## Standard Class Standard_DistanceEstimator

```Object
common:Generic
common:Coloring
Standard:Standard_DistanceEstimator
```

`class GradientColoring:Standard_DistanceEstimator`

Object version of DistanceEstimator in Standard.ucl. Distance-estimator coloring algorithm for Mandelbrot and other z^n fractal types (Phoenix, Julia). This coloring algorithm estimates the distance to the boundary of the fractal (for example the Mandelbrot set) and colors points accordingly. Originally written by Damien M. Jones

Ultra Fractal Source
``` class Standard_DistanceEstimator(common.ulb:GradientColoring) {
;
; Object version of DistanceEstimator in Standard.ucl.
;
; Distance-estimator coloring algorithm for Mandelbrot and other z^n fractal
; types (Phoenix, Julia). This coloring algorithm estimates the distance to the
; boundary of the fractal (for example the Mandelbrot set) and colors points
; accordingly.
;
; Originally written by Damien M. Jones
;
public:
func Init(complex pz, complex ppixel)
fDZ = (0, 0)
endfunc

func Iterate(complex pz)
fDZ = @power * pz^(@power-1) * fDZ + 1
endfunc

float func ResultIndex(complex pz)
float cz = cabs(pz)
return (@power*log(cz) * cz / cabs(fDZ))^(1/@power)
endfunc

private:
complex fDZ

default:
title = "Distance Estimator"
helpfile = "Uf*.chm"
helptopic = "Html/coloring/standard/distanceestimator.html"
param power
caption = "Exponent"
default = 2.0
hint = "This should be set to match the exponent of the \
formula you are using. For Mandelbrot, this is usually 2."
endparam
}
```

Constructor Summary
`Standard_DistanceEstimator()`

Method Summary
` void` ```Init(complex pz, complex ppixel)```
Set up for a sequence of values
` void` `Iterate(complex pz)`
Process the next value in the sequence
` float` `ResultIndex(complex pz)`
Produce a resulting color index after a sequence is finished

`IsGradient, IsSolid, Result`

Methods inherited from class common:Coloring
`GetPixel`

Methods inherited from class common:Generic
`GetParent`

Methods inherited from class Object

Constructor Detail

### Standard_DistanceEstimator

`public Standard_DistanceEstimator()`
Method Detail

### Init

```public void Init(complex pz,
complex ppixel)```
Description copied from class: `GradientColoring`
Set up for a sequence of values

This function will be called at the beginning of each sequence of values (e.g. at the beginning of each fractal orbit).

Overrides:
`Init` in class `GradientColoring`
Parameters:
`pz` - first value for the sequence; for a normal coloring formula, this will be #z
`ppixel` - seed value for the sequence; for a normal coloring formula, this will be #pixel

### Iterate

`public void Iterate(complex pz)`
Description copied from class: `GradientColoring`
Process the next value in the sequence

As long as the sequence has not bailed out, this function will be continually called to produce sequence values. Note that such processing generally will not know in advance precisely how long the sequence is, and should be prepared to deal with sequences of arbitrary length.

Your coloring may determine at some point that a solid color should be used rather than an index value.

Overrides:
`Iterate` in class `GradientColoring`
Parameters:
`pz` - next value in the sequence; corresponds to #z in a coloring formula

### ResultIndex

`public float ResultIndex(complex pz)`
Description copied from class: `GradientColoring`
Produce a resulting color index after a sequence is finished

This corresponds to the final: section in a coloring formula. Once it is called, no further calls to Iterate() should be made without calling Init() first.

Overrides:
`ResultIndex` in class `GradientColoring`
Returns:
the gradient index (corresponding to #index in a coloring formula)