🚀 go-pugleaf

Gottfried Mayer-Kress writes

> Some time I got some advertising file about why NeXT is superior to
> Mac:  because NeXT is a PostScript based machine, and therefore you
> get on the printer "exactly" what you see on the screen, NOT!  I found
> this extremely frustrating when I tried to show off the new NextStep
> 3.0 with PostScript "Level 2" with some simple graphics:  I had a
> perfect alignment of some elements on the screen, when I printed (even
> on the new, fancy color printer) I got a consistent offset of about
> 3mm, a real *&%^&#$-pain in the neck. This happened both in Create
> and also in Appsoft Draw!! I really hope that I am just too dumb for
> PostScript and someone has a nice and simple solution to this problem...

This is an application level problem.  Because of the lower resolution
of the screen, Display PostScript is doing it's best to show the image
as the application asks it to.  If the application asks it to display
a point and a line very close together, they may not show up on the
screen as different points, but they may be far enough apart that the
increased resolution of the printer shows the gap.

Your application needs to have some concept of 'snap' - snap-to-point,
or snap-to-line.  I don't know Create or Draw, but Illustrator has
just such a feature.  By using guides and the snap-to-point feature,
you are guarunteed that two point that claim to be aligned are aligned.

A temporary solution for many programs is to zoom up the maximum amount
and check alignment.  Usually this extra zoom factor will give you
the extra alignment you need, and hide the differences at low (300dpi)
printer resolutions.

Remember, screens have such a pitiful resolution, that it's *impossible*
to get *exactly* WYSIWYG.  The PostScript philosophy is to do the
closest approximation to the mathematical ideal possible given the
limits of the displaying device.

Display PostScript allows applications to be device independant, not
device ignorant.

--
Scott Byer                             NeXTMail: byer@mv.us.adobe.com
Adobe Systems Incorporated               These are *my* opinions, and  
1585 Charleston Road, P.O. Box 7900        do not necessarily reflect
Mountain View, CA 94039-7900             the opinions of my employer.
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