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CXTERM

Section: User Commands (1)
Updated: Version 5.0
Index

NAME

cxterm - Chinese terminal emulator for X

SYNOPSIS

cxterm[-toolkitoption ...] [-option ...]

DESCRIPTION

The cxterm program is a Chinese terminal emulatorfor the X Window System. It provides DEC VT102 compatible terminalswith a capability of interfacing Chinese language input/output.It is fully compatible with X11R6 xterm.Although the Tektronix 4014 window of xterm remains in cxterm,you can only use Chinese in the VT102 window (the default mode).It requires at least two X11 fonts from the X server, one 16-bit Chinesefont and one normal 8-bit terminal character font, to display Chinesecharacters as well as normal 7-bit ASCII.

In cxterm, one Chinese character is represented by 2 bytes, and oneASCII is represented by 1 byte. There are two kinds of Chinese encodingschemes, one requires that the highest-bits (MSB) be set to 1 in both bytesof a Chinese character, the other only requires that the MSB in the firstbyte of a Chinese character be set to 1. Both schemes requires that theMSB in each ASCII code be unset, i.e. second half of the ASCII code set(from 128 to 255) cannot be used in cxterm.The cxterm program recognizes both GB and BIG5 encoding,which are examples of the above two scheme respectively.However, two encoding cannot co-exist in the same time.

Please refer manual page xterm(1) for usage of xterm.This manual will cover only those features related to the Chineselanguage processing part.

CHINESE INPUT BASIC

Cxterm adds a special two-line display area to the bottom of window.It is often called the input area andis used to display and convert key sequences into Chinese characters.Chinese characters are input by theircorresponding input keystroke sequencesdefined in some input mapping method.When a valid input key is pressed,cxterm will first append it to an input key bufferand echo it in the upper line of the input area.It then translates the input key buffer into Chinese character(s)and display the converted character(s)in the lower line of the input area.In case the same input keystroke sequencecan be translated in different ways,all possible candidates will be displayed as a selection list.Each candidate is preceded by a labelthat is usually a digit andis often refered as the selection key for that candidate.Pressing the selection keywill send the corresponding candidateto the cxterm terminal as input.The input area and input key buffer is then cleared and preparedfor the next input cycle.

If the current input keystroke sequence yields more candidates thanthat can be displayed in the input area,only the first group of ten candidates are shown.The rest of the selection list will shown a group at a timeupon a press of the "move-right" key.Conceptually it can be considered as a "viewport"that reveals only a segment of the list.The size of each group or viewport is usually ten candidates;the actual number can be redefinedand it depends on the current width of the window.Initially the viewport is at the beginning of the list.A ``>'' sign at the right edge of the viewportindicates more candidates available to the right.A move-right key (usually ``>'' or ``.'',both on the same physical key button)will move the viewport to the rightand reveal the next group of candidates.A ``<'' sign at the left edge of the viewport suggests more candidates at the right.A move-left key (usually ``<'' or ``,'',both on the same physical key button)will move the viewport backward and reveal the previous group.

Chinese input area in cxterm is not a separate window.Whether the X cursor is in the input areaor elsewhere in the cxterm cxtermmakes no difference to the keyboard input.

Cxterm is always in one of the different input modescorresponding to different input methods.Two built-in methods are the "ASCII" and "IC".The "ASCII" method isto input 7-bit ASCII characters without any translation(just like xterm).The "IC" (Internal Coding) methodtranslates every 4 hexadecimal digits into one double-byte code,corresponding to a Chinese character in the adopted encoding.

Most other input methods are stored as external filesand are loaded in run-time on demand.Such external input methods are user-accessible and expandable.See tit2cit(1) on the format of the input method specificationfile and on how to add your own input method.The name of the input method is determined by the name of theexternal file where the input method is stored.

An input method can be character-based(each candidate is a single Chinese character),phrase-based (each candidate is a multiple Chinese character unit), or both.This makes no different to the cxterm input mechanism.If a keystroke sequence yields to a phrase (a multi-character word),the whole phrase will be displayed as a whole in the selection list,and when the corresponding selection key is pressed,it will be input as a whole unit.

ADVANCED INPUT FEATURES

Cxterm provides the following input features:prefix input, wildcard input, auto-selection of unique choice,word association by composition,continuous input by auto-segmentation, and post-selection association input.

