DynamicLayout.java revision cde6adf45c90ad3fdc94446ede6a228ce264c886
1/* 2 * Copyright (C) 2006 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17package android.text; 18 19import android.graphics.Paint; 20import android.text.style.UpdateLayout; 21import android.text.style.WrapTogetherSpan; 22 23import com.android.internal.util.ArrayUtils; 24 25import java.lang.ref.WeakReference; 26 27/** 28 * DynamicLayout is a text layout that updates itself as the text is edited. 29 * <p>This is used by widgets to control text layout. You should not need 30 * to use this class directly unless you are implementing your own widget 31 * or custom display object, or need to call 32 * {@link android.graphics.Canvas#drawText(java.lang.CharSequence, int, int, float, float, android.graphics.Paint) 33 * Canvas.drawText()} directly.</p> 34 */ 35public class DynamicLayout extends Layout 36{ 37 private static final int PRIORITY = 128; 38 39 /** 40 * Make a layout for the specified text that will be updated as 41 * the text is changed. 42 */ 43 public DynamicLayout(CharSequence base, 44 TextPaint paint, 45 int width, Alignment align, 46 float spacingmult, float spacingadd, 47 boolean includepad) { 48 this(base, base, paint, width, align, spacingmult, spacingadd, 49 includepad); 50 } 51 52 /** 53 * Make a layout for the transformed text (password transformation 54 * being the primary example of a transformation) 55 * that will be updated as the base text is changed. 56 */ 57 public DynamicLayout(CharSequence base, CharSequence display, 58 TextPaint paint, 59 int width, Alignment align, 60 float spacingmult, float spacingadd, 61 boolean includepad) { 62 this(base, display, paint, width, align, spacingmult, spacingadd, 63 includepad, null, 0); 64 } 65 66 /** 67 * Make a layout for the transformed text (password transformation 68 * being the primary example of a transformation) 69 * that will be updated as the base text is changed. 70 * If ellipsize is non-null, the Layout will ellipsize the text 71 * down to ellipsizedWidth. 72 */ 73 public DynamicLayout(CharSequence base, CharSequence display, 74 TextPaint paint, 75 int width, Alignment align, 76 float spacingmult, float spacingadd, 77 boolean includepad, 78 TextUtils.TruncateAt ellipsize, int ellipsizedWidth) { 79 this(base, display, paint, width, align, TextDirectionHeuristics.FIRSTSTRONG_LTR, 80 spacingmult, spacingadd, includepad, ellipsize, ellipsizedWidth); 81 } 82 83 /** 84 * Make a layout for the transformed text (password transformation 85 * being the primary example of a transformation) 86 * that will be updated as the base text is changed. 87 * If ellipsize is non-null, the Layout will ellipsize the text 88 * down to ellipsizedWidth. 89 * * 90 * *@hide 91 */ 92 public DynamicLayout(CharSequence base, CharSequence display, 93 TextPaint paint, 94 int width, Alignment align, TextDirectionHeuristic textDir, 95 float spacingmult, float spacingadd, 96 boolean includepad, 97 TextUtils.TruncateAt ellipsize, int ellipsizedWidth) { 98 super((ellipsize == null) 99 ? display 100 : (display instanceof Spanned) 101 ? new SpannedEllipsizer(display) 102 : new Ellipsizer(display), 103 paint, width, align, textDir, spacingmult, spacingadd); 104 105 mBase = base; 106 mDisplay = display; 107 108 if (ellipsize != null) { 109 mInts = new PackedIntVector(COLUMNS_ELLIPSIZE); 110 mEllipsizedWidth = ellipsizedWidth; 111 mEllipsizeAt = ellipsize; 112 } else { 113 mInts = new PackedIntVector(COLUMNS_NORMAL); 114 mEllipsizedWidth = width; 115 mEllipsizeAt = null; 116 } 117 118 mObjects = new PackedObjectVector<Directions>(1); 119 120 mBlockEnds = new int[] { 0 }; 121 mBlockIndices = new int[] { INVALID_BLOCK_INDEX }; 122 mNumberOfBlocks = 1; 123 124 mIncludePad = includepad; 125 126 /* 127 * This is annoying, but we can't refer to the layout until 128 * superclass construction is finished, and the superclass 129 * constructor wants the reference to the display text. 130 * 131 * This will break if the superclass constructor ever actually 132 * cares about the content instead of just holding the reference. 