Polyspiral
Polyspiral 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.
A Polyspiral is a spiral made of multiple line segments, whereby each segment is larger (or smaller) than the previous one by a given amount. Each segment also changes direction at a given angle.
The task: animate a series of polyspirals, by drawing a complete spiral then incrementing the angle, and (after clearing the background) drawing the next, and so on.
WHILE true x = width / 2 y = height / 2 set length FOR 1 TO 150 drawline change direction by angle increment length ENDFOR increment angle MOD 360
If animation is not practical in your programming environment, you may show 3 frames from different stages of the animation instead.
Java
<lang java>import java.awt.*; import java.awt.event.ActionEvent; import javax.swing.*;
public class PolySpiral extends JPanel {
double inc = 0;
public PolySpiral() { setPreferredSize(new Dimension(640, 640)); setBackground(Color.white);
new Timer(40, (ActionEvent e) -> { inc = (inc + 0.05) % 360; repaint(); }).start(); }
void drawSpiral(Graphics2D g, int len, double angleIncrement) {
double x1 = getWidth() / 2; double y1 = getHeight() / 2; double angle = angleIncrement;
for (int i = 0; i < 150; i++) {
g.setColor(Color.getHSBColor(i / 150f, 1.0f, 1.0f));
double x2 = x1 + Math.cos(angle) * len; double y2 = y1 - Math.sin(angle) * len; g.drawLine((int) x1, (int) y1, (int) x2, (int) y2); x1 = x2; y1 = y2;
len += 3;
angle = (angle + angleIncrement) % (Math.PI * 2); } }
@Override public void paintComponent(Graphics gg) { super.paintComponent(gg); Graphics2D g = (Graphics2D) gg; g.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
drawSpiral(g, 5, Math.toRadians(inc)); }
public static void main(String[] args) { SwingUtilities.invokeLater(() -> { JFrame f = new JFrame(); f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); f.setTitle("PolySpiral"); f.setResizable(true); f.add(new PolySpiral(), BorderLayout.CENTER); f.pack(); f.setLocationRelativeTo(null); f.setVisible(true); }); }
}</lang>