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


NAME
       XTextExtents, XTextExtents16, XQueryTextExtents, XQuery
       TextExtents16 - compute or query text extents

SYNTAX
       XTextExtents(font_struct, string, nchars, direc_
       tion_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, direc_
       tion_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, direc_
       tion_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
       direction_return
		 Returns the value of the direction hint
		 (FontLeftToRight or FontRightToLeft).



X Version 11		   Release 6.1				1





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


       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 char
		 acter 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 met
       rics 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 charac
       ters 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 met
       rics.

       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 con
       tained in the specified GC.  These functions query the X



X Version 11		   Release 6.1				2





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


       server and, therefore, suffer the round-trip overhead 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 met
       rics 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 charac
       ters 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 met
       rics.

       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















X Version 11		   Release 6.1				3


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