Re: How to draw a graph in Java applet
 

I wish I could help you with using more of the Graphics class's functions but unfortunately I truly HATE using Graphics from getGraphics in containers. I wouldn't be able to help you with setting the location of your Graphics object.

I personally prefer using GObjects, GCompounds, GLines that work on GCanvases.

The only method I have an issue with understanding is the move method in most GObject classes. I'm almost certain that it fires a thread that continuously offsets the object but i could be wrong.

Re: How to draw a graph in Java applet
 

import java.awt.*;
import java.applet.*;

public class graphic extends Applet {
Button button1;
public void init() {
}

public void paint(Graphics g) {

int CYCLE=4;
int MAX = 1000;
int x1=0;
int x2=0;
g.setColor(Color.red);//color for axes
g.drawLine(0,150,700,150);//x-axis
g.drawLine(240,0,240,500);//y-axis
g.drawString("X-Axis", 430,140);//Label for x-axis
g.drawString("Y-Axis",200,270);//Label for y-axis
g.setColor(Color.blue);//color for the sin curve

for (int i=-130;i<=368;i++)
{
try
{
Thread.sleep(10); // 10 millisecond delay
}
catch(InterruptedException e)
{
e.printStackTrace();
}

x1 = (int)(100 * Math.sin(((i)*2*Math.PI*CYCLE)/(MAX)));
x2 = (int)(100 * Math.sin(((i+1)*2*Math.PI*CYCLE)/(MAX)));
g.drawLine(i+121,x1+138,(i+1)+121,x2+138);
}
g.setFont(new Font("Times New Roman",Font.BOLD,15));
g.drawString("IT WORKS ; )",100,50); }
}
//Here is the code

Re: How to draw a graph in Java applet
 

import java.awt.*;

import java.applet.*;



public class graphic extends Applet {

        Button button1;

        public void init() {

        }



        public void paint(Graphics g) {

     

        int CYCLE=4;

        int MAX = 1000;

        int WEIGHT = 100;

                int x1=0;

                int x2=0;

                g.setColor(Color.red);//color for axes

                g.drawLine(0,150,700,150);//x-axis

        g.drawLine(240,0,240,500);//y-axis

        g.drawString("X-Axis", 430,140);//Label for x-axis

        g.drawString("Y-Axis",200,270);//Label for y-axis

        g.setColor(Color.blue);//color for the sin curve

        

         for (int i=-130;i<=368;i++)

       {            

               try 

            {

           Thread.sleep(10); // 10 millisecond delay 

            } 

            catch(InterruptedException e)

            {

           e.printStackTrace();

            } 

        

               x1 = (int)(WEIGHT * Math.sin(((i)*2*Math.PI*CYCLE)/(MAX)));

               x2 = (int)(WEIGHT * Math.sin(((i+1)*2*Math.PI*CYCLE)/(MAX)));          

               g.drawLine(i+121,x1+138,(i+1)+121,x2+138);

       }

        g.setFont(new Font("Times New Roman",Font.BOLD,15));

        g.drawString("IT WORKS ; )",100,50);        }        

}

//Here is the code

Keep in mind that the MAX is really the maximum difference between the min-x and max-x values.

For example, if you can go from -100 to 100 in your graph, MAX should be the difference of the two, resulting in MAX = 200

Edit: Added an int named WEIGHT that controls the peak and valley of your sin graph. The greater the WEIGHT the deeper and steeper your waves, the lower the WEIGHT the more subtle your graph will be.

Re: How to draw a graph in Java applet
 

Alex said:Well that's not exactly true; the gradient (i.e. rate of change) of a Sin curve depends on the input. Though I did misread the part about the circle, my bad :icon_redface:

Good work Alex :icon_wink: Though because of the nature of a Sin graph, one did not have to consider the changed between graphics and the Cartesian plane. On the screen y increases as we move down, however, on the Cartesian plane, y increase as we move up. Something to consider if ever you needed to draw, say a straight line.

So perhaps mark this post as Solved :icon_cool: