1 /* 2 * Copyright (c) 2010, 2015, 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 javafx.scene.control.skin; 27 28 import com.sun.javafx.scene.control.Logging; 29 import com.sun.javafx.scene.control.Properties; 30 import com.sun.javafx.scene.control.VirtualScrollBar; 31 import com.sun.javafx.scene.control.skin.Utils; 32 import com.sun.javafx.scene.traversal.Algorithm; 33 import com.sun.javafx.scene.traversal.Direction; 34 import com.sun.javafx.scene.traversal.ParentTraversalEngine; 35 import com.sun.javafx.scene.traversal.TraversalContext; 36 import javafx.animation.KeyFrame; 37 import javafx.animation.Timeline; 38 import javafx.beans.InvalidationListener; 39 import javafx.beans.Observable; 40 import javafx.beans.property.BooleanProperty; 41 import javafx.beans.property.BooleanPropertyBase; 42 import javafx.beans.property.DoubleProperty; 43 import javafx.beans.property.IntegerProperty; 44 import javafx.beans.property.ObjectProperty; 45 import javafx.beans.property.SimpleBooleanProperty; 46 import javafx.beans.property.SimpleDoubleProperty; 47 import javafx.beans.property.SimpleIntegerProperty; 48 import javafx.beans.property.SimpleObjectProperty; 49 import javafx.beans.value.ChangeListener; 50 import javafx.collections.ObservableList; 51 import javafx.event.EventDispatcher; 52 import javafx.event.EventHandler; 53 import javafx.geometry.Orientation; 54 import javafx.scene.AccessibleRole; 55 import javafx.scene.Group; 56 import javafx.scene.Node; 57 import javafx.scene.Parent; 58 import javafx.scene.Scene; 59 import javafx.scene.control.Cell; 60 import javafx.scene.control.IndexedCell; 61 import javafx.scene.control.ListCell; 62 import javafx.scene.control.ScrollBar; 63 import javafx.scene.input.MouseEvent; 64 import javafx.scene.input.ScrollEvent; 65 import javafx.scene.layout.Region; 66 import javafx.scene.layout.StackPane; 67 import javafx.scene.shape.Rectangle; 68 import javafx.util.Callback; 69 import javafx.util.Duration; 70 import sun.util.logging.PlatformLogger; 71 72 import java.util.AbstractList; 73 import java.util.ArrayList; 74 import java.util.BitSet; 75 import java.util.List; 76 77 /** 78 * Implementation of a virtualized container using a cell based mechanism. This 79 * is used by the skin implementations for UI controls such as 80 * {@link javafx.scene.control.ListView}, {@link javafx.scene.control.TreeView}, 81 * {@link javafx.scene.control.TableView}, and {@link javafx.scene.control.TreeTableView}. 82 * 83 * @since 9 84 */ 85 public class VirtualFlow<T extends IndexedCell> extends Region { 86 87 /*************************************************************************** 88 * * 89 * Static fields * 90 * * 91 **************************************************************************/ 92 93 /** 94 * Scroll events may request to scroll about a number of "lines". We first 95 * decide how big one "line" is - for fixed cell size it's clear, 96 * for variable cell size we settle on a single number so that the scrolling 97 * speed is consistent. Now if the line is so big that 98 * MIN_SCROLLING_LINES_PER_PAGE of them don't fit into one page, we make 99 * them smaller to prevent the scrolling step to be too big (perhaps 100 * even more than one page). 101 */ 102 private static final int MIN_SCROLLING_LINES_PER_PAGE = 8; 103 104 /** 105 * Indicates that this is a newly created cell and we need call impl_processCSS for it. 106 * 107 * See RT-23616 for more details. 108 */ 109 private static final String NEW_CELL = "newcell"; 110 111 private static final double GOLDEN_RATIO_MULTIPLIER = 0.618033987; 112 113 114 115 /*************************************************************************** 116 * * 117 * Private fields * 118 * * 119 **************************************************************************/ 120 121 private boolean touchDetected = false; 122 private boolean mouseDown = false; 123 124 /** 125 * The width of the VirtualFlow the last time it was laid out. We 126 * use this information for several fast paths during the layout pass. 127 */ 128 double lastWidth = -1; 129 130 /** 131 * The height of the VirtualFlow the last time it was laid out. We 132 * use this information for several fast paths during the layout pass. 133 */ 134 double lastHeight = -1; 135 136 /** 137 * The number of "virtual" cells in the flow the last time it was laid out. 138 * For example, there may have been 1000 virtual cells, but only 20 actual 139 * cells created and in use. In that case, lastCellCount would be 1000. 140 */ 141 int lastCellCount = 0; 142 143 /** 144 * We remember the last value for vertical the last time we laid out the 145 * flow. If vertical has changed, we will want to change the max & value 146 * for the different scroll bars. Since we do all the scroll bar update 147 * work in the layoutChildren function, we need to know what the old value for 148 * vertical was. 149 */ 150 boolean lastVertical; 151 152 /** 153 * The position last time we laid out. If none of the lastXXX vars have 154 * changed respective to their values in layoutChildren, then we can just punt 155 * out of the method (I hope...) 156 */ 157 double lastPosition; 158 159 /** 160 * The breadth of the first visible cell last time we laid out. 161 */ 162 double lastCellBreadth = -1; 163 164 /** 165 * The length of the first visible cell last time we laid out. 166 */ 167 double lastCellLength = -1; 168 169 /** 170 * The list of cells representing those cells which actually make up the 171 * current view. The cells are ordered such that the first cell in this 172 * list is the first in the view, and the last cell is the last in the 173 * view. When pixel scrolling, the list is simply shifted and items drop 174 * off the beginning or the end, depending on the order of scrolling. 