README.md

Description

Simply accepts integer x,y coordinates and graphs the points on a cartesian plane. The graph is immediately updated upon addition or deletion of a point.

More Info

Was done pretty quickly while learning Java. The code probably isn't as smooth as I would like, but hey... The integer-only text boxes are pretty nice, though (even if I didn't write that part...) Please feel free to refine it and get back to me. It's all about learning to write efficient code, right??

None known.

Submitted On
By	Shawn M. Hershman
Level	Beginner
User Rating	5.0 (20 globes from 4 users)
Compatibility	Java (JDK 1.2)
Category	Graphics
World	Java
Archive File

Source Code

// DrawGraph
// by Shawn Hershman
//
// Allows you to add and delete integer x,y coordinate pairs and
// draws a graph of the points.
import java.util.*;
import java.lang.*;
import java.awt.*;
import java.awt.event.*;
import java.awt.geom.*;
import javax.swing.*;
import javax.swing.event.*;
import javax.swing.text.*;
// The intText... classes prevent the user from entering
// anything that isn't an integer
// This was borrowed from _CoreJava2, Vol 1_
//   by Cay Horstmann and Gary Cornell
class IntTextDocument extends PlainDocument {
  public void insertString(int offs, String str, AttributeSet a)
    throws BadLocationException {
    if (str == null) return;
    String oldString = getText(0, getLength());
    String newString = oldString.substring(0, offs)
              + str + oldString.substring(offs);
    try {
      // Check if new value with 0 concatenated is an integer
      Integer.parseInt(newString + "0");
      super.insertString(offs, str, a);
    }
    catch(NumberFormatException e) {}
  }
}
class IntTextField extends JTextField {
  public IntTextField(int size) {
    super(size);
  }
  public IntTextField(int defval, int size) {
    super("" + defval, size);
  }
  protected Document createDefaultModel() {
    return new IntTextDocument();
  }
  public boolean isValid() {
    try {
      Integer.parseInt(getText());
      return true;
    }
    catch(NumberFormatException e) {
      return false;
    }
  }
  public int getValue() {
    try {
      return Integer.parseInt(getText());
    }
    catch(NumberFormatException e) {
      return 0;
    }
  }
}
class DrawGraphPanel extends JPanel {
  private static final int BORDER_OFFSET = 20;
  private Vector sortedPoints = new Vector();
  private int maxY = 0;
  private int minY = 0;
  private int numPoints = 0;
  public DrawGraphPanel() {
  }
  public void paintComponent(Graphics g) {
    int xAxis;
    int yAxis;
    double xScaleFactor;
    double yScaleFactor;
    int xOffset;
    int yOffset;
    super.paintComponent(g);
    Dimension d = new Dimension();
    d = getSize();
    int panelHeight = (int)Math.round(d.getHeight());
    int panelWidth = (int)Math.round(d.getWidth());
    if (sortedPoints.size() == 1) {
      drawPoint(g, panelWidth/2, panelHeight/2, (int)((Point)sortedPoints.get(0)).getX(),
             (int)((Point)sortedPoints.get(0)).getY() );
      if (((Point)sortedPoints.get(0)).y > 0)
        yAxis = BORDER_OFFSET;
      else if (((Point)sortedPoints.get(0)).y < 0)
        yAxis = panelWidth - BORDER_OFFSET;
      else
        yAxis = panelWidth/2;
      if (((Point)sortedPoints.get(0)).x < 0)
        xAxis = BORDER_OFFSET;
      else if (((Point)sortedPoints.get(0)).x > 0)
        xAxis = panelHeight - BORDER_OFFSET;
      else
        xAxis = panelHeight/2;
      g.drawLine(BORDER_OFFSET, xAxis, panelWidth-BORDER_OFFSET, xAxis);
      g.drawLine(yAxis, BORDER_OFFSET, yAxis, panelHeight-BORDER_OFFSET);
    }
    else if (sortedPoints.size() > 1) {
      int xdiff = (int)((Point)sortedPoints.get(sortedPoints.size()-1)).getX() -
            (int)((Point)sortedPoints.get(0)).getX();
      xScaleFactor = (panelWidth-2*BORDER_OFFSET)/xdiff;
      int ydiff = maxY - minY;
      if (ydiff == 0) ydiff = 1;
      yScaleFactor = (panelHeight-2*BORDER_OFFSET)/ydiff;
      xOffset = (int)(((Point)sortedPoints.get(0)).getX() * xScaleFactor - BORDER_OFFSET);
      yOffset = (int)(minY * yScaleFactor - BORDER_OFFSET);
      // Draw the lines
      for (int i=1; i < sortedPoints.size(); i++) {
        g.drawLine((int)(((Point)sortedPoints.get(i-1)).getX() * xScaleFactor - xOffset),
             panelHeight - (int)(((Point)sortedPoints.get(i-1)).getY() * yScaleFactor - yOffset),
             (int)(((Point)sortedPoints.get(i)).getX() * xScaleFactor - xOffset),
             panelHeight - (int)(((Point)sortedPoints.get(i)).getY() * yScaleFactor - yOffset));
      }
      // Draw the data points
      for (int j=0; j < sortedPoints.size(); j++) {
        int x = (int)(((Point)sortedPoints.get(j)).getX() * xScaleFactor - xOffset);
        int y = panelHeight - (int)(((Point)sortedPoints.get(j)).getY() * yScaleFactor - yOffset);
