Java Swing: Displaying Graphics and Image

Displaying graphics in swing:

java.awt.Graphics class provides many methods for graphics programming.

Commonly used methods of Graphics class:

public abstract void drawString(String str, int x, int y): is used to draw the specified string. public void drawRect(int x, int y, int width, int height): draws a rectangle with the specified width and height. public abstract void fillRect(int x, int y, int width, int height): is used to fill rectangle with the default color and specified width and height. public abstract void drawOval(int x, int y, int width, int height): is used to draw oval with the specified width and height. public abstract void fillOval(int x, int y, int width, int height): is used to fill oval with the default color and specified width and height. public abstract void drawLine(int x1, int y1, int x2, int y2): is used to draw line between the points(x1, y1) and (x2, y2). public abstract boolean drawImage(Image img, int x, int y, ImageObserver observer): is used draw the specified image. public abstract void drawArc(int x, int y, int width, int height, int startAngle, int arcAngle): is used draw a circular or elliptical arc. public abstract void fillArc(int x, int y, int width, int height, int startAngle, int arcAngle): is used to fill a circular or elliptical arc. public abstract void setColor(Color c): is used to set the graphics current color to the specified color. public abstract void setFont(Font font): is used to set the graphics current font to the specified font.

---

Example of displaying graphics in swing:

1. import java.awt.*;  
2. import javax.swing.JFrame;  
3.   
4. public class DisplayGraphics extends Canvas{  
5.       
6.     public void paint(Graphics g) {  
7.         g.drawString("Hello",40,40);  
8.         setBackground(Color.WHITE);  
9.         g.fillRect(130, 30,100, 80);  
10.         g.drawOval(30,130,50, 60);  
11.         setForeground(Color.RED);  
12.         g.fillOval(130,130,50, 60);  
13.         g.drawArc(30, 200, 40,50,90,60);  
14.         g.fillArc(30, 130, 40,50,180,40);  
15.           
16.     }  
17.         public static void main(String[] args) {  
18.         DisplayGraphics m=new DisplayGraphics();  
19.         JFrame f=new JFrame();  
20.         f.add(m);  
21.         f.setSize(400,400);  
22.         //f.setLayout(null);  
23.         f.setVisible(true);  
24.     }  
25.   
26. }  

Displaying image in swing:

For displaying image, we can use the method drawImage() of Graphics class.

Syntax of drawImage() method:

public abstract boolean drawImage(Image img, int x, int y, ImageObserver observer): is used draw the specified image.

---

Example of displaying image in swing:

1. import java.awt.*;  
2. import javax.swing.JFrame;  
3.   
4. public class MyCanvas extends Canvas{  
5.       
6.     public void paint(Graphics g) {  
7.   
8.         Toolkit t=Toolkit.getDefaultToolkit();  
9.         Image i=t.getImage("p3.gif");  
10.         g.drawImage(i, 120,100,this);  
11.           
12.     }  
13.         public static void main(String[] args) {  
14.         MyCanvas m=new MyCanvas();  
15.         JFrame f=new JFrame();  
16.         f.add(m);  
17.         f.setSize(400,400);  
18.         f.setVisible(true);  
19.     }  
20.   
21. }  

Anurag Rana Educator CSE/IT