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41 import java.awt.Graphics  ;
42 import java.util.Stack ;
43 import java.util.Vector ;
44 import java.awt.event.*;
45
46
60 public class CLSFractal
61 extends java.applet.Applet
62 implements Runnable , MouseListener {
63 Thread kicker;
64 ContextLSystem cls;
65 int fractLevel = 1;
66 int repaintDelay = 50;
67 boolean incrementalUpdates;
68 float startAngle = 0;
69 float rotAngle = 45;
70 float Xmin;
71 float Xmax;
72 float Ymin;
73 float Ymax;
74 int border;
75 boolean normalizescaling;
76
77 public void init() {
78 String s;
79 cls = new ContextLSystem(this);
80 s = getParameter("level");
81 if (s != null) fractLevel = Integer.parseInt(s);
82 s = getParameter("incremental");
83 if (s != null) incrementalUpdates = s.equalsIgnoreCase("true");
84 s = getParameter("delay");
85 if (s != null) repaintDelay = Integer.parseInt(s);
86 s = getParameter("startAngle");
87 if (s != null) startAngle = Float.valueOf(s).floatValue();
88 s = getParameter("rotAngle");
89 if (s != null) rotAngle = Float.valueOf(s).floatValue();
90 rotAngle = rotAngle / 360 * 2 * 3.14159265358f;
91 s = getParameter("border");
92 if (s != null) border = Integer.parseInt(s);
93 s = getParameter("normalizescale");
94 if (s != null) normalizescaling = s.equalsIgnoreCase("true");
95 addMouseListener(this);
96 }
97
98 public void destroy() {
99 removeMouseListener(this);
100 }
101
102 public void run() {
103 Thread me = Thread.currentThread();
104 boolean needsRepaint = false;
105 while (kicker == me && cls.getLevel() < fractLevel) {
106 cls.generate();
107 if (kicker == me && incrementalUpdates) {
108 repaint();
109 try {Thread.sleep(repaintDelay);} catch (InterruptedException e){}
110 } else {
111 needsRepaint = true;
112 }
113 }
114 if (kicker == me) {
115 kicker = null;
116 if (needsRepaint) {
117 repaint();
118 }
119 }
120 }
121
122 public void start() {
123 kicker = new Thread (this);
124 kicker.start();
125 }
126
127 public void stop() {
128 kicker = null;
129 }
130
131
132 public void mouseClicked(MouseEvent e) {
133 }
134
135 public void mousePressed(MouseEvent e) {
136 }
137
138 public void mouseReleased(MouseEvent e) {
139 cls = new ContextLSystem(this);
140 savedPath = null;
141 start();
142 e.consume();
143 }
144
145 public void mouseEntered(MouseEvent e) {
146 }
147
148 public void mouseExited(MouseEvent e) {
149 }
150
151 String savedPath;
152
153 public void paint(Graphics g) {
154 String fractalPath = cls.getPath();
155 if (fractalPath == null) {
156 super.paint(g);
157 return;
158 }
159 if (savedPath == null || !savedPath.equals(fractalPath)) {
160 savedPath = fractalPath;
161 render(null, fractalPath);
162 }
163
164 for (int i = 0; i < border; i++) {
165 g.draw3DRect(i, i, getSize().width - i * 2, getSize().height - i * 2,false);
166 }
167 render(g, fractalPath);
168 }
169
170 void render(Graphics g, String path) {
171 Stack turtleStack = new Stack ();
172 CLSTurtle turtle;
173
174 if (g == null) {
175 Xmin = 1E20f;
176 Ymin = 1E20f;
177 Xmax = -1E20f;
178 Ymax = -1E20f;
179 turtle = new CLSTurtle(startAngle, 0, 0, 0, 0, 1, 1);
180 } else {
181 float frwidth = Xmax - Xmin;
182 if (frwidth == 0)
183 frwidth = 1;
184 float frheight = Ymax - Ymin;
185 if (frheight == 0)
186 frheight = 1;
187 float xscale = (getSize().width - border * 2 - 1) / frwidth;
188 float yscale = (getSize().height - border * 2 - 1) / frheight;
189 int xoff = border;
190 int yoff = border;
191 if (normalizescaling) {
192 if (xscale < yscale) {
193 yoff += ((getSize().height - border * 2)
194 - ((Ymax - Ymin) * xscale)) / 2;
195 yscale = xscale;
196 } else if (yscale < xscale) {
197 xoff += ((getSize().width - border * 2)
198 - ((Xmax - Xmin) * yscale)) / 2;
199 xscale = yscale;
200 }
201 }
202 turtle = new CLSTurtle(startAngle, 0 - Xmin, 0 - Ymin,
203 xoff, yoff, xscale, yscale);
204 }
205
206 for (int pos = 0; pos < path.length(); pos++) {
207 switch (path.charAt(pos)) {
208 case '+':
209 turtle.rotate(rotAngle);
210 break;
211 case '-':
212 turtle.rotate(-rotAngle);
213 break;
214 case '[':
215 turtleStack.push(turtle);
216 turtle = new CLSTurtle(turtle);
217 break;
218 case ']':
219 turtle = (CLSTurtle) turtleStack.pop();
220 break;
221 case 'f':
222 turtle.jump();
223 break;
224 case 'F':
225 if (g == null) {
226 includePt(turtle.X, turtle.Y);
227 turtle.jump();
228 includePt(turtle.X, turtle.Y);
229 } else {
230 turtle.draw(g);
231 }
232 break;
233 default:
234 break;
235 }
236 }
237 }
238
239 void includePt(float x, float y) {
240 if (x < Xmin)
241 Xmin = x;
