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| 1 | +/* | |
| 2 | + * Copyright (c) 1999, Oracle and/or its affiliates. All rights reserved. | |
| 3 | + * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. | |
| 4 | + * | |
| 5 | + * This code is free software; you can redistribute it and/or modify it | |
| 6 | + * under the terms of the GNU General Public License version 2 only, as | |
| 7 | + * published by the Free Software Foundation. Oracle designates this | |
| 8 | + * particular file as subject to the "Classpath" exception as provided | |
| 9 | + * by Oracle in the LICENSE file that accompanied this code. | |
| 10 | + * | |
| 11 | + * This code is distributed in the hope that it will be useful, but WITHOUT | |
| 12 | + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
| 13 | + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
| 14 | + * version 2 for more details (a copy is included in the LICENSE file that | |
| 15 | + * accompanied this code). | |
| 16 | + * | |
| 17 | + * You should have received a copy of the GNU General Public License version | |
| 18 | + * 2 along with this work; if not, write to the Free Software Foundation, | |
| 19 | + * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. | |
| 20 | + * | |
| 21 | + * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA | |
| 22 | + * or visit www.oracle.com if you need additional information or have any | |
| 23 | + * questions. | |
| 24 | + */ | |
| 25 | + | |
| 26 | +package sun.java2d.pipe; | |
| 27 | + | |
| 28 | +import java.awt.geom.PathIterator; | |
| 29 | +import java.awt.Rectangle; | |
| 30 | + | |
| 31 | +/** | |
| 32 | + * This class clips a SpanIterator to a Region and outputs the | |
| 33 | + * resulting spans as another SpanIterator. | |
| 34 | + * | |
| 35 | + * Spans are output in the usual y/x order, unless the input span | |
| 36 | + * iterator doesn't conform to this order, or the iterator's span | |
| 37 | + * straddle more than one band of the Region used for clipping. | |
| 38 | + * | |
| 39 | + * Principle of operation: | |
| 40 | + * | |
| 41 | + * The iterator maintains a several cursors onto the RegionIterator | |
| 42 | + * in order to avoid having to buffer spans from the SpanIterator. | |
| 43 | + * They are: | |
| 44 | + * resetState The initial state of the RegionIterator | |
| 45 | + * lwm Low Water Mark, a running start point for | |
| 46 | + * processing each band. Usually goes down, but | |
| 47 | + * can be reset to resetState if a span has a lower | |
| 48 | + * start coordinate than the previous one. | |
| 49 | + * row The start of the current band of the RegionIterator | |
| 50 | + * box The current span of the current row | |
| 51 | + * | |
| 52 | + * The main nextSpan() loop implements a coroutine like structure, with | |
| 53 | + * three producers to get the next span, row and box calling each other | |
| 54 | + * to iterate through the span iterator and region. | |
| 55 | + * | |
| 56 | + * REMIND: Needs a native implementation! | |
| 57 | + */ | |
| 58 | +public class RegionClipSpanIterator implements SpanIterator { | |
| 59 | + | |
| 60 | + // The inputs to the filter | |
| 61 | + Region rgn; | |
| 62 | + SpanIterator spanIter; | |
| 63 | + | |
| 64 | + // The cursors that track the progress through the region | |
| 65 | + RegionIterator resetState; | |
| 66 | + RegionIterator lwm; | |
| 67 | + RegionIterator row; | |
| 68 | + RegionIterator box; | |
| 69 | + | |
| 70 | + // The bounds of the current span iterator span | |
| 71 | + int spanlox, spanhix, spanloy, spanhiy; | |
| 72 | + | |
| 73 | + // The extent of the region band marking the low water mark | |
| 74 | + int lwmloy, lwmhiy; | |
