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Minor clarifications.
Reduce the specific references to X Windows. Refer to "graphical" terminals, rather than window systems. (Text Coding): Renamed from Specify Coding. (Communication Coding, File Name Coding, Terminal Coding): New nodes split out from Text Coding.
This commit is contained in:
Richard M. Stallman
parent
f8c2e4d50a
commit
b3d9da456a
428
man/mule.texi
428
man/mule.texi
@ -40,10 +40,7 @@ including European and Vietnamese variants of the Latin alphabet, as
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well as Cyrillic, Devanagari (for Hindi and Marathi), Ethiopic, Greek,
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Han (for Chinese and Japanese), Hangul (for Korean), Hebrew, IPA,
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Kannada, Lao, Malayalam, Tamil, Thai, Tibetan, and Vietnamese scripts.
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These features have been merged from the modified version of Emacs
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known as MULE (for ``MULti-lingual Enhancement to GNU Emacs'')
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Emacs also supports various encodings of these characters used by
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Emacs also supports various encodings of these characters used by
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other internationalized software, such as word processors and mailers.
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Emacs allows editing text with international characters by supporting
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@ -57,15 +54,15 @@ compilers, spell-checkers, and mailers). Setting your language
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environment (@pxref{Language Environments}) takes care of setting up the
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coding systems and other options for a specific language or culture.
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Alternatively, you can specify how Emacs should encode or decode text
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for each command; see @ref{Specify Coding}.
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for each command; see @ref{Text Coding}.
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@item
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You can display non-@acronym{ASCII} characters encoded by the various scripts.
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This works by using appropriate fonts on X and similar graphics
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displays (@pxref{Defining Fontsets}), and by sending special codes to
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text-only displays (@pxref{Specify Coding}). If some characters are
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displayed incorrectly, refer to @ref{Undisplayable Characters}, which
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describes possible problems and explains how to solve them.
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You can display non-@acronym{ASCII} characters encoded by the various
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scripts. This works by using appropriate fonts on graphics displays
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(@pxref{Defining Fontsets}), and by sending special codes to text-only
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displays (@pxref{Terminal Coding}). If some characters are displayed
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incorrectly, refer to @ref{Undisplayable Characters}, which describes
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possible problems and explains how to solve them.
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@item
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You can insert non-@acronym{ASCII} characters or search for them. To do that,
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@ -73,12 +70,14 @@ you can specify an input method (@pxref{Select Input Method}) suitable
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for your language, or use the default input method set up when you set
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your language environment. If
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your keyboard can produce non-@acronym{ASCII} characters, you can select an
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appropriate keyboard coding system (@pxref{Specify Coding}), and Emacs
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appropriate keyboard coding system (@pxref{Terminal Coding}), and Emacs
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will accept those characters. Latin-1 characters can also be input by
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using the @kbd{C-x 8} prefix, see @ref{Single-Byte Character Support,
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C-x 8}. On X Window systems, your locale should be set to an
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appropriate value to make sure Emacs interprets keyboard input
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correctly; see @ref{Language Environments, locales}.
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C-x 8}.
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On X Window systems, your locale should be set to an appropriate value
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to make sure Emacs interprets keyboard input correctly; see
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@ref{Language Environments, locales}.
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@end itemize
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The rest of this chapter describes these issues in detail.
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@ -93,7 +92,11 @@ correctly; see @ref{Language Environments, locales}.
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* Coding Systems:: Character set conversion when you read and
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write files, and so on.
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* Recognize Coding:: How Emacs figures out which conversion to use.
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* Specify Coding:: Various ways to choose which conversion to use.
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* Text Coding:: Choosing conversion to use for file text.
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* Communications Coding:: Coding systems for interprocess communication.
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* File Name Coding:: Coding systems for file @emph{names}.
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* Terminal Coding:: Specifying coding systems for converting
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terminal input and output.
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* Fontsets:: Fontsets are collections of fonts
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that cover the whole spectrum of characters.
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* Defining Fontsets:: Defining a new fontset.
