[comp.sys.next] DPS, pft, Scene background

m@jacobi.biology.yale.edu (mark mccallum) (10/18/90)

Ok, I started with two tasks; I wanted to duplicate Scene's ability to modify
the background and to produce a calendar including images. I have come up with
some questions and some information.

First the background problem:

I used pft to list out all of the windows in the screen list. It shows that
Scene does create a window, which it places just above the base window in the
screen list. It assigns the base window's context, event mask, and alpha value
to this window. I created a window, positioned it, and set the stated values
to be the same as the base window. It acted like the 'background' script in that
right mouse button clicks fail to bring up the current application's main menu.
I have asked Next Support for an answer to what else Scene does to this window
and was told I should have an answer in a day or two. As a side note you can
indeed draw in the base window, but it is a non-retained window and as such
whenever an area of the window is exposed it is filled with the window's
exposure color.
Using pft to display the screen list, I created a window and displayed the
values there, but at first I tried to just print values out to the terminal
window I ran pft from. I attempted to use writestring.
The ps manuals state that every interpretter should provide %stdin, %stdout,
and %stderr. None of these seemed to work. The closest I got was to see what
I had written displayed in the terminal window after exiting pft. pft issues
error messages, so I know this can be done. I have also posed this question
to Next Support.

Secondly:

I took pscal from the public domain archives and modified it so that whenever
the message in .holiday was the name of a readable file it would grep that
file for a bounding box, translate and scale that box so that it would fit
within a single day, and include the postscript file. This produces very nice
calendars with pictures, diagrams, etc. for certain days. It works very nicely
when displayed on the screen. I have used preview and imported the calendar
into TopDraw and it looks right. However if I try to print it from TopDraw
and there is more than one included image I get the included postscript,
but only part of the calendar. With one image it prints fine. If printing is
attempted from preview I get either an error saying illegal postscript operator,
which is usually one of the pscal defined functions, or just no output at all.
My first thought was that there wasn't enough stack space, but I played with
it enough that I did produce a stack overflow error. So I should have gotten an
error message in the other cases.

Any ideas of where to look next?
I remember someone stating that an image is rasterized and then sent to the
printer. Can anyone provide a detailed description of this process?

I will post a summary and any resulting programs/scripts.

thanks, mark

eps@toaster.SFSU.EDU (Eric P. Scott) (10/18/90)

Question: are you willing to wait for me to post complete,
working sources, or do you just want an explanation of what's
going on and the relevant part of the pswrap I use in my yet-
unreleased background program, knowing that this will become
a permanent part of the archives and is potentially misleading in
an incomplete form?
					-=EPS=-