Computer Science 120
Introduction to Programming
Spring 2012, Siena College
DragAllRoads Demo
A working demo of DragAllRoads will appear below. Click inside the applet to interact with it.
DragAllRoads BlueJ Project
Click here to download a BlueJ project for DragAllRoads.
DragAllRoads Source Code
The Java source code for DragAllRoads is below. Click on a file name to download it.
import objectdraw.*;
import java.awt.*;
import java.util.ArrayList;
/* $Id: DragAllRoads.java 1577 2011-03-28 02:10:20Z terescoj $ */
/**
* Example DragAllRoads: draw "road segments" at mouse
* press points, but drag any existing segment instead
* if it happens to contain the mouse press point.
*
* @author Jim Teresco
* Siena College, CSIS 120, Spring 2011
* Updated to use ArrayLists, Spring 2012
*
*/
public class DragAllRoads extends WindowController {
// the road segments in our drawing
private ArrayList<RoadSegment> segments;
// the road segment currently being dragged, if any
private RoadSegment selectedSegment;
// last mouse point and boolean flag to support dragging
private boolean dragging;
private Location lastMouse;
/**
* Set up: just initialize the array of segments
* and set other instance variables.
*/
public void begin() {
segments = new ArrayList<RoadSegment>();
selectedSegment = null;
dragging = false;
lastMouse = null;
}
/** Draw a road segment at the mouse press point
* unless the most recent road drawn was at that
* point, in which case we begin a drag operation.
*
* @param point the Location of the mouse press
*/
public void onMousePress(Location point) {
// see if we've pressed the mouse on an existing road segment
for (int segmentNum = 0; segmentNum < segments.size(); segmentNum++) {
if (segments.get(segmentNum).contains(point)) {
selectedSegment = segments.get(segmentNum);
dragging = true;
lastMouse = point;
}
}
// if dragging is still false, we create a new segment
if (!dragging) {
// create the new segment and insert it into the list.
segments.add(new RoadSegment(point, canvas));
dragging = false;
}
}
/** Perform dragging operation if we are dragging anything
*
* @param point the Location of the mouse press
*/
public void onMouseDrag(Location point) {
if (dragging) {
selectedSegment.move(point.getX() - lastMouse.getX(),
point.getY() - lastMouse.getY());
lastMouse = point;
}
}
/** Complete dragging operation if we are dragging anything
*
* @param point the Location of the mouse press
*/
public void onMouseRelease(Location point) {
if (dragging) {
selectedSegment.move(point.getX() - lastMouse.getX(),
point.getY() - lastMouse.getY());
dragging = false;
}
}
}
import objectdraw.*;
import java.awt.*;
import java.util.ArrayList;
/* $Id: RoadSegment.java 1577 2011-03-28 02:10:20Z terescoj $ */
/**
* Class to draw a simple road segment at a given point
* on the given canvas, with contains and move capabilities.
*
* @author Jim Teresco
* Siena College, CSIS 120, Spring 2011
* Updated to use ArrayLists, Spring 2012
*/
public class RoadSegment {
// constant parameters defining the sizes for the road segment
private static final int ROAD_WIDTH = 50;
private static final int ROAD_LENGTH = 200;
private static final int STRIPE_WIDTH = 3;
private static final int STRIPE_LENGTH = 20;
private static final int STRIPE_SPACING = 20;
private static final int SIDE_STRIPE_INSET = 2;
// default colors
private static final Color ROAD_COLOR = new Color(32, 32, 32);
private static final Color SIDE_LINE_COLOR = Color.white;
private static final Color CENTER_LINE_COLOR = Color.yellow;
// the graphical components of our road segment
private FilledRect pavement;
private FilledRect sideStripe1, sideStripe2;
private ArrayList<FilledRect> centerStripes;
/**
* Construct a new RoadSegment
*
* @param point the Location of the upper left corner of the segment
* @param canvas the DrawingCanvas on which to draw
*/
public RoadSegment(Location point, DrawingCanvas canvas) {
// the pavement
pavement = new FilledRect(point, ROAD_WIDTH, ROAD_LENGTH, canvas);
pavement.setColor(ROAD_COLOR);
// side stripes
sideStripe1 = new FilledRect(point.getX() + SIDE_STRIPE_INSET, point.getY(),
STRIPE_WIDTH, ROAD_LENGTH, canvas);
sideStripe1.setColor(SIDE_LINE_COLOR);
sideStripe2 = new FilledRect(point.getX() + ROAD_WIDTH - SIDE_STRIPE_INSET - STRIPE_WIDTH,
point.getY(), STRIPE_WIDTH, ROAD_LENGTH, canvas);
sideStripe2.setColor(SIDE_LINE_COLOR);
// center stripes, draw from bottom to top
double nextStripeY = point.getY() + ROAD_LENGTH - STRIPE_LENGTH;
double stripeX = point.getX() + ROAD_WIDTH/2 - STRIPE_WIDTH/2;
// construct an array large enough to hold our stripes
int numStripes = ROAD_LENGTH/(STRIPE_LENGTH + STRIPE_SPACING);
centerStripes = new ArrayList<FilledRect>();
for (int stripeNum = 0; stripeNum < numStripes; stripeNum++) {
FilledRect nextStripe =
new FilledRect(stripeX, nextStripeY, STRIPE_WIDTH, STRIPE_LENGTH, canvas);
centerStripes.add(nextStripe);
nextStripe.setColor(CENTER_LINE_COLOR);
nextStripeY = nextStripeY - STRIPE_LENGTH - STRIPE_SPACING;
}
}
/**
* Return if the given location is within the graphical area covered by this
* road segment
*
* @param point the Location to check for containment
* @return whether the given Location is in this road segment
*/
public boolean contains(Location point) {
return pavement.contains(point);
}
/**
* Move the road segment by the given x and y offsets.
*
* @param dx the amount to move in the x coordinate
* @param dy the amount to move in the y coordinate
*
*/
public void move(double dx, double dy) {
// move each component by these offsets
pavement.move(dx, dy);
sideStripe1.move(dx, dy);
sideStripe2.move(dx, dy);
for (int stripeNum = 0; stripeNum < centerStripes.size(); stripeNum++) {
centerStripes.get(stripeNum).move(dx, dy);
}
}
}