Xref: utzoo comp.graphics:8148 comp.fonts:805
Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!ucbvax!agate!shelby!csli!keith
From: keith@csli.Stanford.EDU (Neil Hunt)
Newsgroups: comp.graphics,comp.fonts
Subject: Re: Converting spatial resolution to intensity resolution
Summary: Look at dvipage for example of swapping resolutions.
Keywords: grey-scale fonts; spatial/grey-scale resolution.
Message-ID: <10828@csli.Stanford.EDU>
Date: 30 Oct 89 19:36:29 GMT
References: <4155@cbnewsc.ATT.COM>
Sender: keith@csli.Stanford.EDU (Neil Hunt)
Reply-To: Neil%teleos.com@ai.sri.com
Followup-To: comp.graphics
Organization: Teleos Research
Lines: 20

In article <4155@cbnewsc.ATT.COM> vgopal@cbnewsc.ATT.COM writes:
>Has anyone written a program that takes a high resolution monochrome
>image (only two levels of intensity - black and white) and converted
>it to low resolution image but with greyscale information ?  Thus
>trading off spatial resolution for intensity resolution..

Check out Dvipage, which renders a page of a document typeset by TeX or LaTeX
using 300 dot per inch bilevel fonts (the same bits used for a LaserWriter)
and then performs averaging and sampling to produce 75 dot per inch
grey scale pages for display on a colour sun.  Lookup tables are used
extensively to enable the conversion process to be performed in about
2 to 5 seconds on sun 4/260 and 3/160 respectively, for 8.5x11 inch pages
(~8.5e6 pixels).  (Other operating modes are also supported.)

Dvipage (3.0) is available (in source) from june.cs.washington.edu, or from
the sun spots archive. I believe that these sources also have the patches
for PK font reading.  (As far as I can tell, no one has made dvipage work
on a 386i yet, due to byte order problems.)

Neil/.		Neil%teleos.com@ai.sri.com	...decwrl!argosy!teleos!Neil