laser-lovers@uw-beaver (04/02/85)
From: rna!dan@nyu.arpa (Dan Ts'o) x, Could someone please fill me in as to the graphical capabilities of the Apple Laserwriter ? Does it have vector drawing instructions ? (e.g. PLOT-10) I assume it can do full bitmap dumps. Maybe what I'm asking are really Postscript questions... Thanks. Cheers, Dan Ts'o Dept. Neurobiology Rockefeller Univ. 1230 York Ave. NY, NY 10021 212-570-7671 ...cmcl2!rna!dan
laser-lovers@uw-beaver (04/02/85)
From: Brian Reid <reid@Glacier>
I thought I had explained this in gruesome detail already. The Apple
LaserWriter can print any image that can be described by a PostScript
file. While it can certainly do bitmaps, that is a wasteful and boring
way to use the machine; it can also do vectors, Bezier cubics (curves),
filled polygons, circular arcs, halftoning and greyscales, generalized
matrix transformations, and (perhaps best of all) fonts.
Just for fun, as a simple example, here is a PostScript file that will
make a solid-area 4-inch 5-pointed star in the middle of the page, in
50% gray. If you send this file, exactly as you see it here, to an
Apple LaserWriter, it will print this star. You can even send it with
the comments on it, just as I have typed it, though obviously in
practice you will not be putting comments like this on most
machine-generated files.
This is a cute example because it shows, in a trivially simple example,
the power of coordinate system transformations in drawing graphics. If
you want to see how it works, take a piece of graph paper, stick a
compass point through its center, put a pencil down at (4,0), and then
do 4 iterations of rotating the paper 2/5 turn clockwise, then
drawing a line from the place that the pencil has moved to (because of
the rotation) to the place that is 4 inches to the right of the compass
point (i.e. the new (4,0) point after the coordinate system rotation).
%! % magic number--identifies it as a PS file
72 72 scale % converts scale to inches (in both x and y axis)
4.25 5.5 translate % move (0,0) origin to center of 8.5x11 page
newpath % start new path
4 0 moveto % move to (x=4 in,y=0)
4 % push a repeat count on the stack
{144 rotate 4 0 lineto} % push a block of code to be repeated
repeat % this goes through 4 iterations of rotating the
% coordinate system 144 degrees clockwise, then
% drawing a line from the current point to
% the point (x=4 inches,y=0)
closepath % loop the path back to itself
0.5 setgray % set gray scale to 50% gray
fill % fill that path with 50% gray
showpage % print the pagelaser-lovers@uw-beaver (04/02/85)
From: tms@cadmus.arpa (Tom Stambaugh) You bet. It does anything you'd like it to do. You want "TranScript", from Adobe, for your Plot-10 stuff. Contact Matt Foley @ 415-852-0271. It is true that doing PLOT-10 on the laserWriter (with PostScript) is a little like putting a heater in the butter compartment of your refigerator to keep the butter soft, but I understand the demands of backwards compatibility. A PostScript Manual set costs $30 from Adobe, and its well worth it. Thanks, Tom Stambaugh