mike@THUMPER.BELLCORE.COM (Mike A. Caplinger at thumper.bellcore.com) (07/22/87)
I recently tried to print a PostScript document, produced and debugged with
an Apple LaserWriter, on a Linotronics phototypesetter. One of the
illustrations in the paper was done with MacDraw, and used a variety
of dashed and patterned lines (using line patterns, which is the only
way to do dashed lines in MacDraw). These looked just fine on the LaserWriter,
but on the Lino some of the lines disappeared completely, and others
looked the same when they were supposed to be different, and were different on
the LaserWriter.
This is a naive question, because I haven't thought through the interaction
of patterns with device resolution, but should this kind of thing be allowed
to happen? One of the reasons I was so enthused about PostScript was
its total device independence, but this experience has told me that it
isn't quite as portable as I thought.
Mike Caplinger
mike@bellcore.com
{decvax,ihnp4}!thumper!mikejmpiazza@sunybcs.UUCP (Joseph M. Piazza) (08/04/87)
In article <8707282034.AA20107@brillig.umd.edu> mike@THUMPER.BELLCORE.COM (Mike A. Caplinger at thumper.bellcore.com) writes: > ... One of the >illustrations in the paper was done with MacDraw, and used a variety >of dashed and patterned lines (using line patterns, which is the only >way to do dashed lines in MacDraw). These looked just fine on the LaserWriter, >but on the Lino some of the lines disappeared completely, and others >looked the same when they were supposed to be different, and were different on >the LaserWriter. ... >This is a naive question, because I haven't thought through the interaction >of patterns with device resolution, but should this kind of thing be allowed >to happen? The Mac uses a graphics language of it's own called QuickDraw. One of the LaerWriter system files called "LaserPrep" is actually a implemtation of QuickDraw in PostScript. Your problem most likely ivolves this. >One of the reasons I was so enthused about PostScript was >its total device independence, but this experience has told me that it >isn't quite as portable as I thought. I would like to point out that I have had problems with line patterns on our Mac-LaserWriter and the problem is n o t Postscript but how the graphics are rendered by the application -- most likely in QuickDraw. Flip side, joe piazza --- Cogito ergo equus sum. CS Dept. SUNY at Buffalo 14260 UU: ...{rocksvax|decvax}!sunybcs!jmpiazza CS: jmpiazza@cs.buffalo.edu BI: jmpiazza@sunybcs [[Editor's note. I think that this message fails to answer the original question. mike@thumper is complaining that he can create a syntactically legal PostScript file that prints in one manner on the LaserWriter and in another manner in the Linotron. Your message actually supports this point---the QuickDraw implementation for PostScript printers is encoded in PostScript, after all. The issues raised here are ones of the definition of "device independence" and how far that concept can be stretched. mike@thumper is saying that as a user of such systems, he feels that the definition that has been implemented is too restrictive. I'm hoping that some of our readers will give a counter argument to this, indicating, perhaps that some of what he trying to do is inherently device-dependent. --Rick ]]