How do I draw a vertical text in Java 2D?

To draw a text / string vertically we need to do a transform on the Graphics2D object. First, create an instance of AffineTransform and set the rotation using the setToRotation() method. And then pass this transform object into g2.setTransform() method.

package org.kodejava.example.geom;

import javax.swing.*;
import java.awt.*;
import java.awt.geom.AffineTransform;

public class DrawVerticalText extends JPanel {
    @Override
    public void paint(Graphics g) {
        Graphics2D g2 = (Graphics2D) g;

        // Define rendering hint, font name, font style and font size
        g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
        g2.setFont(new Font("Segoe Script", Font.BOLD, 22));
        g2.setColor(Color.RED);

        // Rotate 90 degree to make a vertical text
        AffineTransform at = new AffineTransform();
        at.setToRotation(Math.toRadians(90), 80, 100);
        g2.setTransform(at);
        g2.drawString("This is a vertical text", 10, 10);
    }

    public static void main(String[] args) {
        JFrame frame = new JFrame();
        frame.setTitle("Draw Vertical Text Demo");
        frame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
        frame.add(new DrawVerticalText());
        frame.pack();
        frame.setSize(420, 350);
        frame.setVisible(true);
    }
}

Run the snippet and you’ll see the following screen:

Draw Vertical Text Demo

How do I draw a string in Java 2D?

The code snippet below show you how to draw a string using Graphics2D. The drawString() method accept the string to be drawn and their x and y coordinate. Here you can also see how to set the antialiasing mode using the setRenderingHint() method.

package org.kodejava.example.geom;

import javax.swing.*;
import java.awt.*;

public class DrawString extends JPanel {
    @Override
    public void paint(Graphics g) {
        Graphics2D g2 = (Graphics2D) g;

        // Define rendering hint, font name, font style and font size
        g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
        g2.setFont(new Font("Segoe Script", Font.BOLD + Font.ITALIC, 40));
        g2.setPaint(Color.ORANGE);

        // Draw Hello World String
        g2.drawString("Hello World!", 50, 100);
    }

    public static void main(String[] args) {
        JFrame frame = new JFrame();
        frame.setTitle("Draw String Demo");
        frame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
        frame.add(new DrawString());
        frame.pack();
        frame.setSize(420, 300);
        frame.setVisible(true);
    }
}

Run the snippet and you’ll see the following screen:

Draw String Demo

How do I create a gradient paint in Java 2D?

To change the color of a graphics shape we can use the setPaint() method. For a simple coloring we can pass the color object into this method, such as Color.RED or Color.GREEN.

If you want to paint with a gradient paint you can use the GradientPaint class. This class provides a way to fill a shape with a linear color gradient pattern. To create a gradient color pattern you can pass the following parameter to the object constructor.

  • x1: x coordinate of the first specified point in user space
  • y1: y coordinate of the first specified point in user space
  • color1: color at the first specified point
  • x2: x coordinate of the second specified point in user space
  • y2: y coordinate of the second specified point in user space
  • color2: color at the second specified point
package org.kodejava.example.geom;

import javax.swing.*;
import java.awt.*;
import java.awt.geom.Rectangle2D;

public class GradientPaintDemo extends JComponent {
    @Override
    public void paint(Graphics g) {
        Graphics2D g2 = (Graphics2D) g;

        GradientPaint blackToGray = new GradientPaint(50, 50, Color.BLACK,
            300, 100, Color.LIGHT_GRAY);
        g2.setPaint(blackToGray);
        g2.fill(new Rectangle2D.Double(50, 50, 300, 100));

        GradientPaint blueToBlack = new GradientPaint(0, 0, Color.BLUE,
            400, 400, Color.BLACK);
        g2.setPaint(blueToBlack);
        g2.fill(new Rectangle2D.Double(50, 160, 300, 100));
    }

    public static void main(String[] args) {
        JFrame frame = new JFrame("Gradient Paint Demo");
        frame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
        frame.getContentPane().add(new GradientPaintDemo());
        frame.pack();
        frame.setSize(new Dimension(420, 350));
        frame.setVisible(true);
    }
}

This code snippet produce the following output:

Gradient Paint Demo

How do I define stroke when drawing a shape in Java 2D?

package org.kodejava.example.geom;

import javax.swing.*;
import java.awt.*;
import java.awt.geom.Line2D;

public class DrawStrokeDemo extends JComponent {
    @Override
    public void paint(Graphics g) {
        Graphics2D g2 = (Graphics2D) g;

        float[] strokes = {1, 2, 3, 4, 5, 6};
        for (float stroke : strokes) {
            g2.setStroke(new BasicStroke(stroke));
            g2.draw(new Line2D.Float(50, stroke * 20, 350, stroke * 20));
        }
    }

    public static void main(String[] args) {
        JFrame frame = new JFrame("Draw Stroke Demo");
        frame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
        frame.getContentPane().add(new DrawStrokeDemo());
        frame.pack();
        frame.setSize(new Dimension(420, 200));
        frame.setVisible(true);
    }
}