133 */ 134 if (ellipsize != null) { 135 Ellipsizer e = (Ellipsizer) getText(); 136 137 e.mLayout = this; 138 e.mWidth = ellipsizedWidth; 139 e.mMethod = ellipsize; 140 mEllipsize = true; 141 } 142 143 // Initial state is a single line with 0 characters (0 to 0), 144 // with top at 0 and bottom at whatever is natural, and 145 // undefined ellipsis. 146 147 int[] start; 148 149 if (ellipsize != null) { 150 start = new int[COLUMNS_ELLIPSIZE]; 151 start[ELLIPSIS_START] = ELLIPSIS_UNDEFINED; 152 } else { 153 start = new int[COLUMNS_NORMAL]; 154 } 155 156 Directions[] dirs = new Directions[] { DIRS_ALL_LEFT_TO_RIGHT }; 157 158 Paint.FontMetricsInt fm = paint.getFontMetricsInt(); 159 int asc = fm.ascent; 160 int desc = fm.descent; 161 162 start[DIR] = DIR_LEFT_TO_RIGHT << DIR_SHIFT; 163 start[TOP] = 0; 164 start[DESCENT] = desc; 165 mInts.insertAt(0, start); 166 167 start[TOP] = desc - asc; 168 mInts.insertAt(1, start); 169 170 mObjects.insertAt(0, dirs); 171 172 // Update from 0 characters to whatever the real text is 173 174 reflow(base, 0, 0, base.length()); 175 176 if (base instanceof Spannable) { 177 if (mWatcher == null) 178 mWatcher = new ChangeWatcher(this); 179 180 // Strip out any watchers for other DynamicLayouts. 181 Spannable sp = (Spannable) base; 182 ChangeWatcher[] spans = sp.getSpans(0, sp.length(), ChangeWatcher.class); 183 for (int i = 0; i < spans.length; i++) 184 sp.removeSpan(spans[i]); 185 186 sp.setSpan(mWatcher, 0, base.length(), 187 Spannable.SPAN_INCLUSIVE_INCLUSIVE | 188 (PRIORITY << Spannable.SPAN_PRIORITY_SHIFT)); 189 } 190 } 191 192 private void reflow(CharSequence s, int where, int before, int after) { 193 if (s != mBase) 194 return; 195 196 CharSequence text = mDisplay; 197 int len = text.length(); 198 199 // seek back to the start of the paragraph 200 201 int find = TextUtils.lastIndexOf(text, '\n', where - 1); 202 if (find < 0) 203 find = 0; 204 else 205 find = find + 1; 206 207 { 208 int diff = where - find; 209 before += diff; 210 after += diff; 211 where -= diff; 212 } 213 214 // seek forward to the end of the paragraph 215 216 int look = TextUtils.indexOf(text, '\n', where + after); 217 if (look < 0) 218 look = len; 219 else 220 look++; // we want the index after the \n 221 222 int change = look - (where + after); 223 before += change; 224 after += change; 225 226 // seek further out to cover anything that is forced to wrap together 227 228 if (text instanceof Spanned) { 229 Spanned sp = (Spanned) text; 230 boolean again; 231 232 do { 233 again = false; 234 235 Object[] force = sp.getSpans(where, where + after, 236 WrapTogetherSpan.class); 237 238 for (int i = 0; i < force.length; i++) { 239 int st = sp.getSpanStart(force[i]); 240 int en = sp.getSpanEnd(force[i]); 241 242 if (st < where) { 243 again = true; 244 245 int diff = where - st; 246 before += diff; 247 after += diff; 248 where -= diff; 249 } 250 251 if (en > where + after) { 252 again = true; 253 254 int diff = en - (where + after); 255 before += diff; 256 after += diff; 257 } 258 } 259 } while (again); 260 } 261 262 // find affected region of old layout 263 264 int startline = getLineForOffset(where); 265 int startv = getLineTop(startline); 266 267 int endline = getLineForOffset(where + before); 268 if (where + after == len) 269 endline = getLineCount(); 270 int endv = getLineTop(endline); 271 boolean islast = (endline == getLineCount()); 272 273 // generate new layout for affected