Question

I want to create a chat and graph on the basis of give input in Java.i don’t have an idea about to how to implement chart and graph in Java. please give me some idea about the implementation.

Thanks

Answer 1

If you want to implement graph yourself, first get your x, y points in two arrays xarray[], yarray[]. Normally to implement a curved graph, you need points between the data points you already have. Use interpolation for this http://www.webcabcomponents.com has free version of interpolation program. You just give the xarray, yarray, any_x and you get the interpolated y point for any x. You can plot look-continuous curves by code like

[pseudo code]
firstX,firstY =0  //assumed  x=0; y(0)=0 
loop
for x= 0 to panel width;
{ get interpolatedY(x);
  drawLine from (firstX,firstY) to (nextX,nextY);
  //use Graphics.drawLine command
  firstX=nextX; firstY=nextY;
}

You may have to set Scale if necessary and multiply the firstX etc by scale.

For Interpolation these bit of code will get you started. returnedArray has two elements. First returnedArray[0] is the required y. The other is error estimate (neglect for now).

import webcab.lib.math.interpolation.Interpolation;  
Interpolation interpol1 = new Interpolation();  
double[] returnedArray = interpol1.interpolateExtrapolatePolynomial(getQArray(),getEArray(),x);
y=returnedArray[0];

The above method interpolateExtrapolatePolynomial(getQArray(),getEArray(),x) is for polymial type curves. If you data points do follow any other pattern class, Interpolation has other methods. Or you can implement yourself using numerical methods.

Happy coding!