175 * <p> 176 * This is package private ONLY FOR TESTING 177 */ 178 final ArrayLinkedList<T> cells = new ArrayLinkedList<T>(); 179 180 /** 181 * A structure containing cells that can be reused later. These are cells 182 * that at one time were needed to populate the view, but now are no longer 183 * needed. We keep them here until they are needed again. 184 * <p> 185 * This is package private ONLY FOR TESTING 186 */ 187 final ArrayLinkedList<T> pile = new ArrayLinkedList<T>(); 188 189 /** 190 * A special cell used to accumulate bounds, such that we reduce object 191 * churn. This cell must be recreated whenever the cell factory function 192 * changes. This has package access ONLY for testing. 193 */ 194 T accumCell; 195 196 /** 197 * This group is used for holding the 'accumCell'. 'accumCell' must 198 * be added to the skin for it to be styled. Otherwise, it doesn't 199 * report the correct width/height leading to issues when scrolling 200 * the flow 201 */ 202 Group accumCellParent; 203 204 /** 205 * The group which holds the cells. 206 */ 207 final Group sheet; 208 209 final ObservableList<Node> sheetChildren; 210 211 /** 212 * The scroll bar used for scrolling horizontally. This has package access 213 * ONLY for testing. 214 */ 215 private VirtualScrollBar hbar = new VirtualScrollBar(this); 216 217 /** 218 * The scroll bar used to scrolling vertically. This has package access 219 * ONLY for testing. 220 */ 221 private VirtualScrollBar vbar = new VirtualScrollBar(this); 222 223 /** 224 * Control in which the cell's sheet is placed and forms the viewport. The 225 * viewportBreadth and viewportLength are simply the dimensions of the 226 * clipView. This has package access ONLY for testing. 227 */ 228 ClippedContainer clipView; 229 230 /** 231 * When both the horizontal and vertical scroll bars are visible, 232 * we have to 'fill in' the bottom right corner where the two scroll bars 233 * meet. This is handled by this corner region. This has package access 234 * ONLY for testing. 235 */ 236 StackPane corner; 237 238 // used for panning the virtual flow 239 private double lastX; 240 private double lastY; 241 private boolean isPanning = false; 242 243 private boolean fixedCellSizeEnabled = false; 244 245 private boolean needsReconfigureCells = false; // when cell contents are the same 246 private boolean needsRecreateCells = false; // when cell factory changed 247 private boolean needsRebuildCells = false; // when cell contents have changed 248 private boolean needsCellsLayout = false; 249 private boolean sizeChanged = false; 250 private final BitSet dirtyCells = new BitSet(); 251 252 Timeline sbTouchTimeline; 253 KeyFrame sbTouchKF1; 254 KeyFrame sbTouchKF2; 255 256 private boolean needBreadthBar; 257 private boolean needLengthBar; 258 private boolean tempVisibility = false; 259 260 261 262 /*************************************************************************** 263 * * 264 * Constructors * 265 * * 266 **************************************************************************/ 267 268 /** 269 * Creates a new VirtualFlow instance. 270 */ 271 public VirtualFlow() { 272 getStyleClass().add("virtual-flow"); 273 setId("virtual-flow"); 274 275 // initContent 276 // --- sheet 277 sheet = new Group(); 278 sheet.getStyleClass().add("sheet"); 279 sheet.setAutoSizeChildren(false); 280 281 sheetChildren = sheet.getChildren(); 282 283 // --- clipView 284 clipView = new ClippedContainer(this); 285 clipView.setNode(sheet); 286 getChildren().add(clipView); 287 288 // --- accumCellParent 289 accumCellParent = new Group(); 290 accumCellParent.setVisible(false); 291 getChildren().add(accumCellParent); 292 293 294 /* 295 ** don't allow the ScrollBar to handle the ScrollEvent, 296 ** In a VirtualFlow a vertical scroll should scroll on the vertical only, 297 ** whereas in a horizontal ScrollBar it can scroll horizontally. 298 */ 299 // block the event from being passed down to children 300 final EventDispatcher blockEventDispatcher = (event, tail) -> event; 301 // block ScrollEvent from being passed down to scrollbar's skin 302 final EventDispatcher oldHsbEventDispatcher = hbar.getEventDispatcher(); 303 hbar.setEventDispatcher((event, tail) -> { 304 if (event.getEventType() == ScrollEvent.SCROLL && 305 !((ScrollEvent)event).isDirect()) { 306 tail = tail.prepend(blockEventDispatcher); 307 tail = tail.prepend(oldHsbEventDispatcher); 308 return tail.dispatchEvent(event); 309 } 310 return oldHsbEventDispatcher.dispatchEvent(event, tail); 311 }); 312 // block ScrollEvent from being passed down to scrollbar's skin 313 final EventDispatcher oldVsbEventDispatcher = vbar.getEventDispatcher(); 314 vbar.setEventDispatcher((event, tail) -> { 315 if (event.getEventType() == ScrollEvent.SCROLL && 316 !((ScrollEvent)event).isDirect()) { 317 tail = tail.prepend(blockEventDispatcher); 318 tail = tail.prepend(oldVsbEventDispatcher); 319 return tail.dispatchEvent(event); 320 } 321 return oldVsbEventDispatcher.dispatchEvent(event, tail); 322 }); 323 /* 324 ** listen for ScrollEvents over the whole of the VirtualFlow 325 ** area, the above dispatcher having removed the ScrollBars 326 ** scroll event handling. 