XTextExtents16

XTextExtents(3X11)		XLIB FUNCTIONS		   XTextExtents(3X11)



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

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

       int XTextExtents16(XFontStruct *font_struct, 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, 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, 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 con-
		 tains 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 compu-
       tation locally and, thereby, avoid the round-trip overhead of XQuery-
       TextExtents 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 char-
       acter-width metrics of all characters in the string.  For each charac-
       ter 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 func-
       tions query the X server and, therefore, suffer the round-trip over-
       head that is avoided by XTextExtents and XTextExtents16.	 Both func-
       tions 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 char-
       acter-width metrics of all characters in the string.  For each charac-
       ter 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-bear-
       ing 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



							   XTextExtents(3X11)