>># 
>># 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: txtextnt16.m,v 1.5 92/06/11 17:09:30 rws Exp $
>># 
>>#
>>TITLE XTextExtents16 CH06
>>ASSERTION A XTextExtents16-1
A call to XTextExtents16 returns the bounding box of the
specified 16-bit or 2-byte 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.
For each 16 bit xtest font
  Call XTextExtents16.
  Verify by direct calculation from the metrics.
>>ASSERTION - XTextExtents16-2
When the font is defined with linear indexing rather than
2-byte matrix indexing, then each XChar2b structure is
interpreted as a 16-bit number with byte1 as the
most-significant byte.
>>ASSERTION - XTextExtents16-3
The ascent field of overall is set to the maximum of the
ascent metrics of all characters in the string.
>>ASSERTION - XTextExtents16-4
The descent field of overall is set to the maximum of the
descent metrics of all characters in the string.
>>ASSERTION - XTextExtents16-5
The width field of overall is set to the sum of the
character-width metrics of all characters in the string.
>>ASSERTION - XTextExtents16-6
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 - XTextExtents16-7
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 - XTextExtents16-8
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 - XTextExtents16-9
When the font has no defined default character, then
undefined characters in the string are taken to have all
zero metrics.
>>ASSERTION - XTextExtents16-10
Characters with all zero metrics are ignored.
>>ASSERTION - XTextExtents16-11
When the font has no defined default_char, then the
undefined characters in the string are also ignored.
