XTextExtents(3X11)          X Version 11(Release 5)          XTextExtents(3X11)


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

SYNTAX
      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;

ARGUMENTS




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      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
                structure.

DESCRIPTION
      The XTextExtents and XTextExtents16 functions perform the size
      computation locally and, thereby, avoid the round-trip overhead of
      XQueryTextExtents 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
      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 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


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      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 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
                GContext.

SEE ALSO
      XLoadFont(3X11), XTextWidth(3X11)
      Xlib - C Language X Interface
















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