327 */ 328 setOnScroll(new EventHandler<ScrollEvent>() { 329 @Override public void handle(ScrollEvent event) { 330 if (Properties.IS_TOUCH_SUPPORTED) { 331 if (touchDetected == false && mouseDown == false ) { 332 startSBReleasedAnimation(); 333 } 334 } 335 /* 336 ** calculate the delta in the direction of the flow. 337 */ 338 double virtualDelta = 0.0; 339 if (isVertical()) { 340 switch(event.getTextDeltaYUnits()) { 341 case PAGES: 342 virtualDelta = event.getTextDeltaY() * lastHeight; 343 break; 344 case LINES: 345 double lineSize; 346 if (fixedCellSizeEnabled) { 347 lineSize = getFixedCellSize(); 348 } else { 349 // For the scrolling to be reasonably consistent 350 // we set the lineSize to the average size 351 // of all currently loaded lines. 352 T lastCell = cells.getLast(); 353 lineSize = 354 (getCellPosition(lastCell) 355 + getCellLength(lastCell) 356 - getCellPosition(cells.getFirst())) 357 / cells.size(); 358 } 359 360 if (lastHeight / lineSize < MIN_SCROLLING_LINES_PER_PAGE) { 361 lineSize = lastHeight / MIN_SCROLLING_LINES_PER_PAGE; 362 } 363 364 virtualDelta = event.getTextDeltaY() * lineSize; 365 break; 366 case NONE: 367 virtualDelta = event.getDeltaY(); 368 } 369 } else { // horizontal 370 switch(event.getTextDeltaXUnits()) { 371 case CHARACTERS: 372 // can we get character size here? 373 // for now, fall through to pixel values 374 case NONE: 375 double dx = event.getDeltaX(); 376 double dy = event.getDeltaY(); 377 378 virtualDelta = (Math.abs(dx) > Math.abs(dy) ? dx : dy); 379 } 380 } 381 382 if (virtualDelta != 0.0) { 383 /* 384 ** only consume it if we use it 385 */ 386 double result = scrollPixels(-virtualDelta); 387 if (result != 0.0) { 388 event.consume(); 389 } 390 } 391 392 ScrollBar nonVirtualBar = isVertical() ? hbar : vbar; 393 if (needBreadthBar) { 394 double nonVirtualDelta = isVertical() ? event.getDeltaX() : event.getDeltaY(); 395 if (nonVirtualDelta != 0.0) { 396 double newValue = nonVirtualBar.getValue() - nonVirtualDelta; 397 if (newValue < nonVirtualBar.getMin()) { 398 nonVirtualBar.setValue(nonVirtualBar.getMin()); 399 } else if (newValue > nonVirtualBar.getMax()) { 400 nonVirtualBar.setValue(nonVirtualBar.getMax()); 401 } else { 402 nonVirtualBar.setValue(newValue); 403 } 404 event.consume(); 405 } 406 } 407 } 408 }); 409 410 411 addEventFilter(MouseEvent.MOUSE_PRESSED, new EventHandler<MouseEvent>() { 412 @Override 413 public void handle(MouseEvent e) { 414 mouseDown = true; 415 if (Properties.IS_TOUCH_SUPPORTED) { 416 scrollBarOn(); 417 } 418 if (isFocusTraversable()) { 419 // We check here to see if the current focus owner is within 420 // this VirtualFlow, and if so we back-off from requesting 421 // focus back to the VirtualFlow itself. This is particularly 422 // relevant given the bug identified in RT-32869. In this 423 // particular case TextInputControl was clearing selection 424 // when the focus on the TextField changed, meaning that the 425 // right-click context menu was not showing the correct 426 // options as there was no selection in the TextField. 427 boolean doFocusRequest = true; 428 Node focusOwner = getScene().getFocusOwner(); 429 if (focusOwner != null) { 430 Parent parent = focusOwner.getParent(); 431 while (parent != null) { 432 if (parent.equals(VirtualFlow.this)) { 433 doFocusRequest = false; 434 break; 435 } 436 parent = parent.getParent(); 437 } 438 } 439 440 if (doFocusRequest) { 441 requestFocus(); 442 } 443 } 444 445 lastX = e.getX(); 446 lastY = e.getY(); 447 448 // determine whether the user has push down on the virtual flow, 449 // or whether it is the scrollbar. This is done to prevent 450 // mouse events being 'doubled up' when dragging the scrollbar 451 // thumb - it has the side-effect of also starting the panning 452 // code, leading to flicker 453 isPanning = ! (vbar.getBoundsInParent().contains(e.getX(), e.getY()) 454 || hbar.getBoundsInParent().contains(e.getX(), e.getY())); 455 } 456 }); 457 addEventFilter(MouseEvent.MOUSE_RELEASED, e -> { 458 mouseDown = false; 459 if (Properties.IS_TOUCH_SUPPORTED) { 460 startSBReleasedAnimation(); 461 } 462 }); 463 addEventFilter(MouseEvent.MOUSE_DRAGGED, e -> { 464 if (Properties.IS_TOUCH_SUPPORTED) { 465 scrollBarOn(); 466 } 467 if (! isPanning || ! isPannable()) return; 468 469 // With panning enabled, we support panning in both vertical 470 // and horizontal directions, regardless of the fact that 471 // VirtualFlow is virtual in only one direction. 472 double xDelta = lastX - e.getX(); 473 double yDelta = lastY - e.getY(); 474 475 // figure out the distance that the mouse moved in the virtual 476 // direction, and then perform the movement along that axis 477 // virtualDelta will contain the amount we actually did move 478 double virtualDelta = isVertical() ? yDelta : xDelta; 479 double actual = scrollPixels(virtualDelta); 480 if (actual != 0) { 481 // update last* here, as we know we've just adjusted the 482 // scrollbar. This means we don't get the situation where a 483 // user presses-and-drags a long way past the min or max 484 // values, only to change directions and see the scrollbar 485 // start moving immediately. 