2D API - Learn Java by Examples

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

By Wayan in 2D API, Core API Last modified: June 5, 2023 0 Comment

package org.kodejava.awt.geom;

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

public class DrawDashedStroke extends JComponent {
    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);
    }

    @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));
    }
}

This code snippet produce the following output:

Draw 2D Dashed Stroke

How do I draw an arc in Java 2D?

By Wayan in 2D API, Core API Last modified: June 5, 2023 0 Comment

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.awt.geom;

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

public class DrawArc extends JComponent {
    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);
    }

    @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));
    }
}

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

Draw 2D Arc

How do I draw an ellipse in Java 2D?

By Wayan in 2D API, Core API Last modified: June 5, 2023 2 Comments

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.awt.geom;

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

public class DrawEllipse extends JComponent {
    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);
    }

    @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));
    }
}

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

Draw 2D Ellipse

How do I draw a GeneralPath in Java 2D?

By Wayan in 2D API, Core API Last modified: June 5, 2023 0 Comment

package org.kodejava.awt.geom;

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

public class DrawGeneralPath extends JComponent {
    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);
    }

    @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);
    }
}

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

Draw 2D General Path

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

By Wayan in 2D API, Core API Last modified: June 4, 2023 0 Comment

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.awt.geom;

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

public class DrawRoundRectangle extends JComponent {
    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);
    }

    @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));
    }
}

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

Draw 2D Round Rectangle