With this example we are going to see how to draw text in a Java Desktop Application. This is very useful when you have lots of graphics components in your application and you want to display some text in it.
In order to draw text in your Java Desktop Application you should:
- Create a new
Frame. - Add to the frame a new
CustomPaintComponent(). - Create a new class that extends
Componentand override thepaintmethod. - Use
Graphics2D.drawStringto draw a string in the screen.
Let’s see the code:
package com.javacodegeeks.snippets.desktop;
import java.awt.Component;
import java.awt.Font;
import java.awt.FontMetrics;
import java.awt.Frame;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.geom.AffineTransform;
public class DrawText {
public static void main(String[] args) {
// Create a frame
Frame frame = new Frame();
// Add a component with a custom paint method
frame.add(new CustomPaintComponent());
// Display the frame
int frameWidth = 300;
int frameHeight = 300;
frame.setSize(frameWidth, frameHeight);
frame.setVisible(true);
}
/**
* To draw on the screen, it is first necessary to subclass a Component and
* override its paint() method. The paint() method is automatically called
* by the windowing system whenever component's area needs to be repainted.
*/
static class CustomPaintComponent extends Component {
public void paint(Graphics g) {
// Retrieve the graphics context; this object is used to paint shapes
Graphics2D g2d = (Graphics2D) g;
/**
* The coordinate system of a graphics context is such that the
* origin is at the northwest corner and x-axis increases toward the
* right while the y-axis increases toward the bottom.
*/
int x = 0;
int y = 10;
// Set the desired font if different from default font
Font font = new Font("Serif", Font.PLAIN, 12);
g2d.setFont(font);
// Draw a string such that its base line is at x, y
g2d.drawString("This is a test string", x, y);
FontMetrics fontMetrics = g2d.getFontMetrics();
// Draw a string such that the top-left corner is at x, y
g2d.drawString("This is another test string", x, y+fontMetrics.getAscent());
// Draw string rotated clockwise 90 degrees
AffineTransform affineTransform = new AffineTransform();
affineTransform.setToRotation(Math.PI/2.0);
g2d.setTransform(affineTransform);
g2d.drawString("This is a vertical test string", x, y+2*fontMetrics.getAscent());
// Draw string rotated counter-clockwise 90 degrees
affineTransform = new AffineTransform();
affineTransform.setToRotation(-Math.PI/2.0);
g2d.setTransform(affineTransform);
g2d.drawString("This is a another vertical test string", x + fontMetrics.getAscent(), y + 2*fontMetrics.getAscent() + fontMetrics.stringWidth("This is a another vertical test string"));
}
}
}
This was an example on how to draw text in a Java Desktop Application.