        drawPoint(g, x, y, (int)(((Point)sortedPoints.get(j)).getX()),
               (int)(((Point)sortedPoints.get(j)).getY()) );
      }
      // Draw axes
      g.drawLine(BORDER_OFFSET, panelHeight+yOffset, panelWidth-BORDER_OFFSET, panelHeight+yOffset);
      g.drawLine(-xOffset, BORDER_OFFSET, -xOffset, panelHeight-BORDER_OFFSET);
    }
    sortedPoints.removeAllElements();
  }
  private void drawPoint(Graphics g, int x, int y, int xVal, int yVal) {
    g.fillRect(x-1, y-1, 3, 3);
    g.drawRect(x-3, y-3, 6, 6);
    g.drawString( "(" + xVal + "," + yVal + ")", x-15, y+15);
  }
  public void setPoints(Vector rcvdVector) {
    int index;
    int value;
    Vector v = (Vector)rcvdVector.clone();
    sortedPoints.removeAllElements();
    numPoints = v.size();
    if (numPoints > 0) {
      minY = maxY = (int)((Point)v.get(0)).getY();
    }
    while (v.size()>0) {
      value = (int)((Point)v.get(0)).getX();
      index = 0;
      for (int i=1; i<v.size(); i++) {
        if ((int)((Point)v.get(i)).getX() < value) {
          value = (int)((Point)v.get(i)).getX();
          index = i;
        }
      }
      sortedPoints.addElement(v.get(index));
      if ((int)((Point)v.get(index)).getY() < minY) {
        minY = (int)((Point)v.get(index)).getY();
      }
      if ((int)((Point)v.get(index)).getY() > maxY) {
        maxY = (int)((Point)v.get(index)).getY();
      }
      v.remove(index);
    }
  }
}
class DrawGraphFrame extends JFrame
  implements ActionListener, ListSelectionListener {
  private DrawGraphPanel graphPanel = new DrawGraphPanel();
  private JPanel controlPanel = new JPanel();
  private Vector listStrings = new Vector();
  private Vector listPoints = new Vector();
  private String removeString = new String();
  private JList pointList;
  private JScrollPane scrollPane;
  private JButton deletePointButton;
  private JButton clearPointsButton;
  private JButton addPointButton;
  private IntTextField xValue;
  private IntTextField yValue;
  public DrawGraphFrame() {
    setTitle("Draw Graph");
    setSize(750, 500);
    setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    addWindowListener( new WindowAdapter() {
      public void windowClosing() {
        System.exit(0);
      }
    });
    pointList = new JList();
    pointList.setSelectionMode(ListSelectionModel.SINGLE_SELECTION);
    pointList.setFixedCellWidth(100);
    pointList.addListSelectionListener(this);
    scrollPane = new JScrollPane(pointList);
    deletePointButton = new JButton("Delete Point");
    deletePointButton.addActionListener(this);
    clearPointsButton = new JButton("Clear All");
    clearPointsButton.addActionListener(this);
    Box deleteButtons = Box.createHorizontalBox();
    deleteButtons.add(deletePointButton);
    deleteButtons.add(clearPointsButton);
    xValue = new IntTextField(3);
    yValue = new IntTextField(3);
    Box newPoint = Box.createHorizontalBox();
    newPoint.add(new JLabel("X:"));
    newPoint.add(xValue);
    newPoint.add(new JLabel("   Y:"));
    newPoint.add(yValue);
    addPointButton = new JButton("Add Point");
    addPointButton.addActionListener(this);
    Box b = Box.createVerticalBox();
    b.add(scrollPane);
    b.add(deleteButtons);
    b.add(new JLabel("   "));
    b.add(newPoint);
    b.add(addPointButton);
    controlPanel.add(b);
    getContentPane().add(graphPanel, "Center");
    getContentPane().add(controlPanel, "East");
    xValue.requestFocus();
    repaint();
  }
  public void valueChanged(ListSelectionEvent evt) {
    JList source = (JList)evt.getSource();
    if (source == pointList) {
      removeString = (String)pointList.getSelectedValue();
    }
  }
  public void actionPerformed(ActionEvent evt) {
    int index;
    Object s = evt.getSource();
    if (s == addPointButton) {
      Point p = new Point();
      if (xValue.getText().length() > 0 && yValue.getText().length() > 0 ) {
        p.setLocation(xValue.getValue(), yValue.getValue());
        if ( xValueExists(xValue.getValue()) == false ) {
          listStrings.add("(" + p.x + ", " + p.y + ")");
          listPoints.add(p);
          xValue.setText("");
          yValue.setText("");
          xValue.requestFocus();
        }
      }
    }
    else if (s == clearPointsButton) {
      listPoints.clear();
      listStrings.clear();
    }
    else if (s == deletePointButton) {
      if ((index = listStrings.indexOf(removeString)) > -1) {
        listPoints.remove(index);
        listStrings.remove(index);
      }
    }
    pointList.setListData(listStrings);
    graphPanel.setPoints(listPoints);
    repaint();
  }
  private boolean xValueExists(int x) {
    for (int i = 0; i < listPoints.size(); i++) {
      if (((Point)listPoints.get(i)).x == x)
        return true;
    }
    return false;
  }
}
public class DrawGraph {
  public static void main(String[] args) {
    JFrame frame = new DrawGraphFrame();
    frame.show();
  }
}