Chinese input in cxterm requires only minimal keystrokes.If a keystroke sequence matches an input unit(single character or phrase),all its non-empty prefixes also match that input unit.A selection can be made any timewithout waiting for the whole key sequence being typed.It is however a common practice to type more keysto reduce the size of the candidate list for an easy selection.

If the exact keystroke sequence for an input unit is forgotten,the wildcard characters (usually ``*'' and ``?'') can be usedin place of the actual keys.The expansion is similar to the file name generationas in a Unix shell.A wildchar (usually ``?'') can substitute any single key,while a wildcard (usually ``*'') can substituteany number (including zero) of keys.

Automatic selection refers to the automatic input of a candidatewhen it is the only candidatematching the current input keystroke sequence.Cxterm supports three kinds of automatic selection,``NEVER'', ``ALWAYS'', and ``WHENNOMATCH''.Under the ``NEVER'' mode,cxterm will not take any action;a user has to press the corresponding selection key to pick the input unit.Under the ``ALWAYS'' mode,cxterm will automatically pick the unique choiceand sent to the terminal.Under the ``WHENNOMATCH'' mode,cxterm will input the unique choiceonly after the user types another key into the keystroke sequence,and only if the new sequence no longer matches any candidate.The newly typed key will start a new keystroke sequencefor the next input cycle.For example, if the current keystroke sequence ``ab'' yields onlyone candidate ``X'',but after the user types a key ``c'',the key sequence ``abc'' yields nothing,then cxterm will pick the choice ``X'' for the keystroke ``ab''and leave ``c'' alone in the keystroke sequence for the next input.If ``abc'' matches one or more candidates,the input process continues and the automatic selection aborts.

Cxterm provides an alternative wayto input a Chinese phrase by composition.If the input keystroke sequence contains two or more segmentsconnected by association keys (usually ``-''),cxterm will match it against a predefinedlist of phrases (called glossary, or the association list).It produces only those phrase candidates,in which the first Chinese character matches the first segment,and the second character matches the second segment, and so on.

Cxterm usually relies on the association keystyped by the user to segment the keystroke buffer.It also supports an auto-segmentation mode.When this mode is on,cxterm can automatically insert association keysfollowing the rule of longest matches of keystroke segments.That is, if the current keystroke sequence matches some candidatesbut not any more when a new input key is typed,cxterm inserts an artificial associate key beforethe newly input keystroke.Combined with the ``WHENNOMATCH'' auto-selection mode,it is sometimes possible to keep typing input keysand having cxterm making the selection.

If the association input mode is on (the default case),cxterm will form and display a new candidate listwhenever a Chinese character is input.The list consists of all possible subsequencesof the latest input Chinese character.The user can pick up a candidate from the the listinstead of typing another key sequence.

Both phrase input by composition and post-selection association inputrequire a predefined list of phrases (the association list).The list is stored as an external fileand it is loaded each time cxterm starts up.The user can change the file to add or drop phrases.The list is usually in the usage frequency order,since both composition and association will search forand display candidates in that order.

INPUT BUFFER LINE EDITING

Cxterm also provides some basic line editingfor the input keystroke buffer in upper line of the input area.The following table is the key binding in emacs-style.See tit2cit(1) on how to change the definition.

BS or DEL   delete the previous typed input keyctrl-F      move cursor forward one keyctrl-B      move cursor backward one keyctrl-A      move cursor to start of the bufferctrl-E      move cursor to end of the bufferctrl-D      delete input key at the cursor positionctrl-U      delete all keys and clear the bufferctrl-P      fetch the keystrokes of the last input

OPTIONS

The cxterm program accepts all the standard X Toolkitcommand line options, X11R6 xterm command line options, as well asthe following:

-fh chineseFont: This option specifies a Chinese font to be used when display Chinese text.This font should be the same height and twice the width as the normalASCII font.
-fhb chineseFont: This option specifies a Chinese font to be used when display bold Chinese text.This font must be the same height and width as the normal Chinese font.If only one of the normal or bold Chinese fonts is specified, it will beused as the normal font and the bold font will be produced by overstrikingthis font. The default is to do overstriking of the normal font.
-hm inputMethod: This option specifies the name of the initial input method whencxterm starts up.The default is "ASCII"; cxterm will start up in the English mode.
-hz encoding: This option specifies which encoding scheme, GB or BIG5, are to be used. The default is GB.
-GB: This option indicates that cxterm should use GB encoding.It is the same as option "-hz GB".
-BIG5: This option indicates that cxterm should use BIG5 encoding.It is the same as option "-hz BIG5".
-hid hanziInputDir: This option specifies the search path for the directory containing theChinese input methods.Alternative directory names are separated by a colon ``:''.The default is the current directory.
-has hanziAssociationFile: This option specifies the name of the association file,turns on the association input mode,and enables phrase input by composition.The default is no association file and the association input mode off.
-hls lineSpacing: This option specifies the height of the vertical white space (in pixel)which is used to separate two adjacent text lines in the screen.

RESOURCES

The program understands all of the core X Toolkit resource names and classes,all xterm resource names and classes, as well as the followingresources specified as part of the vt100 widget (class VT100):

hanziFont (class HanziFont): Specifies the name of the Chinese font to use.
hanziBoldFont (class HanziBoldFont): Specifies the name of the bold Chinese font to use instead of overstriking.
hanziMode (class HanziMode): Specifies the name of the initial method instead of the ASCII.
hanziEncoding (class HanziEncoding): Specifies the encoding scheme, GB or BIG5.
hanziInputDir (class HanziInputDir): Specifies the search paths for the directory containing the input methods.The names of the directories are separated by ``:'' characters.
hanziAssociation (class HanziAssociation): Specifies the name of the association fileand turns on the association mode.
hanziLineSpacing (class HanziLineSpacing): Specifies the vertical spacing (in pixel) between two text lines.

All the font selection entries in fontMenu can be usedto set Chinese font or fonts as well.

Cxterm adds two more entries to the vtMenu:

line3 (class SmeLine): This is a separator.
cxtermconfig (class SmeBSB): This entry invokes the popup-panel(config) action.

ACTIONS

In addition to all the xterm vt100 translations resources,the following are also accepted by cxterm:

switch-HZ-mode(method)

This action dynamically switch the input method to method.If method is not a built-in input method and does not reside in memory,it is loaded from external file first.The file name must be "method.cit", andit must be under one of the following places:the current directory, the home directory,the directory specified by resource hanziInputDir,or the directory specified by the environment variable HZINPUTDIR.

set-HZ-parameter(param[,...])

The param overrides the input method defaults as followed:

parameter string         meaning----------------         -------auto-select=never        set auto-select mode to "NEVER"auto-select=always       set auto-select mode to "ALWAYS"auto-select=whennomatch  set auto-select mode to "WHENNOMATCH"auto-segment=no          disable auto-segmentationauto-segment=yes         enable auto-segmentationassociation=no           disable post-selection associationassociation=yes          enable post-selection associationinput-conv=disable       temporary disable HZ input conversioninput-conv=enable        enable HZ input conversion againinput-conv=toggle        toggle HZ input conversion enable/disable

The hanzi input conversion is usually enable.When it is set disable,the cxterm input area becomes ``insensitive''and all input key are uninterpreted and treated as ASCII.If hanzi input is current disabled (or enabled),input-conv=toggle enables (or disables) it.Switching of input method automatically enables HZ input.

popup-panel(config)

This action popup the cxterm input configuration panel.

click-HZ-area()

This action triggers input area actionsif the current pointer location is inside the input area.If a candidate in the selection list is clicked,it will be input into the terminal.If the ``<'' or ``>'' sign of the selection list is clicked,the viewport will be moved to the left or right of the selection list.If the input key buffer is clicked,the line editing will be turned onand the cursor will be moved to the pointer location.