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@ -106,15 +109,16 @@ correctly; see @ref{Language Environments, locales}.
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@node International Chars
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@section Introduction to International Character Sets
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The users of international character sets and scripts have established
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many more-or-less standard coding systems for storing files. Emacs
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internally uses a single multibyte character encoding, so that it can
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intermix characters from all these scripts in a single buffer or string.
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This encoding represents each non-@acronym{ASCII} character as a sequence of bytes
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in the range 0200 through 0377. Emacs translates between the multibyte
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character encoding and various other coding systems when reading and
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writing files, when exchanging data with subprocesses, and (in some
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cases) in the @kbd{C-q} command (@pxref{Multibyte Conversion}).
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The users of international character sets and scripts have
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established many more-or-less standard coding systems for storing
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files. Emacs internally uses a single multibyte character encoding,
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so that it can intermix characters from all these scripts in a single
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buffer or string. This encoding represents each non-@acronym{ASCII}
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character as a sequence of bytes in the range 0200 through 0377.
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Emacs translates between the multibyte character encoding and various
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other coding systems when reading and writing files, when exchanging
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data with subprocesses, and (in some cases) in the @kbd{C-q} command
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(@pxref{Multibyte Conversion}).
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@kindex C-h h
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@findex view-hello-file
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@ -138,23 +142,24 @@ to multibyte characters, coding systems, and input methods.
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@node Enabling Multibyte
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@section Enabling Multibyte Characters
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@cindex turn multibyte support on or off
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You can enable or disable multibyte character support, either for
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Emacs as a whole, or for a single buffer. When multibyte characters are
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disabled in a buffer, then each byte in that buffer represents a
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character, even codes 0200 through 0377. The old features for
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supporting the European character sets, ISO Latin-1 and ISO Latin-2,
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work as they did in Emacs 19 and also work for the other ISO 8859
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character sets.
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However, there is no need to turn off multibyte character support to
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use ISO Latin; the Emacs multibyte character set includes all the
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characters in these character sets, and Emacs can translate
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automatically to and from the ISO codes.
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By default, Emacs starts in multibyte mode, because that allows you to
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use all the supported languages and scripts without limitations.
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@cindex turn multibyte support on or off
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You can enable or disable multibyte character support, either for
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Emacs as a whole, or for a single buffer. When multibyte characters
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are disabled in a buffer, we call that @dfn{unibyte mode}. Then each
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byte in that buffer represents a character, even codes 0200 through
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0377.
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The old features for supporting the European character sets, ISO
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Latin-1 and ISO Latin-2, work in unibyte mode as they did in Emacs 19
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and also work for the other ISO 8859 character sets. However, there
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is no need to turn off multibyte character support to use ISO Latin;
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the Emacs multibyte character set includes all the characters in these
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character sets, and Emacs can translate automatically to and from the
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ISO codes.
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To edit a particular file in unibyte representation, visit it using
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@code{find-file-literally}. @xref{Visiting}. To convert a buffer in
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multibyte representation into a single-byte representation of the same
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@ -162,7 +167,7 @@ characters, the easiest way is to save the contents in a file, kill the
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buffer, and find the file again with @code{find-file-literally}. You
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can also use @kbd{C-x @key{RET} c}
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(@code{universal-coding-system-argument}) and specify @samp{raw-text} as
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the coding system with which to find or save a file. @xref{Specify
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the coding system with which to find or save a file. @xref{Text
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Coding}. Finding a file as @samp{raw-text} doesn't disable format
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conversion, uncompression and auto mode selection as
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@code{find-file-literally} does.
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@ -209,8 +214,8 @@ load a Lisp file as unibyte, on any one occasion, by typing @kbd{C-x
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The mode line indicates whether multibyte character support is enabled
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in the current buffer. If it is, there are two or more characters (most
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often two dashes) before the colon near the beginning of the mode line.
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When multibyte characters are not enabled, just one dash precedes the
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colon.
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When multibyte characters are not enabled, nothing precedes the colon
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except a single dash.
