Mercurial > hg > xemacs-beta
comparison man/lispref/display.texi @ 408:501cfd01ee6d r21-2-34
Import from CVS: tag r21-2-34
| author | cvs |
|---|---|
| date | Mon, 13 Aug 2007 11:18:11 +0200 |
| parents | 74fd4e045ea6 |
| children | 697ef44129c6 |
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| 407:ed6218a7d4d3 | 408:501cfd01ee6d |
|---|---|
| 993 However, specifiers are a cleaner and more powerful way of doing | 993 However, specifiers are a cleaner and more powerful way of doing |
| 994 the same thing. FSF Emacs also uses a different format for | 994 the same thing. FSF Emacs also uses a different format for |
| 995 the contents of a display table, using additional indirection | 995 the contents of a display table, using additional indirection |
| 996 to a ``glyph table'' and such. Note that ``glyph'' has a different | 996 to a ``glyph table'' and such. Note that ``glyph'' has a different |
| 997 meaning in XEmacs.) | 997 meaning in XEmacs.) |
| 998 | |
| 999 @defvar current-display-table | |
| 1000 | |
| 1001 The display table currently in use. This is a specifier. | |
| 1002 | |
| 1003 Display tables are used to control how characters are displayed. Each | |
| 1004 time that redisplay processes a character, it is looked up in all the | |
| 1005 display tables that apply (obtained by calling @code{specifier-instance} | |
| 1006 on @code{current-display-table} and any overriding display tables | |
| 1007 specified in currently active faces). The first entry found that | |
| 1008 matches the character determines how the character is displayed. If | |
| 1009 there is no matching entry, the default display method is | |
| 1010 used. (Non-control characters are displayed as themselves and control | |
| 1011 characters are displayed according to the buffer-local variable | |
| 1012 @code{ctl-arrow}. Control characters are further affected by | |
| 1013 @code{control-arrow-glyph} and @code{octal-escape-glyph}.) | |
| 1014 | |
| 1015 Each instantiator in this specifier and the display-table specifiers | |
| 1016 in faces is a display table or a list of such tables. If a list, each | |
| 1017 table will be searched in turn for an entry matching a particular | |
| 1018 character. Each display table is one of | |
| 1019 | |
| 1020 @itemize @bullet | |
| 1021 @item | |
| 1022 A vector, specifying values for characters starting at 0. | |
| 1023 @item | |
| 1024 A char table, either of type @code{char} or @code{generic}. | |
| 1025 @item | |
| 1026 A range table. | |
| 1027 @end itemize | |
| 1028 | |
| 1029 Each entry in a display table should be one of | |
| 1030 | |
| 1031 @itemize @bullet | |
| 1032 @item | |
| 1033 nil (this entry is ignored and the search continues). | |
| 1034 @item | |
| 1035 A character (use this character; if it happens to be the same as | |
| 1036 the original character, default processing happens, otherwise | |
| 1037 redisplay attempts to display this character directly; | |
| 1038 #### At some point recursive display-table lookup will be | |
| 1039 implemented). | |
| 1040 @item | |
| 1041 A string (display each character in the string directly; | |
| 1042 #### At some point recursive display-table lookup will be | |
| 1043 implemented). | |
| 1044 @item | |
| 1045 A glyph (display the glyph; | |
| 1046 #### At some point recursive display-table lookup will be | |
| 1047 implemented when a string glyph is being processed). | |
| 1048 @item | |
| 1049 A cons of the form (format "@var{string}") where @var{string} is a | |
| 1050 printf-like spec used to process the character. #### Unfortunately no | |
| 1051 formatting directives other than %% are implemented. | |
| 1052 @item | |
| 1053 A vector (each element of the vector is processed recursively; | |
| 1054 in such a case, nil elements in the vector are simply ignored). | |
| 1055 | |
| 1056 #### At some point in the near future, display tables are likely to | |
| 1057 be expanded to include other features, such as referencing characters | |
| 1058 in particular fonts and allowing the character search to continue | |
| 1059 all the way up the chain of specifier instantiators. These features | |
| 1060 are necessary to properly display Unicode characters. | |
| 1061 @end itemize | |
| 1062 @end defvar | |
| 998 | 1063 |
| 999 Individual faces can also specify an overriding display table; | 1064 Individual faces can also specify an overriding display table; |
| 1000 this is set using @code{set-face-display-table}. @xref{Faces}. | 1065 this is set using @code{set-face-display-table}. @xref{Faces}. |
| 1001 | 1066 |
| 1002 If no display table can be determined for a particular window, | 1067 If no display table can be determined for a particular window, |