Writing fractal formulas

Fractal formulas are put in fractal formula files with the .ufm extension. They can have the following 

sections, in this order:

G     

global

G     

builtin

G     

init

G     

loop

G     

bailout

G     

default

G     

switch

If a fractal formula does not start with a label, it is assumed to start with the init section. If a fractal 

formula contains an empty label (a single colon), it is assumed to start the loop section, and in this 

case, the last statement in the loop section is assumed to be the boolean expression from the 

bailout section (so the formula should not contain a separate bailout section). This set of rules 

ensures compatibility with old Fractint formula. It is not recommended to use this when writing new 

formulas, though.

The optional setting within parentheses after the entry identifier specifies the symmetry of the fractal 

formula. See 

Symmetry

.

The global section is executed only once per image and can be used to fill look up tables and 

initialize read only variables. See 

Global sections

.

The builtin section is used for accessing built in fractal formulas. If this section is used, the global, 

init, loop, and bailout sections are not allowed. The builtin section can contain the following 

settings:

G     

type

The init section is executed only once per pixel, and is useful for initializing variables.

The loop section is executed once per iteration. It should update the value of the predefined 

complex variable 

z

 (you can also write to #z) using the old value of z.

The bailout section contains a single boolean expression. The loop section is repeated as long as 

this expression evaluates to true (but it is always executed at least once).

The default section can contain the following settings:

G     

angle

G     

center

G     

helpfile

G     

helptopic

G     

magn

G     

maxiter

G     

method

G     

periodicity

G     

precision

G     

render

283