Hi, I'm Duncan C

[Duncan C]

Hello all.

I just stumbled upon your forum.

My name's Duncan C. Im a software consultant/developer by profession, and a math/science enthusiast. I've been interested in Fractals since the mid 80's. I did wrote an application for rendering of Mandelbrot and Julia sets on a 16 mhz Mac II computer with an early FPU. In those days it would take over half an hour to do ONE plot at 255 iterations, and generating animated sequences took OVERNIGHT.

I've recently started development on a new version of my program, which I'm calling FractalWorks. My interests are as much in the aesthetics and computer science as they are in the pure mathematics of fractals. The more arcane mathematical concepts behind fractals are a little beyond my understanding.

I have a copy of "The Beauty of Fractals," which is a wonderful introduction to the subject, but I get a bit lost in the deeper mathematical discussions. I could use some coaching. (I've only had one year of calculus, and that a long time ago, so I'm a little under-educated for some of this stuff.)

One of the things I've focused on is using custom color tables to get aesthetically pleasing images. Back in the 80's, a friend and I came up with the idea of using logarithmic color tables, where the color for points outside the set varies from a start color to an end color using a log curve, so that there are large color changes for small iteration changes, and much smaller color changes for high iteration value pixels. That approach produces images that are visually very pleasing.

Here's an early example image I've created using the new version of my "FractalWorks" application, currently under development:



Right now my program only uses one color transition for an entire plot. Another task is to have the option to create several different gradient "color bands".


Duncan C

[Nahee_Enterprises]

Greetings, Duncan C.  And welcome to this Forum !!   

May I inquire as to the language you are using to code your fractal program, and the particular vendor (Microsoft, Borland, etc.)??

There are many knowledgeable individuals available as Members here, so if you have specific questions, ask away.

[heneganj]

Welcome to the forums Duncan! Mr Nahee here is all knowing about Fractal Software.

[Nahee_Enterprises]

Jason Henegan wrote:
>
>    Mr Nahee here is all knowing about Fractal Software.

Contrary to popular belief (or to facetious comments    ), I am far from "all knowing", and definitely should never be referred to as an expert.  Let us just say that I have many years/decades of experience with both fractals and professional programming.   
 
 

[Duncan C]

Thanks for the welcome. Is anybody else on these boards writing their own fractal generating software? I'm starting to make real progress on my application, FractalWorks, which is written for Macintosh OS X. I'm focusing on MandelBrot and Julia sets for now, and paying special attention to color choices. I saw on some of the links from Mr. Nahee's site that people post the color tables they use. Do some of the fractal generating applications out there let you load and save color tables? I'm planning on supporting the loading and saving of color "schemes" in my app.

I say schemes because some of my approaches to color mapping neighborhoods of Mandelbrot and Julia sets are adaptive. They use the number of pixels in each iteration band to determine the color change from the neighboring band. That way the very small "gnarly bits" at high iteration values are not a riot of color, but take on a discernable shape.

[Sockratease]

Hello and Welcome!

To answer your question, and reveal a secret at the same time, I am working on a CRAPPY Fractal Generator!

I Just Got Visual Basic for free!

So I am trying to make something just for fun.

I only recently made my first computer upgrade in over 20 years and all this new-fangled programming is alien to me.

I figured a Fractal Generator would be a great way to teach myself VB.

Can't even render a pixel yet...

My Big-Book-of-Visual-Basic is advanced and missing it's example CD.  I need a beginner's Book!  I'm sure it's easily had online...

Meanwhile, I'll be having LOTS of questions once I can make a button that will actually draw a graph of any kind!  Then I can worry  about Fractaldactyl (Working Title).

Nice to see more folks showing up!

Be seeing you.

Peace.

[Nahee_Enterprises]

Duncan Champney wrote:
>
>    Is anybody else on these boards writing their own fractal generating software?

There are several authors whom are Members of this Forum.  Some have programs they wrote in the past, and some have ones they are working on at the present.  Listed below are just a few of them:

• Christian Kleinhuis (Trifox)
• Thomas Ludwig (lycium)
• M. Hilpert (dentaku)
• Glenn Andreas (gandreas)
• Stefan Vitanov
• David J. Makin
• Paul N. Lee (Nahee)

>
>    I saw on some of the links from Mr. Nahee's site that people
>    post the color tables they use.  Do some of the fractal generating
>    applications out there let you load and save color tables?

I would say most of the major fractal applications written over the years have some way of using saved "color tables".  Probably the most well known, and definitely the most widely used, are the .MAP files produced and used by FractInt:
   http://www.Nahee.com/Fractals/FractInt/MAP_s.zip
Some of the many fractal programs which have used FractInt coloring files are:

• XFractInt
• WinFract
• ChaosPro
• Chaoscope
• Fractal Forge
• Fractal Zoomer
• Gnofract 4D
• L-system Explorer
• QS Flame
• UltraFractal
• programs by Terry W. Gintz
• and several other applications.

[gandreas]

Do some of the fractal generating applications out there let you load and save color tables? I'm planning on supporting the loading and saving of color "schemes" in my app.

