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Re: Friendly Windows
Posted:
Sep 21, 1998 1:27 PM
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On Tue, 15 Sep 1998, "James O. Wilson" <Wilsonj@hillsboro.isd.tenet.edu> wrote
> I had a question this morning from a colleague about working in a
> window in the TI - 82.
>
> I did not remember how to set up a "friendly window".
>
> Will someone please refresh my memory?
Here is a program for the TI-82/83 that takes *any* window and makes it
into a friendly window.
ZNICEX takes whatever the current window is and adjusts it slightly to
make the x-coordinates nice: it keeps the same center as the current
window, and keeps almost the same bounds, but expands the window
slightly in the x direction (if necessary) so that the pixel size is 1,
2 or 5 times a power of 10.
To use ZNICEX, you get the window the way you want it by manually
entering the window bounds and/or by using ZOOM BOX, ZOOM...IN, etc. Then
you run ZNICEX to convert your window into a nice window.
In the following listing:
"->" represents the STO key.
"deltax" represents the delta-x symbol (VARS/WINDOW menu).
The spaces are included to make it more legible: don't type them in.
ZNICEX
:(Xmax-Xmin)/94 -> P P = current pixel size
:int(log P) -> E separate P into P = x*(10^e) with 1<=x<10 ...
:P/(10^E) -> X ...
:If X>5 : 10 -> X round x to a nice number (1, 2, 5, or 10) ...
:If X>2 and X<=5 : 5 -> X ...
:If X>1 and X<=2 : 2 -> X ...
:If X<=1 : 1 -> X ...
:X*10^E -> P P = new pixel size
:(Xmin+Xmax)/2 -> C C = center x coordinate
:round(C/P,0)*P -> C round C to a multiple of P
:C-47P -> Xmin set new window ...
:P -> deltax ...
:DispGraph show graph
If you are using this program, you may want to set the ZOOM FACTORS to
10. That way, once you have a nice window, after you zoom in or out you
will still have a nice window. (In zooming out, you need to be careful
to place the center on a pixel which is a multiple of 10 times the
current pixel size, or the new window won't be nice.)
[The program BETTRPTS, by Matthew Weaver, is similar to ZNICEX, although
we wrote them independently. See "Friendlier Windows for the TI-85,"
Eightysomething, vol. 3, no. 2 (spring 1994), p. 9.]
------------------------------------------------------------------
Evan Romer Susquehanna Valley HS
sv_golden@SUNYbroome.edu Conklin NY 13748
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