Article View: comp.lang.postscript
Article #4964Re: setscreen pixels
From: Jim Dumser
Date: Sat, 09 Mar 1991 16:00
Date: Sat, 09 Mar 1991 16:00
40 lines
2122 bytes
2122 bytes
In article <1474@vidiot.UUCP> brown@vidiot.UUCP (Vidiot) writes: |In article <2349@umriscc.isc.umr.edu> jmd@ee.umr.edu (Jim Dumser) writes: |< |<[ Quote from the red (& white) book ] | |Ya, I read that, but it doesn't answer the question asked next. It doesn't |say how the the number of pixels in the cell is computed, which is what I |was asking for. | |<> [ Vidiot's question about fractions (ie. sqrt(40) = 7.5) ] |< |<[p314]: |< "the *sethalftone* or *setscreen* operator may make slight |< adjustments to the requested frequency and angle to ensure that the |< patterns of enclosed pixels remain constant as the screen cells are |< replicated over the entire page." | |Ya, I read that too. Still doesn't answer the question. | |<>In other words, what is the internal working formula for determining |<>what the printer will use for the number of pixels in the cell? Are |<>the formulas different for the Apple LaserWriter IINT and the |<>Lintotronic 1270 dpi? |< |<In Level 2, halftone dictionaries have an optional entry, |<AccurateScreens, that cause "extremely precise, but computationally |<expensive" algorithms to be used. Also, they can have entries that get |<set with the actual frequency and angle used. | |So, what are the internal formulas?????? Ok, here's your answer: They are unspecified. In otherwords, they are implementation dependent. Probably a Lintotronic printer will not use the same algorithm as a LaserWriter. If you are writing for Level 2, you can iterate until you get the ActualFrequency and ActualAngle you want. Jim
Technical Details
Message-ID:
<2364@umriscc.isc.umr.edu>Path:
arc1-ca.pugleaf.net!utzoo!utgpu!news-server.csri.toronto.edu!rutgers!tut.cis.ohio-state.edu!magnus.ircc.ohio-state.edu!zaphod.mps.ohio-state.edu!uakari.primate.wisc.edu!umriscc!ee.umr.eduReferences:
<1454@vidiot.UUCP> <2349@umriscc.isc.umr.edu> <1474@vidiot.UUCP>Show Full Headers
Complete Article Headers
Path: arc1-ca.pugleaf.net!utzoo!utgpu!news-server.csri.toronto.edu!rutgers!tut.cis.ohio-state.edu!magnus.ircc.ohio-state.edu!zaphod.mps.ohio-state.edu!uakari.primate.wisc.edu!umriscc!ee.umr.edu From: jmd@ee.umr.edu (Jim Dumser) Newsgroups: comp.lang.postscript Subject: Re: setscreen pixels Message-ID: <2364@umriscc.isc.umr.edu> Date: 9 Mar 91 16:00:04 GMT References: <1454@vidiot.UUCP> <2349@umriscc.isc.umr.edu> <1474@vidiot.UUCP> Sender: news@umriscc.isc.umr.edu Organization: University of Missouri - Rolla Lines: 40