The defaults bindings in cxterm window are:

 Shift <KeyPress> Prior: scroll-back(1,halfpage) \n\  Shift <KeyPress> Next: scroll-forw(1,halfpage) \n\Shift <KeyPress> Select: select-cursor-start() \                         select-cursor-end(PRIMARY, CUT_BUFFER0) \n\Shift <KeyPress> Insert: insert-selection(PRIMARY, CUT_BUFFER0) \n\          <KeyPress> F1: switch-HZ-mode(ASCII) \n\          <KeyPress> F2: switch-HZ-mode(IC) \n\        ~Meta<KeyPress>: insert-seven-bit() \n\         Meta<KeyPress>: insert-eight-bit() \n\   Ctrl ~Meta<Btn1Down>: popup-menu(mainMenu) \n\       ~Meta <Btn1Down>: select-start() \n\     ~Meta <Btn1Motion>: select-extend() \n\  Ctrl ~Meta <Btn2Down>: popup-menu(vtMenu) \n\ ~Ctrl ~Meta <Btn2Down>: ignore() \n\   ~Ctrl ~Meta <Btn2Up>: insert-selection(PRIMARY, CUT_BUFFER0) \n\  Ctrl ~Meta <Btn3Down>: popup-menu(fontMenu) \n\ ~Ctrl ~Meta <Btn3Down>: start-extend() \n\     ~Meta <Btn3Motion>: select-extend() \n\    ~Ctrl ~Meta <BtnUp>: select-end(PRIMARY, CUT_BUFFER0) \n\              <BtnDown>: bell(0)

Below is a sample of how to use switch-HZ-mode() action to add moreinput methods, or redefine input mode switch keys:

cxterm*VT100.Translations: #override \           <KeyPress> F1:     set-HZ-parameter(input-conv=toggle) \n\           <KeyPress> F2:     switch-HZ-mode(IC) \n\           <KeyPress> F3:     popup-panel(config) \n\    ~Shift <KeyPress> F4:     switch-HZ-mode(TONEPY) \n\     Shift <KeyPress> F4:     switch-HZ-mode(PY) \n\    ~Shift <KeyPress> F5:     switch-HZ-mode(WuBi) \n\     Shift <KeyPress> F5:     switch-HZ-mode(CangJie) \n\ ~Meta <KeyPress> Escape:     insert() set-HZ-parameter(input-conv=off)

In this example, pressing <F2> willswitch the current input method to IC;<F4> will switch again to TONEPY method(external input method, requires TONEPY.cit to be in the search path(s) ofthe .cit files);<shift>+<F4> will switch again to PY method, and so on.The last line above may be a good setting for those who use vi (or celvis).Pressing <ESC> will pass ESC to vi to end the insertion mode, andtemporarily disable cxterm hanzi input(so that you can enter subsequent vi commands as ASCII).

The following xterm actions have additional meaning:

set-vt-font(d/1/2/3/4/5/6/e/s [,normalfont [, boldfont]]): This action sets Chinese font or fonts as well,if the Chinese font or fonts are indicated in the resourcesor as arguments. The font selection entries in fontMenucan be also used to set Chinese font and fonts.
hard-reset(): This action also resets the input area, dropping all the externalinput methods which are already loaded.It is also invoked from the hardreset entry in vtMenu.

CONTROL SEQUENCES

All thextermescape sequences can be used incxtermwithout any change.(See theXterm Control Sequencesdocument.)A set of new escape sequences are added to deal with Chinese characters:

<ESC>]160;string<BEL>: Set the input method search paths to string.It affects the subsequence loading of input methods.However, it has no effect on those input methodsthat has already been loaded.
<ESC>]161;string<BEL>: Switch the input method to string,equivalent to action switch-HZ-mode(string).
<ESC>]162;string<BEL>: Change the input parameters of the current input modeaccording to string.See action set-HZ-parameter for the format of the parameters.

ENVIRONMENT VARIABLE

HZINPUTDIR: It defines the external input method searching pathin absent of -hid options or ``hanziInputDir'' resource.
CHAR_ENCODING: Process(es) running on the new cxterm windowwill have this new environment variable.Its value is the name of the encoding scheme specifiedwhen cxterm starts.

EXAMPLES

Start a cxterm in reserve video with scroll bar:(It is in GB encoding and uses X11 fonts hanzigb16st and 8x16 by default).

cxterm -rv -sb

Start a cxterm in BIG5 encoding (where hku16et is a BIG5encoding X11 font):

cxterm -fh hku16et -fn 8x16 -BIG5

COPYRIGHT

Copyright 1994, 1995, Yongguang Zhang.
Copyright 1991, Yongguang Zhang and Man-Chi Pong.
This version of cxterm is derived from from xterm,which is part of the X window system Version 11 Release 6developed by X Consortium.Please also see X(1) for a full statement of rightsand permissions for X11.

This document was created byman2html,using the manual pages.