In quadrium (both quadrium2 and quadrium | flame, since the share the same framework for lots of the basic support), I support importing:

• .map (FractInt)
• .par (xfrac parameter files)
• .ugr (UltraFractal)
• .gif (since the are 8 bit images that include a color table)
• .xml (such as found in the various ifs/flame formats)
• .ggr (GIMP gradients)

Other than the gif file, the rest are all text formats which are fairly straight forward to parse.

I've also investigated both Photoshop and Illustrator gradients, but those are significantly more difficult (especially with the changes between versions, as well as being extremely complex in their file format), and haven't had a demand for such a feature...

[heneganj]

Jason Henegan wrote:
>
>    Mr Nahee here is all knowing about Fractal Software.

Contrary to popular belief (or to facetious comments    ), I am far from "all knowing", and definitely should never be referred to as an expert.  Let us just say that I have many years/decades of experience with both fractals and professional programming.   
 

You are far too modest!

[Duncan C]

Hello and Welcome!

To answer your question, and reveal a secret at the same time, I am working on a CRAPPY Fractal Generator!

I Just Got Visual Basic for free!

So I am trying to make something just for fun.

I only recently made my first computer upgrade in over 20 years and all this new-fangled programming is alien to me.

I figured a Fractal Generator would be a great way to teach myself VB.

Can't even render a pixel yet...

My Big-Book-of-Visual-Basic is advanced and missing it's example CD.  I need a beginner's Book!  I'm sure it's easily had online...

Meanwhile, I'll be having LOTS of questions once I can make a button that will actually draw a graph of any kind!  Then I can worry  about Fractaldactyl (Working Title).

Sockratease,

Visual basic is not going to be a good choice for a fractal generator. It's an interpreted langugage, and not nearly "close enough to the machine." There's far too much junk between you and the CPU that's actually doing the calculations required to render a fractal.

I'm guessing that a visual basic program would take hundreds of times longer - if not thousands of times longer - than a compiled language like C/C++/Pascal/Fortran to compute a fractal.

Back in the 80's when I wrote my first fractal generating program, I hand-wrote the calculation code in assembly language. That let me squeeze every clock cycle I  could out of my code.

These days compilers are good enough, and the processors complicated enough, that it's quite hard to write assembler code that's faster than well-crafted C.

You might want to talk to a developer and ask them to write you some fractal calculation code and package it as a DLL for you. You could then use it in VB and build buttons and forms to your heart's content, while still getting good performance.

I mostly develop for the Macintosh so building DLLs not something I could do easily. I've done a couple of stints of development for Windows, but don't have the current tools and would have to re-remember how to use them if I did.


Duncan C

[Duncan C]

Do some of the fractal generating applications out there let you load and save color tables? I'm planning on supporting the loading and saving of color "schemes" in my app.

In quadrium (both quadrium2 and quadrium | flame, since the share the same framework for lots of the basic support), I support importing:

• .map (FractInt)
• .par (xfrac parameter files)
• .ugr (UltraFractal)
• .gif (since the are 8 bit images that include a color table)
• .xml (such as found in the various ifs/flame formats)
• .ggr (GIMP gradients)

Other than the gif file, the rest are all text formats which are fairly straight forward to parse.

I've also investigated both Photoshop and Illustrator gradients, but those are significantly more difficult (especially with the changes between versions, as well as being extremely complex in their file format), and haven't had a demand for such a feature...

gandreas,

Is there public documentation for these file formats? If not public documentation, do you have header files you'd be willing to share that would give some information? (Just headers, mind. Not code)

What platform(s) do your applications run on?

And what do you do about color table selection? In my experience, picking good colors is key to getting good-looking images. I just completed coding on a design that lets me specify colors for neighborhoods of mandelbrot and julia sets in gradient bands. My program lets me set up an arbitrary number of color bands where each band can be logorithmic, linear, stepped linear, or histogram-based, with other types of gradients to follow.

In fact, I just got the code working in the wee hours of this morning. So far, it builds the color tables from hard-coded values. The next step is to add support for a file format to specify the values. I am also planning

I allocate a separate color value for every iteration value in a plot.

Here's a test image using 3 color bands, where the band at lower iteration values is histogram based, and the inner two bands are logarithmic. It's a bit garish, but it shows the approach I'm using:

[Duncan C]

Duncan Champney wrote:
>
>    Is anybody else on these boards writing their own fractal generating software?

There are several authors whom are Members of this Forum.  Some have programs they wrote in the past, and some have ones they are working on at the present.  Listed below are just a few of them:

• Christian Kleinhuis (Trifox)
• Thomas Ludwig (lycium)
• M. Hilpert (dentaku)
• Glenn Andreas (gandreas)
• Stefan Vitanov
• David J. Makin
• Paul N. Lee (Nahee)

>
>    I saw on some of the links from Mr. Nahee's site that people
>    post the color tables they use.  Do some of the fractal generating
>    applications out there let you load and save color tables?

