ak10+@andrew.cmu.edu (Andrew Joseph Kompanek) (03/09/89)
I am giving consideration to buying a NeXT machine and I have a few questions
concerning the machine's support of display PostScript which I haven't
been able to find answers to.
1) Is the display setup as a (logical) device so you can send it a stream
of PostScript source just like any other PostScript device?
2) Is any of the graphics support in hardware?
3) Do you setup a PostScript "display list" that is interpreted
in (pseudo)parallel with other CPU tasks (analogous to the copper display
list on the Amiga or the old Atari 8-bit graphics display list).
4) How close to the "standard" is the display PostScript used in the machine?
And, is so-called "Display" PostScript really any different from a standard
"Printing" PostScript implementation?
5) If there is no/little hardware support is there any chance that there
will eventually be a graphics coprocessor/graphics engine available
for the NeXT machine?
6) (This follows from the answers to the other questions, but I'll ask
it explicitly anyway). Will the display support "artifacted"/dithered
(I can't think of the right term off-hand) display of gray levels
above and beyond the 4 gray scales supported. Also, can the brightnesses
for the four colors (gray scales) be changed?
7) Are the gray scales implemented with bit-planes so that eventual color
(well, at least more gray scales) support will be "consistent" with
original graphics model?
and finally, (8) if the support is all in software and this is a true
implementation of PostScript, how the h*ll can it be as fast as it is?
Thanks,
Drew
( If someone thinks answers to these questions are relevant to the pop. of this
board post an answer, otherwise send me personal e-mail. Also, could someone
tell me exactly WHO has NeXT machines at this point in time? )
Andrew Kompanek ARPA: ak10+@andrew.cmu.edu
Carnegie Mellon University
Research Assistant, The Robotics Institutejohnl@ima.ima.isc.com (John R. Levine) (03/10/89)
In article <UY5U9ry00W0GEIP0wK@andrew.cmu.edu> ak10+@andrew.cmu.edu (Andrew Joseph Kompanek) writes: >I am giving consideration to buying a NeXT machine and I have a few questions >concerning the machine's support of display PostScript which I haven't >been able to find answers to. > >1) Is the display setup as a (logical) device so you can send it a stream > of PostScript source just like any other PostScript device? Sort of. The connection to the postscript server is through mach ports rather than via something like /dev/postscript, but it is perfectly simple to tell it to eat a bunch of ASCII postscript. There's a demo program called yap that does just that. >2) Is any of the graphics support in hardware? Not as far as I can tell. >3) Do you setup a PostScript "display list" that is interpreted > in (pseudo)parallel with other CPU tasks (analogous to the copper display > list on the Amiga or the old Atari 8-bit graphics display list). The postscript server is a Unix process that runs in parallel with yours. You blat postscript at it, and it does it. Although you can send regular ASCII postscript, what programs do in practice is to send a new compact encoding, defined in Display postscript, which you get from a compile-time preprocessor. >4) How close to the "standard" is the display PostScript used in the machine? > And, is so-called "Display" PostScript really any different from a standard > "Printing" PostScript implementation? DPS is a superset of regular printer postscript. It adds a bunch of stuff that is quite handy for working on screens, e.g. graphic state objects that encapsulate the context of a window. >5) If there is no/little hardware support is there any chance that there > will eventually be a graphics coprocessor/graphics engine available > for the NeXT machine? Widely spread rumors claim that Pixar is building one. >6) (This follows from the answers to the other questions, but I'll ask > it explicitly anyway). Will the display support "artifacted"/dithered > (I can't think of the right term off-hand) display of gray levels > above and beyond the 4 gray scales supported. Also, can the brightnesses > for the four colors (gray scales) be changed? You can set your gray level to any floating point value from 0.0 to 1.0 and DPS will dither as best it can. Looks pretty decent. You can't change the four hardware colors other than turning the brightness up and down. >7) Are the gray scales implemented with bit-planes so that eventual color > (well, at least more gray scales) support will be "consistent" with > original graphics model? Yes. DPS already has support for arbitrary colors, though at this point setting your color to .32334 red, .98745 green, and .27458 blue doesn't do you much good. >and finally, (8) if the support is all in software and this is a true >implementation of PostScript, how the h*ll can it be as fast as it is? I guess it's magic. More to the point, for all of the fast animation you see, they precompute bitmaps and composite them around, which turns out to be quite effective. -- John R. Levine, Segue Software, POB 349, Cambridge MA 02238, +1 617 492 3869 { bbn | spdcc | decvax | harvard | yale }!ima!johnl, Levine@YALE.something You're never too old to have a happy childhood.
dorner@pequod.cso.uiuc.edu (Steve Dorner) (03/13/89)
In article <3448@ima.ima.isc.com> johnl@ima.UUCP (John R. Levine) writes: >>2) Is any of the graphics support in hardware? >Not as far as I can tell. I think this is wrong; I remember reading that there was "hardware assist for compositing". If I read this correctly, it means there are at least pieces of a blitter. It certainly would explain why you can drag windows and their contents around. Steve -- Steve Dorner, U of Illinois Computing Services Office Internet: dorner@garcon.cso.uiuc.edu UUCP: {convex,uunet}!uiucuxc!dorner IfUMust: (217) 244-1765