486 if (isVertical()) lastY = e.getY(); 487 else lastX = e.getX(); 488 } 489 490 // similarly, we do the same in the non-virtual direction 491 double nonVirtualDelta = isVertical() ? xDelta : yDelta; 492 ScrollBar nonVirtualBar = isVertical() ? hbar : vbar; 493 if (nonVirtualBar.isVisible()) { 494 double newValue = nonVirtualBar.getValue() + nonVirtualDelta; 495 if (newValue < nonVirtualBar.getMin()) { 496 nonVirtualBar.setValue(nonVirtualBar.getMin()); 497 } else if (newValue > nonVirtualBar.getMax()) { 498 nonVirtualBar.setValue(nonVirtualBar.getMax()); 499 } else { 500 nonVirtualBar.setValue(newValue); 501 502 // same as the last* comment above 503 if (isVertical()) lastX = e.getX(); 504 else lastY = e.getY(); 505 } 506 } 507 }); 508 509 /* 510 * We place the scrollbars _above_ the rectangle, such that the drag 511 * operations often used in conjunction with scrollbars aren't 512 * misinterpreted as drag operations on the rectangle as well (which 513 * would be the case if the scrollbars were underneath it as the 514 * rectangle itself doesn't block the mouse. 515 */ 516 // --- vbar 517 vbar.setOrientation(Orientation.VERTICAL); 518 vbar.addEventHandler(MouseEvent.ANY, event -> { 519 event.consume(); 520 }); 521 getChildren().add(vbar); 522 523 // --- hbar 524 hbar.setOrientation(Orientation.HORIZONTAL); 525 hbar.addEventHandler(MouseEvent.ANY, event -> { 526 event.consume(); 527 }); 528 getChildren().add(hbar); 529 530 // --- corner 531 corner = new StackPane(); 532 corner.getStyleClass().setAll("corner"); 533 getChildren().add(corner); 534 535 536 537 // initBinds 538 // clipView binds 539 InvalidationListener listenerX = valueModel -> { 540 updateHbar(); 541 }; 542 verticalProperty().addListener(listenerX); 543 hbar.valueProperty().addListener(listenerX); 544 hbar.visibleProperty().addListener(listenerX); 545 546 // ChangeListener listenerY = new ChangeListener() { 547 // @Override public void handle(Bean bean, PropertyReference property) { 548 // clipView.setClipY(isVertical() ? 0 : vbar.getValue()); 549 // } 550 // }; 551 // addChangedListener(VERTICAL, listenerY); 552 // vbar.addChangedListener(ScrollBar.VALUE, listenerY); 553 554 ChangeListener<Number> listenerY = (ov, t, t1) -> { 555 clipView.setClipY(isVertical() ? 0 : vbar.getValue()); 556 }; 557 vbar.valueProperty().addListener(listenerY); 558 559 super.heightProperty().addListener((observable, oldHeight, newHeight) -> { 560 // Fix for RT-8480, where the VirtualFlow does not show its content 561 // after changing size to 0 and back. 562 if (oldHeight.doubleValue() == 0 && newHeight.doubleValue() > 0) { 563 recreateCells(); 564 } 565 }); 566 567 568 /* 569 ** there are certain animations that need to know if the touch is 570 ** happening..... 571 */ 572 setOnTouchPressed(e -> { 573 touchDetected = true; 574 scrollBarOn(); 575 }); 576 577 setOnTouchReleased(e -> { 578 touchDetected = false; 579 startSBReleasedAnimation(); 580 }); 581 582 setImpl_traversalEngine(new ParentTraversalEngine(this, new Algorithm() { 583 584 Node selectNextAfterIndex(int index, TraversalContext context) { 585 T nextCell; 586 while ((nextCell = getVisibleCell(++index)) != null) { 587 if (nextCell.isFocusTraversable()) { 588 return nextCell; 589 } 590 Node n = context.selectFirstInParent(nextCell); 591 if (n != null) { 592 return n; 593 } 594 } 595 return null; 596 } 597 598 Node selectPreviousBeforeIndex(int index, TraversalContext context) { 599 T prevCell; 600 while ((prevCell = getVisibleCell(--index)) != null) { 601 Node prev = context.selectLastInParent(prevCell); 602 if (prev != null) { 603 return prev; 604 } 605 if (prevCell.isFocusTraversable()) { 606 return prevCell; 607 } 608 } 609 return null; 610 } 611 612 @Override 613 public Node select(Node owner, Direction dir, TraversalContext context) { 614 T cell; 615 if (cells.isEmpty()) return null; 616 if (cells.contains(owner)) { 617 cell = (T) owner; 618 } else { 619 cell = findOwnerCell(owner); 620 Node next = context.selectInSubtree(cell, owner, dir); 621 if (next != null) { 622 return next; 623 } 624 if (dir == Direction.NEXT) dir = Direction.NEXT_IN_LINE; 625 } 626 int cellIndex = cell.getIndex(); 627 switch(dir) { 628 case PREVIOUS: 629 return selectPreviousBeforeIndex(cellIndex, context); 630 case NEXT: 631 Node n = context.selectFirstInParent(cell); 632 if (n != null) { 633 return n; 634 } 635 // Intentional fall-through 636 case NEXT_IN_LINE: 637 return selectNextAfterIndex(cellIndex, context); 638 } 639 return null; 640 } 641 642 private T findOwnerCell(Node owner) { 643 Parent p = owner.getParent(); 644 while (!cells.contains(p)) { 645 p = p.getParent(); 646 } 647 return (T)p; 648 } 649 650 @Override 651 public Node selectFirst(TraversalContext context) { 652 T firstCell = cells.getFirst(); 653 if (firstCell == null) return null; 654 if (firstCell.isFocusTraversable()) return firstCell; 655 Node n = context.selectFirstInParent(firstCell); 656 if (n != null) { 657 return n; 658 } 659 return selectNextAfterIndex(firstCell.getIndex(), context); 660 } 661 662 @Override 663 public Node selectLast(TraversalContext context) { 664 T lastCell = cells.getLast(); 665 if (lastCell == null) return null; 666 Node p = context.selectLastInParent(lastCell); 667 if (p != null) { 668 return p; 669 } 670 if (lastCell.isFocusTraversable()) return lastCell; 671 return selectPreviousBeforeIndex(lastCell.getIndex(), context); 672 } 673 })); 674 } 675 676 677 678 /*************************************************************************** 679 * * 680 * Properties * 681 * * 682 **************************************************************************/ 683 684 /** 685 * There are two main complicating factors in the implementation of the 686 * VirtualFlow, which are made even more complicated due to the performance 687 * sensitive nature of this code. The first factor is the actual 688 * virtualization mechanism, wired together with the PositionMapper. 