XTextExtents(3) - NetBSD Manual Pages

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XTextExtents(3)                                                XTextExtents(3)




NAME

       XTextExtents,  XTextExtents16, XQueryTextExtents, XQueryTextExtents16 -
       compute or query text extents


SYNTAX

       int XTextExtents(XFontStruct *font_struct, _Xconst  char  *string,  int
              nchars,  int  *direction_return,  int  *font_ascent_return,  int
              *font_descent_return, XCharStruct *overall_return);

       int XTextExtents16(XFontStruct *font_struct, _Xconst  XChar2b  *string,
              int  nchars, int *direction_return, int *font_ascent_return, int
              *font_descent_return, XCharStruct *overall_return);

       int  XQueryTextExtents(Display  *display,  XID  font_ID,  _Xconst  char
              *string,     int     nchars,    int    *direction_return,    int
              *font_ascent_return,   int   *font_descent_return,   XCharStruct
              *overall_return);

       int  XQueryTextExtents16(Display *display, XID font_ID, _Xconst XChar2b
              *string,    int    nchars,    int     *direction_return,     int
              *font_ascent_return,   int   *font_descent_return,   XCharStruct
              *overall_return);


ARGUMENTS

       direction_return
                 Returns the value of the direction hint  (FontLeftToRight  or
                 FontRightToLeft).

       display   Specifies the connection to the X server.

       font_ID   Specifies either the font ID or the GContext ID that contains
                 the font.

       font_ascent_return
                 Returns the font ascent.

       font_descent_return
                 Returns the font descent.

       font_struct
                 Specifies the XFontStruct structure.

       nchars    Specifies the number of characters in the character string.

       string    Specifies the character string.

       overall_return
                 Returns the overall size in the specified XCharStruct  struc-
                 ture.


DESCRIPTION

       The XTextExtents and XTextExtents16 functions perform the size computa-
       tion locally and, thereby, avoid the round-trip overhead of  XQueryTex-
       tExtents and XQueryTextExtents16.  Both functions return an 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 charac-
       ter-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 index-
       ing, 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 characters in the string are  taken  to  have  all
       zero metrics.

       The  XQueryTextExtents  and  XQueryTextExtents16  functions  return the
       bounding box of the specified 8-bit and 16-bit character string in  the
       specified  font or the font contained in the specified GC.  These func-
       tions 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 charac-
       ter-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 index-
       ing,  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  characters  in  the string are taken to have all
       zero metrics.

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

       XQueryTextExtents and  XQueryTextExtents16  can  generate  BadFont  and
       BadGC errors.


DIAGNOSTICS

       BadFont   A  value  for  a  Font  or  GContext argument does not name a
                 defined Font.

       BadGC     A value for a GContext argument does not name a defined GCon-
                 text.


SEE ALSO

       XLoadFont(3), XTextWidth(3)
       Xlib - C Language X Interface



XLIB FUNCTIONS                   X Version 11                  XTextExtents(3)