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41 import java.applet.Applet  ;
42 import java.awt.event.*;
43 import java.awt.*;
44 import java.awt.image.ColorModel ;
45 import java.awt.image.MemoryImageSource ;
46
47 public class DitherTest extends Applet implements Runnable {
48 final private static int NOOP = 0;
49 final private static int RED = 1;
50 final private static int GREEN = 2;
51 final private static int BLUE = 3;
52 final private static int ALPHA = 4;
53 final private static int SATURATION = 5;
54
55 private Thread runner;
56
57 private DitherControls XControls;
58 private DitherControls YControls;
59 private DitherCanvas canvas;
60
61 public static void main(String args[]) {
62 Frame f = new Frame("DitherTest");
63 DitherTest ditherTest = new DitherTest();
64 ditherTest.init();
65 f.add("Center", ditherTest);
66 f.pack();
67 f.setVisible(true);
68 ditherTest.start();
69 }
70
71 public void init() {
72 String xspec = null, yspec = null;
73 int xvals[] = new int[2];
74 int yvals[] = new int[2];
75
76 try {
77 xspec = getParameter("xaxis");
78 yspec = getParameter("yaxis");
79 } catch (NullPointerException npe) {
80 }
82
83 if (xspec == null) {
84 xspec = "red";
85 }
86 if (yspec == null) {
87 yspec = "blue";
88 }
89 int xmethod = colormethod(xspec, xvals);
90 int ymethod = colormethod(yspec, yvals);
91
92 setLayout(new BorderLayout());
93 XControls = new DitherControls(this, xvals[0], xvals[1],
94 xmethod, false);
95 YControls = new DitherControls(this, yvals[0], yvals[1],
96 ymethod, true);
97 YControls.addRenderButton();
98 add("North", XControls);
99 add("South", YControls);
100 add("Center", canvas = new DitherCanvas());
101 }
102
103 private int colormethod(String s, int vals[]) {
104 int method = NOOP;
105 if (s == null) {
106 s = "";
107 }
108 String lower = s.toLowerCase();
109 int len = 0;
110 if (lower.startsWith("red")) {
111 method = RED;
112 lower = lower.substring(3);
113 } else if (lower.startsWith("green")) {
114 method = GREEN;
115 lower = lower.substring(5);
116 } else if (lower.startsWith("blue")) {
117 method = BLUE;
118 lower = lower.substring(4);
119 } else if (lower.startsWith("alpha")) {
120 method = ALPHA;
121 lower = lower.substring(5);
122 } else if (lower.startsWith("saturation")) {
123 method = SATURATION;
124 lower = lower.substring(10);
125 }
126 if (method == NOOP) {
127 vals[0] = 0;
128 vals[1] = 0;
129 return method;
130 }
131 int begval = 0;
132 int endval = 255;
133 try {
134 int dash = lower.indexOf('-');
135 if (dash < 0) {
136 endval = Integer.parseInt(lower);
137 } else {
138 begval = Integer.parseInt(lower.substring(0, dash));
139 endval = Integer.parseInt(lower.substring(dash + 1));
140 }
141 } catch (NumberFormatException nfe) {
142 }
143
144 if (begval < 0) {
145 begval = 0;
146 } else if (begval > 255) {
147 begval = 255;
148 }
149
150 if (endval < 0) {
151 endval = 0;
152 } else if (endval > 255) {
153 endval = 255;
154 }
155
156 vals[0] = begval;
157 vals[1] = endval;
158 return method;
159 }
160
161
165 private Image calculateImage() {
166 Thread me = Thread.currentThread();
167
168 int width = canvas.getSize().width;
169 int height = canvas.getSize().height;
170 int xvals[] = new int[2];
171 int yvals[] = new int[2];
172 int xmethod = XControls.getParams(xvals);
173 int ymethod = YControls.getParams(yvals);
174 int pixels[] = new int[width * height];
175 int c[] = new int[4]; int index = 0;
177 for (int j = 0; j < height; j++) {
178 for (int i = 0; i < width; i++) {
179 c[0] = c[1] = c[2] = 0;
180 c[3] = 255;
181 if (xmethod < ymethod) {
182 applymethod(c, xmethod, i, width, xvals);
183 applymethod(c, ymethod, j, height, yvals);
184 } else {
185 applymethod(c, ymethod, j, height, yvals);
186 applymethod(c, xmethod, i, width, xvals);
187 }
188 pixels[index++] = ((c[3] << 24) |
189 (c[0] << 16) |
190 (c[1] << 8) |
191 c[2]);
192 }
193
194 if (runner != me) {
196 return null;
197 }
198 }
199 return createImage(new MemoryImageSource (width, height,
200 ColorModel.getRGBdefault(), pixels, 0, width));
201 }
202
203 private void applymethod(int c[], int method, int step,
204 int total, int vals[]) {
205 if (method == NOOP) {
206 return;
207 }
208 int val = ((total < 2)
209 ? vals[0]
210 : vals[0] + ((vals[1] - vals[0]) * step / (total - 1)));
211 switch (method) {
212 case RED:
213 c[0] = val;
214 break;
215 case GREEN:
216 c[1] = val;
217 break;
218 case BLUE:
219 c[2] = val;
220 break;
221 case ALPHA:
222 c[3] = val;
223 break;
224 case SATURATION:
225 int max = Math.max(Math.max(c[0], c[1]), c[2]);
226 int min = max * (255 - val) / 255;
227 if (c[0] == 0) {
228 c[0] = min;
229 }
230 if (c[1] == 0) {
231 c[1] = min;
232 }
233 if (c[2] == 0) {
234 c[2] = min;
