Computer Science 120
Introduction to Programming

Spring 2012, Siena College

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Scribble Demo

A working demo of Scribble will appear below. Click inside the applet to interact with it.

Scribble BlueJ Project

Click here to download a BlueJ project for Scribble.

Scribble Source Code

The Java source code for Scribble is below. Click on a file name to download it.

Scribble.java

import objectdraw.*;

/*
 * This program is a "scribbler".  When the mouse is pressed then dragged,
 * a series of lines are drawn from the previous point to the current location.
 *
 * Jim Teresco, Siena College, CSCI 120, Spring 2011
 * Based on similar example from Williams College CS 134.
 *
 * $Id: Scribble.java 1496 2011-01-20 20:01:52Z terescoj $
 */
public class Scribble extends WindowController {

  // Last coordinate, to be used to draw next line segment
  private Location prevPoint;

  /*
   * When the mouse is pressed, save the press point to be used as
   * the first endpoint of the first line drawn during dragging
   */
  public void onMousePress(Location point) {
    prevPoint = point;
  } 

  /*
   * As the user is dragging, draw a line from the last saved point to
   * current point, and update last saved point.
   */
  public void onMouseDrag(Location point) {

    new Line(prevPoint, point, canvas);
    prevPoint = point;
  }
}