Path: utzoo!utgpu!water!watmath!clyde!att!osu-cis!tut.cis.ohio-state.edu!bloom-beacon!apple!casseres
From: casseres@Apple.COM (David Casseres)
Newsgroups: comp.sys.next
Subject: Re: WYSIWYG
Keywords: WYSIWYG
Message-ID: <144@internal.Apple.COM>
Date: 25 Oct 88 19:10:52 GMT
References: <6937@orstcs.CS.ORST.EDU> <12908@oberon.USC.EDU>
Organization: Apple Computer Inc, Cupertino, CA
Lines: 66

In article <12908@oberon.USC.EDU> venkat@brand.usc.edu (V. Venkat) writes:

>With a 17" diameter screen i.e. apprx 12" X 12" screen and a 1024X1024 pixels
>-- the screen resolution will be about 86 pixels per inch.
>Since the printing is essentially WYSIWYG a laser printer with 86 dpi
>will suffice. What is the use of a 400 dpi laser printer unless the screen
>represents only a part of the printed page and you have some scrolling 
>mechanism? Maybe I haven't understood the fundamentals here. Can someone
>illuminate me further on this matter. Much thanks.

Aha, we are into the wonderful wierd world of "just what DOES WYSIWYG really
mean, anyway?"  First, when Alan Kay coined the phrase it was not about
visual fidelity between a computer screen and printed paper at all; it was
about having a good visual representation (on screen) of your work, i.e.
the contents of your head.  At least that's how I understand it.

But of course Kay's meaning has now disappeared in a fog of marketing hype.
In its purest form the hype goes "what you see on the screen is EXACTLY
what will be printed."  Of course this is baloney.  If it were true it would
mean you just get a printed screen dump, at screen resolution, but nobody
has ever been satisfied with that.

A slightly more evolved form of the hype is "what gets printed is exactly
what you saw on screen, only you couldn't see ALL of it on screen without
scrolling, and the printed image is nicer because the printer has higher
resolution."  A very simple but bogus statement is struggling to turn into
a rather complicated, somewhat less bogus statement.

Myself, I like to avoid the term WYSIWYG when talking about printing, and
use the term "visual fidelity."  To me this means that the imaging and
printing software will go through whatever contortions are necessary to
render an ideal page image on the screen and on the printer, finding the
best balance of A) quality of the printed image, B) quality of the screen
image, and C) geometric and graphical correspondence between the two images.
This is an extremely complicated and difficult problem to solve, EVEN when
you get to use PostScript for both the screen and the printer.

For example, users want to have 8-point text.  Hell, they even want 6-
point, and the printer prints 6- point beautifully.  If you use the same
letter designs on the screen (graphical fidelity), the tiny letters are
illegible.  If you change the letter designs for small sizes so as to make
them legible, they don't lay out the same way any more, i.e., you find you
have not only given up graphical fidelity but geometric fidelity as well.
The string of letters may overlap something on paper that it didn't overlap
on the screen, or a margin that was straight on the screen is ragged on
paper, etc.

For another example, PostScript is "resolution independent" and everything
you draw can be arbitrarily scaled.  That's a nice way to take care of
differing resolutions on the screen and printer.  But people want to in-
corporate scanned images into their documents, and scanned images are bitmaps,
and bitmaps are NOT resolution independent.  When you scale them, ugly
artifacts appear.

Because of problems like these, achieving visual fidelity is as much an art
as a science; a lot of judgement has to be used, and ultimately the solutions
that emerge are the result of history and the interactions of system designers,
application designers, and end users.  The solutions on the Mac have always
had a strong tendency to become printer-dependent, as third party developers
sought to squeeze every bit of advantage out of each kind of printer; this
has added to the general complexity of the problem.

I'll be watching NeXT's development from a relatively clean slate with great
fascination.

David Casseres