001 package javaeyes;
002
003 import cs101.lang.*;
004 import cs101.util.*;
005 import java.awt.*;
006 import java.awt.event.*;
007
008 /**
009 * The <code>JavaEyes</code> class is a Java-based implementation of the
010 * familiar "xeyes" program, available on many Unix-based systems.
011 *
012 */
013 public class JavaEyes extends Frame implements Animate {
014
015 // Class constants
016
017 // Default background color
018 private static final Color DEFAULT_BG_COLOR = Color.white;
019 // Default foreground color
020 private static final Color DEFAULT_FG_COLOR = Color.black;
021
022 // Non-varying instance data
023 private Color bgColor; // Actual background color
024 private Color fgColor; // Actual foreground color
025 private Panel buttonPanel; // A Panel used to hold the quit button
026 private Panel eyesPanel; // A Panel used to hold the eyes graphic
027 private Button quitButton; // The "quit" button
028
029 // State variables:
030 private Point mousePosition; // The current position of the mouse
031
032 // Objects used to animate the eyes,
033 private AnimatorThread animator;
034 private Image offscreenImage;
035
036
037 /**
038 * Default class constructor. Builds a <code>JavaEyes</code> object,
039 * and starts a <code>Thread</code> to animate the eyes in
040 * response to the <code>mouseMoved</code> event.
041 * Uses the default background and foreground colors.
042 *
043 */
044 public JavaEyes() {
045 this(DEFAULT_BG_COLOR, DEFAULT_FG_COLOR);
046 }
047
048 /**
049 * Class constructor. Builds a <code>JavaEyes</code> object,
050 * and starts a <code>Thread</code> to animate the eyes in
051 * response to the <code>mouseMoved</code> event.
052 *
053 * @param bgColor the background color of the <code>JavaEyes</code> window
054 * @param fgColor the foreground color of the <code>JavaEyes</code> window
055 */
056 public JavaEyes(Color bgColor, Color fgColor) {
057 super("JavaEyes");
058
059 //+++++++++++++++++++++++++++++++++++++++++++++++++++++++//
060 // //
061 // Add components to the window //
062 // //
063 // (In other words, add whatever buttons, icons, and //
064 // and graphics we'd like this window to contain). //
065 // //
066 //+++++++++++++++++++++++++++++++++++++++++++++++++++++++//
067
068 // First, add a "quit" Button
069 //
070 this.buttonPanel = new Panel();
071 this.quitButton = new Button("Quit");
072 this.buttonPanel.add(quitButton);
073 this.add("North", buttonPanel);
074
075 // Next, add a Panel in which to display the "eyes" graphic
076 //
077 this.eyesPanel = new Panel();
078 this.add("Center", eyesPanel);
079
080 //+++++++++++++++++++++++++++++++++++++++++++++++++++++++//
081 // //
082 // Initialize the event handlers //
083 // //
084 // (In other words, tell the window what to do when the //
085 // the user clicks a mouse on it, or types something //
086 // at the keyboard). //
087 // //
088 //+++++++++++++++++++++++++++++++++++++++++++++++++++++++//
089
090 // Set up an event handler to listen for the mouseMoved event
091 //
092 MouseMotionListener mouseMotionListener = new MouseMotionAdapter() {
093 public void mouseMoved(MouseEvent e) {
094 JavaEyes.this.setMousePos(e.getX(),e.getY());
095 }
096 };
097
098 this.addMouseMotionListener(mouseMotionListener);
099 this.eyesPanel.addMouseMotionListener(mouseMotionListener);
100 this.buttonPanel.addMouseMotionListener(mouseMotionListener);
101
102 // Set up an event handler to detect when the user attempts
103 // to close the program by pressing the "quit" button
104 //
105
106 ActionListener actionListener = new ActionListener() {
107 public void actionPerformed(ActionEvent e) {
108 animator.stopExecution();
109 JavaEyes.this.dispose();
110 System.exit(0);
111 }
112 };
113
114 this.quitButton.addActionListener(actionListener);
115
116 // Set up an event handler to detect when the user attempts
117 // to close the program by pressing the window's close button