text 274 275 StaticLayout reflowed; 276 277 synchronized (sLock) { 278 reflowed = sStaticLayout; 279 sStaticLayout = null; 280 } 281 282 if (reflowed == null) { 283 reflowed = new StaticLayout(null); 284 } else { 285 reflowed.prepare(); 286 } 287 288 reflowed.generate(text, where, where + after, 289 getPaint(), getWidth(), getTextDirectionHeuristic(), getSpacingMultiplier(), 290 getSpacingAdd(), false, 291 true, mEllipsizedWidth, mEllipsizeAt); 292 int n = reflowed.getLineCount(); 293 294 // If the new layout has a blank line at the end, but it is not 295 // the very end of the buffer, then we already have a line that 296 // starts there, so disregard the blank line. 297 298 if (where + after != len && 299 reflowed.getLineStart(n - 1) == where + after) 300 n--; 301 302 // remove affected lines from old layout 303 mInts.deleteAt(startline, endline - startline); 304 mObjects.deleteAt(startline, endline - startline); 305 updateBlocks(startline, endline - 1, n); 306 307 // adjust offsets in layout for new height and offsets 308 309 int ht = reflowed.getLineTop(n); 310 int toppad = 0, botpad = 0; 311 312 if (mIncludePad && startline == 0) { 313 toppad = reflowed.getTopPadding(); 314 mTopPadding = toppad; 315 ht -= toppad; 316 } 317 if (mIncludePad && islast) { 318 botpad = reflowed.getBottomPadding(); 319 mBottomPadding = botpad; 320 ht += botpad; 321 } 322 323 mInts.adjustValuesBelow(startline, START, after - before); 324 mInts.adjustValuesBelow(startline, TOP, startv - endv + ht); 325 326 // insert new layout 327 328 int[] ints; 329 330 if (mEllipsize) { 331 ints = new int[COLUMNS_ELLIPSIZE]; 332 ints[ELLIPSIS_START] = ELLIPSIS_UNDEFINED; 333 } else { 334 ints = new int[COLUMNS_NORMAL]; 335 } 336 337 Directions[] objects = new Directions[1]; 338 339 for (int i = 0; i < n; i++) { 340 ints[START] = reflowed.getLineStart(i) | 341 (reflowed.getParagraphDirection(i) << DIR_SHIFT) | 342 (reflowed.getLineContainsTab(i) ? TAB_MASK : 0); 343 344 int top = reflowed.getLineTop(i) + startv; 345 if (i > 0) 346 top -= toppad; 347 ints[TOP] = top; 348 349 int desc = reflowed.getLineDescent(i); 350 if (i == n - 1) 351 desc += botpad; 352 353 ints[DESCENT] = desc; 354 objects[0] = reflowed.getLineDirections(i); 355 356 if (mEllipsize) { 357 ints[ELLIPSIS_START] = reflowed.getEllipsisStart(i); 358 ints[ELLIPSIS_COUNT] = reflowed.getEllipsisCount(i); 359 } 360 361 mInts.insertAt(startline + i, ints); 362 mObjects.insertAt(startline + i, objects); 363 } 364 365 synchronized (sLock) { 366 sStaticLayout = reflowed; 367 reflowed.finish(); 368 } 369 } 370 371 /** 372 * This method is called every time the layout is reflowed after an edition. 373 * It updates the internal block data structure. The text is split in blocks 374 * of contiguous lines, with at least one block for the entire text. 375 * When a range of lines is edited, new blocks (from 0 to 3 depending on the 376 * overlap structure) will replace the set of overlapping blocks. 377 * Blocks are listed in order and are represented by their ending line number. 378 * An index is associated to each block (which will be used by display lists), 379 * this class simply invalidates the index of blocks overlapping a modification. 380 * 381 * @param startLine the first line of the range of modified lines 382 * @param endLine the last line of the range, possibly equal to startLine, lower 383 * than getLineCount() 384 * @param newLineCount the number of lines that will replace the range, possibly 0 385 */ 386 private void updateBlocks(int startLine, int endLine, int newLineCount) { 387 int firstBlock = -1; 388 int lastBlock = -1; 389 for (int i = 0; i < mNumberOfBlocks; i++) { 390 if (mBlockEnds[i] >= startLine) { 391 firstBlock = i; 392 break; 393 } 394 } 395 for (int i = firstBlock; i < mNumberOfBlocks; i++) { 396 if (mBlockEnds[i] >= endLine) { 397 lastBlock = i; 398 break; 399 } 400 } 401 final int lastBlockEndLine = mBlockEnds[lastBlock]; 402 403 boolean createBlockBefore = startLine > (firstBlock == 0 ? 