242 if (x > Xmax)
243 Xmax = x;
244 if (y < Ymin)
245 Ymin = y;
246 if (y > Ymax)
247 Ymax = y;
248 }
249
250 public String getAppletInfo() {
251 return "Title: CLSFractal 1.1f, 27 Mar 1995 \nAuthor: Jim Graham \nA (not yet) Context Sensitive L-System production rule. \nThis class encapsulates a production rule for a Context Sensitive\n L-System \n(pred, succ, lContext, rContext). The matches() method, however, does not \n(yet) verify the lContext and rContext parts of the rule.";
252 }
253
254 public String [][] getParameterInfo() {
255 String [][] info = {
256 {"level", "int", "Maximum number of recursions. Default is 1."},
257 {"incremental","boolean","Whether or not to repaint between recursions. Default is true."},
258 {"delay","integer","Sets delay between repaints. Default is 50."},
259 {"startAngle","float","Sets the starting angle. Default is 0."},
260 {"rotAngle","float","Sets the rotation angle. Default is 45."},
261 {"border","integer","Width of border. Default is 2."},
262 {"normalizeScale","boolean","Whether or not to normalize the scaling. Default is true."},
263 {"pred","String","Initializes the rules for Context Sensitive L-Systems."},
264 {"succ","String","Initializes the rules for Context Sensitive L-Systems."},
265 {"lContext","String","Initializes the rules for Context Sensitive L-Systems."},
266 {"rContext","String","Initializes the rules for Context Sensitive L-Systems."}
267 };
268 return info;
269 }
270 }
271
272
281 class CLSTurtle {
282 float angle;
283 float X;
284 float Y;
285 float scaleX;
286 float scaleY;
287 int xoff;
288 int yoff;
289
290 public CLSTurtle(float ang, float x, float y,
291 int xorg, int yorg, float sx, float sy) {
292 angle = ang;
293 scaleX = sx;
294 scaleY = sy;
295 X = x * sx;
296 Y = y * sy;
297 xoff = xorg;
298 yoff = yorg;
299 }
300
301 public CLSTurtle(CLSTurtle turtle) {
302 angle = turtle.angle;
303 X = turtle.X;
304 Y = turtle.Y;
305 scaleX = turtle.scaleX;
306 scaleY = turtle.scaleY;
307 xoff = turtle.xoff;
308 yoff = turtle.yoff;
309 }
310
311 public void rotate(float theta) {
312 angle += theta;
313 }
314
315 public void jump() {
316 X += (float) Math.cos(angle) * scaleX;
317 Y += (float) Math.sin(angle) * scaleY;
318 }
319
320 public void draw(Graphics g) {
321 float x = X + (float) Math.cos(angle) * scaleX;
322 float y = Y + (float) Math.sin(angle) * scaleY;
323 g.drawLine((int) X + xoff, (int) Y + yoff,
324 (int) x + xoff, (int) y + yoff);
325 X = x;
326 Y = y;
327 }
328 }
329
330
341 class ContextLSystem {
342 String axiom;
343 Vector rules = new Vector ();
344 int level;
345
346 public ContextLSystem(java.applet.Applet app) {
347 axiom = app.getParameter("axiom");
348 int num = 1;
349 while (true) {
350 String pred = app.getParameter("pred"+num);
351 String succ = app.getParameter("succ"+num);
352 if (pred == null || succ == null) {
353 break;
354 }
355 rules.addElement(new CLSRule(pred, succ,
356 app.getParameter("lContext"+num),
357 app.getParameter("rContext"+num)));
358 num++;
359 }
360 currentPath = new StringBuffer (axiom);
361 level = 0;
362 }
363
364 public int getLevel() {
365 return level;
366 }
367
368 StringBuffer currentPath;
369
370 public synchronized String getPath() {
371 return ((currentPath == null) ? null : currentPath.toString());
372 }
373
374 private synchronized void setPath(StringBuffer path) {
375 currentPath = path;
376 level++;
377 }
378
379 public void generate() {
380 StringBuffer newPath = new StringBuffer ();
381 int pos = 0;
382 while (pos < currentPath.length()) {
383 CLSRule rule = findRule(pos);
384 if (rule == null) {
385 newPath.append(currentPath.charAt(pos));
386 pos++;
387 } else {
388 newPath.append(rule.succ);
389 pos += rule.pred.length();
390 }
391 }
392 setPath(newPath);
393 }
394
395 public CLSRule findRule(int pos) {
396 for (int i = 0; i < rules.size(); i++) {
397 CLSRule rule = (CLSRule) rules.elementAt(i);
398 if (rule.matches(currentPath, pos)) {
399 return rule;
400 }
401 }
402 return null;
403 }
404 }
405
406
417 class CLSRule {
418 String pred;
419 String succ;
420 String lContext;
421 String rContext;
422
423 public CLSRule(String p, String d, String l, String r) {
424 pred = p;
425 succ = d;
426 lContext = l;
427 rContext = r;
428 }
429
430 public boolean matches(StringBuffer sb, int pos) {
431 if (pos + pred.length() > sb.length()) {
432 return false;
433 }
434 char cb[] = new char[pred.length()];
435 sb.getChars(pos, pos + pred.length(), cb, 0);
436 return pred.equals(new String (cb));
437 }
438 }
439 |
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