Displaying Graphics in Applet
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 Graphics in applet:
1. import java.applet.Applet;
2. import java.awt.*;
3.
4. public class GraphicsDemo extends Applet{
5.
6. public void paint(Graphics g){
7. g.setColor(Color.red);
8. g.drawString("Welcome",50, 50);
9. g.drawLine(20,30,20,300);
10. g.drawRect(70,100,30,30);
11. g.fillRect(170,100,30,30);
12. g.drawOval(70,200,30,30);
13.
14. g.setColor(Color.pink);
15. g.fillOval(170,200,30,30);
16. g.drawArc(90,150,30,30,30,270);
17. g.fillArc(270,150,30,30,0,180);
18.
19. }
20. }
myapplet.html
1. <html>
2. <body>
3. <applet code="GraphicsDemo.class" width="300" height="300">
4. </applet>
5. </body>
6. </html>
Displaying Image in Applet
Applet is mostly used in games
and animation. For this purpose image is required to be displayed. The
java.awt.Graphics class provide a method drawImage() to display the image.
Syntax of drawImage() method:
|
1. public abstract
boolean drawImage(Image img, int x, int y, ImageObserver observer): is used draw the specified image.
|
How to get the object of Image:
|
The
java.applet.Applet class provides getImage() method that returns the object
of Image. Syntax:
|
1. public Image getImage(URL u, String image){}
Other required methods of Applet class to display image:
|
1. public URL
getDocumentBase(): is
used to return the URL of the document in which applet is embedded.
2. public URL
getCodeBase(): is
used to return the base URL.
|
Example of displaying image in applet:
1. import java.awt.*;
2. import java.applet.*;
3.
4.
5. public class DisplayImage extends Applet {
6.
7. Image picture;
8.
9. public void init() {
10. picture = getImage(getDocumentBase(),"sonoo.jpg");
11. }
12.
13. public void paint(Graphics g) {
14. g.drawImage(picture, 30,30, this);
15. }
16.
17. }
|
In
the above example, drawImage() method of Graphics class is used to display
the image. The 4th argument of drawImage() method of is ImageObserver object.
The Component class implements ImageObserver interface. So current class
object would also be treated as ImageObserver because Applet class indirectly
extends the Component class.
|
myapplet.html
1. <html>
2. <body>
3. <applet code="DisplayImage.class" width="300" height="300">
4. </applet>
5. </body>
6. </html>
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