118 //
119 WindowListener windowListener = new WindowAdapter() {
120 public void windowClosing(WindowEvent e) {
121 animator.stopExecution();
122 JavaEyes.this.dispose();
123 System.exit(0);
124 }
125 };
126
127 this.addWindowListener(windowListener);
128
129 //+++++++++++++++++++++++++++++++++++++++++++++++++++++++//
130 // //
131 // Initialize the state of this class //
132 // //
133 // (As a program runs, things about it will change. For //
134 // example, in the JavaEyes program, the position of //
135 // eyeballs changes. This changeable data is called //
136 // "state". When you start a program which uses state, //
137 // it is generally necesssary to initialize it to some //
138 // default value. In this case, we tell JavaEyes to //
139 // look at the top left corner of the window. If we //
140 // failed to do this, the result of our program might //
141 // be unpredictable, and that is the last thing we //
142 // want!). //
143 // //
144 //+++++++++++++++++++++++++++++++++++++++++++++++++++++++//
145
146 this.bgColor = bgColor;
147 this.fgColor = fgColor;
148 this.mousePosition = new Point(0,0); // Tell the eyes where to look
149 this.setBackground(this.bgColor); // Set the background color
150 this.setForeground(this.fgColor); // Set the foreground color
151
152 //+++++++++++++++++++++++++++++++++++++++++++++++++++++++//
153 // //
154 // Standard window stuff //
155 // //
156 // (Don't worry about this for now). //
157 // //
158 //+++++++++++++++++++++++++++++++++++++++++++++++++++++++//
159
160 this.pack();
161 this.show();
162 this.setLocation(1,1);
163
164 this.animator = new AnimatorThread(this, true, 0, 100);
165 }
166
167 /**
168 * The standard entry point into a Java program.
169 *
170 * @param argv command-line arguments passed to the program
171 */
172 public static void main(String argv[]) {
173 Color bgColor = JavaEyes.DEFAULT_BG_COLOR;
174 Color fgColor = JavaEyes.DEFAULT_FG_COLOR;
175 int argnum = 0;
176 String usage = "Usage: java JavaEyes [-fg <color>] [-bg <color>]";
177
178 if (argv.length==0) {
179 new JavaEyes();
180 }
181 else {
182 try {
183 while (argnum < argv.length) {
184 if (argv[argnum].equals("-bg")) {
185 bgColor = Coerce.stringToColor(argv[++argnum]);
186 argnum++;
187 }
188 else if (argv[argnum].equals("-fg")) {
189 fgColor = Coerce.stringToColor(argv[++argnum]);
190 argnum++;
191 }
192 else { throw new Error(usage); }
193 }
194 }
195 catch (ArrayIndexOutOfBoundsException exc) { throw new Error(usage); }
196
197 new JavaEyes(bgColor, fgColor);
198 }
199 }
200
201 /**
202 * @deprecated use <code>getPreferredSize()</code> instead.
203 */
204 public Dimension preferredSize() {
205 return this.getPreferredSize();
206 }
207
208 /**
209 * Returns the preferred size of this component. This method is
210 * implemented so that calling the <code>pack()</code> method on
211 * an instance of this class will not change the size of the
212 * window unpredictably.
213 *
214 * @return the preferred size of this component.
215 */
216 public Dimension getPreferredSize() {
217 // You will comment the subsequent line out during your lab:
218 return new Dimension(400,300);
219 }
220
221 /**
222 * The <code>JavaEves</code> implementation of the
223 * <code>cs101.lang.Animate</code> interface. Continually updates
224 * the eyes graphic to point to the current location of the
225 * mouse pointer.
226 */
227 public void act() {
228 this.updateEyes();
229 }
230
231
232 //+++++++++++++++++++++++++++++++++++++++++++++++++++++++//
233 // //
234 // Utility Methods //
235 // //
236 //+++++++++++++++++++++++++++++++++++++++++++++++++++++++//
237
238 private synchronized void setMousePos(int x, int y) {
239 this.mousePosition.setLocation(x, y);
240 }
241
242 private synchronized Point getMousePos() {
243 return this.mousePosition.getLocation();
244 }
245
246
247 /*
248 * A lot of this is grungy math to position the eyes.