| 75 | + | |
| 76 | + // The bounds of the current region box | |
| 77 | + int rgnlox, rgnloy, rgnhix, rgnhiy; | |
| 78 | + | |
| 79 | + // The bounding box of the input Region. Used for click | |
| 80 | + // rejection of iterator spans | |
| 81 | + int rgnbndslox, rgnbndsloy, rgnbndshix, rgnbndshiy; | |
| 82 | + | |
| 83 | + // The array used to hold coordinates from the region iterator | |
| 84 | + int rgnbox[] = new int[4]; | |
| 85 | + | |
| 86 | + // The array used to hold coordinates from the span iterator | |
| 87 | + int spanbox[] = new int[4]; | |
| 88 | + | |
| 89 | + // True if the next iterator span should be read on the next | |
| 90 | + // iteration of the main nextSpan() loop | |
| 91 | + boolean doNextSpan; | |
| 92 | + | |
| 93 | + // True if the next region box should be read on the next | |
| 94 | + // iteration of the main nextSpan() loop | |
| 95 | + boolean doNextBox; | |
| 96 | + | |
| 97 | + // True if there are no more spans or the Region is empty | |
| 98 | + boolean done = false; | |
| 99 | + | |
| 100 | + /* | |
| 101 | + * Creates an instance that filters the spans generated by | |
| 102 | + * spanIter through the region described by rgn. | |
| 103 | + */ | |
| 104 | + public RegionClipSpanIterator(Region rgn, SpanIterator spanIter) { | |
| 105 | + | |
| 106 | + this.spanIter = spanIter; | |
| 107 | + | |
| 108 | + resetState = rgn.getIterator(); | |
| 109 | + lwm = resetState.createCopy(); | |
| 110 | + | |
| 111 | + if (!lwm.nextYRange(rgnbox)) { | |
| 112 | + done = true; | |
| 113 | + return; | |
| 114 | + } | |
| 115 | + | |
| 116 | + rgnloy = lwmloy = rgnbox[1]; | |
| 117 | + rgnhiy = lwmhiy = rgnbox[3]; | |
| 118 | + | |
| 119 | + rgn.getBounds(rgnbox); | |
| 120 | + rgnbndslox = rgnbox[0]; | |
| 121 | + rgnbndsloy = rgnbox[1]; | |
| 122 | + rgnbndshix = rgnbox[2]; | |
| 123 | + rgnbndshiy = rgnbox[3]; | |
| 124 | + if (rgnbndslox >= rgnbndshix || | |
| 125 | + rgnbndsloy >= rgnbndshiy) { | |
| 126 | + done = true; | |
| 127 | + return; | |
| 128 | + } | |
| 129 | + | |
| 130 | + this.rgn = rgn; | |
| 131 | + | |
| 132 | + | |
| 133 | + row = lwm.createCopy(); | |
| 134 | + box = row.createCopy(); | |
| 135 | + doNextSpan = true; | |
| 136 | + doNextBox = false; | |
| 137 | + } | |
| 138 | + | |
| 139 | + /* | |
| 140 | + * Gets the bbox of the available path segments, clipped to the | |
| 141 | + * Region. | |
| 142 | + */ | |
| 143 | + public void getPathBox(int pathbox[]) { | |
| 144 | + int[] rgnbox = new int[4]; | |
| 145 | + rgn.getBounds(rgnbox); | |
| 146 | + spanIter.getPathBox(pathbox); | |
| 147 | + | |
| 148 | + if (pathbox[0] < rgnbox[0]) { | |
| 149 | + pathbox[0] = rgnbox[0]; | |
| 150 | + } | |
| 151 | + | |
| 152 | + if (pathbox[1] < rgnbox[1]) { | |
| 153 | + pathbox[1] = rgnbox[1]; | |
| 154 | + } | |
| 155 | + | |
| 156 | + if (pathbox[2] > rgnbox[2]) { | |
| 157 | + pathbox[2] = rgnbox[2]; | |
| 158 | + } | |
| 159 | + | |
| 160 | + if (pathbox[3] > rgnbox[3]) { | |
| 161 | + pathbox[3] = rgnbox[3]; | |
| 162 | + } | |
| 163 | +} | |
| 164 | + | |
| 165 | + /* | |
| 166 | + * Intersects the path box with the given bbox. | |
| 167 | + * Returned spans are clipped to this region, or discarded | |
| 168 | + * altogether if they lie outside it. | |
| 169 | + */ | |
| 170 | + public void intersectClipBox(int lox, int loy, int hix, int hiy) { | |
| 171 | + spanIter.intersectClipBox(lox, loy, hix, hiy); | |
| 172 | + } | |
| 173 | + | |
| 174 | + | |
| 175 | + /* | |
| 176 | + * Fetches the next span that needs to be operated on. | |
| 177 | + * If the return value is false then there are no more spans. | |
| 178 | + */ | |
| 179 | + public boolean nextSpan(int resultbox[]) { | |
