>># 
>># Copyright 1990, 1991 by the Massachusetts Institute of Technology and
>># UniSoft Group Limited.
>># 
>># Permission to use, copy, modify, distribute, and sell this software and
>># its documentation for any purpose is hereby granted without fee,
>># provided that the above copyright notice appear in all copies and that
>># both that copyright notice and this permission notice appear in
>># supporting documentation, and that the names of MIT and UniSoft not be
>># used in advertising or publicity pertaining to distribution of the
>># software without specific, written prior permission.  MIT and UniSoft
>># make no representations about the suitability of this software for any
>># purpose.  It is provided "as is" without express or implied warranty.
>># 
>># $XConsortium: txtextnts.m,v 1.8 92/06/11 17:09:38 rws Exp $
>># 
>>#
>>TITLE XTextExtents CH06
>>ASSERTION A XTextExtents-1
A call to XTextExtents returns the bounding box of the
specified 8-bit character string, string, as rendered in
the font referenced by font_struct.
>>STRATEGY
The known good font information structures are used so that these tests
are isolated from XLoadQueryFont.
Make a string consisting of all characters from 0 to 255
Call XTextExtents.
Verify by direct calculation from the metrics.
>>ASSERTION - XTextExtents-2
The ascent field of overall is set to the maximum of the
ascent metrics of all characters in the string.
>>ASSERTION - XTextExtents-3
The descent field of overall is set to the maximum of the
descent metrics of all characters in the string.
>>ASSERTION - XTextExtents-4
The width field of overall is set to the sum of the
character-width metrics of all characters in the string.
>>ASSERTION - XTextExtents-5
The lbearing field of overall is set to the minimum L of
all characters in the string, where for each character L is
the left-side-metric plus the sum of the character widths of
all preceding characters in the string.
>>ASSERTION - XTextExtents-6
The rbearing field of overall is set to the maximum R of
all characters in the string, where for each character R is
the right-side-bearing metric plus the sum of the character
widths of all preceding characters in the string.
>>ASSERTION - XTextExtents-7
The font_ascent_return argument is set to the logical
ascent of the font, the font_descent_return argument is set
to the logical descent of the font and the direction_return
argument is set to either FontLeftToRight or
FontRightToLeft.
>>ASSERTION - XTextExtents-8
When the font has no defined default character, then
undefined characters in the string are taken to have all
zero metrics.
>>ASSERTION - XTextExtents-9
Characters with all zero metrics are ignored.
>>ASSERTION - XTextExtents-10
When the font has no defined default_char, then the
undefined characters in the string are also ignored.