249 * This paints onto a graphic that is only 200 by 80 pixels,
250 * but it is using the coordinates of the mouse in a much larger
251 * panel. Thus, we are going to be painting using coordinates
252 * within the (200,80) rectangle, but calculating the position
253 * of the pupils using greater coordinates
254 */
255 private void paintEyes(Graphics g) {
256
257 // it's a 200 by 80 rectangle
258 int g_width= 200;
259 int g_height= 80;
260
261 // Get the dimensions of the central Panel
262 Dimension d= this.eyesPanel.getSize();
263 int w= d.width;
264 int h= d.height;
265
266 // The offset of the (200,80) rectangle in the Panel
267 int x_offset= (w-g_width)/2;
268 int y_offset= h-g_height;
269
270 // Get the mouse position
271 Point p = this.getMousePos();
272
273 // Set the color to the background color,
274 // and draw the background rectangle for the eyes
275 g.setColor(bgColor);
276 g.fillRect(0,0,g_width,g_height);
277
278 // Set the color to the foreground color and draw the eyes
279 g.setColor(fgColor);
280
281 // draw the outline of the eyes
282 g.drawOval(35,20,50,50);
283 // Set breakpoint on the subsequent line:
284 g.drawOval(105,20,50,50);
285
286 // the centers of the eyes, using the small rectangle coordinates
287 int eye1_x= 55 ;
288 int eye1_y= 40;
289 int eye2_x= 125;
290 int eye2_y= 40;
291
292 // the centers of the eyes, with offsets, in the panel coordinates
293 int eye1_offset_x= eye1_x + x_offset;
294 int eye1_offset_y= eye1_y + y_offset;
295 int eye2_offset_x= eye2_x + x_offset;
296 int eye2_offset_y= eye2_y + y_offset;
297
298 int x1,y1,x2,y2,dist;
299
300 dist= (int)Math.sqrt((p.x-eye1_offset_x)*(p.x-eye1_offset_x)+(p.y-eye1_offset_y)*(p.y-eye1_offset_y));
301 dist = (dist == 0) ? 1 : dist; // prevent arithmetic exception
302 x1=(int) ((p.x-eye1_offset_x) * 16 / dist);
303 y1=(int) ((p.y-eye1_offset_y) * 16 / dist);
304
305 dist= (int)Math.sqrt((p.x-eye2_offset_x)*(p.x-eye2_offset_x)+(p.y-eye2_offset_y)*(p.y-eye2_offset_y));
306 dist = (dist == 0) ? 1 : dist; // prevent arithmetic exception
307 x2=(int) ((p.x-eye2_offset_x) * 16/dist);
308 y2=(int) ((p.y-eye2_offset_y) * 16/dist);
309
310 // At last, we can draw the eyes!!
311
312 // Set breakpoint on the subsequent line:
313 g.fillOval(eye1_x+x1,eye1_y+y1,12,12);
314 g.fillOval(eye2_x+x2,eye2_y+y2,12,12);
315 }
316
317 /* This implements a graphical technique called Double Buffering.
318 * You need not worry about what this does, although it will be
319 * explained later on in the course
320 */
321 private void updateEyes() {
322 // If no offscreen image has yet been created, create one.
323 if (this.offscreenImage==null) {
324 this.offscreenImage = this.createImage(200,80);
325 }
326
327 paintEyes(this.offscreenImage.getGraphics());
328
329 // paint the offscreen image onto the Panel
330 Dimension d = this.eyesPanel.getSize();
331 this.eyesPanel.getGraphics().drawImage(this.offscreenImage,d.width/2-100,d.height-80,this);
332 this.repaint();
333 }
334 }
335
336 /*
337 * $Log: JavaEyes.java,v $
338 * Revision 1.5 2004/01/26 21:48:14 gus
339 * prevent arithmetic exception in paint method
340 *
341 * Revision 1.4 2004/01/26 21:32:39 gus
342 * Stop the animator before disposing the window to avoid NPEs
343 *
344 * Revision 1.3 2003/03/28 16:58:37 gus
345 * addign log comment
346 *
347 */