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@node Language Environments
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@section Language Environments
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@ -314,12 +319,12 @@ file.
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@findex describe-language-environment
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To display information about the effects of a certain language
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environment @var{lang-env}, use the command @kbd{C-h L @var{lang-env}
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@key{RET}} (@code{describe-language-environment}). This tells you which
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languages this language environment is useful for, and lists the
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@key{RET}} (@code{describe-language-environment}). This tells you
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which languages this language environment is useful for, and lists the
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character sets, coding systems, and input methods that go with it. It
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also shows some sample text to illustrate scripts used in this language
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environment. By default, this command describes the chosen language
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environment.
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also shows some sample text to illustrate scripts used in this
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language environment. If you give an empty input for @var{lang-env},
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this command describes the chosen language environment.
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@vindex set-language-environment-hook
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You can customize any language environment with the normal hook
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@ -483,9 +488,9 @@ language environment that it is meant to be used with. The variable
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@findex toggle-input-method
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@kindex C-\
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Input methods use various sequences of @acronym{ASCII} characters to stand for
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non-@acronym{ASCII} characters. Sometimes it is useful to turn off the input
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method temporarily. To do this, type @kbd{C-\}
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Input methods use various sequences of @acronym{ASCII} characters to
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stand for non-@acronym{ASCII} characters. Sometimes it is useful to
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turn off the input method temporarily. To do this, type @kbd{C-\}
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(@code{toggle-input-method}). To reenable the input method, type
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@kbd{C-\} again.
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@ -674,13 +679,14 @@ variants @code{iso-latin-1-unix}, @code{iso-latin-1-dos} and
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@code{iso-latin-1-mac}.
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The coding system @code{raw-text} is good for a file which is mainly
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@acronym{ASCII} text, but may contain byte values above 127 which are not meant to
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encode non-@acronym{ASCII} characters. With @code{raw-text}, Emacs copies those
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byte values unchanged, and sets @code{enable-multibyte-characters} to
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@code{nil} in the current buffer so that they will be interpreted
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properly. @code{raw-text} handles end-of-line conversion in the usual
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way, based on the data encountered, and has the usual three variants to
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specify the kind of end-of-line conversion to use.
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@acronym{ASCII} text, but may contain byte values above 127 which are
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not meant to encode non-@acronym{ASCII} characters. With
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@code{raw-text}, Emacs copies those byte values unchanged, and sets
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@code{enable-multibyte-characters} to @code{nil} in the current buffer
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so that they will be interpreted properly. @code{raw-text} handles
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end-of-line conversion in the usual way, based on the data
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encountered, and has the usual three variants to specify the kind of
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end-of-line conversion to use.
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In contrast, the coding system @code{no-conversion} specifies no
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character code conversion at all---none for non-@acronym{ASCII} byte values and
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@ -822,16 +828,16 @@ pattern, are decoded correctly. One of the builtin
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If Emacs recognizes the encoding of a file incorrectly, you can
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reread the file using the correct coding system by typing @kbd{C-x
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@key{RET} r @var{coding-system}
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@key{RET}}. To see what coding system Emacs actually used to decode
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the file, look at the coding system mnemonic letter near the left edge
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of the mode line (@pxref{Mode Line}), or type @kbd{C-h C @key{RET}}.
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@key{RET} r @var{coding-system} @key{RET}}. To see what coding system
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Emacs actually used to decode the file, look at the coding system
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mnemonic letter near the left edge of the mode line (@pxref{Mode
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Line}), or type @kbd{C-h C @key{RET}}.
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@findex unify-8859-on-decoding-mode
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The command @code{unify-8859-on-decoding-mode} enables a mode that
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``unifies'' the Latin alphabets when decoding text. This works by
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converting all non-@acronym{ASCII} Latin-@var{n} characters to either Latin-1 or
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Unicode characters. This way it is easier to use various
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converting all non-@acronym{ASCII} Latin-@var{n} characters to either
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Latin-1 or Unicode characters. This way it is easier to use various
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Latin-@var{n} alphabets together. In a future Emacs version we hope
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to move towards full Unicode support and complete unification of
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character sets.
