XTextExtents(3X)                                 XTextExtents(3X)



NAME
     XTextExtents, XTextExtents16, XQueryTextExtents,
     XQueryTextExtents16 - compute and query text extents

SYNOPSIS
     XTextExtents (font-struct, string, nchars,
     direction-return,  font-ascent-return,  font-descent-return,
     overall-return)
     XFontStruct *font-struct;
     char *string;
     int nchars;
     int *direction-return;
     int *font-ascent-return,*font-descent-return;
     XCharStruct *overall-return;

     XTextExtents16 (font-struct, string, nchars,
     direction-return, font-ascent-return, font-descent-return,
     overall-return)
     XFontStruct *font-struct;
     XChar2b *string;
     int nchars;
     int *direction-return;
     int *font-ascent-return,*font-descent-return;
     XCharStruct *overall-return;

     XQueryTextExtents (display, font-ID, string, nchars,
     direction-return, font-ascent-return, font-descent-return,
     overall-return)
     Display *display;
     XID font-ID;
     char *string;
     int nchars;
     int *direction-return;
     int *font-ascent-return,*font-descent-return;
     XCharStruct *overall-return;

     XQueryTextExtents16 (display, font-ID, string,
     nchars, direction-return, font-ascent-return,
     font-descent-return, overall-return)
     Display *display;
     XID font-ID;
     XChar2b *string;
     int nchars;
     int *direction-return;
     int *font-ascent-return,*font-descent-return;
     XCharStruct *overall-return

DESCRIPTION
     The XTextExtents and XTextExtents16 functions compute text
     extents, perform the size computation locally and, thereby,
     avoid the round-trip overhead of XQueryTextExtents and
     XQueryTextExtents16.  Both functions return an



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XTextExtents(3X)                                 XTextExtents(3X)



     XCharStruct structure, whose members are set to the values
     as follows.

     The ascent member is set to the maximum of the ascent
     metrics of all characters in the string.  The descent member
     is set to the maximum of the descent metrics.  The width
     member is set to the sum of the character-width metrics of
     all characters in the string.  For each character in the
     string, let W be the sum of the character-width metrics of
     all characters preceding it in the string.  Let L be the
     left-side-bearing metric of the character plus W.  Let R be
     the right-side-bearing metric of the character plus W.  The
     lbearing member is set to the minimum L of all characters in
     the string.  The rbearing member is set to the maximum R.

     For fonts defined with linear indexing rather than 2-byte
     matrix indexing, each XChar2b structure is interpreted as a
     16-bit number with byte1 as the most-significant byte.  If
     the font has no defined default character, undefined charac-
     ters in the string are taken to have all zero metrics.

     The XQueryTextExtents and XQueryTextExtents16 functions re-
     turn the bounding box of the specified 8-bit and 16-bit
     character string in the specified font or the font contained
     in the specified graphic context.  These functions query the
     X server and, therefore, suffer the round-trip overhead that
     is avoided by
     XTextExtents and XTextExtents16.  Both functions return a
     XCharStruct structure, whose members are set to the values
     as follows.

     The ascent member is set to the maximum of the ascent
     metrics of all characters in the string.  The descent member
     is set to the maximum of the descent metrics.  The width
     member is set to the sum of the character-width metrics of
     all characters in the string.  For each character in the
     string, let W be the sum of the character-width metrics of
     all characters preceding it in the string.  Let L be the
     left-side-bearing metric of the character plus W.  Let R be
     the right-side-bearing metric of the character plus W.  The
     lbearing member is set to the minimum L of all characters in
     the string.  The rbearing member is set to the maximum R.

     For fonts defined with linear indexing rather than 2-byte
     matrix indexing, each XChar2b structure is interpreted as a
     16-bit number with byte1 as the most-significant byte.  If
     the font has no defined default character, undefined charac-
     ters in the string are taken to have all zero metrics.

     Characters with all zero metrics are ignored.  If the font
     has no defined default chararacter, the undefined characters
     in the string are also ignored.



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XTextExtents(3X)                                 XTextExtents(3X)



   Arguments
     These functions accept the following arguments:

     font-ascent-return
             Returns the font ascent member.

     font-descent-return
             Returns the font descent member.

     direction-return
             Returns the value of the direction hint member:
             FontLeftToRight or FontRightToLeft.

     display Specifies the connection to the X server.

     font-ID Specifies either the font ID or the graphic context
             that contains the font.

     font-struct
             Specifies a pointer to the XFontStruct structure.

     nchars  Specifies the number of characters in the character
             string.

     string  Specifies the character string.






























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XTextExtents(3X)                                 XTextExtents(3X)



     overall-return
             Returns the overall size in the specified XChar-
             Struct structure.

ERRORS
     BadFont A value for a Font or GC argument does not name a
             defined font.

     BadGC   A value for a GC argument does not name a defined
             graphic context.

     The XQueryTextExtents and XQueryTextExtents16 functions can
     generate BadFont and BadGC errors.

SEE ALSO
     XLoadFont(3X), XTextWidth(3X)

     Xlib - C Language Interface






































4                                                  November, 1990