| 180 | + if (done) { | |
| 181 | + return false; | |
| 182 | + } | |
| 183 | + | |
| 184 | + int resultlox, resultloy, resulthix, resulthiy; | |
| 185 | + boolean doNextRow = false; | |
| 186 | + | |
| 187 | + // REMIND: Cache the coordinate inst vars used in this loop | |
| 188 | + // in locals vars. | |
| 189 | + while (true) { | |
| 190 | + // We've exhausted the current span so get the next one | |
| 191 | + if (doNextSpan) { | |
| 192 | + if (!spanIter.nextSpan(spanbox)) { | |
| 193 | + done = true; | |
| 194 | + return false; | |
| 195 | + } else { | |
| 196 | + spanlox = spanbox[0]; | |
| 197 | + // Clip out spans that lie outside of the rgn's bounds | |
| 198 | + if (spanlox >= rgnbndshix) { | |
| 199 | + continue; | |
| 200 | + } | |
| 201 | + | |
| 202 | + spanloy = spanbox[1]; | |
| 203 | + if (spanloy >= rgnbndshiy) { | |
| 204 | + continue; | |
| 205 | + } | |
| 206 | + | |
| 207 | + spanhix = spanbox[2]; | |
| 208 | + if (spanhix <= rgnbndslox) { | |
| 209 | + continue; | |
| 210 | + } | |
| 211 | + | |
| 212 | + spanhiy = spanbox[3]; | |
| 213 | + if (spanhiy <= rgnbndsloy) { | |
| 214 | + continue; | |
| 215 | + } | |
| 216 | + } | |
| 217 | + // If the span starts higher up than the low-water mark, | |
| 218 | + // reset the lwm. This can only happen if spans aren't | |
| 219 | + // returned in strict y/x order, or the first time through. | |
| 220 | + if (lwmloy > spanloy) { | |
| 221 | + lwm.copyStateFrom(resetState); | |
| 222 | + lwm.nextYRange(rgnbox); | |
| 223 | + lwmloy = rgnbox[1]; | |
| 224 | + lwmhiy = rgnbox[3]; | |
| 225 | + } | |
| 226 | + // Skip to the first rgn row whose bottom edge is | |
| 227 | + // below the top of the current span. This will only | |
| 228 | + // execute >0 times when the current span starts in a | |
| 229 | + // lower region row than the previous one, or possibly the | |
| 230 | + // first time through. | |
| 231 | + while (lwmhiy <= spanloy) { | |
| 232 | + if (!lwm.nextYRange(rgnbox)) | |
| 233 | + break; | |
| 234 | + lwmloy = rgnbox[1]; | |
| 235 | + lwmhiy = rgnbox[3]; | |
| 236 | + } | |
| 237 | + // If the row overlaps the span, process it, otherwise | |
| 238 | + // fetch another span | |
| 239 | + if (lwmhiy > spanloy && lwmloy < spanhiy) { | |
| 240 | + // Update the current row if it's different from the | |
| 241 | + // new lwm | |
| 242 | + if (rgnloy != lwmloy) { | |
| 243 | + row.copyStateFrom(lwm); | |
| 244 | + rgnloy = lwmloy; | |
| 245 | + rgnhiy = lwmhiy; | |
| 246 | + } | |
| 247 | + box.copyStateFrom(row); | |
| 248 | + doNextBox = true; | |
| 249 | + doNextSpan = false; | |
| 250 | + } | |
| 251 | + continue; | |
| 252 | + } | |
| 253 | + | |
| 254 | + // The current row's spans are exhausted, do the next one | |
| 255 | + if (doNextRow) { | |
| 256 | + // Next time we either do the next span or the next box | |
| 257 | + doNextRow = false; | |
| 258 | + // Get the next row | |
| 259 | + boolean ok = row.nextYRange(rgnbox); | |
| 260 | + // If there was one, update the bounds | |
| 261 | + if (ok) { | |
| 262 | + rgnloy = rgnbox[1]; | |
| 263 | + rgnhiy = rgnbox[3]; | |
| 264 | + } | |
| 265 | + if (!ok || rgnloy >= spanhiy) { | |
| 266 | + // If we've exhausted the rows or this one is below the span, | |
| 267 | + // go onto the next span | |
| 268 | + doNextSpan = true; | |
| 269 | + } | |
| 270 | + else { | |
| 271 | + // Otherwise get the first box on this row | |
| 272 | + box.copyStateFrom(row); | |
| 273 | + doNextBox = true; | |
| 274 | + } | |
| 275 | + continue; | |
| 276 | + } | |
| 277 | + | |
| 278 | + // Process the next box in the current row | |
| 279 | + if (doNextBox) { | |
| 280 | + boolean ok = box.nextXBand(rgnbox); | |