This code snippet produce the following output:

Draw Stroke Demo

How do I create a dashed stroke in Java 2D?

package org.kodejava.example.geom;

import javax.swing.*;
import java.awt.*;
import java.awt.geom.RoundRectangle2D;

public class DrawDashedStroke extends JComponent {
    @Override
    public void paint(Graphics g) {
        Graphics2D g2 = (Graphics2D) g;
        float[] dash = {10.0f, 5.0f, 3.0f};

        // Creates a dashed stroke
        Stroke dashed = new BasicStroke(2.0f, BasicStroke.CAP_BUTT,
            BasicStroke.JOIN_MITER, 10.0f, dash, 0.0f);

        g2.setStroke(dashed);
        g2.setPaint(Color.RED);
        g2.draw(new RoundRectangle2D.Double(50, 50, 300, 100, 10, 10));
    }

    public static void main(String[] args) {
        JFrame frame = new JFrame("Draw Dashed Stroke Demo");
        frame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
        frame.getContentPane().add(new DrawDashedStroke());
        frame.pack();
        frame.setSize(new Dimension(420, 250));
        frame.setVisible(true);
    }
}

This code snippet produce the following output:

Draw Dashed Stroke Demo

How do I draw an arc in Java 2D?

Arc2D is the abstract superclass for all objects that store a 2D arc defined by a framing rectangle, start angle, angular extent (length of the arc), and a closure type (Arc2D.OPEN, Arc2D.CHORD, or Arc2D.PIE).

To constructs a new arc in double values, such as defining the specified location, size, angular extents, and closure type we can use the Arc2D.Double static-inner class.

package org.kodejava.example.geom;

import javax.swing.*;
import java.awt.*;
import java.awt.geom.Arc2D;

public class DrawArc extends JComponent {
    @Override
    public void paint(Graphics g) {
        Graphics2D g2 = (Graphics2D) g;

        g2.setStroke(new BasicStroke(2.0f));
        g2.setPaint(Color.RED);
        g2.draw(new Arc2D.Double(50, 50, 300, 300, 0, 90, Arc2D.PIE));
        g2.setPaint(Color.GREEN);
        g2.draw(new Arc2D.Double(50, 50, 300, 300, 90, 90, Arc2D.PIE));
        g2.setPaint(Color.BLUE);
        g2.fill(new Arc2D.Double(50, 50, 300, 300, 180, 90, Arc2D.PIE));
    }

    public static void main(String[] args) {
        JFrame frame = new JFrame("Draw Arc Demo");
        frame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
        frame.getContentPane().add(new DrawArc());
        frame.pack();
        frame.setSize(new Dimension(420, 450));
        frame.setVisible(true);
    }
}

Here is the result you’ll get when you run the snippet:

Draw Arc Demo

How do I draw an ellipse in Java 2D?

The Ellipse2D class define an ellipse that is defined by a framing rectangle. You can create an ellipse using a double or float values. When creating an ellipse using double values use the Ellipse2D.Double class. And for the float values you can use the Ellipse2D.Float class.

package org.kodejava.example.geom;

import javax.swing.*;
import java.awt.*;
import java.awt.geom.Ellipse2D;

public class DrawEllipse extends JComponent {
    @Override
    public void paint(Graphics g) {
        Graphics2D g2 = (Graphics2D) g;

        g2.setPaint(Color.RED);
        g2.setStroke(new BasicStroke(5.0f));
        g2.draw(new Ellipse2D.Double(50, 50, 250, 250));

        g2.setPaint(Color.BLUE);
        g2.fill(new Ellipse2D.Double(10, 10, 40, 40));

        g2.setPaint(Color.YELLOW);
        g2.fill(new Ellipse2D.Double(10, 300, 40, 40));

        g2.setPaint(Color.GREEN);
        g2.fill(new Ellipse2D.Double(300, 300, 40, 40));

        g2.setPaint(Color.ORANGE);
        g2.fill(new Ellipse2D.Double(300, 10, 40, 40));
    }

    public static void main(String[] args) {
        JFrame frame = new JFrame("Draw Ellipse Demo");
        frame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
        frame.getContentPane().add(new DrawEllipse());
        frame.pack();
        frame.setSize(new Dimension(420, 400));
        frame.setVisible(true);
    }
}

Here is the result you’ll get when you run the snippet:

Draw Ellipse Demo

How do I draw a GeneralPath in Java 2D?

