File:JuliaModifiedDecomposition.png
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Summary
DescriptionJuliaModifiedDecomposition.png |
English: Modified binary decomposition of exterior of Julia set |
Date | |
Source | Own work |
Author | Adam majewski |
C src code
/*
c console program
1. draws Julia setfor Fc(z)=z*z +c using :
colors exterior of Julia set using modified decomposition
dynamic 1D array for 24-bit color values
-------------------------------
2. technic of creating ppm file is based on the code of Claudio Rocchini
http://en.wikipedia.org/wiki/Image:Color_complex_plot.jpg
create 24 bit color graphic file , portable pixmap file = PPM
see http://en.wikipedia.org/wiki/Portable_pixmap
to see the file use external application ( graphic viewer)
I think that manual creating graphic can't be simpler
-------------------------------------------------
Adam Majewski
fraktal.republika.pl
======================
Linux console :
save as n.c
to compile :
gcc -lm n.c
to run :
./a.out
It creates ppm file.
To see it use image viewer
To convert use Image Magic command line tools :
convert j.ppm -resize 1000x1000 j.png
Source code was formatted with emacs
*/
#include <stdio.h>
#include <stdlib.h> /* for ISO C Random Number Functions */
#include <math.h>
int main()
{ const double Cx=0.0,Cy=0.0;
/* screen coordinate = coordinate of pixels */
int iX, iY,
iXmin=0, iXmax=10000,
iYmin=0, iYmax=10000,
iWidth=iXmax-iXmin+1,
iHeight=iYmax-iYmin+1,
/* 3D data : X , Y, color */
/* number of bytes = number of pixels of image * number of bytes of color */
iLength=iWidth*iHeight*3,/* 3 bytes of color */
index; /* of array */
/* int iXinc, iYinc,iIncMax=12; */
/* world ( double) coordinate = parameter plane*/
const double ZxMin=-5;
const double ZxMax=5;
const double ZyMin=-5;
const double ZyMax=5;
/* */
double PixelWidth=(ZxMax-ZxMin)/iWidth;
double PixelHeight=(ZyMax-ZyMin)/iHeight;
double Zx,Zy, /* Z=Zx+Zy*i */
Z0x, Z0y, /* Z0 = Z0x + Z0y*i */
Zx2,Zy2;
/* */
int Iteration,
IterationMax=600 , /*for loop */
iTemp;
/* bail-out value , radius of circle ; */
const int EscapeRadius=100;
/* PPM file */
FILE * fp;
char *filename="m.ppm";
char *comment="# this is julia set for c= 0";/* comment should start with # */
const int MaxColorComponentValue=255;/* color component ( R or G or B) is coded from 0 to 255 */
/* dynamic 1D array for 24-bit color values */
unsigned char *array;
/*-------------------------------------------------------------------*/
array = malloc( iLength * sizeof(unsigned char) );
if (array == NULL)
{
fprintf(stderr,"Could not allocate memory");
getchar();
return 1;
}
else
{
/* fill the data array with white points */
for(index=0;index<iLength-1;++index) array[index]=255;
/* ---------------------------------------------------------------*/
for(iY=0;iY<iYmax;++iY)
{
Z0y=ZyMin + iY*PixelHeight; /* reverse Y axis */
if (fabs(Z0y)<PixelHeight/2) Z0y=0.0; /* */
for(iX=0;iX<iXmax;++iX)
{ /* initial value of orbit Z0 */
Z0x=ZxMin + iX*PixelWidth;
/*----------- main loop without checking of abs(zn) -------------*/
Zx=Z0x;
Zy=Z0y;
Zx2=Zx*Zx;
Zy2=Zy*Zy;
Iteration=0;
while (Iteration<IterationMax && (fabs(Zy)<EscapeRadius) )
{
Zy=2*Zx*Zy + Cy;
Zx=Zx2-Zy2 +Cx;
Zx2=Zx*Zx;
Zy2=Zy*Zy;
Iteration+=1;
}
/* --------------- compute pixel color (24 bit = 3 bajts) */
iTemp=((iYmax-iY-1)*iXmax+iX)*3;
/* interior of Filled-in Julia set = green */
if (Iteration==IterationMax)
{
array[iTemp]=0; /* Red*/
array[iTemp+1]=255; /* Green */
array[iTemp+2]=0;/* Blue */
}
else
/* exterior of Filled-in Julia set */
if (Zy>0 )
{
array[iTemp]=255; /* Red*/
array[iTemp+1]=255; /* Green */
array[iTemp+2]=255;/* Blue */
}
else
{
array[iTemp]=0; /* Red*/
array[iTemp+1]=0; /* Green */
array[iTemp+2]=0;/* Blue */
};
/*----------------- check the orientation of Z-plane by marking first quadrant of cartesian plane ----- */
/* if (Z0x>0 && Z0y>0) array[((iYmax-iY-1)*iXmax+iX)*3]=255-array[((iYmax-iY-1)*iXmax+iX)*3]; */
}
}
/* --------------------- write the whole data array to ppm file in one step ----------------------------------------- */
/*create new file,give it a name and open it in binary mode */
fp= fopen(filename,"wb"); /* b - binary mode */
if (fp == NULL){ fprintf(stderr,"file error"); }
else
{
/*write ASCII header to the file*/
fprintf(fp,"P6\n %s\n %d\n %d\n %d\n",comment,iXmax,iYmax,MaxColorComponentValue);
/*write image data bytes to the file*/
fwrite(array,iLength ,1,fp);
fclose(fp);
fprintf(stderr,"file %s saved\n",filename);
getchar();
}
free(array);
return 0;
} /* if (array .. else ... */
}
Licensing
I, the copyright holder of this work, hereby publish it under the following license:
This file is licensed under the Creative Commons Attribution-Share Alike 3.0 Unported license.
- You are free:
- to share – to copy, distribute and transmit the work
- to remix – to adapt the work
- Under the following conditions:
- attribution – You must give appropriate credit, provide a link to the license, and indicate if changes were made. You may do so in any reasonable manner, but not in any way that suggests the licensor endorses you or your use.
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11 June 2011
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Date/Time | Thumbnail | Dimensions | User | Comment | |
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current | 08:01, 11 June 2011 | 1,000 × 1,000 (121 KB) | Soul windsurfer |
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