Data commit

Task/Dragon-curve/Java/dragon-curve.java

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+import java.awt.Color;
+import java.awt.Graphics;
+import java.util.*;
+import javax.swing.JFrame;
+
+public class DragonCurve extends JFrame {
+
+    private List<Integer> turns;
+    private double startingAngle, side;
+
+    public DragonCurve(int iter) {
+        super("Dragon Curve");
+        setBounds(100, 100, 800, 600);
+        setDefaultCloseOperation(EXIT_ON_CLOSE);
+        turns = getSequence(iter);
+        startingAngle = -iter * (Math.PI / 4);
+        side = 400 / Math.pow(2, iter / 2.);
+    }
+
+    public List<Integer> getSequence(int iterations) {
+        List<Integer> turnSequence = new ArrayList<Integer>();
+        for (int i = 0; i < iterations; i++) {
+            List<Integer> copy = new ArrayList<Integer>(turnSequence);
+            Collections.reverse(copy);
+            turnSequence.add(1);
+            for (Integer turn : copy) {
+                turnSequence.add(-turn);
+            }
+        }
+        return turnSequence;
+    }
+
+    @Override
+    public void paint(Graphics g) {
+        g.setColor(Color.BLACK);
+        double angle = startingAngle;
+        int x1 = 230, y1 = 350;
+        int x2 = x1 + (int) (Math.cos(angle) * side);
+        int y2 = y1 + (int) (Math.sin(angle) * side);
+        g.drawLine(x1, y1, x2, y2);
+        x1 = x2;
+        y1 = y2;
+        for (Integer turn : turns) {
+            angle += turn * (Math.PI / 2);
+            x2 = x1 + (int) (Math.cos(angle) * side);
+            y2 = y1 + (int) (Math.sin(angle) * side);
+            g.drawLine(x1, y1, x2, y2);
+            x1 = x2;
+            y1 = y2;
+        }
+    }
+
+    public static void main(String[] args) {
+        new DragonCurve(14).setVisible(true);
+    }
+}