Lab 5: Drawing and Comparing Circles

The Circles Class

Objectives

Call methods with parameters and return values.

Use the DrawingPanel and Graphics classes.

Use if statements to control return values and print statements.

Task

Ask the user for information to draw three circles in a DrawingPanel. Print information about the circles. Each item of information should correspond to a different static method.

Similar to previous programs, your program should start by printing

Lab 5 written by YOURNAME

Details

The DrawingPanel should be 400x300.

Circles

Ask the user for the center and radius of each circle. Use the fillOval method to draw the circles. Note that the parameters to fillOval (the upper-left corner and the width and height of the bounding box) need to be calculated from the information provided by the user (the center and the radius). Also, fill the circles using three different colors.

Methods

Each of the following items should be performed by a separate static method. Each method might have up to six parameters. Each circle is described by three values: the x and y values of the center, and the radius.

One static method should have parameters for the radiuses of two circles (two parameters), and the method should return -1 if the first circle is smaller, return 0 if the two circles have the same size, or return 1 if the first circle is larger. Based on the return value from this method, the main method should print a line of output like:

The green circle is smaller than the red circle.

Another static method should have parameters for the radiuses and locations of two circles (six paramters), and the method should return 1 if the circles intersect or return 0 if the circles do not intersect (alternatively, you could return true or false). If (x1,y1) and (x2,y2) are the centers of the circles and if r1 and r2 are their radiuses, then the circles intersect if the distance between the centers, the square root of:

(x1 - x2)² + (y1 - y2)²

is less than or equal to r1 + r2. Based on the return values from this method, the main method should print a line of output like:

The blue circle intersects the red circle.

(Optional) Given a circle, return 1 if the circle is completely within the window, return 0 if the circle is partially within the window, or return -1 if the circle is completely outside the window. The program should print something appropriate.

Note that each method needs to be called three times. If your circles are blue, green, and red, then the first method needs to be called for three pairs: blue and green, blue and red, and green and red.

this is the code for the drawing panel:

/* Stuart Reges and Marty Stepp February 24, 2007 Changes by Tom Bylander in 2010 (no anti-alias, repaint on sleep) Changes by Tom Bylander in 2012 (track mouse clicks and movement) Changes by Tom Bylander in 2013 (fix bug in tracking mouse clicks) Changes by S. Robbins in 2014 (getters for width and height) Changes by S. Robbins in 2014 (addKeyListener added) Changes by S. Robbins in 2014 (catch exception on default close so that it works in an applet) Changes by S. Robbins in 2015 (buffer key events) Changes by S. Robbins in 2015 (show mouse status by default is off) The DrawingPanel class provides a simple interface for drawing persistent images using a Graphics object. An internal BufferedImage object is used to keep track of what has been drawn. A client of the class simply constructs a DrawingPanel of a particular size and then draws on it with the Graphics object, setting the background color if they so choose. To ensure that the image is always displayed, a timer calls repaint at regular intervals. */ import java.awt.*; import java.awt.event.*; import java.awt.image.*; import javax.swing.*; import javax.swing.event.*; import java.util.ArrayList; public class DrawingPanel implements ActionListener { private static final String versionMessage = "Drawing Panel version 1.1, January 25, 2015"; private static final int DELAY = 100; // delay between repaints in millis private static final boolean PRETTY = false; // true to anti-alias private static boolean showStatus = false; private static final int MAX_KEY_BUF_SIZE = 10; private int width, height; // dimensions of window frame private JFrame frame; // overall window frame private JPanel panel; // overall drawing surface private BufferedImage image; // remembers drawing commands private Graphics2D g2; // graphics context for painting private JLabel statusBar; // status bar showing mouse position private volatile MouseEvent click; // stores the last mouse click private volatile boolean pressed; // true if the mouse is pressed private volatile MouseEvent move; // stores the position of the mouse private ArrayList keys; // construct a drawing panel of given width and height enclosed in a window public DrawingPanel(int width, int height) { this.width = width; this.height = height; keys = new ArrayList(); image = new BufferedImage(width, height, BufferedImage.TYPE_INT_ARGB); statusBar = new JLabel(" "); statusBar.setBorder(BorderFactory.createLineBorder(Color.BLACK)); statusBar.setText(versionMessage); panel = new JPanel(new FlowLayout(FlowLayout.CENTER, 0, 0)); panel.setBackground(Color.WHITE); panel.setPreferredSize(new Dimension(width, height)); panel.add(new JLabel(new ImageIcon(image))); click = null; move = null; pressed = false; // listen to mouse movement MouseInputAdapter listener = new MouseInputAdapter() { public void mouseMoved(MouseEvent e) { pressed = false; move = e; if (showStatus) statusBar.setText("moved (" + e.getX() + ", " + e.getY() + ")"); } public void mousePressed(MouseEvent e) { pressed = true; move = e; if (showStatus) statusBar.setText("pressed (" + e.getX() + ", " + e.getY() + ")"); } public void mouseDragged(MouseEvent e) { pressed = true; move = e; if (showStatus) statusBar.setText("dragged (" + e.getX() + ", " + e.getY() + ")"); } public void mouseReleased(MouseEvent e) { click = e; pressed = false; if (showStatus) statusBar.setText("released (" + e.getX() + ", " + e.getY() + ")"); } public void mouseEntered(MouseEvent e) { // System.out.println("mouse entered"); panel.requestFocus(); } }; panel.addMouseListener(listener); panel.addMouseMotionListener(listener); new DrawingPanelKeyListener(); g2 = (Graphics2D)image.getGraphics(); g2.setColor(Color.BLACK); if (PRETTY) { g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON); g2.setStroke(new BasicStroke(1.1f)); } frame = new JFrame("Drawing Panel"); frame.setResizable(false); try { frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); // so that this works in an applet } catch (Exception e) {} frame.getContentPane().add(panel); frame.getContentPane().add(statusBar, "South"); frame.pack(); frame.setVisible(true); toFront(); frame.requestFocus(); // repaint timer so that the screen will update new Timer(DELAY, this).start(); } public void showMouseStatus(boolean f) { showStatus = f; } public void addKeyListener(KeyListener listener) { panel.addKeyListener(listener); panel.requestFocus(); } // used for an internal timer that keeps repainting public void actionPerformed(ActionEvent e) { panel.repaint(); } // obtain the Graphics object to draw on the panel public Graphics2D getGraphics() { return g2; } // set the background color of the drawing panel public void setBackground(Color c) { panel.setBackground(c); } // show or hide the drawing panel on the screen public void setVisible(boolean visible) { frame.setVisible(visible); } // makes the program pause for the given amount of time, // allowing for animation public void sleep(int millis) { panel.repaint(); try { Thread.sleep(millis); } catch (InterruptedException e) {} } // close the drawing panel public void close() { frame.dispose(); } // makes drawing panel become the frontmost window on the screen public void toFront() { frame.toFront(); } // return panel width public int getWidth() { return width; } // return panel height public int getHeight() { return height; } // return the X position of the mouse or -1 public int getMouseX() { if (move == null) { return -1; } else { return move.getX(); } } // return the Y position of the mouse or -1 public int getMouseY() { if (move == null) { return -1; } else { return move.getY(); } } // return the X position of the last click or -1 public int getClickX() { if (click == null) { return -1; } else { return click.getX(); } } // return the Y position of the last click or -1 public int getClickY() { if (click == null) { return -1; } else { return click.getY(); } } // return true if a mouse button is pressed public boolean mousePressed() { return pressed; } public synchronized int getKeyCode() { if (keys.size() == 0) return 0; return keys.remove(0).keyCode; } public synchronized char getKeyChar() { if (keys.size() == 0) return 0; return keys.remove(0).keyChar; } public synchronized int getKeysSize() { return keys.size(); } private synchronized void insertKeyData(char c, int code) { keys.add(new KeyInfo(c,code)); if (keys.size() > MAX_KEY_BUF_SIZE) { keys.remove(0); // System.out.println("Dropped key"); } } private class KeyInfo { public int keyCode; public char keyChar; public KeyInfo(char keyChar, int keyCode) { this.keyCode = keyCode; this.keyChar = keyChar; } } private class DrawingPanelKeyListener implements KeyListener { int repeatCount = 0; public DrawingPanelKeyListener() { panel.addKeyListener(this); panel.requestFocus(); } public void keyPressed(KeyEvent event) { // System.out.println("key pressed"); repeatCount++; if ((repeatCount == 1) || (getKeysSize() < 2)) insertKeyData(event.getKeyChar(),event.getKeyCode()); } public void keyTyped(KeyEvent event) { } public void keyReleased(KeyEvent event) { repeatCount = 0; } } }