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@ -843,7 +849,7 @@ system, by default, for operations that write from this buffer into a
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file. This includes the commands @code{save-buffer} and
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@code{write-region}. If you want to write files from this buffer using
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a different coding system, you can specify a different coding system for
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the buffer using @code{set-buffer-file-coding-system} (@pxref{Specify
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the buffer using @code{set-buffer-file-coding-system} (@pxref{Text
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Coding}).
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You can insert any possible character into any Emacs buffer, but
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@ -901,11 +907,12 @@ default value is @code{nil}, which means that Rmail files are not
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translated (they are read and written in the Emacs internal character
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code).
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@node Specify Coding
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@section Specifying a Coding System
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@node Text Coding
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@section Specifying a Coding System for File Text
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In cases where Emacs does not automatically choose the right coding
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system, you can use these commands to specify one:
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system for a file's contents, you can use these commands to specify
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one:
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@table @kbd
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@item C-x @key{RET} f @var{coding} @key{RET}
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@ -919,32 +926,9 @@ command.
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@item C-x @key{RET} r @var{coding} @key{RET}
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Revisit the current file using the coding system @var{coding}.
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@item C-x @key{RET} k @var{coding} @key{RET}
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Use coding system @var{coding} for keyboard input.
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@item C-x @key{RET} t @var{coding} @key{RET}
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Use coding system @var{coding} for terminal output.
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@item C-x @key{RET} p @var{input-coding} @key{RET} @var{output-coding} @key{RET}
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Use coding systems @var{input-coding} and @var{output-coding} for
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subprocess input and output in the current buffer.
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@item C-x @key{RET} x @var{coding} @key{RET}
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Use coding system @var{coding} for transferring selections to and from
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other programs through the window system.
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@item C-x @key{RET} F @var{coding} @key{RET}
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Use coding system @var{coding} for encoding and decoding file
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@emph{names}. This affects the use of non-ASCII characters in file
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names. It has no effect on reading and writing the @emph{contents} of
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files.
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@item C-x @key{RET} X @var{coding} @key{RET}
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Use coding system @var{coding} for transferring @emph{one}
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selection---the next one---to or from the window system.
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@item M-x recode-region
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Convert the region from a previous coding system to a new one.
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@item M-x recode-region @key{RET} @var{right} @key{RET} @var{wrong} @key{RET}
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Convert a region that was decoded using coding system @var{wrong},
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decoding it using coding system @var{right} instead.
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@end table
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@kindex C-x RET f
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@ -978,10 +962,9 @@ contains characters that the coding system cannot handle.
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Other file commands affected by a specified coding system include
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@kbd{C-x C-i} and @kbd{C-x C-v}, as well as the other-window variants
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of @kbd{C-x C-f}. @kbd{C-x @key{RET} c} also affects commands that
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start subprocesses, including @kbd{M-x shell} (@pxref{Shell}).
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If the immediately following command does not use the coding system,
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then @kbd{C-x @key{RET} c} ultimately has no effect.
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start subprocesses, including @kbd{M-x shell} (@pxref{Shell}). If the
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immediately following command does not use the coding system, then
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@kbd{C-x @key{RET} c} ultimately has no effect.
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An easy way to visit a file with no conversion is with the @kbd{M-x
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find-file-literally} command. @xref{Visiting}.
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@ -1000,6 +983,136 @@ environment.
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with @kbd{C-x @key{RET} r} (@code{revert-buffer-with-coding-system}).
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This visits the current file again, using a coding system you specify.
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@findex recode-region
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If a piece of text has already been inserted into a buffer using the
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wrong coding system, you can redo the decoding of it using @kbd{M-x
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recode-region}. This prompts you for the proper coding system, then
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for the wrong coding system that was actually used, and does the
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conversion. It first encodes the region using the wrong coding system,
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then decodes it again using the proper coding system.
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@node Communication Coding
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@section Coding Systems for Interprocess Communication
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This section explains how to specify coding systems for use
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in communication with other processes.