| 281 | + if (ok) { | |
| 282 | + rgnlox = rgnbox[0]; | |
| 283 | + rgnhix = rgnbox[2]; | |
| 284 | + } | |
| 285 | + if (!ok || rgnlox >= spanhix) { | |
| 286 | + // If there was no next rgn span or it's beyond the | |
| 287 | + // source span, go onto the next row or span | |
| 288 | + doNextBox = false; | |
| 289 | + if (rgnhiy >= spanhiy) { | |
| 290 | + // If the current row totally overlaps the span, | |
| 291 | + // go onto the next span | |
| 292 | + doNextSpan = true; | |
| 293 | + } else { | |
| 294 | + // otherwise go onto the next rgn row | |
| 295 | + doNextRow = true; | |
| 296 | + } | |
| 297 | + } else { | |
| 298 | + // Otherwise, if the new rgn span overlaps the | |
| 299 | + // spanbox, no need to get another box | |
| 300 | + doNextBox = rgnhix <= spanlox; | |
| 301 | + } | |
| 302 | + continue; | |
| 303 | + } | |
| 304 | + | |
| 305 | + // Prepare to do the next box either on this call or | |
| 306 | + // or the subsequent one | |
| 307 | + doNextBox = true; | |
| 308 | + | |
| 309 | + // Clip the current span against the current box | |
| 310 | + if (spanlox > rgnlox) { | |
| 311 | + resultlox = spanlox; | |
| 312 | + } | |
| 313 | + else { | |
| 314 | + resultlox = rgnlox; | |
| 315 | + } | |
| 316 | + | |
| 317 | + if (spanloy > rgnloy) { | |
| 318 | + resultloy = spanloy; | |
| 319 | + } | |
| 320 | + else { | |
| 321 | + resultloy = rgnloy; | |
| 322 | + } | |
| 323 | + | |
| 324 | + if (spanhix < rgnhix) { | |
| 325 | + resulthix = spanhix; | |
| 326 | + } | |
| 327 | + else { | |
| 328 | + resulthix = rgnhix; | |
| 329 | + } | |
| 330 | + | |
| 331 | + if (spanhiy < rgnhiy) { | |
| 332 | + resulthiy = spanhiy; | |
| 333 | + } | |
| 334 | + else { | |
| 335 | + resulthiy = rgnhiy; | |
| 336 | + } | |
| 337 | + | |
| 338 | + // If the result is empty, try then next box | |
| 339 | + // otherwise return the box. | |
| 340 | + // REMIND: I think by definition it's non-empty | |
| 341 | + // if we're here. Need to think about this some more. | |
| 342 | + if (resultlox >= resulthix || | |
| 343 | + resultloy >= resulthiy) { | |
| 344 | + continue; | |
| 345 | + } | |
| 346 | + else { | |
| 347 | + break; | |
| 348 | + } | |
| 349 | + } | |
| 350 | + | |
| 351 | + resultbox[0] = resultlox; | |
| 352 | + resultbox[1] = resultloy; | |
| 353 | + resultbox[2] = resulthix; | |
| 354 | + resultbox[3] = resulthiy; | |
| 355 | + return true; | |
| 356 | + | |
| 357 | + } | |
| 358 | + | |
| 359 | + | |
| 360 | + /** | |
| 361 | + * This method tells the iterator that it may skip all spans | |
| 362 | + * whose Y range is completely above the indicated Y coordinate. | |
| 363 | + */ | |
| 364 | + public void skipDownTo(int y) { | |
| 365 | + spanIter.skipDownTo(y); | |
| 366 | + } | |
| 367 | + | |
| 368 | + /** | |
| 369 | + * This method returns a native pointer to a function block that | |
| 370 | + * can be used by a native method to perform the same iteration | |
| 371 | + * cycle that the above methods provide while avoiding upcalls to | |
| 372 | + * the Java object. | |
| 373 | + * The definition of the structure whose pointer is returned by | |
| 374 | + * this method is defined in: | |
| 375 | + * <pre> | |
| 376 | + * src/share/native/sun/java2d/pipe/SpanIterator.h | |
| 377 | + * </pre> | |
| 378 | + */ | |
| 379 | + public long getNativeIterator() { | |
| 380 | + return 0; | |
| 381 | + } | |
| 382 | + | |
| 383 | + /* | |
| 384 | + * Cleans out all internal data structures. | |
| 385 | + */ | |
| 386 | + //public native void dispose(); | |
| 387 | + | |
| 388 | + protected void finalize() { | |
| 389 | + //dispose(); | |
| 390 | + } | |
| 391 | + | |
| 392 | +} | |