Help with 2D Graphics - How do I send Variable data to paint method?

Question

I am working on a program that figures mortgage payments and an amortization schedule when a user inputs the principle, APR, and term length in years. After it figures all of those, I want to be able to display a chart that shows the principle and interest amounts for each year. My problem is, how do I get my loan information into my paint method so that I can draw a chart using that data? Any help would be greatly appreciated. The graph class in the code below is called after pressing a "Display Graph" button from my GUI.
I'm pasting my code below. This does not include my main method or my GUI method. I can post those if necessary. Here is my code so far:
import java.util.*;
import java.lang.*;
import java.awt.*;
import java.awt.event.*;
import java.awt.geom.*;
import javax.swing.*;
import java.io.*;
import java.lang.Math;
public class Graph extends JFrame
     public Graph(double dCurrentBalance, double dMonthlyPmt, double dRate, int iTime)
          final double balance = dCurrentBalance;
          JFrame graphFrame;
          int iCounter = 0;
          int iPmtNumber = 0;
          double dCurrentInt = 0.0;
          double dCurrentPrinciple = 0.0;
          double dMPR = 0.0;
          int yCoordInt = 0;               //integer for Y coordinate for Interest
          int yCoordPrinciple = 0;     //integer for Y coordinate for Principle
          iTime *= 12;               //determine number of months for this loan
          iCounter = iTime;          //set loop counter to number of months for this loan
          dMPR = dRate/12;          //determine monthly periodic rate
          graphFrame = new JFrame ("mCalc Graph");
          graphFrame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
          graphFrame.setSize(800,600);
          graphFrame.setResizable(false);
          // center graphFrame on the screen
     Dimension ScreenSize = Toolkit.getDefaultToolkit().getScreenSize();
     Dimension FrameSize = graphFrame.getSize();
     if (FrameSize.height > ScreenSize.height)
     FrameSize.height = ScreenSize.height;
     if (FrameSize.width > ScreenSize.width)
     FrameSize.width = ScreenSize.width;
     graphFrame.setLocation((ScreenSize.width - FrameSize.width) / 2,
               (ScreenSize.height - FrameSize.height) / 2);
          //Displays graphFrame
          Graphic graphicPane = new Graphic();
          graphFrame.add(graphicPane);
          graphFrame.setVisible(true);
          //This loops until all payments have been figured
          for (; iCounter > 0; )
     iPmtNumber++;
     dCurrentInt = dCurrentBalance * dMPR;
     dCurrentPrinciple = dMonthlyPmt - dCurrentInt;
     dCurrentBalance = dCurrentBalance - dCurrentPrinciple;
               if (iPmtNumber%12 == 0)
//           System.out.println("dCurrentBalance = " + dCurrentBalance);
//                    System.out.println("Payment # = " + iPmtNumber);
//                    System.out.println("dCurrentInt = " + dCurrentInt);
//                    System.out.println("dCurrentPrinciple = " + dCurrentPrinciple);
     iCounter = iCounter-1;
          } //end for loop
     } //end Graph constructor
/* This class needs to be personalized to include my own variable names,
*     etc. I also need to find a way to bring in data from the Graph class.
     class Graphic extends JPanel
          public void paintComponent(Graphics comp)
                         int i; // Declare the variables used to generate the chart
float xLoc = 50; // Location of the X Axis along Y
float yLoc = 50; // Location of the Y Axis along X
Line2D.Float LnA; //
super.paintComponent(comp);
               // Establish a tie between this subroutine and the Graphic
Graphics2D comp2D = (Graphics2D) comp;
// Cast the Graphics named comp to a Graphics2D as comp2D
comp2D.setColor(Color.white);
// Set the background color
comp2D.fillRect(0,0,800,600);
// Draw the X and Y axis
comp2D.setColor(Color.black); // Set the pen color to black
Line2D.Float YAxis = new Line2D.Float(50,50,50,getSize().height - 50); // Define the Y-Axis
Line2D.Float XAxis = new Line2D.Float(50F,getSize().height - 50F, getSize().width -50F, getSize().height -50F); //Define the X-Axis
comp2D.draw(YAxis); // Draw the Y-Axis
comp2D.draw(XAxis); // Draw the X-Axis
Font font = new Font("Dialog", Font.BOLD, 12); // Set the font for the Axis labels
comp2D.setFont(font);
float increment = 15;
// Draw the line
xLoc += increment;
comp2D.setColor(Color.red);
/* Need to find a way to bring in my own data to use for the
* yLoc variables.
for (i=1; i<=45; i++)
{ // Begin making the graph
if (i < 30)
     yLoc += increment;
} else {
     yLoc -= increment;
// Scale the location to the graph height
LnA = new Line2D.Float( xLoc, getSize().height - 50F , xLoc, yLoc); // Create the line
comp2D.draw(LnA); // Draw the line
xLoc += increment;
                         }//end for
               }//end paintComponent
          } //end class Graphic
} //end class Graph
Any help would be GREATLY appreciated! Thanks.
Message was edited by:
russedl
My email address iss [email protected] if you wish to reply privately. I can send my entire program code if that will help. Thanks!

Answer 1

Hi Deca,
You can use the CmdExecuteSync method of the DIAdem.TOCommand interface to set the value of a text channel. For example passing the string "CHT(1,1) := 'test'" as a parameter to the CmdExecuteSync method will set the 1st row of the 1st channel to "test". Please refer to the DIAdem help for more documentation on the CHT function.
I hope this helps! Please post back if I wasn't clear enough in explaining how to do this or if you have any problems getting it to work.
Regards,
Sarah Miracle
National Instruments