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@table @kbd
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@item C-x @key{RET} x @var{coding} @key{RET}
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Use coding system @var{coding} for transferring selections to and from
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other programs through the window system.
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@item C-x @key{RET} X @var{coding} @key{RET}
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Use coding system @var{coding} for transferring @emph{one}
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selection---the next one---to or from the window system.
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@item C-x @key{RET} p @var{input-coding} @key{RET} @var{output-coding} @key{RET}
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Use coding systems @var{input-coding} and @var{output-coding} for
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subprocess input and output in the current buffer.
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@item C-x @key{RET} c @var{coding} @key{RET}
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Specify coding system @var{coding} for the immediately following
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command.
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@end table
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@kindex C-x RET x
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@kindex C-x RET X
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@findex set-selection-coding-system
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@findex set-next-selection-coding-system
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The command @kbd{C-x @key{RET} x} (@code{set-selection-coding-system})
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specifies the coding system for sending selected text to other windowing
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applications, and for receiving the text of selections made in other
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applications. This command applies to all subsequent selections, until
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you override it by using the command again. The command @kbd{C-x
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@key{RET} X} (@code{set-next-selection-coding-system}) specifies the
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coding system for the next selection made in Emacs or read by Emacs.
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@kindex C-x RET p
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@findex set-buffer-process-coding-system
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The command @kbd{C-x @key{RET} p} (@code{set-buffer-process-coding-system})
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specifies the coding system for input and output to a subprocess. This
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command applies to the current buffer; normally, each subprocess has its
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own buffer, and thus you can use this command to specify translation to
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and from a particular subprocess by giving the command in the
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corresponding buffer.
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You can also use @kbd{C-x @key{RET} c} just before the command that
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runs or starts a subprocess, to specify the coding system to use for
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communication with that subprocess.
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The default for translation of process input and output depends on the
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current language environment.
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@vindex locale-coding-system
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@cindex decoding non-@acronym{ASCII} keyboard input on X
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The variable @code{locale-coding-system} specifies a coding system
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to use when encoding and decoding system strings such as system error
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messages and @code{format-time-string} formats and time stamps. That
|
||||
coding system is also used for decoding non-@acronym{ASCII} keyboard input on X
|
||||
Window systems. You should choose a coding system that is compatible
|
||||
with the underlying system's text representation, which is normally
|
||||
specified by one of the environment variables @env{LC_ALL},
|
||||
@env{LC_CTYPE}, and @env{LANG}. (The first one, in the order
|
||||
specified above, whose value is nonempty is the one that determines
|
||||
the text representation.)
|
||||
|
||||
@node File Name Coding
|
||||
@section Coding Systems for File Names
|
||||
|
||||
@table @kbd
|
||||
@item C-x @key{RET} F @var{coding} @key{RET}
|
||||
Use coding system @var{coding} for encoding and decoding file
|
||||
@emph{names}.
|
||||
@end table
|
||||
|
||||
@vindex file-name-coding-system
|
||||
@cindex file names with non-@acronym{ASCII} characters
|
||||
The variable @code{file-name-coding-system} specifies a coding
|
||||
system to use for encoding file names. It has no effect on reading
|
||||
and writing the @emph{contents} of files.
|
||||
|
||||
@findex set-file-name-coding-system
|
||||
@kindex C-x @key{RET} F
|
||||
If you set the variable to a coding system name (as a Lisp symbol or
|
||||
a string), Emacs encodes file names using that coding system for all
|
||||
file operations. This makes it possible to use non-@acronym{ASCII}
|
||||
characters in file names---or, at least, those non-@acronym{ASCII}
|
||||
characters which the specified coding system can encode. Use @kbd{C-x
|
||||
@key{RET} F} (@code{set-file-name-coding-system}) to specify this
|
||||
interactively.
|
||||
|
||||
If @code{file-name-coding-system} is @code{nil}, Emacs uses a
|
||||
default coding system determined by the selected language environment.
