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//   Program mandel
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#include "complex.h"
#include "nxgraph.h"

//---- graphics setting
const int WIN_WIDTH  = 256;
const int WIN_HEIGHT = 256;

//---- experimental setting
const int N_MAX      = 256;
const Complex Ao( -0.5, 0.0 );
const double  Mag = 1.0/128.0;

//---- Calculate the recurrence formula
int CalcMandel( const Complex& A )
{
  int n;
  Complex Z( 0.0, 0.0 );
  for( n=0; norm(Z)<4.0 && n<N_MAX; n++ ){
    Z = Z*Z + A;
  }

  return n;
}


//---- main function
int main( void )
{
  u_long pixels[32];

  NXOpenWindow( "Mandelbrot", WIN_WIDTH, WIN_HEIGHT );
  NXGetGradation( pixels, NX_BLACK, NX_BLUE, NX_WHITE, 32 );

  for( int ay=0; ay<WIN_HEIGHT; ay++ ){
    for( int ax=0; ax<WIN_WIDTH; ax++ ){
      Complex A = Ao + Mag*Complex( ax-WIN_WIDTH/2, ay-WIN_HEIGHT/2 );
      int n = CalcMandel(A);

      if( n%64 >= 32 ){
	NXSetColor( pixels[63-n%64] );
      }else{
	NXSetColor( pixels[n%64] );
      }
      NXDrawPoint( ax, ay );
    }
  }

  NXPause();
  NXCloseWindow();
  return 0;
}