689 * The second complicating factor is the desire to do minimal layout 690 * and minimal updates to CSS. 691 * 692 * Since the layout mechanism runs at most once per pulse, we want to hook 693 * into this mechanism for minimal recomputation. Whenever a layout pass 694 * is run we record the width/height that the virtual flow was last laid 695 * out to. In subsequent passes, if the width/height has not changed then 696 * we know we only have to rebuild the cells. If the width or height has 697 * changed, then we can make appropriate decisions based on whether the 698 * width / height has been reduced or expanded. 699 * 700 * In various places, if requestLayout is called it is generally just 701 * used to indicate that some form of layout needs to happen (either the 702 * entire thing has to be reconstructed, or just the cells need to be 703 * reconstructed, generally). 704 * 705 * The accumCell is a special cell which is used in some computations 706 * when an actual cell for that item isn't currently available. However, 707 * the accumCell must be cleared whenever the cellFactory function is 708 * changed because we need to use the cells that come from the new factory. 709 * 710 * In addition to storing the lastWidth and lastHeight, we also store the 711 * number of cells that existed last time we performed a layout. In this 712 * way if the number of cells change, we can request a layout and when it 713 * occurs we can tell that the number of cells has changed and react 714 * accordingly. 715 * 716 * Because the VirtualFlow can be laid out horizontally or vertically a 717 * naming problem is present when trying to conceptualize and implement 718 * the flow. In particular, the words "width" and "height" are not 719 * precise when describing the unit of measure along the "virtualized" 720 * axis and the "orthogonal" axis. For example, the height of a cell when 721 * the flow is vertical is the magnitude along the "virtualized axis", 722 * and the width is along the axis orthogonal to it. 723 * 724 * Since "height" and "width" are not reliable terms, we use the words 725 * "length" and "breadth" to describe the magnitude of a cell along 726 * the virtualized axis and orthogonal axis. For example, in a vertical 727 * flow, the height=length and the width=breadth. In a horizontal axis, 728 * the height=breadth and the width=length. 729 * 730 * These terms are somewhat arbitrary, but chosen so that when reading 731 * most of the below code you can think in just one dimension, with 732 * helper functions converting width/height in to length/breadth, while 733 * also being different from width/height so as not to get confused with 734 * the actual width/height of a cell. 735 */ 736 737 // --- vertical 738 /** 739 * Indicates the primary direction of virtualization. If true, then the 740 * primary direction of virtualization is vertical, meaning that cells will 741 * stack vertically on top of each other. If false, then they will stack 742 * horizontally next to each other. 743 */ 744 private BooleanProperty vertical; 745 public final void setVertical(boolean value) { 746 verticalProperty().set(value); 747 } 748 749 public final boolean isVertical() { 750 return vertical == null ? true : vertical.get(); 751 } 752 753 public final BooleanProperty verticalProperty() { 754 if (vertical == null) { 755 vertical = new BooleanPropertyBase(true) { 756 @Override protected void invalidated() { 757 pile.clear(); 758 sheetChildren.clear(); 759 cells.clear(); 760 lastWidth = lastHeight = -1; 761 setMaxPrefBreadth(-1); 762 setViewportBreadth(0); 763 setViewportLength(0); 764 lastPosition = 0; 765 hbar.setValue(0); 766 vbar.setValue(0); 767 setPosition(0.0f); 768 setNeedsLayout(true); 769 requestLayout(); 770 } 771 772 @Override 773 public Object getBean() { 774 return VirtualFlow.this; 775 } 776 777 @Override 778 public String getName() { 779 return "vertical"; 780 } 781 }; 782 } 783 return vertical; 784 } 785 786 // --- pannable 787 /** 788 * Indicates whether the VirtualFlow viewport is capable of being panned 789 * by the user (either via the mouse or touch events). 790 */ 791 private BooleanProperty pannable = new SimpleBooleanProperty(this, "pannable", true); 792 public final boolean isPannable() { return pannable.get(); } 793 public final void setPannable(boolean value) { pannable.set(value); } 794 public final BooleanProperty pannableProperty() { return pannable; } 795 796 // --- cell count 797 /** 798 * Indicates the number of cells that should be in the flow. The user of 799 * the VirtualFlow must set this appropriately. When the cell count changes 800 * the VirtualFlow responds by updating the visuals. If the items backing 801 * the cells change, but the count has not changed, you must call the 802 * reconfigureCells() function to update the visuals. 803 */ 804 private IntegerProperty cellCount = new SimpleIntegerProperty(this, "cellCount", 0) { 805 private int oldCount = 0; 806 807 @Override protected void invalidated() { 808 int cellCount = get(); 809 810 boolean countChanged = oldCount != cellCount; 811 oldCount = cellCount; 812 813 // ensure that the virtual scrollbar adjusts in size based on the current 814 // cell count. 