235 }
236 break;
237 }
238 }
239
240 public void start() {
241 runner = new Thread (this);
242 runner.start();
243 }
244
245 public void run() {
246 canvas.setImage(null); Image img = calculateImage();
248 if (img != null && runner == Thread.currentThread()) {
249 canvas.setImage(img);
250 }
251 }
252
253 public void stop() {
254 runner = null;
255 }
256
257 public void destroy() {
258 remove(XControls);
259 remove(YControls);
260 remove(canvas);
261 }
262
263 public String getAppletInfo() {
264 return "An interactive demonstration of dithering.";
265 }
266
267 public String [][] getParameterInfo() {
268 String [][] info = {
269 {"xaxis", "{RED, GREEN, BLUE, ALPHA, SATURATION}",
270 "The color of the Y axis. Default is RED."},
271 {"yaxis", "{RED, GREEN, BLUE, ALPHA, SATURATION}",
272 "The color of the X axis. Default is BLUE."}
273 };
274 return info;
275 }
276 }
277
278 class DitherCanvas extends Canvas {
279 private Image img;
280 private static String calcString = "Calculating...";
281
282 public void paint(Graphics g) {
283 int w = getSize().width;
284 int h = getSize().height;
285 if (img == null) {
286 super.paint(g);
287 g.setColor(Color.black);
288 FontMetrics fm = g.getFontMetrics();
289 int x = (w - fm.stringWidth(calcString)) / 2;
290 int y = h / 2;
291 g.drawString(calcString, x, y);
292 } else {
293 g.drawImage(img, 0, 0, w, h, this);
294 }
295 }
296
297 public void update(Graphics g) {
298 paint(g);
299 }
300
301 public Dimension getMinimumSize() {
302 return new Dimension(20, 20);
303 }
304
305 public Dimension getPreferredSize() {
306 return new Dimension(200, 200);
307 }
308
309 public Image getImage() {
310 return img;
311 }
312
313 public void setImage(Image img) {
314 this.img = img;
315 repaint();
316 }
317 }
318
319 class DitherControls extends Panel implements ActionListener {
320 private CardinalTextField start;
321 private CardinalTextField end;
322 private Button button;
323 private Choice choice;
324 private DitherTest applet;
325
326 private static LayoutManager dcLayout = new FlowLayout(FlowLayout.CENTER,
327 10, 5);
328
329 public DitherControls(DitherTest app, int s, int e, int type,
330 boolean vertical) {
331 applet = app;
332 setLayout(dcLayout);
333 add(new Label(vertical ? "Vertical" : "Horizontal"));
334 add(choice = new Choice());
335 choice.addItem("Noop");
336 choice.addItem("Red");
337 choice.addItem("Green");
338 choice.addItem("Blue");
339 choice.addItem("Alpha");
340 choice.addItem("Saturation");
341 choice.select(type);
342 add(start = new CardinalTextField(Integer.toString(s), 4));
343 add(end = new CardinalTextField(Integer.toString(e), 4));
344 }
345
346
347 public void addRenderButton() {
348 add(button = new Button("New Image"));
349 button.addActionListener(this);
350 }
351
352
353 public int getParams(int vals[]) {
354 try {
355 vals[0] = scale(Integer.parseInt(start.getText()));
356 } catch (NumberFormatException nfe) {
357 vals[0] = 0;
358 }
359 try {
360 vals[1] = scale(Integer.parseInt(end.getText()));
361 } catch (NumberFormatException nfe) {
362 vals[1] = 255;
363 }
364 return choice.getSelectedIndex();
365 }
366
367
368 private int scale(int number) {
369 if (number < 0) {
370 number = 0;
371 } else if (number > 255) {
372 number = 255;
373 }
374 return number;
375 }
376
377
378 public void actionPerformed(ActionEvent e) {
379 if (e.getSource() == button) {
380 applet.start();
381 }
382 }
383 }
384
385 class CardinalTextField extends TextField {
386
387 String oldText = null;
388
389 public CardinalTextField(String text, int columns) {
390 super(text, columns);
391 enableEvents(AWTEvent.KEY_EVENT_MASK | AWTEvent.TEXT_EVENT_MASK);
392 oldText = getText();
393 }
394
395 protected void processEvent(AWTEvent evt) {
401 int id = evt.getID();
402 if (id != KeyEvent.KEY_TYPED) {
403 super.processEvent(evt);
404 return;
405 }
406
407 KeyEvent kevt = (KeyEvent) evt;
408 char c = kevt.getKeyChar();
409
410 if (Character.isDigit(c) || (c == '\b') || (c == '\u007f')) {
413 super.processEvent(evt);
414 return;
415 }
416
417 Toolkit.getDefaultToolkit().beep();
418 kevt.consume();
419 }
420
421 protected void processTextEvent(TextEvent te) {
430 String newText = getText();
432 if (newText.equals("") || textIsCardinal(newText)) {
433 oldText = newText;
434 super.processTextEvent(te);
435 return;
436 }
437
438 Toolkit.getDefaultToolkit().beep();
439 setText(oldText);
440 }
441
442 private boolean textIsCardinal(String textToCheck) {
445 int value = -1;
446
447 try {
448 value = Integer.parseInt(textToCheck, 10);
449 return (value >= 0);
450 } catch (NumberFormatException nfe) {
451 return false;
452 }
453 }
454 }
455
456 |
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