|
||||
In the default language environment, any non-@acronym{ASCII}
|
||||
characters in file names are not encoded specially; they appear in the
|
||||
file system using the internal Emacs representation.
|
||||
|
||||
@strong{Warning:} if you change @code{file-name-coding-system} (or the
|
||||
language environment) in the middle of an Emacs session, problems can
|
||||
result if you have already visited files whose names were encoded using
|
||||
the earlier coding system and cannot be encoded (or are encoded
|
||||
differently) under the new coding system. If you try to save one of
|
||||
these buffers under the visited file name, saving may use the wrong file
|
||||
name, or it may get an error. If such a problem happens, use @kbd{C-x
|
||||
C-w} to specify a new file name for that buffer.
|
||||
|
||||
@findex recode-file-name
|
||||
If a mistake occurs when encoding a file name, use the command
|
||||
@kbd{M-x recode-file-name} to change the file name's coding
|
||||
system. This prompts for an existing file name, its old coding
|
||||
system, and the coding system to which you wish to convert.
|
||||
|
||||
@node Terminal Coding
|
||||
@section Coding Systems for Terminal I/O
|
||||
|
||||
@table @kbd
|
||||
@item C-x @key{RET} k @var{coding} @key{RET}
|
||||
Use coding system @var{coding} for keyboard input.
|
||||
|
||||
@item C-x @key{RET} t @var{coding} @key{RET}
|
||||
Use coding system @var{coding} for terminal output.
|
||||
@end table
|
||||
|
||||
@kindex C-x RET t
|
||||
@findex set-terminal-coding-system
|
||||
The command @kbd{C-x @key{RET} t} (@code{set-terminal-coding-system})
|
||||
@ -1049,92 +1162,15 @@ the sequences that are translated are typically sequences of @acronym{ASCII}
|
||||
printing characters. Coding systems typically translate sequences of
|
||||
non-graphic characters.
|
||||
|
||||
@kindex C-x RET x
|
||||
@kindex C-x RET X
|
||||
@findex set-selection-coding-system
|
||||
@findex set-next-selection-coding-system
|
||||
The command @kbd{C-x @key{RET} x} (@code{set-selection-coding-system})
|
||||
specifies the coding system for sending selected text to the window
|
||||
system, and for receiving the text of selections made in other
|
||||
applications. This command applies to all subsequent selections, until
|
||||
you override it by using the command again. The command @kbd{C-x
|
||||
@key{RET} X} (@code{set-next-selection-coding-system}) specifies the
|
||||
coding system for the next selection made in Emacs or read by Emacs.
|
||||
|
||||
@kindex C-x RET p
|
||||
@findex set-buffer-process-coding-system
|
||||
The command @kbd{C-x @key{RET} p} (@code{set-buffer-process-coding-system})
|
||||
specifies the coding system for input and output to a subprocess. This
|
||||
command applies to the current buffer; normally, each subprocess has its
|
||||
own buffer, and thus you can use this command to specify translation to
|
||||
and from a particular subprocess by giving the command in the
|
||||
corresponding buffer.
|
||||
|
||||
The default for translation of process input and output depends on the
|
||||
current language environment.
|
||||
|
||||
@findex recode-region
|
||||
If a piece of text has already been inserted into a buffer using the
|
||||
wrong coding system, you can decode it again using @kbd{M-x
|
||||
recode-region}. This prompts you for the old coding system and the
|
||||
desired coding system, and acts on the text in the region.
|
||||
|
||||
@vindex file-name-coding-system
|
||||
@cindex file names with non-@acronym{ASCII} characters
|
||||
@findex set-file-name-coding-system
|
||||
@kindex C-x @key{RET} F
|
||||
The variable @code{file-name-coding-system} specifies a coding
|
||||
system to use for encoding file names. If you set the variable to a
|
||||
coding system name (as a Lisp symbol or a string), Emacs encodes file
|
||||
names using that coding system for all file operations. This makes it
|
||||
possible to use non-@acronym{ASCII} characters in file names---or, at
|
||||
least, those non-@acronym{ASCII} characters which the specified coding
|
||||
system can encode. Use @kbd{C-x @key{RET} F}
|
||||
(@code{set-file-name-coding-system}) to specify this interactively.
