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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:

  1. public abstract void drawString(String str, int x, int y): is used to draw the specified string.
  2. public void drawRect(int x, int y, int width, int height): draws a rectangle with the specified width and height.
  3. 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.
  4. public abstract void drawOval(int x, int y, int width, int height): is used to draw oval with the specified width and height.
  5. 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.
  6. 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).
  7. public abstract boolean drawImage(Image img, int x, int y, ImageObserver observer): is used draw the specified image.
  8. public abstract void drawArc(int x, int y, int width, int height, int startAngle, int arcAngle): is used draw a circular or elliptical arc.
  9. 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.
  10. public abstract void setColor(Color c): is used to set the graphics current color to the specified color.
  11. public abstract void setFont(Font font): is used to set the graphics current font to the specified font.

Example of displaying graphics in swing:

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:

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

Example of displaying image in swing:

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

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