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Updated: Thursday, June 13, 2019
 
 

FcPatternFormat (3)

Name

FcPatternFormat - Format a pattern into a string according to a format specifier

Synopsis

#include <fontconfig/fontconfig.h>

FcChar8 * FcPatternFormat (FcPattern *pat, const FcChar8 *format);

Description

FcPatternFormat(3)                                          FcPatternFormat(3)



NAME
       FcPatternFormat  - Format a pattern into a string according to a format
       specifier

SYNOPSIS
       #include <fontconfig/fontconfig.h>

       FcChar8 * FcPatternFormat (FcPattern *pat, const FcChar8 *format);

DESCRIPTION
       Converts given pattern pat into text described by the format  specifier
       format.  The return value refers to newly allocated memory which should
       be freed by the caller using free(), or NULL if format is invalid.

       The format is loosely modeled after printf-style  format  string.   The
       format  string is composed of zero or more directives: ordinary charac-
       ters (not "%"), which are copied unchanged to the  output  stream;  and
       tags  which  are  interpreted  to  construct text from the pattern in a
       variety of ways (explained below).  Special characters can  be  escaped
       using  backslash.  C-string style special characters like \n and \r are
       also supported (this is useful when the format string is not a C string
       literal).  It is advisable to always escape curly braces that are meant
       to be copied to the output as ordinary characters.

       Each tag is introduced by the character "%", followed  by  an  optional
       minimum field width, followed by tag contents in curly braces ({}).  If
       the minimum field width value is provided the tag will be expanded  and
       the  result  padded to achieve the minimum width.  If the minimum field
       width is positive, the padding  will  right-align  the  text.  Negative
       field  width will left-align.  The rest of this section describes vari-
       ous supported tag contents and their expansion.

       A simple tag is one where the content is  an  identifier.  When  simple
       tags  are  expanded,  the named identifier will be looked up in pattern
       and the resulting list of values returned, joined together using comma.
       For example, to print the family name and style of the pattern, use the
       format "%{family} %{style}\n". To extend the  family  column  to  forty
       characters use "%-40{family}%{style}\n".

       Simple tags expand to list of all values for an element. To only choose
       one of the values, one can index using the  syntax  "%{elt[idx]}".  For
       example, to get the first family name only, use "%{family[0]}".

       If  a simple tag ends with "=" and the element is found in the pattern,
       the name of the element followed by "=" will be output before the  list
       of  values.   For  example,  "%{weight=}"  may  expand  to  the  string
       "weight=80". Or to the empty string if pattern  does  not  have  weight
       set.

       If  a  simple  tag starts with ":" and the element is found in the pat-
       tern, ":" will be printed first. For example, combining this  with  the
       =,  the format "%{:weight=}" may expand to ":weight=80" or to the empty
       string if pattern does not have weight set.

       If a simple tag contains the string ":-", the rest of the the tag  con-
       tents will be used as a default string. The default string is output if
       the element is not found  in  the  pattern.  For  example,  the  format
       "%{:weight=:-123}"   may  expand  to  ":weight=80"  or  to  the  string
       ":weight=123" if pattern does not have weight set.

       A count tag is one that starts with the character "#"  followed  by  an
       element  name,  and  expands to the number of values for the element in
       the pattern.  For example, "%{#family}" expands to the number of family
       names pattern has set, which may be zero.

       A sub-expression tag is one that expands a sub-expression. The tag con-
       tents are the sub-expression to expand placed  inside  another  set  of
       curly  braces.   Sub-expression  tags are useful for aligning an entire
       sub-expression, or to apply converters (explained later) to the  entire
       sub-expression   output.    For  example,  the  format  "%40{{%{family}
       %{style}}}" expands the sub-expression to  construct  the  family  name
       followed  by the style, then takes the entire string and pads it on the
       left to be at least forty characters.

       A filter-out tag is one starting with the character "-" followed  by  a
       comma-separated  list  of  element  names, followed by a sub-expression
       enclosed in curly braces. The sub-expression will be expanded but  with
       a  pattern  that has the listed elements removed from it.  For example,
       the format "%{-size,pixelsize{sub-expr}}" will expand  "sub-expr"  with
       pattern sans the size and pixelsize elements.

       A  filter-in  tag  is one starting with the character "+" followed by a
       comma-separated list of element names,  followed  by  a  sub-expression
       enclosed  in curly braces. The sub-expression will be expanded but with
       a pattern that only has the listed elements from the  surrounding  pat-
       tern.   For  example, the format "%{+family,familylang{sub-expr}}" will
       expand "sub-expr" with a sub-pattern consisting  only  the  family  and
       family lang elements of pattern.