|
||||
|
||||
If @code{file-name-coding-system} is @code{nil}, Emacs uses a default
|
||||
coding system determined by the selected language environment. In the
|
||||
default language environment, any non-@acronym{ASCII} characters in file names are
|
||||
not encoded specially; they appear in the file system using the internal
|
||||
Emacs representation.
|
||||
|
||||
@strong{Warning:} if you change @code{file-name-coding-system} (or the
|
||||
language environment) in the middle of an Emacs session, problems can
|
||||
result if you have already visited files whose names were encoded using
|
||||
the earlier coding system and cannot be encoded (or are encoded
|
||||
differently) under the new coding system. If you try to save one of
|
||||
these buffers under the visited file name, saving may use the wrong file
|
||||
name, or it may get an error. If such a problem happens, use @kbd{C-x
|
||||
C-w} to specify a new file name for that buffer.
|
||||
|
||||
@findex recode-file-name
|
||||
If a mistake occurs when encoding a file name, use the command
|
||||
@kbd{M-x recode-file-name} to change the file name's coding
|
||||
system. This prompts for an existing file name, its old coding
|
||||
system, and the coding system to which you wish to convert.
|
||||
|
||||
@vindex locale-coding-system
|
||||
@cindex decoding non-@acronym{ASCII} keyboard input on X
|
||||
The variable @code{locale-coding-system} specifies a coding system
|
||||
to use when encoding and decoding system strings such as system error
|
||||
messages and @code{format-time-string} formats and time stamps. That
|
||||
coding system is also used for decoding non-@acronym{ASCII} keyboard input on X
|
||||
Window systems. You should choose a coding system that is compatible
|
||||
with the underlying system's text representation, which is normally
|
||||
specified by one of the environment variables @env{LC_ALL},
|
||||
@env{LC_CTYPE}, and @env{LANG}. (The first one, in the order
|
||||
specified above, whose value is nonempty is the one that determines
|
||||
the text representation.)
|
||||
|
||||
@node Fontsets
|
||||
@section Fontsets
|
||||
@cindex fontsets
|
||||
|
||||
A font for X typically defines shapes for a single alphabet or script.
|
||||
Therefore, displaying the entire range of scripts that Emacs supports
|
||||
requires a collection of many fonts. In Emacs, such a collection is
|
||||
called a @dfn{fontset}. A fontset is defined by a list of fonts, each
|
||||
assigned to handle a range of character codes.
|
||||
A font for X Windows typically defines shapes for a single alphabet
|
||||
or script. Therefore, displaying the entire range of scripts that
|
||||
Emacs supports requires a collection of many fonts. In Emacs, such a
|
||||
collection is called a @dfn{fontset}. A fontset is defined by a list
|
||||
of fonts, each assigned to handle a range of character codes.
|
||||
|
||||
Each fontset has a name, like a font. The available X fonts are
|
||||
defined by the X server; fontsets, however, are defined within Emacs
|
||||
@ -1148,11 +1184,11 @@ additional font support.}
|
||||
|
||||
Emacs creates two fontsets automatically: the @dfn{standard fontset}
|
||||
and the @dfn{startup fontset}. The standard fontset is most likely to
|
||||
have fonts for a wide variety of non-@acronym{ASCII} characters; however, this is
|
||||
not the default for Emacs to use. (By default, Emacs tries to find a
|
||||
font that has bold and italic variants.) You can specify use of the
|
||||
standard fontset with the @samp{-fn} option, or with the @samp{Font} X
|
||||
resource (@pxref{Font X}). For example,
|
||||
have fonts for a wide variety of non-@acronym{ASCII} characters;
|
||||
however, this is not the default for Emacs to use. (By default, Emacs
|
||||
tries to find a font that has bold and italic variants.) You can
|
||||
specify use of the standard fontset with the @samp{-fn} option, or
|
||||
with the @samp{Font} X resource (@pxref{Font X}). For example,
|
||||
|
||||
@example
|
||||
emacs -fn fontset-standard
|
||||
@ -1295,13 +1331,13 @@ call this function explicitly to create a fontset.
