julia.java

java程序设计源代码

import java.awt.*;
class Julia
{
	public static void main( String []args ){
		Frame frm = new Frame("Julia");
		frm.setSize( 300, 300 );
		frm.show();
		Julia p = new Julia( frm );
		p.drawJulia();
	}
	
	private Frame frm;
	private Graphics graphics;
	private int width;
	private int height;

	public Julia(Frame frm)
	{
		graphics = frm.getGraphics();
		width = frm.getSize().width;
		height = frm.getSize().height;
	}
	public void drawJulia(){    
		//Scale (-1.5, 1.5)-(1.5, -1.5)
		
		final double a = 0.5;     //c=a+bi为Julia集的参数
		final double b = 0.55;
		
		for( double x0 = -1.5; x0 < 1.5; x0+=0.01 )
		for( double y0 = -1.5; y0 < 1.5; y0+=0.01 ){
			double x=x0, y=y0;
			int n;
			for( n = 1; n<100; n++ ){
				double x2 = x * x - y * y + a;
				double y2 = 2 * x * y + b;
				x = x2;
				y = y2;
				if( x * x + y * y > 4 ) break;
			}
			pSet(x0, y0, n ); //按n值来将(x,y)点进行着色
		}
	}
	public void pSet(double x, double y, int n){
		graphics.setColor( new Color( n* 0xff8855 ) );
		graphics.drawLine( 
			(int)(x*width/3 + width/2),
			(int)(y*height/3 + height/2 ),
			(int)(x*width/3 + width/2),
			(int)(y*height/3 + height/2 )
			);
	}

}