815 if (countChanged) { 816 VirtualScrollBar lengthBar = isVertical() ? vbar : hbar; 817 lengthBar.setMax(cellCount); 818 } 819 820 // I decided *not* to reset maxPrefBreadth here for the following 821 // situation. Suppose I have 30 cells and then I add 10 more. Just 822 // because I added 10 more doesn't mean the max pref should be 823 // reset. Suppose the first 3 cells were extra long, and I was 824 // scrolled down such that they weren't visible. If I were to reset 825 // maxPrefBreadth when subsequent cells were added or removed, then the 826 // scroll bars would erroneously reset as well. So I do not reset 827 // the maxPrefBreadth here. 828 829 // Fix for RT-12512, RT-14301 and RT-14864. 830 // Without this, the VirtualFlow length-wise scrollbar would not change 831 // as expected. This would leave items unable to be shown, as they 832 // would exist outside of the visible area, even when the scrollbar 833 // was at its maximum position. 834 // FIXME this should be only executed on the pulse, so this will likely 835 // lead to performance degradation until it is handled properly. 836 if (countChanged) { 837 layoutChildren(); 838 839 // Fix for RT-13965: Without this line of code, the number of items in 840 // the sheet would constantly grow, leaking memory for the life of the 841 // application. This was especially apparent when the total number of 842 // cells changes - regardless of whether it became bigger or smaller. 843 sheetChildren.clear(); 844 845 Parent parent = getParent(); 846 if (parent != null) parent.requestLayout(); 847 } 848 // TODO suppose I had 100 cells and I added 100 more. Further 849 // suppose I was scrolled to the bottom when that happened. I 850 // actually want to update the position of the mapper such that 851 // the view remains "stable". 852 } 853 }; 854 public final int getCellCount() { return cellCount.get(); } 855 public final void setCellCount(int value) { cellCount.set(value); } 856 public final IntegerProperty cellCountProperty() { return cellCount; } 857 858 859 // --- position 860 /** 861 * The position of the VirtualFlow within its list of cells. This is a value 862 * between 0 and 1. 863 */ 864 private DoubleProperty position = new SimpleDoubleProperty(this, "position") { 865 @Override public void setValue(Number v) { 866 super.setValue(com.sun.javafx.util.Utils.clamp(0, get(), 1)); 867 } 868 869 @Override protected void invalidated() { 870 super.invalidated(); 871 requestLayout(); 872 } 873 }; 874 public final double getPosition() { return position.get(); } 875 public final void setPosition(double value) { position.set(value); } 876 public final DoubleProperty positionProperty() { return position; } 877 878 // --- fixed cell size 879 /** 880 * For optimisation purposes, some use cases can trade dynamic cell length 881 * for speed - if fixedCellSize is greater than zero we'll use that rather 882 * than determine it by querying the cell itself. 883 */ 884 private DoubleProperty fixedCellSize = new SimpleDoubleProperty(this, "fixedCellSize") { 885 @Override protected void invalidated() { 886 fixedCellSizeEnabled = get() > 0; 887 needsCellsLayout = true; 888 layoutChildren(); 889 } 890 }; 891 public final void setFixedCellSize(final double value) { fixedCellSize.set(value); } 892 public final double getFixedCellSize() { return fixedCellSize.get(); } 893 public final DoubleProperty fixedCellSizeProperty() { return fixedCellSize; } 894 895 896 // --- Cell Factory 897 private ObjectProperty<Callback<VirtualFlow<T>, T>> cellFactory; 898 899 /** 900 * Sets a new cell factory to use in the VirtualFlow. This forces all old 901 * cells to be thrown away, and new cells to be created with 902 * the new cell factory. 903 */ 904 public final void setCellFactory(Callback<VirtualFlow<T>, T> value) { 905 cellFactoryProperty().set(value); 906 } 907 908 /** 909 * Returns the current cell factory. 910 */ 911 public final Callback<VirtualFlow<T>, T> getCellFactory() { 912 return cellFactory == null ? null : cellFactory.get(); 913 } 914 915 /** 916 * <p>Setting a custom cell factory has the effect of deferring all cell 917 * creation, allowing for total customization of the cell. Internally, the 918 * VirtualFlow is responsible for reusing cells - all that is necessary 919 * is for the custom cell factory to return from this function a cell 920 * which might be usable for representing any item in the VirtualFlow. 921 * 922 * <p>Refer to the {@link Cell} class documentation for more detail. 923 */ 924 public final ObjectProperty<Callback<VirtualFlow<T>, T>> cellFactoryProperty() { 925 if (cellFactory == null) { 926 cellFactory = new SimpleObjectProperty<Callback<VirtualFlow<T>, T>>(this, "cellFactory") { 927 @Override protected void invalidated() { 928 if (get() != null) { 929 accumCell = null; 930 setNeedsLayout(true); 931 recreateCells(); 932 if (getParent() != null) getParent().requestLayout(); 933 } 934 } 935 }; 936 } 937 return cellFactory; 938 } 939 940 941 942 /*************************************************************************** 943 * * 944 * Public API * 945 * * 946 **************************************************************************/ 947 948 /** 949 * Overridden to implement somewhat more efficient support for layout. The 950 * VirtualFlow can generally be considered as being unmanaged, in that 951 * whenever the position changes, or other such things change, we need 952 * to perform a layout but there is no reason to notify the parent. However 953 * when things change which may impact the preferred size (such as 954 * vertical, createCell, and configCell) then we need to notify the 955 * parent. 