Making Slides for the Web

From: Marc Levoy
To: gcafe@graphics
Subject: Online slide presentations
Date: Tue, 24 Sep 1996 01:26:32 -0700

Fellow orators,

Many of us are generating slide presentations that, for one reason or another,
we wish to place publically online.  For this purpose, I have created a new
branch of our web hierarchy called "Slides from technical presentations" and
accessible directly from our home page.

So far, there are three presentations on this web page.  All three were
produced in PowerPoint on a Mac, printed with one slide per page to a
Postscript file, transferred from the Mac to UNIX, and then run through
ps2www and iconv, a fabulous set of Perl scripts written by Tolis.
What follows below is a brief tutorial on using these scripts.
If anybody knows of other scripts, e.g. by Microsoft, for performing
these conversions, please bring them to everybody's attention.

For an example of a presentation made using Tolis's scripts, look on
www-graphics.stanford.edu/talks/ at my presentation entitled "Digitizing the
Shape and Appearance of Physical Objects".  The inputs files for making this
presentation consist of a customized copy of "ps2www" (you can grab a reference
copy from ~levoy/bin/sgi) and a Postscript file as described previously.  For
this particular presentation, my inputs files are in
~levoy/public_talks/nae-3d-scanning.

ps2www contains templates for the .html files that will be created, so typical
customizations include the title of the presentation, where and when it was
presented, and any additional links to technical papers or project home pages
that you wish to add.  Other customizations might include flips, rotates, or
other image manipulations you need to have performed on each slide after it has
been extracted from the Postscript file.

A typical invocation is "ps2www  ".
ps2www in turn invokes "iconv" (you can grab a copy from ~levoy/bin/sgi).
iconv in turn invokes fromps and psrip, which currently only run on an IRIX 5.3
system, e.g. aperture.  The output is a set of .html files and associated image
files in the named subdirectory.  In my example, I named the subdirectory
"slides".  This subdirectory, whose full pathname is
~levoy/public_talks/nae-3d-scanning/slides, may then be linked into the web
hierarchy as shown in www-graphics.stanford.edu/talks/talks.html.

-Marc


From: Apostolos Lerios 
To: curless@aegean (Brian Curless)
Cc: glab@graphics (Graphics Group)
Subject: Re: iconv
Date: Mon, 9 Dec 1996 14:04:37 -0800 (PST)

> I've used your ps2www converter (which in turn uses imconv) for
> putting together slides on the web.  Nice!  One modification I made
> was to have imconv use a higher quality factor for jpeg encoding.  The
> default is 75, but I get decent compression and much better visual
> results at 90.  Perhaps imconv could use a -q switch on the command
> line?
> 
> Brian


Thanks for the tip, Brian. Adding a command-line switch will screw up
the interface... but, instead, I extended the "www" format
specification which "imconv" uses. Now, 

imconv -t www foo.rgb

will use the default quality for cjpeg, while

imconv -t www80 foo.rgb

will use -q 80. Actually, any number tagged onto "www" will become
cjpeg's quality factor.

Unfortunately (well, maybe not), "ps2www" has spread from person to
person (each using slightly different headers/footers/formats) and so
I cannot add the necessary command-line switch to "ps2www"...


Apostolos "Toli" Lerios               | "I have the heart of a little boy --
Stanford University                   | pickled, atop my desk."
http://graphics.stanford.edu/~tolis/  |                        - Robert Bloch