns 0. Otherwise, it returns -1. The function can setup ic->info to keep various information that is referred by the other driver functions.

void(* MInputDriver::destroy_ic)(MInputContext *ic)

Destroy an input context. This function is called from the function minput_destroy_ic() and destroys the input context ic. It frees all memory allocated for ic->info (if any) after finishing all the tasks of destroying the input method. But, the other members of ic should not be touched.

int(* MInputDriver::filter)(MInputContext *ic, MSymbol key, void *arg)

Filter an input key. This function is called from the function minput_filter() and filters an input key. key and arg are the same as what given to minput_filter().

The task of the function is to handle key, update the internal state of ic. If key is absorbed by the input method and no text is produced, it returns 1. Otherwise, it returns 0.

It may update ic->status, ic->preedit, ic->cursor_pos, ic->ncandidates, ic->candidates, and ic->produced if that is necessary for the member <callback>.

The meaning of arg depends on the input method river. See the documentation of minput_default_driver and minput_gui_driver for instance.

int(* MInputDriver::lookup)(MInputContext *ic, MSymbol key, void *arg, MText *mt)

Lookup a produced text in an input context. It is called from the function minput_lookup() and looks up a produced text in the input context ic. This function concatenate a text produced by the input key key (if any) to M-text mt. If key was correctly handled by the input method of ic, it returns 0. Otherwise, it returns 1.

The meaning of arg depends on the input method driver. See the documentation of minput_default_driver and minput_gui_driver for instance.

MPlist* MInputDriver::callback_list

List of callback functions. List of callback functions. Keys are one of Minput_preedit_start, Minput_preedit_draw, Minput_preedit_done, Minput_status_start, Minput_status_draw, Minput_status_done, Minput_candidates_start, Minput_candidates_draw, Minput_candidates_done, Minput_set_spot, Minput_toggle, Minput_reset, Minput_get_surrounding_text, Minput_delete_surrounding_text. Values are functions of type MInputCallbackFunc.

MInputMethod

FIELD DOCUMENTATION:

MSymbol MInputMethod::language

MSymbol MInputMethod::name

MInputDriver MInputMethod::driver

void* MInputMethod::arg

void* MInputMethod::info

MInputContext

FIELD DOCUMENTATION:

MInputMethod* MInputContext::im

MText* MInputContext::produced

void* MInputContext::arg

int MInputContext::active

int MInputContext::x

int MInputContext::y

int MInputContext::ascent

int MInputContext::descent

int MInputContext::fontsize

MText* MInputContext::mt

int MInputContext::pos

struct { ... } MInputContext::spot

void* MInputContext::info

MText* MInputContext::status

int MInputContext::status_changed

MText* MInputContext::preedit

int MInputContext::preedit_changed

int MInputContext::cursor_pos

int MInputContext::cursor_pos_changed

MPlist* MInputContext::candidate_list

int MInputContext::candidate_index

int MInputContext::candidate_from

int MInputContext::candidate_to

int MInputContext::candidate_show

int MInputContext::candidates_changed

MPlist* MInputContext::plist

Typedef Documentation

typedef void(* MInputCallbackFunc)(MInputContext *ic, MSymbol command)

Type of input method callback functions. This is the type of callback functions called from input method drivers. ic is a pointer to an input context, command is a name of callback for which the function is called.

Enumeration Type Documentation

enum MInputCandidatesChanged

Bit-masks to specify how candidates of input method is changed.

Enumerator:

MINPUT_CANDIDATES_LIST_CHANGED
MINPUT_CANDIDATES_INDEX_CHANGED
MINPUT_CANDIDATES_SHOW_CHANGED
MINPUT_CANDIDATES_CHANGED_MAX

Variable Documentation

MSymbol Minput_method

Symbol whose name is 'input-method'.

MSymbol Minput_preedit_start

MSymbol Minput_preedit_done

MSymbol Minput_preedit_draw

MSymbol Minput_status_start

MSymbol Minput_status_done

MSymbol Minput_status_draw

MSymbol Minput_candidates_start

MSymbol Minput_candidates_done

MSymbol Minput_candidates_draw

MSymbol Minput_set_spot

MSymbol Minput_toggle

MSymbol Minput_reset

MSymbol Minput_get_surrounding_text

MSymbol Minput_delete_surrounding_text

MSymbol Minput_focus_out

MSymbol Minput_focus_in

MSymbol Minput_focus_move

MSymbol MinheritedThese are the predefined symbols describing status of input method command and variable, and are used in a return value of minput_get_command() and minput_get_variable().

MSymbol Mcustomized

MSymbol Mconfigured

MInputDriver minput_default_driver

The default driver for internal input methods. The variable minput_default_driver is the default driver for internal input methods.

The member MInputDriver::open_im() searches the m17n database for an input method that matches the tag < Minput_method, language, name> and loads it.

The member MInputDriver::callback_list() is NULL. Thus, it is programmers responsibility to set it to a plist of proper callback functions. Otherwise, no feedback information (e.g. preedit text) can be shown to users.

The macro M17N_INIT() sets the variable minput_driver to the pointer to this driver so that all internal input methods use it.

