Education Sampler 1992 [NeXTSTEP]/Education_1992_Sampler.iso/NeXT/Misc/HigherEducationMailbox.mbox/Archives_provide_val_.attach/May_91/postscript.537

Text File | 1991-05-21 | 2KB | 29 lines

{\rtf0\ansi{\fonttbl\f0\fnil Times-Roman;\f1\fmodern Courier;}
\paperw11440
\paperh9000
\margl120
\margr120
\pard\tx520\tx1060\tx1600\tx2120\tx2660\tx3200\tx3720\tx4260\tx4800\tx5320\tx5860\tx6400\tx6920\tx7460\tx8000\tx8540\f0\b0\i0\ul0\fs28 malformed postscript alphaimage\
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Q:  Why do I get a "malformed postscript" error message when I send PostScript that includes the
\b alphaimage
\b0  operator
\pard  to a printer
\pard\tx520\tx1060\tx1600\tx2120\tx2660\tx3200\tx3720\tx4260\tx4800\tx5320\tx5860\tx6400\tx6920\tx7460\tx8000\tx8540 ?\
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A:  There were some extensions made to PostScript so that it can be used onscreen; the new form is called Display PostScript (DPS).  We have to handle the new operators (such as
\b alphaimage
\b0 ) specially whenever we send anything to a conventional PostScript printer.  We do that by inserting the print package at the beginning of the data that is sent to the Window Server.  The print package—/usr/lib/NextStep/printPackage1.0.ps—redefines the DPS operators that can be simulated and no-ops those that don't mean anything on the display.  Other DPS operators are not redefined and will cause a "malformed postscript" message if sent to a printer.\
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The philosophy behind this is that we don't want to image something on a printer differently from the way it looks on the screen.
\b alphaimage
\b0  can't be imitated on paper, so it's an obvious one not to redefine.  It probably really is a mistake to try to send PostScript code that uses it to a printer.\
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See also NextAnswer postscript.61.\

Not Valid for 2.0 Superceded by postscript.583\
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QA537\
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