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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 | } | ||