|
||||
@section Undisplayable Characters
|
||||
|
||||
There may be a some non-@acronym{ASCII} characters that your terminal cannot
|
||||
display. Most non-windowing terminals support just a single character
|
||||
display. Most text-only terminals support just a single character
|
||||
set (use the variable @code{default-terminal-coding-system}
|
||||
(@pxref{Specify Coding}) to tell Emacs which one); characters which
|
||||
(@pxref{Terminal Coding}) to tell Emacs which one); characters which
|
||||
can't be encoded in that coding system are displayed as @samp{?} by
|
||||
default.
|
||||
|
||||
Windowing terminals can display a broader range of characters, but
|
||||
Graphical displays can display a broader range of characters, but
|
||||
you may not have fonts installed for all of them; characters that have
|
||||
no font appear as a hollow box.
|
||||
|
||||
@ -1335,8 +1371,8 @@ such as @samp{Latin-@var{n}}.
|
||||
|
||||
For more information about unibyte operation, see @ref{Enabling
|
||||
Multibyte}. Note particularly that you probably want to ensure that
|
||||
your initialization files are read as unibyte if they contain non-@acronym{ASCII}
|
||||
characters.
|
||||
your initialization files are read as unibyte if they contain
|
||||
non-@acronym{ASCII} characters.
|
||||
|
||||
@vindex unibyte-display-via-language-environment
|
||||
Emacs can also display those characters, provided the terminal or font
|
||||
@ -1377,11 +1413,11 @@ If your keyboard can generate character codes 128 (decimal) and up,
|
||||
representing non-@acronym{ASCII} characters, you can type those character codes
|
||||
directly.
|
||||
|
||||
On a window system, you should not need to do anything special to use
|
||||
On a graphical display, you should not need to do anything special to use
|
||||
these keys; they should simply work. On a text-only terminal, you
|
||||
should use the command @code{M-x set-keyboard-coding-system} or the
|
||||
variable @code{keyboard-coding-system} to specify which coding system
|
||||
your keyboard uses (@pxref{Specify Coding}). Enabling this feature
|
||||
your keyboard uses (@pxref{Terminal Coding}). Enabling this feature
|
||||
will probably require you to use @kbd{ESC} to type Meta characters;
|
||||
however, on a console terminal or in @code{xterm}, you can arrange for
|
||||
Meta to be converted to @kbd{ESC} and still be able type 8-bit
|
||||
@ -1417,11 +1453,11 @@ Use @kbd{C-x 8 C-h} to list all the available @kbd{C-x 8} translations.
|
||||
Emacs groups all supported characters into disjoint @dfn{charsets}.
|
||||
Each character code belongs to one and only one charset. For
|
||||
historical reasons, Emacs typically divides an 8-bit character code
|
||||
for an extended version of @acronym{ASCII} into two charsets: @acronym{ASCII}, which
|
||||
covers the codes 0 through 127, plus another charset which covers the
|
||||
``right-hand part'' (the codes 128 and up). For instance, the
|
||||
characters of Latin-1 include the Emacs charset @code{ascii} plus the
|
||||
Emacs charset @code{latin-iso8859-1}.
|
||||
for an extended version of @acronym{ASCII} into two charsets:
|
||||
@acronym{ASCII}, which covers the codes 0 through 127, plus another
|
||||
charset which covers the ``right-hand part'' (the codes 128 and up).
|
||||
For instance, the characters of Latin-1 include the Emacs charset
|
||||
@code{ascii} plus the Emacs charset @code{latin-iso8859-1}.
|
||||
|
||||
Emacs characters belonging to different charsets may look the same,
|
||||
but they are still different characters. For example, the letter
|
||||
|
||||
Loading…
Reference in New Issue
Block a user