Path: utzoo!utgpu!watmath!clyde!att!osu-cis!tut.cis.ohio-state.edu!bloom-beacon!gatech!ncar!ames!ucsd!sdcsvax!ucsdhub!esosun!seismo!uunet!munnari!jkjl
From: jkjl@munnari.oz (John Lim)
Newsgroups: comp.sys.mac.programmer
Subject: Re: Laserwriters vs. Transfer modes
Keywords: Laserwriter postscript modes regions
Message-ID: <2579@munnari.oz>
Date: 21 Nov 88 07:56:22 GMT
References: <6496@csli.STANFORD.EDU>
Reply-To: jkjl@munnari.UUCP (John Lim)
Organization: Comp Sci, Melbourne Uni, Australia
Lines: 42

In article <6496@csli.STANFORD.EDU> wilson@csli.UUCP (Nathan Wilson) writes:
>Could someone in the know with regard to PostScript or LaserWriter drivers
>please explain why it is that the LWII NTX doesn't support all the transfer
>modes rather than just srcCopy and scrNotCopy?  And why it doesn't support
>regions?  I personally really like to be able to use inverted objects and
>transparent objects (ie the 'white' bits in patterns are clear), and it
>would be nice to get them to come out on the LaserWriter as well as the
>ImageWriter.  Is this just laziness on the part of Apple because no one
>has asked for it or is there some underlying reason that makes it really
>hard?  Are there graphics packages out there that support transparent,
>invert or 'Bic' mode on the laserwriter?  SuperPaint 1.0 supports
>transparent on the screen but it don't come out on the LW. :-(
>
>	Please, somebody answer!
>		Nathan Wilson
>		Teleos Research
>---
>These aren't opinions, they're questions so I guess I don't need to say
>anything.

I have never programed in postscript, but have studied the language. I
really can see no reason why regions couldnt be implemented in postscript
as a region can be easily interpreted and converted to a path. This looks
like laziness on apple's part.

The transfer modes problem looks a bit more difficult. Postscript is
more object orientated than QuickDraw. I have always thought that
postscript is a better tool for object orientated drawing, and quickdraw
better with bitmaps. There are no transfer modes per se in Postscript.
Furthermore bitmaps are transfered as hexadecimal characters in postscript.
With the conversion overheads, implementing transfer modes in ps is just
too slow i suspect (and too difficult ?).

Why dont you just save all your object orientated stuff as a macpaint file
and then use laserbits to get the high quality you're looking for.

Anyone out there know how Display Postscript is implemented. Is it 100%
interpreted ?

	john

Disclaimer : i bet i don't know what i'm talking about...