MirOS Manual: XCreateFontSet(3), XFreeFontSet(3)


XCreateFontSet(3X11)     XLIB FUNCTIONS      XCreateFontSet(3X11)

NAME

     XCreateFontSet, XFreeFontSet - create and free an interna-
     tional text drawing font set

SYNTAX

     XFontSet XCreateFontSet(Display *display, char
          *base_font_name_list, char
          ***missing_charset_list_return, int
          *missing_charset_count_return, char
          **def_string_return);

     void XFreeFontSet(Display *display, XFontSet font_set);

ARGUMENTS

     display   Specifies the connection to the X server.

     base_font_name_list
               Specifies the base font names.

     def_string_return
               Returns the string drawn for missing charsets.

     font_set  Specifies the font set.

     missing_charset_count_return
               Returns the number of missing charsets.

     missing_charset_list_return
               Returns the missing charsets.

DESCRIPTION

     The XCreateFontSet function creates a font set for the
     specified display. The font set is bound to the current
     locale when XCreateFontSet is called. The font set may be
     used in subsequent calls to obtain font and character infor-
     mation and to image text in the locale of the font set.

     The base_font_name_list argument is a list of base font
     names that Xlib uses to load the fonts needed for the
     locale. The base font names are a comma-separated list. The
     string is null-terminated and is assumed to be in the Host
     Portable Character Encoding; otherwise, the result is
     implementation-dependent. White space immediately on either
     side of a separating comma is ignored.

     Use of XLFD font names permits Xlib to obtain the fonts
     needed for a variety of locales from a single locale-
     independent base font name. The single base font name should
     name a family of fonts whose members are encoded in the
     various charsets needed by the locales of interest.

XFree86                   Version 4.5.0                         1

XCreateFontSet(3X11)     XLIB FUNCTIONS      XCreateFontSet(3X11)

     An XLFD base font name can explicitly name a charset needed
     for the locale. This allows the user to specify an exact
     font for use with a charset required by a locale, fully con-
     trolling the font selection.

     If a base font name is not an XLFD name, Xlib will attempt
     to obtain an XLFD name from the font properties for the
     font. If this action is successful in obtaining an XLFD
     name, the XBaseFontNameListOfFontSet function will return
     this XLFD name instead of the client-supplied name.

     Xlib uses the following algorithm to select the fonts that
     will be used to display text with the XFontSet.

     For each font charset required by the locale, the base font
     name list is searched for the first appearance of one of the
     following cases that names a set of fonts that exist at the
     server:

     +    The first XLFD-conforming base font name that specifies
          the required charset or a superset of the required
          charset in its CharSetRegistry and CharSetEncoding
          fields. The implementation may use a base font name
          whose specified charset is a superset of the required
          charset, for example, an ISO8859-1 font for an ASCII
          charset.

     +    The first set of one or more XLFD-conforming base font
          names that specify one or more charsets that can be
          remapped to support the required charset. The Xlib
          implementation may recognize various mappings from a
          required charset to one or more other charsets and use
          the fonts for those charsets. For example, JIS Roman is
          ASCII with tilde and backslash replaced by yen and
          overbar; Xlib may load an ISO8859-1 font to support
          this character set if a JIS Roman font is not avail-
          able.

     +    The first XLFD-conforming font name or the first non-
          XLFD font name for which an XLFD font name can be
          obtained, combined with the required charset (replacing
          the CharSetRegistry and CharSetEncoding fields in the
          XLFD font name). As in case 1, the implementation may
          use a charset that is a superset of the required char-
          set.

     +    The first font name that can be mapped in some
          implementation-dependent manner to one or more fonts
          that support imaging text in the charset.