0 : 404 mBlockEnds[firstBlock - 1] + 1); 405 boolean createBlock = newLineCount > 0; 406 boolean createBlockAfter = endLine < mBlockEnds[lastBlock]; 407 408 int numAddedBlocks = 0; 409 if (createBlockBefore) numAddedBlocks++; 410 if (createBlock) numAddedBlocks++; 411 if (createBlockAfter) numAddedBlocks++; 412 413 final int numRemovedBlocks = lastBlock - firstBlock + 1; 414 final int newNumberOfBlocks = mNumberOfBlocks + numAddedBlocks - numRemovedBlocks; 415 416 if (newNumberOfBlocks == 0) { 417 // Even when text is empty, there is actually one line and hence one block 418 mBlockEnds[0] = 0; 419 mBlockIndices[0] = INVALID_BLOCK_INDEX; 420 mNumberOfBlocks = 1; 421 return; 422 } 423 424 if (newNumberOfBlocks > mBlockEnds.length) { 425 final int newSize = ArrayUtils.idealIntArraySize(newNumberOfBlocks); 426 int[] blockEnds = new int[newSize]; 427 int[] blockIndices = new int[newSize]; 428 System.arraycopy(mBlockEnds, 0, blockEnds, 0, firstBlock); 429 System.arraycopy(mBlockIndices, 0, blockIndices, 0, firstBlock); 430 System.arraycopy(mBlockEnds, lastBlock + 1, 431 blockEnds, firstBlock + numAddedBlocks, mNumberOfBlocks - lastBlock - 1); 432 System.arraycopy(mBlockIndices, lastBlock + 1, 433 blockIndices, firstBlock + numAddedBlocks, mNumberOfBlocks - lastBlock - 1); 434 mBlockEnds = blockEnds; 435 mBlockIndices = blockIndices; 436 } else { 437 System.arraycopy(mBlockEnds, lastBlock + 1, 438 mBlockEnds, firstBlock + numAddedBlocks, mNumberOfBlocks - lastBlock - 1); 439 System.arraycopy(mBlockIndices, lastBlock + 1, 440 mBlockIndices, firstBlock + numAddedBlocks, mNumberOfBlocks - lastBlock - 1); 441 } 442 443 mNumberOfBlocks = newNumberOfBlocks; 444 final int deltaLines = newLineCount - (endLine - startLine + 1); 445 for (int i = firstBlock + numAddedBlocks; i < mNumberOfBlocks; i++) { 446 mBlockEnds[i] += deltaLines; 447 } 448 449 int blockIndex = firstBlock; 450 if (createBlockBefore) { 451 mBlockEnds[blockIndex] = startLine - 1; 452 mBlockIndices[blockIndex] = INVALID_BLOCK_INDEX; 453 blockIndex++; 454 } 455 456 if (createBlock) { 457 mBlockEnds[blockIndex] = startLine + newLineCount - 1; 458 mBlockIndices[blockIndex] = INVALID_BLOCK_INDEX; 459 blockIndex++; 460 } 461 462 if (createBlockAfter) { 463 mBlockEnds[blockIndex] = lastBlockEndLine + deltaLines; 464 mBlockIndices[blockIndex] = INVALID_BLOCK_INDEX; 465 } 466 } 467 468 /** 469 * @hide 470 */ 471 public int[] getBlockEnds() { 472 return mBlockEnds; 473 } 474 475 /** 476 * @hide 477 */ 478 public int[] getBlockIndices() { 479 return mBlockIndices; 480 } 481 482 /** 483 * @hide 484 */ 485 public int getNumberOfBlocks() { 486 return mNumberOfBlocks; 487 } 488 489 @Override 490 public int getLineCount() { 491 return mInts.size() - 1; 492 } 493 494 @Override 495 public int getLineTop(int line) { 496 return mInts.getValue(line, TOP); 497 } 498 499 @Override 500 public int getLineDescent(int line) { 501 return mInts.getValue(line, DESCENT); 502 } 503 504 @Override 505 public int getLineStart(int line) { 506 return mInts.getValue(line, START) & START_MASK; 507 } 508 509 @Override 510 public boolean getLineContainsTab(int line) { 511 return (mInts.getValue(line, TAB) & TAB_MASK) != 0; 512 } 513 514 @Override 515 public int getParagraphDirection(int line) { 516 return mInts.getValue(line, DIR) >> DIR_SHIFT; 517 } 518 519 @Override 520 public final Directions getLineDirections(int line) { 521 return mObjects.getValue(line, 0); 522 } 523 524 @Override 525 public int getTopPadding() { 526 return mTopPadding; 527 } 