Therefore, unless minput_driver is set differently, the driver dependent arguments arg of the functions whose name begins with 'minput_' are all ignored.

MInputDriver* minput_driver

The driver for internal input methods. The variable minput_driver is a pointer to the input method driver that is used by internal input methods. The macro M17N_INIT() initializes it to a pointer to minput_default_driver if <m17n.h> is included.

MSymbol Minput_driverThe variable Minput_driver is a symbol for a foreign input method. See foreign input method for the detail.

Author

Generated automatically by Doxygen for The m17n Library from the source code.

Function Documentation

MPlist* minput_get_variables (MSymbol language, MSymbol name)

Get a list of variables of an input method (obsolete). This function is obsolete. Use minput_get_variable() instead.

The minput_get_variables() function returns a plist (MPlist) of variables used to control the behavior of the input method specified by language and name. The plist is well-formed (Property List) of the following format: 

    (VARNAME (DOC-MTEXT DEFAULT-VALUE [ VALUE ... ] )
     VARNAME (DOC-MTEXT DEFAULT-VALUE [ VALUE ... ] )
     ...)

VARNAME is a symbol representing the variable name.

DOC-MTEXT is an M-text describing the variable.

DEFAULT-VALUE is the default value of the variable. It is a symbol, integer, or M-text.

VALUEs (if any) specifies the possible values of the variable. If DEFAULT-VALUE is an integer, VALUE may be a plist (FROM TO), where FROM and TO specifies a range of possible values.

For instance, suppose an input method has the variables:

  • name:intvar, description:'value is an integer', initial value:0, value-range:0..3,10,20

  • name:symvar, description:'value is a symbol', initial value:nil, value-range:a, b, c, nil

  • name:txtvar, description:'value is an M-text', initial value:empty text, no value-range (i.e. any text)

Then, the returned plist is as follows. 

    (intvar ("value is an integer" 0 (0 3) 10 20)
     symvar ("value is a symbol" nil a b c nil)
     txtvar ("value is an M-text" ""))

RETURN VALUE

If the input method uses any variables, a pointer to MPlist is returned. As the plist is kept in the library, the caller must not modify nor free it. If the input method does not use any variable, NULL is returned.

int minput_set_variable (MSymbol language, MSymbol name, MSymbol variable, void * value)

Set the initial value of an input method variable. The minput_set_variable() function sets the initial value of input method variable variable to value for the input method specified by language and name.

By default, the initial value is 0.

This setting gets effective in a newly opened input method.

RETURN VALUE

If the operation was successful, 0 is returned. Otherwise -1 is returned, and merror_code is set to MERROR_IM.

MPlist* minput_get_commands (MSymbol language, MSymbol name)

Get information about input method commands. The minput_get_commands() function returns information about input method commands of the input method specified by language and name. An input method command is a pseudo key event to which one or more actual input key sequences are assigned.

There are two kinds of commands, global and local. Global commands are used by multiple input methods for the same purpose, and have global key assignments. Local commands are used only by a specific input method, and have only local key assignments.

Each input method may locally change key assignments for global commands. The global key assignment for a global command is effective only when the current input method does not have local key assignments for that command.

If name is Mnil, information about global commands is returned. In this case language is ignored.

If name is not Mnil, information about those commands that have local key assignments in the input method specified by language and name is returned.

RETURN VALUE

If no input method commands are found, this function returns NULL.

Otherwise, a pointer to a plist is returned. The key of each element in the plist is a symbol representing a command, and the value is a plist of the form COMMAND-INFO described below.

The first element of COMMAND-INFO has the key Mtext, and the value is an M-text describing the command.

If there are no more elements, that means no key sequences are assigned to the command. Otherwise, each of the remaining elements has the key Mplist, and the value is a plist whose keys are Msymbol and values are symbols representing input keys, which are currently assigned to the command.

As the returned plist is kept in the library, the caller must not modify nor free it.

int minput_assign_command_keys (MSymbol language, MSymbol name, MSymbol command, MPlist * keyseq)

Assign a key sequence to an input method command (obsolete). This function is obsolete. Use minput_config_command() instead.

The minput_assign_command_keys() function assigns input key sequence keyseq to input method command command for the input method specified by language and name. If name is Mnil, the key sequence is assigned globally no matter what language is. Otherwise the key sequence is assigned locally.

Each element of keyseq must have the key msymbol and the value must be a symbol representing an input key.

keyseq may be NULL, in which case, all assignments are deleted globally or locally.

This assignment gets effective in a newly opened input method.

RETURN VALUE

If the operation was successful, 0 is returned. Otherwise -1 is returned, and merror_code is set to MERROR_IM.

int minput_callback (MInputContext * ic, MSymbol command)

Call a callback function. The minput_callback() functions calls a callback function command assigned for the input context ic. The caller must set specific elements in ic->plist if the callback function requires.

RETURN VALUE

If there exists a specified callback function, 0 is returned. Otherwise -1 is returned. By side effects, ic->plist may be modified.

COPYRIGHT

Copyright (C) 2001 Information-technology Promotion Agency (IPA)
Copyright (C) 2001-2011 National Institute of Advanced Industrial Science and Technology (AIST)
Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License <http://www.gnu.org/licenses/fdl.html>.

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