Path: utzoo!utgpu!jarvis.csri.toronto.edu!rutgers!sun-barr!decwrl!adobe!mills
From: mills@adobe.com (Dan Mills)
Newsgroups: comp.lang.postscript
Subject: Re: Using a postscript printer for previewing?
Message-ID: <1565@adobe.UUCP>
Date: 27 Dec 89 20:25:09 GMT
References: <1989Dec22.210230.863@ibmpcug.co.uk>
Sender: news@adobe.COM
Reply-To: mills@adobe.COM (Dan Mills)
Organization: Adobe Systems Incorporated, Mountain View
Lines: 50

In article <1989Dec22.210230.863@ibmpcug.co.uk> ccain@ibmpcug.co.uk (chris cain) writes:
>I can only ask if the hint's distort nothing why do you need 2 sets of outline
>data in ANY fonts. I could see only 2 possible reasons either the hinting
>required some compromise to the outline shape or there were some founts
>which the hinting  needed to start from a distorted outline and then
>hinted it back to the correct shape. A press release from Bitstream
>when they released Type 1 fonts suggested that they had not used hints
>because of the compromises requred to the outline shape to produce the
>hinted fonts. Now this may have been ad hype on the part of Bitstream and
>it may have caused me to jump to an incorrect conclusion on seeing the 
>2 outline fonts but that is part of the penalty you have to pay for
>having closed technology fonts. People will guess about what you are 
>doing and why you are doing it they may guess wrong but we are all human
>(mostly) and so make misteaks.
>
>I'm sorry about the large number comment it was probably
>foolish comeing as it did from a sample of about 6 fonts where 2 had double
>data sets so I must have been lucky (unlucky?) in hitting so high a percentage.
>I have had a large number of requests for the program so perhaps you can
>comment on Adobes position on a posting of this program ?.

A few fonts have a second set of outlines because their design makes
extensive use of features that are especially difficult to render on raster
output devices. Optima* has very shallow curves that are nearly horizontal
or vertical. ITC Eras(R) is very slightly slanted.

Simply put, we couldn't get decent results so we made "simplified" versions
for use at low resolution. It has very little to do with hints, except to
the extent that the hints failed to work their magic adequately.

My original vehemance was in response to your statement that hinting
"distorts the font shapes badly". The vast majority of our hints don't
modify the outlines at all, so they couldn't possibly distort them. Our
hints are declarative rather than procedural. They just state some fact
about a character or set of characters -- a fact that would be difficult or
time consuming to derive on the fly. It is up to the rasterizing algorithm
to use this information to achieve the desired results. In short, the smarts
are mostly in the rasterizer, not in the fonts. The primary advantage of
this is that you don't completely obsolete the installed base of fonts every
time you get a great new idea about how to render characters. (Adobe Type
Manager is a shining example of this.)

Sorry, I obviously can't comment on legal issues relating to your program.
Since the font format will be publicly available in a matter of weeks, it
will soon be a moot question.

- Dan Mills

ITC Eras is a registered trademark of International Typeface Corporation.
* Optima is a trademark of Linotype AG and/or its subsidiaries.