Data commit

Task/Draw-a-clock/Java/draw-a-clock.java

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+import java.awt.*;
+import java.awt.event.*;
+import static java.lang.Math.*;
+import java.time.LocalTime;
+import javax.swing.*;
+
+class Clock extends JPanel {
+
+    final float degrees06 = (float) (PI / 30);
+    final float degrees30 = degrees06 * 5;
+    final float degrees90 = degrees30 * 3;
+
+    final int size = 590;
+    final int spacing = 40;
+    final int diameter = size - 2 * spacing;
+    final int cx = diameter / 2 + spacing;
+    final int cy = diameter / 2 + spacing;
+
+    public Clock() {
+        setPreferredSize(new Dimension(size, size));
+        setBackground(Color.white);
+
+        new Timer(1000, (ActionEvent e) -> {
+            repaint();
+        }).start();
+    }
+
+    @Override
+    public void paintComponent(Graphics gg) {
+        super.paintComponent(gg);
+        Graphics2D g = (Graphics2D) gg;
+        g.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
+                RenderingHints.VALUE_ANTIALIAS_ON);
+
+        drawFace(g);
+
+        final LocalTime time  = LocalTime.now();
+        int hour = time.getHour();
+        int minute = time.getMinute();
+        int second = time.getSecond();
+
+        float angle = degrees90 - (degrees06 * second);
+        drawHand(g, angle, diameter / 2 - 30, Color.red);
+
+        float minsecs = (minute + second / 60.0F);
+        angle = degrees90 - (degrees06 * minsecs);
+        drawHand(g, angle, diameter / 3 + 10, Color.black);
+
+        float hourmins = (hour + minsecs / 60.0F);
+        angle = degrees90 - (degrees30 * hourmins);
+        drawHand(g, angle, diameter / 4 + 10, Color.black);
+    }
+
+    private void drawFace(Graphics2D g) {
+        g.setStroke(new BasicStroke(2));
+        g.setColor(Color.white);
+        g.fillOval(spacing, spacing, diameter, diameter);
+        g.setColor(Color.black);
+        g.drawOval(spacing, spacing, diameter, diameter);
+    }
+
+    private void drawHand(Graphics2D g, float angle, int radius, Color color) {
+        int x = cx + (int) (radius * cos(angle));
+        int y = cy - (int) (radius * sin(angle));
+        g.setColor(color);
+        g.drawLine(cx, cy, x, y);
+    }
+
+    public static void main(String[] args) {
+        SwingUtilities.invokeLater(() -> {
+            JFrame f = new JFrame();
+            f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
+            f.setTitle("Clock");
+            f.setResizable(false);
+            f.add(new Clock(), BorderLayout.CENTER);
+            f.pack();
+            f.setLocationRelativeTo(null);
+            f.setVisible(true);
+        });
+    }
+}