       A  conditional tag is one starting with the character "?" followed by a
       comma-separated list of element conditions, followed by two sub-expres-
       sion  enclosed  in curly braces. An element condition can be an element
       name, in which case it tests whether the element is defined in pattern,
       or  the  character  "!"  followed by an element name, in which case the
       test is negated. The conditional passes if all the  element  conditions
       pass.   The  tag  expands  the  first sub-expression if the conditional
       passes, and expands the second sub-expression otherwise.  For  example,
       the  format "%{?size,dpi,!pixelsize{pass}{fail}}" will expand to "pass"
       if pattern has size and dpi elements but no pixelsize element,  and  to
       "fail" otherwise.

       An  enumerate  tag  is  one starting with the string "[]" followed by a
       comma-separated list of element names,  followed  by  a  sub-expression
       enclosed in curly braces. The list of values for the named elements are
       walked in parallel and the sub-expression expanded  each  time  with  a
       pattern  just  having  a single value for those elements, starting from
       the first value and continuing as long as any of those elements  has  a
       value.    For   example,  the  format  "%{[]family,familylang{%{family}
       (%{familylang})\n}}" will  expand  the  pattern  "%{family}  (%{family-
       lang})\n"  with a pattern having only the first value of the family and
       familylang elements, then expands it with the second values,  then  the
       third, etc.

       As  a  special case, if an enumerate tag has only one element, and that
       element has only one value in the pattern, and that value  is  of  type
       FcLangSet, the individual languages in the language set are enumerated.

       A  builtin  tag  is  one  starting with the character "=" followed by a
       builtin name. The following builtins are defined:

       unparse
              Expands to the result of calling FcNameUnparse() on the pattern.

       fcmatch
              Expands to the output of the default output format  of  the  fc-
              match command on the pattern, without the final newline.

       fclist Expands  to  the  output of the default output format of the fc-
              list command on the pattern, without the final newline.

       fccat  Expands to the output of the default output format of the fc-cat
              command on the pattern, without the final newline.

       pkgkit Expands  to  the list of PackageKit font() tags for the pattern.
              Currently this includes tags for each family name, and each lan-
              guage  from  the pattern, enumerated and sanitized into a set of
              tags terminated by newline. Package management systems  can  use
              these tags to tag their packages accordingly.

       For  example,  the format "%{+family,style{%{=unparse}}}\n" will expand
       to an unparsed name containing only the family and style element values
       from pattern.

       The  contents  of any tag can be followed by a set of zero or more con-
       verters. A converter is specified by the character "|" followed by  the
       converter name and arguments. The following converters are defined:

       basename
              Replaces text with the results of calling FcStrBasename() on it.

       dirname
              Replaces text with the results of calling FcStrDirname() on it.

       downcase
              Replaces text with the results of calling FcStrDowncase() on it.

       shescape
              Escapes text for one level of shell expansion.  (Escapes single-
              quotes, also encloses text in single-quotes.)

       cescape
              Escapes text such that it can be used as part of a C string lit-
              eral.  (Escapes backslash and double-quotes.)

       xmlescape
              Escapes text such that it can be used in XML and HTML.  (Escapes
              less-than, greater-than, and ampersand.)

       delete(chars)
              Deletes all occurrences of each of the characters in chars  from
              the text.  FIXME: This converter is not UTF-8 aware yet.

       escape(chars)
              Escapes  all  occurrences  of each of the characters in chars by
              prepending it by the first character in chars.  FIXME: This con-
              verter is not UTF-8 aware yet.

       translate(from,to)
              Translates  all occurrences of each of the characters in from by
              replacing them with their corresponding character in to.  If  to
              has fewer characters than from, it will be extended by repeating
              its last character.  FIXME: This converter is  not  UTF-8  aware
              yet.

       For example, the format "%{family|downcase|delete( )}\n" will expand to
       the values of the family element in pattern, lower-cased and with  spa-
       ces removed.

SINCE
       version 2.9.0



ATTRIBUTES
       See attributes(7) for descriptions of the following attributes:


       +---------------+---------------------------+
       |ATTRIBUTE TYPE |     ATTRIBUTE VALUE       |
       +---------------+---------------------------+
       |Availability   | system/library/fontconfig |
       +---------------+---------------------------+
       |Stability      | Volatile                  |
       +---------------+---------------------------+
NOTES
       This     software     was    built    from    source    available    at
       https://github.com/oracle/solaris-userland.   The  original   community
       source  was  downloaded  from   https://fontconfig.org/release/fontcon-
       fig-2.12.1.tar.bz2

       Further information about this software can be found on the open source
       community website at https://fontconfig.org/.



Fontconfig 2.12.1                  05 8 2016                FcPatternFormat(3)