I would say most of the major fractal applications written over the years have some way of using saved "color tables".  Probably the most well known, and definitely the most widely used, are the .MAP files produced and used by FractInt:
   http://www.nahee.com/Fractals/FractInt/MAP_s.zip
Some of the many fractal programs which have used FractInt coloring files are:

• XFractInt
• WinFract
• ChaosPro
• Chaoscope
• Fractal Forge
• Fractal Zoomer
• Gnofract 4D
• L-system Explorer
• QS Flame
• UltraFractal
• programs by Terry W. Gintz
• and several other applications.

Mr. Lee,

Thanks for the detailed reply. I've got my head down programming like crazy these days, and haven't spent much time investigating other programs that are out there. Do you know which of the above programs are available for Macintosh? I found a couple, but couldn't really get a decent impression of them from the crippled demo versions that were available for free download.


Duncan C

[gandreas]

gandreas,

Is there public documentation for these file formats? If not public documentation, do you have header files you'd be willing to share that would give some information? (Just headers, mind. Not code)

Most of these are readily available from looking their source code or even just a couple of the sample files, but roughly

• .map (FractInt) - a series of three RGB values (0..255) per line (up to 256)
• .par (xfrac parameter files) - potentially more than one gradient/image per file, each inside curly braces, with a series of "tag=value" pairs, with the tag "color" having a special format that is roughly a "sparse base 64 encoding"
• .ugr (UltraFractal), similar to .par (curly braces, tag=value pairs) but a series of index=# color=# for each point in the gradient (where color is a 24 bit RGB value), with a separate list for their alpha values (in the "opacity:" section)
• .gif - This is a binary format (I cheat and let the system read it and then I just ask for the color table)
• .xml - a couple of different formats, but XML tagged data, either in a "palette" or "colors" tag and a string of hex values (for RGB data)
• .ggr (GIMP gradients) - a count of how many segments, and then for each segment a floating value for the start, middle, and end index, and then the starting and ending RGBA values, ending with information about how the curve is shaped

What platform(s) do your applications run on?

quadrium2 and quadrium | flame are OS X only

And what do you do about color table selection? In my experience, picking good colors is key to getting good-looking images.

In general, I let the end user pick whatever they want.  I provide a bunch of basic gradients, let the user pick a coloring algorithm, pipe that through the gradient (scaled and offset, with a wide variety of ways to handle remapping values outside of 0.0 to 1.0) to make an RGB value, and then allow them to modify the result in any number of ways (such as by using another coloring algorithm to adjust the hue or saturation, etc...).  Usually, it's pretty rare when just a simple single algorithm produces anything truly remarkable (or at least not just another "been there, seen that"), but once you start doing things like traps and more complex blending and composing of multiple techniques, you can get much more interesting results...

[Nahee_Enterprises]

Duncan Champney wrote:
>
>    

In quadrium (both quadrium2 and quadrium | flame, since the share the same framework for lots of the basic support), I support importing:

• .map (FractInt)
• .par (xfrac parameter files)
• .ugr (UltraFractal)
• .gif (since the are 8 bit images that include a color table)
• .xml (such as found in the various ifs/flame formats)
• .ggr (GIMP gradients)

Other than the gif file, the rest are all text formats which are fairly straight forward to parse.

>
>    Is there public documentation for these file formats?

MAP details
    http://www.Nahee.com/spanky/www/fractint/palette_maps.html
    http://www.Nahee.com/PNL/Palette.html

GIF Specification
     http://www.w3.org/Graphics/GIF/spec-gif89a.txt


>
>    And what do you do about color table selection?

It is best to allow the User to choose from a wide selection of saved color table files.  These files could be shared between the user community which renders fractals with your software.
 

[Nahee_Enterprises]

Duncan Champney wrote:
>
>    Thanks for the detailed reply.  I've got my head down programming
>    like crazy these days, and haven't spent much time investigating
>    other programs that are out there.

You are more than welcome.  And believe me, I do understand the lack of time needed to do serious explorations into everything fractal related, even just the more popular rendering applications.   ;-}

>
>    Do you know which of the above programs are available for Macintosh?

There was a port of FractInt to the MAC platform years ago, but I do not believe that much has been done with that since then.

And some of the programs by Terry W. Gintz have been converted over to MAC available applications:
    http://www.MysticFractal.com/

>
>    I found a couple, but couldn't really get a decent impression of them
>    from the crippled demo versions that were available for free download.


If you are wanting to know about some of the MAC fractal applications, here are a few places you may wish to look into:

FracPPC & Fractal Domains
    http://www.FractalDomains.com/

SpangFract
    http://groups.yahoo.com/group/Spangfract

QuaSZ Mac, iDynaMaSZ, iVizionaire, MacOrbits & iSwirlique
    http://www.MysticFractal.com/

other MAC programs:
    http://www.Nahee.com/Software/+MAC/
    http://www.Nahee.com/spanky/pub/fractals/programs/mac/
    http://www.ArosMagic.com/Fractals/
    http://www.lor-thil.dircon.co.uk/
    http://www.hypertextbook.com/chaos/92.shtml
    http://archives.math.utk.edu/software/mac/fractals/
    http://www.radagast.org/~dplatt/mac/
    http://www.swin.edu.au/astronomy/pbourke/
    http://www.gandreas.com/projects/quadriumflame/