johnl@ima.ima.isc.com (John R. Levine) (02/22/89)
I see in the display postscript extensions chapter of the manual a swell
operator called dissolve. It takes n% of one window and (100-n)% of the
current window and dissolves them together. But I can't figure out how to
get it to work.
The problem is that the source window is specified as a graphics state, a
complex object that lives inside display postscript and can't be passed back
to a user program. That's OK, I have a bitmap full of bits that I want to
dissolve, and I know that it has a secret window and an associated gstate.
(I know this because the composite operator also takes a gstate and the
Bitmap object can composite like crazy.) The manual suggests that I make
the gstate a "userobject" thing so I write some pswrapped code that locks
the focus into the bitmap, thus activating its window and gstate and then:
0 gstate defineuserobject
which seems to me should store a copy of the current gstate into userobject
number 0. Instead, it tells me that there's no defineuserobject operator.
I suppose I could try to define the gstate with a name, but it's quite unclear
to me how windows map into postscript contexts -- do all the windows in a
single application share a name space? I'm confused.
--
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.