     For example, assume that a locale required the charsets:

XFree86                   Version 4.5.0                         2

XCreateFontSet(3X11)     XLIB FUNCTIONS      XCreateFontSet(3X11)

     ISO8859-1
     JISX0208.1983
     JISX0201.1976
     GB2312-1980.0

     The user could supply a base_font_name_list that explicitly
     specifies the charsets, ensuring that specific fonts are
     used if they exist. For example:

     "-JIS-Fixed-Medium-R-Normal--26-180-100-100-C-240-JISX0208.1983-0,\
     -JIS-Fixed-Medium-R-Normal--26-180-100-100-C-120-JISX0201.1976-0,\
     -GB-Fixed-Medium-R-Normal--26-180-100-100-C-240-GB2312-1980.0,\
     -Adobe-Courier-Bold-R-Normal--25-180-75-75-M-150-ISO8859-1"

     Alternatively, the user could supply a base_font_name_list
     that omits the charsets, letting Xlib select font charsets
     required for the locale. For example:

     "-JIS-Fixed-Medium-R-Normal--26-180-100-100-C-240,\
     -JIS-Fixed-Medium-R-Normal--26-180-100-100-C-120,\
     -GB-Fixed-Medium-R-Normal--26-180-100-100-C-240,\
     -Adobe-Courier-Bold-R-Normal--25-180-100-100-M-150"

     Alternatively, the user could simply supply a single base
     font name that allows Xlib to select from all available
     fonts that meet certain minimum XLFD property requirements.
     For example:

     "-*-*-*-R-Normal--*-180-100-100-*-*"

     If XCreateFontSet is unable to create the font set, either
     because there is insufficient memory or because the current
     locale is not supported, XCreateFontSet returns NULL,
     missing_charset_list_return is set to NULL, and
     missing_charset_count_return is set to zero. If fonts exist
     for all of the charsets required by the current locale,
     XCreateFontSet returns a valid XFontSet,
     missing_charset_list_return is set to NULL, and
     missing_charset_count_return is set to zero.

     If no font exists for one or more of the required charsets,
     XCreateFontSet sets missing_charset_list_return to a list of
     one or more null-terminated charset names for which no font
     exists and sets missing_charset_count_return to the number
     of missing fonts. The charsets are from the list of the
     required charsets for the encoding of the locale and do not
     include any charsets to which Xlib may be able to remap a
     required charset.

     If no font exists for any of the required charsets or if the
     locale definition in Xlib requires that a font exist for a
     particular charset and a font is not found for that charset,

XFree86                   Version 4.5.0                         3

XCreateFontSet(3X11)     XLIB FUNCTIONS      XCreateFontSet(3X11)

     XCreateFontSet returns NULL. Otherwise, XCreateFontSet
     returns a valid XFontSet to font_set.

     When an Xmb/wc drawing or measuring function is called with
     an XFontSet that has missing charsets, some characters in
     the locale will not be drawable. If def_string_return is
     non-NULL, XCreateFontSet returns a pointer to a string that
     represents the glyphs that are drawn with this XFontSet when
     the charsets of the available fonts do not include all font
     glyphs required to draw a codepoint. The string does not
     necessarily consist of valid characters in the current
     locale and is not necessarily drawn with the fonts loaded
     for the font set, but the client can draw and measure the
     default glyphs by including this string in a string being
     drawn or measured with the XFontSet.

     If the string returned to def_string_return is the empty
     string (""), no glyphs are drawn, and the escapement is
     zero. The returned string is null-terminated. It is owned by
     Xlib and should not be modified or freed by the client. It
     will be freed by a call to XFreeFontSet with the associated
     XFontSet. Until freed, its contents will not be modified by
     Xlib.

     The client is responsible for constructing an error message
     from the missing charset and default string information and
     may choose to continue operation in the case that some fonts
     did not exist.

     The returned XFontSet and missing charset list should be
     freed with XFreeFontSet and XFreeStringList, respectively.
     The client-supplied base_font_name_list may be freed by the
     client after calling XCreateFontSet.

     The XFreeFontSet function frees the specified font set. The
     associated base font name list, font name list, XFontStruct
     list, and XFontSetExtents, if any, are freed.

SEE ALSO

     XExtentsofFontSet(3X11), XFontsOfFontSet(3X11),
     XFontSetExtents(3X11)
     Xlib - C Language X Interface

XFree86                   Version 4.5.0                         4

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