Image Calculation Parameters


PASSES=1|2|3|g|g1|g2|g3|g4|g5|g6|b|t

Selects single-pass, dual-pass, triple-pass, solid-Guessing mode, solid- Guessing stop after pass n, Boundary Tracing, or the Tesseral algorithm. See Drawing Method .

FILLCOLOR=normal|<nnn>

Sets a color to be used for block fill by Boundary Tracing and Tesseral algorithms. See Drawing Method .

FLOAT=yes

Most fractal types have both a fast integer math and a floating point version. The faster, but possibly less accurate, integer version is the default. The default is to use integer math, but in this age of pentium (amd later) CPUS we now recommend your making float=yes the default by adding this line to your SSTOOLS.INI file. Also see "Limitations of Integer Math (And How We Cope)"

SYMMETRY=xxx

Forces symmetry to None, Xaxis, Yaxis, XYaxis, Origin, or Pi symmetry. Useful as a speedup for symmetrical fractals. This is not a kaleidoscope feature for imposing symmetry where it doesn't exist. Use only when the fractal actual exhibits the symmetry, or else results may not be satisfactory.

BFDIGITS=<nnn>

Forces nnn digits if arbitrary precision used. You can use this if fractint's precision detection changes to arbitrary precision too late and regular double precision is used with poor results.

MATHTOLERANCE=<nnn>/<nnn>

This commands controls the logic that automatically selects one of integer/float/arbitrary precision based on precision requirements of the current zoom depth. The first number controls the integer/float transition, and the second number controls the float/arbitrary precision transition. The default value of .05 for both means that the ratio between the exact and calculated width and height is between .95 and 1.05. A larger value than .05 (say .10) makes the test looser so that the lower precision math is used longer. A value <= 0 means the test is always failed and the higher precision math type is used. A value >= 1 means that the test is always passed and the lower precision math type is used.

MINSTACK=<nnn>

This sets the minimum number of stack bytes required for passes=s in order to do another SOI recursion. If you get bad results, try setting this to a value above the default value of 1100. If the value is too large, the image will be OK but generation will be slower.

MAXITER=<nnn>

Reset the iteration maximum (the number of iterations at which the program gives up and says "OK, this point seems to be part of the set in question and should be colored [insidecolor]") from the default 150. Values range from 2 to 2,147,483,647 (super-high iteration limits like 200000000 are useful when using logarithmic palettes). See The Mandelbrot Set for a description of the iteration method of calculating fractals. "maxiter=" can also be used to adjust the number of orbits plotted for 3D "attractor" fractal types such as lorenz3d and kamtorus.

CORNERS=[xmin/xmax/ymin/ymax[/x3rd/y3rd]]

Example: corners=-0.739/-0.736/0.288/0.291

Begin with these coordinates as the range of x and y coordinates, rather than the default values of (for type=mandel) -2.0/2.0/-1.5/1.5. When you specify four values (the usual case), this defines a rectangle: x- coordinates are mapped to the screen, left to right, from xmin to xmax, y-coordinates are mapped to the screen, bottom to top, from ymin to ymax. Six parameters can be used to describe any rotated or stretched parallelogram: (xmin,ymax) are the coordinates used for the top-left corner of the screen, (xmax,ymin) for the bottom-right corner, and (x3rd,y3rd) for the bottom-left. Entering just "CORNERS=" tells Fractint to use this form (the default mode) rather than CENTER-MAG (see below) when saving parameters with the [B] command.

CENTER-MAG=[Xctr/Yctr/Mag[/Xmagfactor/Rotation/Skew]]

This is an alternative way to enter corners as a center point and a magnification that is popular with some fractal programs and publications. Entering just "CENTER-MAG=" tells Fractint to use this form rather than CORNERS (see above) when saving parameters with the [B] command. The [TAB] status display shows the "corners" in both forms. When you specify three values (the usual case), this defines a rectangle: (Xctr, Yctr) specifies the coordinates of the center of the image while Mag indicates the amount of magnification to use. Six parameters can be used to describe any rotated or stretched parallelogram: Xmagfactor tells how many times bigger the x- magnification is than the y-magnification, Rotation indicates how many degrees the image has been turned, and Skew tells how many degrees the image is leaning over. Positive angles will rotate and skew the image counter-clockwise.

BAILOUT=<nnn>

Over-rides the default bailout criterion for escape-time fractals. Can also be set from the parameters screen after selecting a fractal type. See description of bailout in The Mandelbrot Set .

BAILOUTEST=mod|real|imag|or|and|manh|manr

Specifies the Bailout Test used to determine when the fractal calculation has exceeded the bailout value. The default is mod and not all fractal types can utilize the additional tests.

RESET

Causes Fractint to reset all calculation related parameters to their default values. Non-calculation parameters such as "printer=", "sound=", and "savename=" are not affected. RESET should be specified at the start of each parameter file entry (used with the [@] command) which defines an image, so that the entry need not describe every possible parameter - when invoked, all parameters not specifically set by the entry will have predictable values (the defaults).

INITORBIT=pixel
INITORBIT=<nnn/nnn>

Allows control over the value used to begin each Mandelbrot-type orbit. "initorbit=pixel" is the default for most types; this command initializes the orbit to the complex number corresponding to the screen pixel. The command "initorbit=nnn/nnn" uses the entered value as the initializer. See the discussion of the Mandellambda Sets for more on this topic.

PERIODICITY=no|show|nnn

Controls periodicity checking (see Periodicity Logic ). "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.

RSEED=nnnn

The initial random-number "seed" for plasma clouds is taken from your PC's internal clock-timer. This argument forces a value (which you can see in the [Tab] display), and allows you to reproduce plasma clouds. A detailed discussion of why a TRULY random number may be impossible to define, let alone generate, will have to wait for "FRACTINT: The 3-MB Doc File."

SHOWDOT=[auto|bright|medium|dark|<nnn>/<size>]

Colors the current dot being calculated color [nn] or an automatically calculated color taken from the current palette. The second parameter is the size of the traveling pointer in units of pixels of 1/1024th of a screen.

The travelling pointer strobes with fast fractals because of interaction with the monitor's vertical refresh. The orbitdelay parameter can be used to introduce a per-pixel delay when showdot is turned on. Try orbitdelay=1000 with showdot=b/20 to get a feel for how the showdot triangle works.

ASPECTDRIFT=[nn]

When zooming in or out, the aspect ratio (the width to height ratio) can change slightly due to rounding and the noncontinuous nature of pixels. If the aspect changes by a factor less than [nn], then the aspect is set to it's normal value, making the center-mag Xmagfactor parameter equal to 1. (see CENTER-MAG above.) The default is 0.01. A larger value adjusts more often. A value of 0 does no adjustment at all.

See also Doodad parameters and Color parameters.


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