What is the importance of JViewport class in Java?
JViewport
- A JViewport class defines the basic scrolling model and it is designed to support both logical scrolling and pixel-based scrolling.
- The viewport's child called the view is scrolled by calling JViewport.setViewPosition() method.
- A JViewport class supports logical scrolling, that is a kind of scrolling in which view coordinates are not pixels.
- To support a logical scrolling, JViewport defines a small set of methods that can be used to define the geometry of a viewport and a view. By default, these methods just report the pixel dimensions of the viewport and view.
Example
import java.awt.*;
import javax.swing.*;
public class JViewportTest extends JFrame {
public JViewportTest() {
setTitle("JViewport Test");
setLayout(new FlowLayout());
JLabel label = new JLabel(new ImageIcon("C:/Users/User/Desktop/Java Answers/logo.jpg"));
JViewport viewport = new JViewport();
viewport.setView(label);
viewport.setExtentSize(new Dimension(350, 350));
viewport.setViewPosition(new Point(50, 25));
viewport.setPreferredSize(new Dimension(350, 275));
add(viewport);
setSize(400, 300);
setLocationRelativeTo(null);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setVisible(true);
}
public static void main(String[] args) {
new JViewportTest();
}
}
Output

Published on 17-Jul-2019 11:01:53