Provided by: libfontconfig1-dev_2.13.0-5ubuntu3_amd64 bug

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 characters  (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 various 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 pattern, ":" 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 contents 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 contents 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 pattern.   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-expression 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} (%{familylang})\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 language 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 converters.  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 literal.  (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 converter 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 spaces removed.

SINCE

       version 2.9.0