XCreateFontSet()XCreateFontSet()NameXCreateFontSet – create a font set.
Synopsis
XFontSet XCreateFontSet(display, base_font_name_list,
missing_charset_list_return, missing_charset_count_return,
def_string_return)
Display *display;
char *base_font_name_list;
char ***missing_charset_list_return;
int *missing_charset_count_return;
char **def_string_return;
Arguments
display Specifies the connection to the X server.
base_font_name_list
Specifies the base font names.
missing_charset_list_return
Returns the missing charsets.
missing_charset_count_return
Returns the number of missing charsets.
def_string_return
Returns the string drawn for missing charsets.
Returns
The created font set.
Availability
Release 5 and later.
DescriptionXCreateFontSet() 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 information, and to image text in the locale of the
font_set.
The base_font_name_list argument is a comma-separated list of base font
names which Xlib uses to load the fonts needed for the locale. The
string is NULL-terminated, and is assumed to be in the Host Portable
Character Encoding; otherwise, the result is implementation-dependent.
Whitespace 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.
When used, this single base font name should name a family of fonts
whose members are encoded in the various charsets needed by the locales
of interest.
Alternatively, 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 controlling 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.
The following algorithm is used 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 one of the following cases that names a set
of fonts that exist at the server:
1. 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.
2. 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 available.
3. 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 which is a superset of the required charset.
4. The first font name that can be mapped in some implementation-depen‐
dent manner to one or more fonts that support imaging text in the
charset.
For example, assume a locale required the charsets:
ISO8859-1 JISX0208.1983 JISX0201.1976 GB2312-1980.0
Users could supply a base_font_name_list which explicitly specifies the
charsets, insuring that specific fonts get used if they exist:
<">-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<">
Or they could supply a base_font_name_list which omits the charsets,
letting Xlib select font charsets required for the locale:
<">-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-Nor‐
mal--26-180-100-100-C-240,\ -Adobe-Courier-Bold-R-Nor‐
mal--25-180-100-100-M-150<">
Or they could simply supply a single base font name which allows Xlib
to select from all available fonts which meet certain minimum XLFD
property requirements:
<">-*-*-*-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 sup‐
ported, 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, XCreate‐
FontSet() 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, XCreate‐
FontSet() sets missing_charset_list_return to a list of one or more
NULL-terminated charset names for which no font exists, and sets miss‐
ing_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, 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 which represents the glyph(s) which are drawn with
this XFontSet when the charsets of the available fonts do not include
all font glyph(s) 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 modi‐
fied by Xlib.
The client is responsible for constructing an error message from the
missing charset and default string information, and may choose to con‐
tinue 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-sup‐
plied base_font_name_list may be freed by the client after calling
XCreateFontSet().
See AlsoXExtentsOfFontSet(), XFontsOfFontSet(), XFreeFontSet().
Xlib - Internationalized Text Output XCreateFontSet()