package org.kodejava.example.geom;

import javax.swing.*;
import java.awt.*;
import java.awt.geom.GeneralPath;

public class DrawGeneralPath extends JComponent {
    @Override
    public void paint(Graphics g) {
        Graphics2D g2 = (Graphics2D) g;

        g2.setStroke(new BasicStroke(4.0f));
        g2.setPaint(Color.GREEN);

        int[] xPoints = {10, 50, 100, 150, 200, 250, 300, 350};
        int[] yPoints = {10, 50,  10,  50,  10,  50,  10,  50};
        GeneralPath path = new GeneralPath(GeneralPath.WIND_EVEN_ODD,
            xPoints.length);

        // Adds point to the path by moving to the specified
        // coordinates.
        path.moveTo(xPoints[0], yPoints[0]);
        for (int i = 1; i < xPoints.length; i++) {
            // Adds a point to the path by drawing a straight
            // line from the current position to the specified
            // coordinates.
            path.lineTo(xPoints[i], yPoints[i]);
        }
        path.curveTo(150, 150, 300, 300, 50, 250);
        path.closePath();
        g2.draw(path);

        // Draw another path, a start
        g2.setPaint(Color.RED);
        g2.setStroke(new BasicStroke(2.0f));
        path = new GeneralPath(GeneralPath.WIND_NON_ZERO);
        path.moveTo(200, 50);
        path.lineTo(270, 300);
        path.lineTo(100, 120);
        path.lineTo(300, 120);
        path.lineTo(130, 300);
        path.closePath();
        g2.draw(path);

    }

    public static void main(String[] args) {
        JFrame frame = new JFrame("Draw GeneralPath Demo");
        frame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
        frame.getContentPane().add(new DrawGeneralPath());
        frame.pack();
        frame.setSize(new Dimension(420, 400));
        frame.setVisible(true);
    }
}

Here is the result you’ll get when you run the snippet:

Draw General Path

How do I draw a round rectangle in Java 2D?

The RoundRectangle2D class defines a rectangle with rounded corners defined by a location (x,y), dimension (w x h), and the width and height of an arc with which to round the corners.

The RoundRectangle2D.Double class constructs a RoundRectangle2D from the specified values in double, including the location, width and the arch of the round rectangle.

package org.kodejava.example.geom;

import javax.swing.*;
import java.awt.*;
import java.awt.geom.RoundRectangle2D;

public class DrawRoundRectangle extends JComponent {
    @Override
    public void paint(Graphics g) {
        Graphics2D g2 = (Graphics2D) g;

        g2.setPaint(Color.RED);
        g2.setStroke(new BasicStroke(2.0f));

        double x = 50;
        double y = 50;
        double w = x + 250;
        double h = y + 100;
        g2.draw(new RoundRectangle2D.Double(x, y, w, h, 50, 50));
    }

    public static void main(String[] args) {
        JFrame frame = new JFrame("Rounded Rectangle Demo");
        frame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
        frame.getContentPane().add(new DrawRoundRectangle(), BorderLayout.CENTER);
        frame.pack();
        frame.setSize(420, 300);
        frame.setVisible(true);
    }
}

Here is the result you’ll get when you run the snippet:

Rounded Rectangle

How do I draw a rectangle in Java 2D?

The code snippet below show you how to use the Graphics2D class the draw a rectangle. You can see the snippet in the paintComponent(Graphics g) method defined in the anonymous JPanel object.

To draw a rectangle we use the Rectangle2D.Double static-inner class. The constructor of this class accept the information about the rectangle x, y coordinates and its width and height.

package org.kodejava.example.awt.geom;

import javax.swing.*;
import java.awt.*;
import java.awt.geom.Rectangle2D;

public class DrawRectangle {
    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable() {
            @Override
            public void run() {
                JFrame frame = new JFrame("Draw Rectangle");
                frame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
                frame.add(new JPanel() {
                    @Override
                    protected void paintComponent(Graphics g) {
                        // Draw a rectangle using Rectangle2D class
                        Graphics2D g2 = (Graphics2D) g;
                        g2.setColor(Color.RED);

                        double x = 100;
                        double y = 100;
                        double width = x + 200;
                        double height = y + 50;

                        // Draw the red rectangle
                        g2.draw(new Rectangle2D.Double(x, y, width, height));

                        g2.setColor(Color.BLUE);
                        // Draw the blue rectangle
                        g2.draw(new Rectangle2D.Double(150, 50, 200, 250));
                    }
                }, BorderLayout.CENTER);

                frame.pack();
                frame.setSize(new Dimension(500, 400));
                frame.setVisible(true);
            }
        });
    }
}

Here is the result you’ll get when you run the snippet:

Draw Rectangle