956 */ 957 @Override public void requestLayout() { 958 // isNeedsLayout() is commented out due to RT-21417. This does not 959 // appear to impact performance (indeed, it may help), and resolves the 960 // issue identified in RT-21417. 961 setNeedsLayout(true); 962 } 963 964 /** {@inheritDoc} */ 965 @Override protected void layoutChildren() { 966 if (needsRecreateCells) { 967 lastWidth = -1; 968 lastHeight = -1; 969 releaseCell(accumCell); 970 // accumCell = null; 971 // accumCellParent.getChildren().clear(); 972 sheet.getChildren().clear(); 973 for (int i = 0, max = cells.size(); i < max; i++) { 974 cells.get(i).updateIndex(-1); 975 } 976 cells.clear(); 977 pile.clear(); 978 releaseAllPrivateCells(); 979 } else if (needsRebuildCells) { 980 lastWidth = -1; 981 lastHeight = -1; 982 releaseCell(accumCell); 983 for (int i=0; i<cells.size(); i++) { 984 cells.get(i).updateIndex(-1); 985 } 986 addAllToPile(); 987 releaseAllPrivateCells(); 988 } else if (needsReconfigureCells) { 989 setMaxPrefBreadth(-1); 990 lastWidth = -1; 991 lastHeight = -1; 992 } 993 994 if (! dirtyCells.isEmpty()) { 995 int index; 996 final int cellsSize = cells.size(); 997 while ((index = dirtyCells.nextSetBit(0)) != -1 && index < cellsSize) { 998 T cell = cells.get(index); 999 // updateIndex(-1) works for TableView, but breaks ListView. 1000 // For now, the TableView just does not use the dirtyCells API 1001 // cell.updateIndex(-1); 1002 if (cell != null) { 1003 cell.requestLayout(); 1004 } 1005 dirtyCells.clear(index); 1006 } 1007 1008 setMaxPrefBreadth(-1); 1009 lastWidth = -1; 1010 lastHeight = -1; 1011 } 1012 1013 final boolean hasSizeChange = sizeChanged; 1014 boolean recreatedOrRebuilt = needsRebuildCells || needsRecreateCells || sizeChanged; 1015 1016 needsRecreateCells = false; 1017 needsReconfigureCells = false; 1018 needsRebuildCells = false; 1019 sizeChanged = false; 1020 1021 if (needsCellsLayout) { 1022 for (int i = 0, max = cells.size(); i < max; i++) { 1023 Cell<?> cell = cells.get(i); 1024 if (cell != null) { 1025 cell.requestLayout(); 1026 } 1027 } 1028 needsCellsLayout = false; 1029 1030 // yes, we return here - if needsCellsLayout was set to true, we 1031 // only did it to do the above - not rerun the entire layout. 1032 return; 1033 } 1034 1035 final double width = getWidth(); 1036 final double height = getHeight(); 1037 final boolean isVertical = isVertical(); 1038 final double position = getPosition(); 1039 1040 // if the width and/or height is 0, then there is no point doing 1041 // any of this work. In particular, this can happen during startup 1042 if (width <= 0 || height <= 0) { 1043 addAllToPile(); 1044 lastWidth = width; 1045 lastHeight = height; 1046 hbar.setVisible(false); 1047 vbar.setVisible(false); 1048 corner.setVisible(false); 1049 return; 1050 } 1051 1052 // we check if any of the cells in the cells list need layout. This is a 1053 // sign that they are perhaps animating their sizes. Without this check, 1054 // we may not perform a layout here, meaning that the cell will likely 1055 // 'jump' (in height normally) when the user drags the virtual thumb as 1056 // that is the first time the layout would occur otherwise. 1057 boolean cellNeedsLayout = false; 1058 boolean thumbNeedsLayout = false; 1059 1060 if (Properties.IS_TOUCH_SUPPORTED) { 1061 if ((tempVisibility == true && (hbar.isVisible() == false || vbar.isVisible() == false)) || 1062 (tempVisibility == false && (hbar.isVisible() == true || vbar.isVisible() == true))) { 1063 thumbNeedsLayout = true; 1064 } 1065 } 1066 1067 if (!cellNeedsLayout) { 1068 for (int i = 0; i < cells.size(); i++) { 1069 Cell<?> cell = cells.get(i); 1070 cellNeedsLayout = cell.isNeedsLayout(); 1071 if (cellNeedsLayout) break; 1072 } 1073 } 1074 1075 final int cellCount = getCellCount(); 1076 final T firstCell = getFirstVisibleCell(); 1077 1078 // If no cells need layout, we check other criteria to see if this 1079 // layout call is even necessary. If it is found that no layout is 1080 // needed, we just punt. 1081 if (! cellNeedsLayout && !thumbNeedsLayout) { 1082 boolean cellSizeChanged = false; 1083 if (firstCell != null) { 1084 double breadth = getCellBreadth(firstCell); 1085 double length = getCellLength(firstCell); 1086 cellSizeChanged = (breadth != lastCellBreadth) || (length != lastCellLength); 1087 lastCellBreadth = breadth; 1088 lastCellLength = length; 1089 } 1090 1091 if (width == lastWidth && 1092 height == lastHeight && 1093 cellCount == lastCellCount && 1094 isVertical == lastVertical && 1095 position == lastPosition && 1096 ! cellSizeChanged) 1097 { 1098 // TODO this happens to work around the problem tested by 1099 // testCellLayout_LayoutWithoutChangingThingsUsesCellsInSameOrderAsBefore 1100 // but isn't a proper solution. Really what we need to do is, when 1101 // laying out cells, we need to make sure that if a cell is pressed 1102 // AND we are doing a full rebuild then we need to make sure we 1103 // use that cell in the same physical location as before so that 1104 // it gets the mouse release event. 