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Almathera Ten Pack 3: CDPD 3
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Almathera Ten on Ten - Disc 3: CDPD3.iso
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scope
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026-050
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scopedisk46
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mj-pgs
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instruct_t
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1995-03-18
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1) It is advantageous to have a library of 16-color palettes (and fun
to make). Load Sel.Cols (real name is SelectColors, but I need to
arc it) into Amigabasic. Use the numbers 1 to 15 as dummy break-
points, later to be over-written by "bp" files.
2) Run MJ.Gen_T. If a Mandelbrot, or you wish to plot the interior of
a Julia set in the solid background color (usually black), enter 0
for "max. size". Opt for plotting, and select a reasonably small,
mode 1 screen. It won't make a good picture, but it'll be fast.
3) Test plot to establish accurate figures for real and imaginary co-
ordinates, and appropriate values for lowest and highest counts.
The plot program in this group will use each color only once and a
value for lowest count in a high-magnification region causes loss of
some low palettes. Replot with different values until each color ap-
pears in properly sized areas, including (the highest) palette 15.
4) Prepare a formatted, empty disk and re-run the program set for writ-
ing. Choose a mode 4 screen (hires, interlaced) preferably with 0 to
386 (i.e. 387) vertical pixels and enough horizontal pixels to main-
tain the proper aspect ratio. Make sure that the hor. pixels (max =
632) is even for a symmetric Julia set. Writing of the files will
take approximately 1/2 to several hours depending on the size of the
window and the number of high counts which are present.
5) Run divide_T or div.Combs_T and write the "bp" file. This is the
series of 15 "breakpoints" (counts where the color should change for
equal-area representation), and make a note of the lowest count
shown. You might now also wish to see how well this agrees with
your estimate while test-plotting with the generator. At this time,
you might also wish to run Brkpts_T, using this as the low entry.
I often got nice results by averaging the divide and brkpt values
for each point and save this as a "hybrid" file. Finally, you may run
M-graph_T, look at the bargraph and hand-select breakpoints on the
basis of the hills and valleys of the display.
6) Run MJ.plot_T. When asked for a file of breakpoint/color data, enter
the file produced by Sel.Col. When asked whether you want to modify
this with a bp-file, respond with "y" if the breakpoints are the
dummy numbers 1 to 15. If you have run divide first and then Sel.Cols
and entered the real breakpoints, then respond with "n".
You will now have the opportunity to save the combined breakpoint-
colors data file. When asked if you want a color change with each
count, agree only if you plot a low-count region, e.g. the environ-
ment of a Julia set, otherwise you'll get a mess. Save the plot if
you like it.
7) Plot again, using different parameters, or use the just-saved data-
file and avail yourself of the opportunity to modify any of the in-
dividual breakpoints and/or palettes to suit your taste.
General: A square plot of 452 x 387 pixels (my aspect ratio is 1.169)
produces a MKI$-based count file of 349848 bytes. With a few IFF
picture and data files, this uses about 65-75% of a disk. It is
therefore advantageous to reserve a fresh disk for each region in-
vestigated and thus leave some room for more artistic ideas.
MJ.plot runs significantly faster if compiled with AC-Basic. Since
compiled programs exit from memory when allowed to END, a provision
is made to re-run the program with different parameters without end-
ing. The same was done with MJ.Gen_T, although the speed advantage
here is minimal (abt. 1% or so).
I have written two plot programs in which the number of breakpoints
is independent of the number of palettes, i.e. unlimited. These are
not yet edited for the use of "inform" files. I can submit those if
there is enough interest.
Anselm Wachtel