Java Drawing Polygons

What is Polygon?

• Polygons are nothing but shapes with many sides or set of lines connected together.
• The end of the first line is beginning of second line and second line is beginning of third line and so on.
• Example - Triangles,quadrilaterals,pentagons,hexagons etc.

Java has drawPolygon() and fillPolygon() methods of Graphics class which takes 3 arguments.

drawPolygon() - It draws hollow polygon shape.

fillPolygon() - It draws filled polygon shape.

Syntax

g.drawPolygon(int xCoordinateArray, int yCoordinateArray, int TotalPoints);
g.fillPolygon(int xCoordinateArray, int yCoordinateArray, int TotalPoints);

Example

Drawing a triangle shape.

X coordinate array[] = {60,100,20,60}

X coordinate array[] = {20,90,90,20}

Total points = 4

Program

import java.awt.*;
import java.applet.*;
/* < applet code="DrawPolygon.class" width=300 height=300>
< /applet> */

public class DrawPolygon extends Applet
{	
	int xpoints [] = {60,100,20,60};
	int ypoints [] = {20,90,90,20};
	int npoints = 4;
	public void paint(Graphics g)
	{
		g.drawPolygon(xpoints,ypoints,npoints);
	}
}

Output

Polygon Class

Java has alternate method of calling methods of polygon like drawPolygon() and fillPolygon() by creating object of Polygon class.

Steps

• Define xCoordinate array
• Define yCoordinate array
• Define Total ponts of array.
• Create polygon object and pass above 3 values to Polygon constructor.
• Call drawPolygon)() or fillPolygon() methods using Polygon object

Syntax

Polygon Polyobject = new Polygon(xpointsarray,ypointsarray,totalpoints);

Example

Drawing above triangle using polygon object

import java.awt.*;
import java.applet.*;
/* < applet code="DrawPolygon.class" width=300 height=300>
</applet> */

public class DrawPolygon extends Applet
{	
	int xpoints [] = {60,100,20,60};
	int ypoints [] = {20,90,90,20};
	int npoints = 4;
	public void paint(Graphics g)
	{
	    Polygon triangle = new Polygon(xpoints,ypoints,npoints);
	    g.drawPolygon(triangle);
	}
}