From: williamj@cs.man.ac.uk (Gareth Williams)
Newsgroups: comp.windows.x.pex
Subject: PEX-SI observations
Date: 5 Oct 92 10:53:03 GMT
Distribution: comp.windows.x.pex
Organization: Department of Computer Science, University of Manchester


The following information is also provided in the PHIGS Toolkit 
release 3.1 in the file README.PEXSI
Hope you find it useful!

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                      PEX-SI Information file
                      -----------------------

Copyright (c) 1992, The Victoria University of Manchester.

The PHIGS Toolkit is produced by Department of Computer Science, and the
Computer Graphics Unit, Manchester Computing Centre, both of the Victoria
University of Manchester.  The PHIGS Toolkit has been tested with care but
is not guaranteed for any particular purpose. Neither the authors, nor the
University of Manchester offer any warranties or representations, nor do
they accept any liabilities with respect to the software and documentation.
The PHIGS Toolkit may be used freely within the academic community, but it
may not be used for commmercial gain without the written permission of the
authors.

This README file contains information and observations regarding
the PHIGS implementation known as the PEX-SI which is released with MIT's
X Windows X11/R5. The following observations have been made while
running PEX-SI with X11R5/twm on SunOS 4.1.1.

PHIGS PLUS functions have not been investigated. 
Please send any comments/contributions regarding the following
information to phigstoolkit@uk.ac.man.cs, or:

Toby Howard
Department of Computer Science
University of Manchester
Oxford Road
Manchester M13 9PL
United Kingom
Tel: +44 61 275 6274
Fax: +44 61 275 6236

PEX-SI UNIX environment
-----------------------

The following environment variables must be set:

  Variable            Example value

  PEXAPIDIR           /usr/common/lib/X11R5/PEX

  PEX_FONTPATH        /usr/common/lib/X11R5

Input functions
---------------

1) PEX-SI appends a newline character \n on the end of the input string
when using the STRING INPUT device. For example, typing in the 5 character
word "hello" will result in the 7 character string "hello\n\0". This
is dealt with in the PHIGS Toolkit by changing the \n to \0:

      str[strlen(str) - 1] = '\0';

2) Only the first name in the pick filter is recognised by the PICK
INPUT device. This implies that only one name at a time can be used
to make structures pickable. Assuming all structures use the same pick 
name, however, only the first structure drawn on a workstation is actually 
pickable. This is either the first structure to be posted or the structure
with the lowest priority. This is dealt with in the PHIGS Toolkit
debugger by giving both the topology diagram and the structure content
diagram the same pick name. To pick from either diagram, however,
the appropriate PTK window must be given the lowest priority by
selecting BACK from the window menu.

Inquiry functions
-----------------

1) The INQUIRE TEXT EXTENT function works fine for the concatenation
offset and string width but always returns 0.0 for the upper right of
the text bounding rectangle. For this reason the PHIGS Toolkit
always assumes text font 1 is being used.

2) The INQUIRE CURRENT ELEMENT CONTENT function will crash the X server
if the element pointer is set to 0 (a NIL element).

Search functions
----------------

1) The INCREMENTAL SPATIAL SEARCH function does not appear to work
properly. The PHIGS Toolkit simulates this function when scanning
menus and windows by using the PTK TSL simulation functions.

Workstation Types
-----------------

1) The two available workstation types are PHIGS_X_TOOL and 
PHIGS_X_DRAWABLE. You must use the PHIGS_X_TOOL workstation type
if you want to use PHIGS input devices. There is no hardcopy workstation
type (PHIGS_CGM_OUT in SunPHIGS) and so hardcopy is best made by
taking an X window dump.




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Gareth Williams       Computer Science Dept, University of Manchester,
Research Assistant    Oxford Road, Manchester, M13 9PL, U.K.

           janet:       williamj@uk.ac.man.cs
           internet:    williamj%cs.man.ac.uk@nsfnet-relay.ac.uk
           earn/bitnet: williamj%uk.ac.man.cs@UKACRL
           voice: +44 061-275-6141
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