5.21 Passes Parameters
PERIODICITY=no|show|nnn
Controls periodicity checking (see Periodicity Logic (p. 166)). "no"
turns it off, "show" lets you see which pixels were painted as "inside"
due to being caught by periodicity. Specifying a number causes a more
conservative periodicity test (each increase of 1 divides test tolerance
by 2). Entering a negative number lets you turn on "show" with that
number. Type lambdafn function=exp needs periodicity turned off to be
accurate -- there may be other cases.
A non-zero value of the "periodicity=" option causes "passes=o" to not
plot orbits that have reached the bailout conditions or where an orbit
goes off the visible area of the image. A zero value of periodicity
will plot all orbits except as modified by orbitdelay and orbitinterval.
ORBITDELAY=<nn>
This option controls how many orbits are computed before the orbits are
displayed on the screen when using the "passes=o" option, or the fractal
types mandelcloud and dynamic. This allows the orbits to settle down
before plotting starts.
This option also slows down the display of orbits using the <O> command
for folks with hot new computers. Units are in 1/10000 seconds per orbit
point. ORBITDELAY=10 therefore allows you to see each pixel's orbit
point for about one millisecond. For best display of orbits, try
passes=1 and a moderate resolution such as 320x200. Note that the first
time you press the 'O' key with the 'orbitdelay' function active, your
computer will pause for a half-second or so to calibrate a high-
resolution timer.
ORBITINTERVAL=<nn>
This parameter causes "passes=o" to plot every nth orbit point ranging
from 1, which plots every orbit, to 255, which plots every 255th orbit.
This value must be lower than the value of maxit to make any sense.
SCREENCOORDS=yes|no
This parameter maintains the screen coordinates and lets you zoom into
an image changing the coordinates of the line or rectangle used to
generate the image, but keeps the display coordinates the same. The
screen coordinates can be zoomed, rotated, and skewed using the <F2>
Screen Coordinates Screen (p. 151). If set to no, the screen and image
coordinates are maintained the same when an image is zoomed.
ORBITDRAWMODE=rect|line
The rect(angle) method plots the orbits in a rectangle that can be
zoomed, rotated, and skewed using the <F6> Image Coordinates Screen
(p. 151), and the straight line method plots the orbits between two
points specified on the <F6> image coordinates screen.