528 529 @Override 530 public int getBottomPadding() { 531 return mBottomPadding; 532 } 533 534 @Override 535 public int getEllipsizedWidth() { 536 return mEllipsizedWidth; 537 } 538 539 private static class ChangeWatcher implements TextWatcher, SpanWatcher { 540 public ChangeWatcher(DynamicLayout layout) { 541 mLayout = new WeakReference<DynamicLayout>(layout); 542 } 543 544 private void reflow(CharSequence s, int where, int before, int after) { 545 DynamicLayout ml = mLayout.get(); 546 547 if (ml != null) 548 ml.reflow(s, where, before, after); 549 else if (s instanceof Spannable) 550 ((Spannable) s).removeSpan(this); 551 } 552 553 public void beforeTextChanged(CharSequence s, int where, int before, int after) { 554 // Intentionally empty 555 } 556 557 public void onTextChanged(CharSequence s, int where, int before, int after) { 558 reflow(s, where, before, after); 559 } 560 561 public void afterTextChanged(Editable s) { 562 // Intentionally empty 563 } 564 565 public void onSpanAdded(Spannable s, Object o, int start, int end) { 566 if (o instanceof UpdateLayout) 567 reflow(s, start, end - start, end - start); 568 } 569 570 public void onSpanRemoved(Spannable s, Object o, int start, int end) { 571 if (o instanceof UpdateLayout) 572 reflow(s, start, end - start, end - start); 573 } 574 575 public void onSpanChanged(Spannable s, Object o, int start, int end, int nstart, int nend) { 576 if (o instanceof UpdateLayout) { 577 reflow(s, start, end - start, end - start); 578 reflow(s, nstart, nend - nstart, nend - nstart); 579 } 580 } 581 582 private WeakReference<DynamicLayout> mLayout; 583 } 584 585 @Override 586 public int getEllipsisStart(int line) { 587 if (mEllipsizeAt == null) { 588 return 0; 589 } 590 591 return mInts.getValue(line, ELLIPSIS_START); 592 } 593 594 @Override 595 public int getEllipsisCount(int line) { 596 if (mEllipsizeAt == null) { 597 return 0; 598 } 599 600 return mInts.getValue(line, ELLIPSIS_COUNT); 601 } 602 603 private CharSequence mBase; 604 private CharSequence mDisplay; 605 private ChangeWatcher mWatcher; 606 private boolean mIncludePad; 607 private boolean mEllipsize; 608 private int mEllipsizedWidth; 609 private TextUtils.TruncateAt mEllipsizeAt; 610 611 private PackedIntVector mInts; 612 private PackedObjectVector<Directions> mObjects; 613 614 /** 615 * Value used in mBlockIndices when a block has been created or recycled and indicating that its 616 * display list needs to be re-created. 617 * @hide 618 */ 619 public static final int INVALID_BLOCK_INDEX = -1; 620 // Stores the line numbers of the last line of each block 621 private int[] mBlockEnds; 622 // The indices of this block's display list in TextView's internal display list array or 623 // INVALID_BLOCK_INDEX if this block has been invalidated during an edition 624 private int[] mBlockIndices; 625 // Number of items actually currently being used in the above 2 arrays 626 private int mNumberOfBlocks; 627 628 private int mTopPadding, mBottomPadding; 629 630 private static StaticLayout sStaticLayout = new StaticLayout(null); 631 632 private static final Object[] sLock = new Object[0]; 633 634 private static final int START = 0; 635 private static final int DIR = START; 636 private static final int TAB = START; 637 private static final int TOP = 1; 638 private static final int DESCENT = 2; 639 private static final int COLUMNS_NORMAL = 3; 640 641 private static final int ELLIPSIS_START = 3; 642 private static final int ELLIPSIS_COUNT = 4; 643 private static final int COLUMNS_ELLIPSIZE = 5; 644 645 private static final int START_MASK = 0x1FFFFFFF; 646 private static final int DIR_SHIFT = 30; 647 private static final int TAB_MASK = 0x20000000; 648 649 private static final int ELLIPSIS_UNDEFINED = 0x80000000; 650} 651