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thebaubauthebaubau
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Draw a circle in different ways (#18912)
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3 files changed

+204
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lines changed

‎image-processing/src/main/java/com/baeldung/drawcircle/DrawBufferedCircle.java‎

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package com.baeldung.drawcircle;
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import javax.swing.*;
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import java.awt.*;
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import java.awt.geom.Ellipse2D;
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import java.awt.image.BufferedImage;
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public class DrawBufferedCircle {
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public static void main(String[] args) {
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SwingUtilities.invokeLater(() -> {
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JFrame f = new JFrame("Circle");
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f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
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f.add(new CircleImagePanel(64, 3)); // final size: 64x64, supersample: 3x
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f.pack();
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f.setLocationRelativeTo(null);
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f.setVisible(true);
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});
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}
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static class CircleImagePanel extends JPanel {
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private final int finalSize;
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private final BufferedImage circleImage;
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public CircleImagePanel(int finalSize, int scale) {
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this.finalSize = finalSize;
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this.circleImage = makeCircleImage(finalSize, scale);
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setPreferredSize(new Dimension(finalSize + 16, finalSize + 16));
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setBackground(Color.WHITE);
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}
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@Override
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protected void paintComponent(Graphics g) {
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super.paintComponent(g);
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Graphics2D g2 = (Graphics2D) g.create();
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try {
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int x = (getWidth() - finalSize) / 2;
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int y = (getHeight() - finalSize) / 2;
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g2.setRenderingHint(RenderingHints.KEY_INTERPOLATION,
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RenderingHints.VALUE_INTERPOLATION_BICUBIC);
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g2.drawImage(circleImage, x, y, finalSize, finalSize, null);
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} finally {
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g2.dispose();
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}
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}
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private BufferedImage makeCircleImage(int finalSize, int scale) {
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int hi = finalSize * scale;
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BufferedImage img = new BufferedImage(hi, hi, BufferedImage.TYPE_INT_ARGB);
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Graphics2D g2 = img.createGraphics();
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try {
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g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
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RenderingHints.VALUE_ANTIALIAS_ON);
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g2.setRenderingHint(RenderingHints.KEY_RENDERING,
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RenderingHints.VALUE_RENDER_QUALITY);
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g2.setRenderingHint(RenderingHints.KEY_STROKE_CONTROL,
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RenderingHints.VALUE_STROKE_PURE);
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g2.setComposite(AlphaComposite.Src);
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float stroke = 6f * scale / 3f;
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double diameter = hi - stroke - (4 * scale);
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double x = (hi - diameter) / 2.0;
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double y = (hi - diameter) / 2.0;
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Shape circle = new Ellipse2D.Double(x, y, diameter, diameter);
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g2.setPaint(new Color(0xBBDEFB));
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g2.fill(circle);
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g2.setPaint(new Color(0x0D47A1));
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g2.setStroke(new BasicStroke(stroke, BasicStroke.CAP_ROUND, BasicStroke.JOIN_ROUND));
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g2.draw(circle);
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} finally {
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g2.dispose();
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}
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return img;
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}
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}
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}

‎image-processing/src/main/java/com/baeldung/drawcircle/DrawCircle.java‎

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package com.baeldung.drawcircle;
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import java.awt.*;
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import java.awt.geom.Ellipse2D;
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import javax.swing.*;
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public class DrawCircle extends JPanel {
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@Override
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protected void paintComponent(Graphics g) {
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super.paintComponent(g);
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Graphics2D g2 = (Graphics2D) g.create();
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try {
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g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
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g2.setRenderingHint(RenderingHints.KEY_STROKE_CONTROL, RenderingHints.VALUE_STROKE_PURE);
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g2.setRenderingHint(RenderingHints.KEY_RENDERING, RenderingHints.VALUE_RENDER_QUALITY);
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float stroke = 2f;
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double diameter = Math.min(getWidth(), getHeight()) - 12; // padding
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double x = (getWidth() - diameter) / 2.0;
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double y = (getHeight() - diameter) / 2.0;
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Ellipse2D circle = new Ellipse2D.Double(x, y, diameter, diameter);
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g2.setColor(new Color(0xBBDEFB));
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g2.fill(circle);
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g2.setColor(new Color(0x0D47A1));
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g2.setStroke(new BasicStroke(stroke, BasicStroke.CAP_ROUND, BasicStroke.JOIN_ROUND));
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g2.draw(circle);
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} finally {
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g2.dispose();
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}
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}
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public static void main(String[] args) {
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SwingUtilities.invokeLater(() -> {
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JFrame f = new JFrame("Circle");
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f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
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f.add(new DrawCircle());
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f.setSize(320, 240);
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f.setLocationRelativeTo(null);
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f.setVisible(true);
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});
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}
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}

‎image-processing/src/main/java/com/baeldung/drawcircle/DrawSupersampledCircle.java‎

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package com.baeldung.drawcircle;
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import javax.swing.*;
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import java.awt.*;
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import java.awt.geom.Ellipse2D;
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import java.awt.image.BufferedImage;
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public class DrawSupersampledCircle {
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public static void main(String[] args) {
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SwingUtilities.invokeLater(() -> {
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JFrame f = new JFrame("SupersampledCircle");
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f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
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f.add(new CirclePanel());
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f.pack();
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f.setLocationRelativeTo(null);
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f.setVisible(true);
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});
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}
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static class CirclePanel extends JPanel {
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private final BufferedImage hiResImage;
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private final int finalSize = 6;
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public CirclePanel() {
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int scale = 3;
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float stroke = 6f;
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hiResImage = makeSupersampledCircle(scale, stroke);
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setPreferredSize(new Dimension(finalSize + 32, finalSize + 32));
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setBackground(Color.WHITE);
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}
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@Override
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protected void paintComponent(Graphics g) {
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super.paintComponent(g);
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Graphics2D g2 = (Graphics2D) g.create();
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try {
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int x = (getWidth() - finalSize) / 2;
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int y = (getHeight() - finalSize) / 2;
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g2.setRenderingHint(RenderingHints.KEY_INTERPOLATION,
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RenderingHints.VALUE_INTERPOLATION_BICUBIC);
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g2.drawImage(hiResImage, x, y, finalSize, finalSize, null);
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} finally {
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g2.dispose();
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}
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}
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private BufferedImage makeSupersampledCircle(int scale, float stroke) {
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int hi = finalSize * scale;
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BufferedImage img = new BufferedImage(hi, hi, BufferedImage.TYPE_INT_ARGB);
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Graphics2D g2 = img.createGraphics();
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try {
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g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
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g2.setRenderingHint(RenderingHints.KEY_STROKE_CONTROL, RenderingHints.VALUE_STROKE_PURE);
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g2.setRenderingHint(RenderingHints.KEY_RENDERING, RenderingHints.VALUE_RENDER_QUALITY);
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double d = hi - stroke;
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Shape circle = new Ellipse2D.Double(stroke / 2.0, stroke / 2.0, d, d);
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g2.setPaint(new Color(0xBBDEFB));
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g2.fill(circle);
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g2.setPaint(new Color(0x0D47A1));
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g2.setStroke(new BasicStroke(stroke, BasicStroke.CAP_ROUND, BasicStroke.JOIN_ROUND));
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g2.draw(circle);
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} finally {
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g2.dispose();
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}
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return img;
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}
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}
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}

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