diff options
Diffstat (limited to 'README.i18n')
| -rw-r--r-- | README.i18n | 199 |
1 files changed, 199 insertions, 0 deletions
diff --git a/README.i18n b/README.i18n new file mode 100644 index 0000000..511ee60 --- /dev/null +++ b/README.i18n @@ -0,0 +1,199 @@ +-- $XFree86: xc/programs/xterm/README.i18n,v 1.1 2003/11/13 01:16:37 dickey Exp $ + +Using xterm in your language +============================ + +Since XFree86 version 4.0, the internationalization (i18n) feature of +xterm is gradually improved. Xterm is being improved even now. You +need only set the standard locale environment variables such as +LC_CTYPE, LC_ALL, LC_CTYPE, or LANG. Once the locale is set up you can +use xterm in your favorite character encoding. + +This document explains how the i18n feature is realized and how to +configure xterm for your character encoding. + +Refer to locale(7) for details of the locale mechanism. + + +Basic i18n-related settings and resources +========================================= + +These settings apply to XFree86 xterm patch #181, and the program luit +which is distributed with XFree86 4.4 + +1. Usage of "locale mode" + + On startup, xterm must be in "locale mode" to make it follow the + current locale. You can invoke xterm in locale mode in these ways: + + a. Set "vt100.locale" resource "true". This resource was + introduced since XFree86 4.3. The default value of the "locale" + resource is "medium", which means xterm follows the locale only + in Chinese, Japanese, Korean, or Thai locales. For example, + + XTerm*locale: true + + in your ~/.Xresources file. + + or + + b. Invoke xterm with the "-lc" option. + +2. Converter program "luit" + + The "luit" must be available in the standard XFree86 binary + directory. It is usually available because it is part of the + XFree86 distribution. The standard binary directory may differ from + system to system. /usr/X11R6/bin/luit is an example. + + "luit" is used to convert between Unicode and the character encoding + for your locale. When built for XFree86, xterm includes logic for + invoking luit. + +3. Locale setting + + Finally, you will need to configure your locale. We expect that you + have already configured your locale for other software. For example, + + LANG=de_DE@euro + export LANG + + in your ~/.xsession file. There are many ways to configure locale. + For example, your display manager may have a mechanism to invoke a + window manager in your favorite locale, or you may have system-wide + locale setting in /etc/environment. You may also have set the + LC_ALL variable instead of the LANG variable. + + +How to use xterm in different locale temporarily +================================================ + +You may sometimes need to invoke xterm in a different character encoding +than your current locale. For example, use xterm to login remote systems +in different locale. + +Do this by invoking xterm in the target locale. For example, + + $ LANG=ru_RU.KOI8-R xterm & + +Previously, font setting has been used in such cases. + + $ xterm -fn -misc-fixed-medium-r-normal--10-*-*-*-*-*-koi8-r & + +This does not work well in conjunction with the "locale" resource, +because luit and xterm combined rely upon Unicode fonts. + + +How to set fonts for UTF-8/locale modes +======================================= + +Since xterm patch #181, xterm can automatically use Unicode fonts in +UTF-8 mode and locale mode. Few of you will need to modify the default +setting to display your language. In particular, Unicode fonts in +combination with locale mode will satisfy the needs of not only +ISO-8859-1 users but also East Asian and other non-ISO-8859-1 users. + +If you want to set your favorite Unicode font for UTF-8 and locale +modes, you should add a line such as the following in your ~/.Xresources +file: + + XTerm*VT100.utf8Fonts.font: \ + -misc-fixed-medium-r-semicondensed--13-120-75-75-c-60-iso10646-1 + +The leading "XTerm*" pattern is more specific than the system's +app-defaults file, therefore it overrides the corresponding line +beginning with + + *VT100.utf8Fonts.font: + +Here is an additional note. If you want to display East Asian +doublewidth characters (CJK Ideogram, Hiragana, Katakana, Hangul, +and so on), we recommend using + + -misc-fixed-medium-r-semicondensed--13-*-*-*-*-*-iso10646-1 + +or + + -misc-fixed-medium-r-normal--18-*-*-*-*-*-iso10646-1 + +because these two fonts have corresponding doublewidth fonts. These +fonts are used as default font and default "Large" font, respectively. + + +The internals of xterm i18n +=========================== + +You do not need to read this section if you only want to configure your +xterm. Here we describe how xterm is implemented to support i18n. + +The original version of xterm does not support locale or character +encoding. Its I/O stream is interpreted as a mere 8-bit index for a +font. + +Beginning with XFree86 4.0, xterm supported UTF-8. It was implemented +as a separate UTF-8 mode from the conventional 8-bit mode. Character +encodings had no effect on the 8-bit mode. The UTF-8 mode has been +extended to support doublewidth characters (for East Asian characters) +and combining characters (such as accents for Latin alphabets and Thai +vowels/tone marks). + +Doublewidth characters are characters that occupy two continuing +columns on the terminal. Xterm uses separate fonts for normal +(singlewidth) characters and doublewidth characters. Though xterm has +configuration items for specifying doublewidth fonts, it will +automatically search for a font with exactly twice as wide and the same +name as the specified normal font. + +The default behavior of xterm was modified to use this UTF-8 mode in +UTF-8 locales. A command line option of "-u8" and a resource of "utf8" +were introduced to choose UTF-8 mode. + +"luit" was introduced to XFree86 at version 4.2. It converts between +UTF-8 and other encodings. When luit is invoked in a UTF-8 terminal, +the terminal acts as if it is really running in the other encoding. + +Since XFree86 version 4.3, xterm provides a new mode to invoke luit +automatically to support various encodings. The mode where xterm +invokes luit is called "locale mode". It is the third mode following +conventional 8-bit mode and UTF-8 mode. In the locale mode, xterm is +aware of the current locale and character encoding. Since locale mode +uses luit, it is based on the UTF-8 mode. That is, xterm works in UTF-8 +mode and luit works as a converter between UTF-8 and the character +encoding for your locale. This is why the locale mode always needs +Unicode fonts. The default behavior of xterm is modified so that the +"locale mode" will be adopted in Chinese (Big5 and GB2312), Japanese +(EUC-JP), Korean (EUC-KR), and Thai (ISO-8859-11, as known as TIS-620) +locales. Locale mode is chosen for these character encodings because +these encodings are not supported by conventional 8-bit mode even by +changing fonts (ISO-8859-11 needs combining characters and others need +doublewidth characters). + +To control the locale mode, command line options of "-lc" and "-en" and +a resource of "locale" were introduced. The command line option of +"-u8" and a resource of "utf8" were made obsolete by them, though +retained for compatibility. + +Since XFree86 version 4.4, xterm can have two sets of default fonts, +one for conventional 8-bit mode and another for UTF-8 and locale modes, +by introducing the "utf8Fonts" subresource. + + +Future TODO Items +================= + +We anticipate that xterm's locale mode will be used increasingly in the +future. Since the UTF-8 and locale modes use more resources than +conventional 8-bit mode (because it needs larger fonts and another +process "luit"), faster hardware may be needed to gain complete +acceptance by users. However, the locale mechanism allows users +to manipulate data in a standard form. Its usefulness compensates +in part for reduced performance. + +Xterm supports antialiased fonts ("-fa" and "-fs" command line options). +Currently UTF-8 nor locale modes do not work with antialiased fonts. + +Xterm does not support bi-directional or RTL languages such as Hebrew +and Arab. A simple standard how terminal should behave for these +languages is needed. + +Xterm does not support Unicode characters above U+10000. |