[comp.lang.postscript] Generalised patterns

cn@allgfx.agi.oz (Con Neri) (11/28/90)

Has anybody out there done any extensive work on patterns in Postscript?

In particular, has anybody found any problems with Prog 15 in the blue book?
The example works fine as given but if you ask for a 45 degree screen then
a rangecheck error occurs. Does anybody have a fix for this?

With this same program I am experiencing some inconsistencies between the
rsults from a Laserwriter and from a software rip. On the Laserwriter, I
cannot increase the cellsize for the screen and see an expected difference.
There is a difference but trivial. I have changed the line

pat 8 1 ang 72 300 32 div div setpattern to
pat 8 1 ang 72 300 64 div div setpattern and
pat 8 1 ang 72 300 80 div div setpattern and
pat 8 1 ang 72 300 128 div div setpattern

and still there is no difference and no errors. On the software rip, the screen
increases in size (frequency decreases) as expected. 
Does anyone have any ideas?

Also, where is the magic number 72 200 32 div div plucked from?

Thanks in advance for any help

CON NERI

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