From fa095a4504cbe668e4244547e2c141597bea4ecf Mon Sep 17 00:00:00 2001 From: Andreas Rottmann Date: Mon, 14 Sep 2009 12:32:44 +0200 Subject: Imported Upstream version 0.9.1 --- doc/uniwidth.texi | 43 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 43 insertions(+) create mode 100644 doc/uniwidth.texi (limited to 'doc/uniwidth.texi') diff --git a/doc/uniwidth.texi b/doc/uniwidth.texi new file mode 100644 index 00000000..a05d101d --- /dev/null +++ b/doc/uniwidth.texi @@ -0,0 +1,43 @@ +@node uniwidth.h +@chapter Display width @code{} + +@cindex width +This include file declares functions that return the display width, measured +in columns, of characters or strings, when output to a device that uses +non-proportional fonts. + +@cindex ambiguous width +Note that for some rarely used characters the actual fonts or terminal +emulators can use a different width. There is no mechanism for communicating +the display width of characters across a Unix pseudo-terminal (tty). Also, +there are scripts with complex rendering, like the Indic scripts. For these +scripts, there is no such concept as non-proportional fonts. Therefore +the results of these functions usually work fine on most scripts and on +most characters but can fail to represent the actual display width. + +These functions are locale dependent. The @var{encoding} argument identifies +the encoding (e.g@. @code{"ISO-8859-2"} for Polish). + +@cindex Unicode character, width +@cindex halfwidth +@cindex fullwidth +@deftypefun int uc_width (ucs4_t @var{uc}, const char *@var{encoding}) +Determines and returns the number of column positions required for @var{uc}. +Returns -1 if @var{uc} is a control character that has an influence on the +column position when output. +@end deftypefun + +@deftypefun int u8_width (const uint8_t *@var{s}, size_t @var{n}, const char *@var{encoding}) +@deftypefunx int u16_width (const uint16_t *@var{s}, size_t @var{n}, const char *@var{encoding}) +@deftypefunx int u32_width (const uint32_t *@var{s}, size_t @var{n}, const char *@var{encoding}) +Determines and returns the number of column positions required for first +@var{n} units (or fewer if @var{s} ends before this) in @var{s}. This +function ignores control characters in the string. +@end deftypefun + +@deftypefun int u8_strwidth (const uint8_t *@var{s}, const char *@var{encoding}) +@deftypefunx int u16_strwidth (const uint16_t *@var{s}, const char *@var{encoding}) +@deftypefunx int u32_strwidth (const uint32_t *@var{s}, const char *@var{encoding}) +Determines and returns the number of column positions required for @var{s}. +This function ignores control characters in the string. +@end deftypefun -- cgit v1.2.3