Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Path: utzoo!mnetor!seismo!ut-sally!husc6!think!ames!ucbcad!ucbvax!dewey.soe.berkeley.edu!oster
From: oster@dewey.soe.berkeley.edu (David Phillip Oster)
Newsgroups: comp.sys.mac
Subject: Re: Cheap LW without PS?
Message-ID: <19461@ucbvax.BERKELEY.EDU>
Date: Wed, 24-Jun-87 13:27:36 EDT
Article-I.D.: ucbvax.19461
Posted: Wed Jun 24 13:27:36 1987
Date-Received: Fri, 26-Jun-87 05:43:46 EDT
References: <1604@tekig4.TEK.COM>
Sender: usenet@ucbvax.BERKELEY.EDU
Reply-To: oster@dewey.soe.berkeley.edu.UUCP (David Phillip Oster)
Organization: School of Education, UC-Berkeley
Lines: 82
Keywords: Apple LaserWriter PostScript


A cheap LW with only postscript could still be quite a nice product,
for any Macintosh owner with a hard disk:

1.) QuickDraw only draws in pixels, but quickdraw doesn't care how big
a pixel is: It is easy to have the printer driver tell the application
that the canvas is 300dpi instead of 72dpi, and, if the application
follows Apple's guidlines it will do the right thing.

2.) Some applications don't follow apple's guidlines, and won;t be
able to correctly draw on a 8"x10" page at 300 dpi. For these
applications, you still get lines and arcs out of the printer that are
drawn with 300 dpi pixels, not 72 (laserwriter size (almost invisible)
jaggies, not imagewriter size.)

3.) An example of this is the "best" quality drawing mode that the
imagewriter driver supports. it provides type (1) drawing for
applications that can handle it and type (2) drawing for the rest.

4.) Well what about text? PostScript represents a font family as a set
of spline equations, and QuickDraw as whatever the font manager tells
it it is. One could, in theory, write a font manager that used an
internal spline representation, but let's just talk about what is
easy. The current font manager stores a font as a bitmap. When you
print at a different size resolution than the screen, the font manager
and quickdraw cooperate to do font substitution, i.e. they pick a
bitmap that will do a better job. You see this all the time in "best"
quality printing on the imagewriter: 12 point text gets printed using
not the 12 point, screen font bitmap, but the 24 point bitmap, because
it is a better match to the 144dpi environment of the imagewriter in
best mode.  If you want good text on the laser writer, all that needs
to happen is somebody needs to draw it and sell it. Big bitmap fonts
are currently bulky, so the user will want a hard disk very fast, but
you can by a lot of hard disk for the difference in price between this
rumored laser printer and a LaserWriter Plus.

What would you really lose? Well, any application that emits
postscript and also draws on the screen, should work just fine on this
new printer: if it can draw on the screen at 72dpi, it has all the
smarts it needs to draw on the printer at 300. Any application that
just emits postscript, and doesn't do any screen drawing ("just text"
for example, as I understand it.) won't work.

I expect that the current crop of postscript emitting products will
need an upgrade to handle the new printer: blindness and expediency, a
lack of printers to test on, and Apple providing no clear way to
discover whther a printer has postscript or not
kept the developers from really following apple's guidlines for
writing a printing program. I kind of expect that Adobe will not
upgrade "Illustrator" to work with non-postscript printers.

I've been thinking about putting together a company that takes this
one step further: You all ready have a machine that executes
QuickDraw, why buy a second? I want to sell a memory upgrade and a
laser printer on a SCSI port. When you print, the Printer Manager
calls the Memory manager to allocate a 1 Meg buffer. Quickdraw draws
directly into a buffer in the Mac, and when it is done, my product
just pumps bits directly to the writing laser. 
advantages:
1.) Cheap, 'cause it uses
the mac to do all the drawing. 
2.) Fast, 'cause it transfers bits direct
from main memory to paper. (No waiting for postscript to figure out
what QuickDarw already knows). Now, Quickdraw draws the page, ships it
over a serial link much slower than my DMA channel to another computer
in the LaserWriter that draws it a second time. With my scheme
QuickDraw draws it once, and the printer is ready to roll.
3.) When you aren't printing, that Meg of memory could be used for
something else (for example, the cache could go there, and I
automatically flush the cache before you start to print.)

I figure I'm worth 15% for the idea
plus my software, but I haven't been able to get Canon to take me
seriously enough to sell me printer engines.

Maybe people should write Apple not to knock a QuickDraw only
laserwriter, but to tell them to fund me doing this :-)


--- David Phillip Oster            --My Good News: "I'm a perfectionist."
Arpa: oster@dewey.soe.berkeley.edu --My Bad News: "I don't charge by the hour."
Uucp: {seismo,decvax,...}!ucbvax!oster%dewey.soe.berkeley.edu