chavez@sumex-aim.stanford.edu (R. Martin Chavez) (01/12/90)
My colleagues and I would like to fill PostScript paths with patterns defined as 8x8 bit matrices. We need the fill operation to be extremely fast, and so we'd like to use the halftone mechanism (which would clearly win over replicated tiling of the region with the pattern). We're presently using code from the Blue Book that purports to call setscreen with frequency, angle, and spot-function parameters that accurately represent predefined bit patterns. Unfortunately, the results look terrible (and wrong) on the MegaPixel display, with its 4 gray levels. Instead of setting pixels to either black or white, DPS seems to want to choose intermediate values, with unacceptable results. We know that FrameMaker has some mechanism (presently unknown to us) for filling regions. Can anyone out there point us to PostScript code that does the job? Thanks, R. Martin Chavez Stanford University School of Medicine
glc@c3po.UUCP (Greg Cockroft) (01/16/90)
Checkout FrameMaker.app/.fminit2.0/next/makerbegin.ps. search for pattern. The only way to do fast patterns in NeXTStep, or NeWS is to tile on offscreen window, and then later clip & do a window to window copy operation. The halftoning mechanism method only works if you have a 1 bit display, because all you get to specify is the order to set the dots, not the actual values. Notice how patterns in FrameMaker documents look horrible when previewed, this is because the halftoning mechanism is being used on printout. NeWS never implemented halftoning. Not in the PostScript sense anyway.