Julia set
Julia set is a draft programming task. It is not yet considered ready to be promoted as a complete task, for reasons that should be found in its talk page.
Generate and draw a Julia set.
- Cf
Java
<lang java>import java.awt.*; import java.awt.image.BufferedImage; import javax.swing.*;
public class JuliaSet extends JPanel {
private final int maxIter = 300; private final double zoom = 1; private double cY, cX;
public JuliaSet() { setPreferredSize(new Dimension(800, 600)); setBackground(Color.white); }
void drawJuliaSet(Graphics2D g) { int w = getWidth(); int h = getHeight(); BufferedImage image = new BufferedImage(w, h, BufferedImage.TYPE_INT_RGB);
cX = -0.7; cY = 0.27015; double moveX = 0, moveY = 0; double zx, zy;
for (int x = 0; x < w; x++) { for (int y = 0; y < h; y++) { zx = 1.5 * (x - w / 2) / (0.5 * zoom * w) + moveX; zy = (y - h / 2) / (0.5 * zoom * h) + moveY; float i = maxIter; while (zx * zx + zy * zy < 4 && i > 0) { double tmp = zx * zx - zy * zy + cX; zy = 2.0 * zx * zy + cY; zx = tmp; i--; } int c = Color.HSBtoRGB((maxIter / i) % 1, 1, i > 0 ? 1 : 0); image.setRGB(x, y, c); } } g.drawImage(image, 0, 0, null); }
@Override public void paintComponent(Graphics gg) { super.paintComponent(gg); Graphics2D g = (Graphics2D) gg; g.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON); drawJuliaSet(g); }
public static void main(String[] args) { SwingUtilities.invokeLater(() -> { JFrame f = new JFrame(); f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); f.setTitle("Julia Set"); f.setResizable(false); f.add(new JuliaSet(), BorderLayout.CENTER); f.pack(); f.setLocationRelativeTo(null); f.setVisible(true); }); }
}</lang>
zkl
Uses the PPM class from http://rosettacode.org/wiki/Bitmap/Bresenham%27s_line_algorithm#zkl
<lang zkl>fcn juliaSet{
w,h,zoom:=800,600, 1; bitmap:=PPM(w,h,0xFF|FF|FF); // White background
cX,cY:=-0.7, 0.27015; moveX,moveY:=0.0, 0.0; maxIter:=255;
foreach x,y in (w,h){ zx:=1.5*(x - w/2)/(0.5*zoom*w) + moveX; zy:=1.0*(y - h/2)/(0.5*zoom*h) + moveY; i:=maxIter; while(zx*zx + zy*zy < 4 and i > 1){
tmp:=zx*zx - zy*zy + cX; zy,zx=2.0*zx*zy + cY, tmp; i-=1;
} // convert byte to RGB (3 bytes), kinda magic to get nice colors bitmap[x,y]=i.shiftLeft(21) + i.shiftLeft(10) + i*8; }
bitmap.writeJPGFile("juliaSet.jpg",True);
}();</lang>