1105 return; 1106 } 1107 } 1108 1109 /* 1110 * This function may get called under a variety of circumstances. 1111 * It will determine what has changed from the last time it was laid 1112 * out, and will then take one of several execution paths based on 1113 * what has changed so as to perform minimal layout work and also to 1114 * give the expected behavior. One or more of the following may have 1115 * happened: 1116 * 1117 * 1) width/height has changed 1118 * - If the width and/or height has been reduced (but neither of 1119 * them has been expanded), then we simply have to reposition and 1120 * resize the scroll bars 1121 * - If the width (in the vertical case) has expanded, then we 1122 * need to resize the existing cells and reposition and resize 1123 * the scroll bars 1124 * - If the height (in the vertical case) has expanded, then we 1125 * need to resize and reposition the scroll bars and add 1126 * any trailing cells 1127 * 1128 * 2) cell count has changed 1129 * - If the number of cells is bigger, or it is smaller but not 1130 * so small as to move the position then we can just update the 1131 * cells in place without performing layout and update the 1132 * scroll bars. 1133 * - If the number of cells has been reduced and it affects the 1134 * position, then move the position and rebuild all the cells 1135 * and update the scroll bars 1136 * 1137 * 3) size of the cell has changed 1138 * - If the size changed in the virtual direction (ie: height 1139 * in the case of vertical) then layout the cells, adding 1140 * trailing cells as necessary and updating the scroll bars 1141 * - If the size changed in the non virtual direction (ie: width 1142 * in the case of vertical) then simply adjust the widths of 1143 * the cells as appropriate and adjust the scroll bars 1144 * 1145 * 4) vertical changed, cells is empty, maxPrefBreadth == -1, etc 1146 * - Full rebuild. 1147 * 1148 * Each of the conditions really resolves to several of a handful of 1149 * possible outcomes: 1150 * a) reposition & rebuild scroll bars 1151 * b) resize cells in non-virtual direction 1152 * c) add trailing cells 1153 * d) update cells 1154 * e) resize cells in the virtual direction 1155 * f) all of the above 1156 * 1157 * So this function first determines what outcomes need to occur, and 1158 * then will execute all the ones that really need to happen. Every code 1159 * path ends up touching the "reposition & rebuild scroll bars" outcome, 1160 * so that one will be executed every time. 1161 */ 1162 boolean needTrailingCells = false; 1163 boolean rebuild = cellNeedsLayout || 1164 isVertical != lastVertical || 1165 cells.isEmpty() || 1166 getMaxPrefBreadth() == -1 || 1167 position != lastPosition || 1168 cellCount != lastCellCount || 1169 hasSizeChange || 1170 (isVertical && height < lastHeight) || (! isVertical && width < lastWidth); 1171 1172 if (!rebuild) { 1173 // Check if maxPrefBreadth didn't change 1174 double maxPrefBreadth = getMaxPrefBreadth(); 1175 boolean foundMax = false; 1176 for (int i = 0; i < cells.size(); ++i) { 1177 double breadth = getCellBreadth(cells.get(i)); 1178 if (maxPrefBreadth == breadth) { 1179 foundMax = true; 1180 } else if (breadth > maxPrefBreadth) { 1181 rebuild = true; 1182 break; 1183 } 1184 } 1185 if (!foundMax) { // All values were lower 1186 rebuild = true; 1187 } 1188 } 1189 1190 if (! rebuild) { 1191 if ((isVertical && height > lastHeight) || (! isVertical && width > lastWidth)) { 1192 // resized in the virtual direction 1193 needTrailingCells = true; 1194 } 1195 } 1196 1197 initViewport(); 1198 1199 // Get the index of the "current" cell 1200 int currentIndex = computeCurrentIndex(); 1201 if (lastCellCount != cellCount) { 1202 // The cell count has changed. We want to keep the viewport 1203 // stable if possible. If position was 0 or 1, we want to keep 1204 // the position in the same place. If the new cell count is >= 1205 // the currentIndex, then we will adjust the position to be 1. 1206 // Otherwise, our goal is to leave the index of the cell at the 1207 // top consistent, with the same translation etc. 1208 if (position == 0 || position == 1) { 1209 // Update the item count 1210 // setItemCount(cellCount); 1211 } else if (currentIndex >= cellCount) { 1212 setPosition(1.0f); 1213 // setItemCount(cellCount); 1214 } else if (firstCell != null) { 1215 double firstCellOffset = getCellPosition(firstCell); 1216 int firstCellIndex = getCellIndex(firstCell); 1217 // setItemCount(cellCount); 1218 adjustPositionToIndex(firstCellIndex); 1219 double viewportTopToCellTop = -computeOffsetForCell(firstCellIndex); 1220 adjustByPixelAmount(viewportTopToCellTop - firstCellOffset); 1221 } 1222 1223 // Update the current index 1224 currentIndex = computeCurrentIndex(); 1225 } 1226 1227 if (rebuild) { 1228 setMaxPrefBreadth(-1); 1229 // Start by dumping all the cells into the pile 1230 addAllToPile(); 1231 1232 // The distance from the top of the viewport to the top of the 1233 // cell for the current index. 1234 double offset = -computeViewportOffset(getPosition()); 1235 1236 // Add all the leading and trailing cells (the call to add leading 1237 // cells will add the current cell as well -- that is, the one that 1238 // represents the current position on the mapper). 1239 addLeadingCells(currentIndex, offset); 1240 1241 // Force filling of space with empty cells if necessary 1242 addTrailingCells(true); 1243 } else if (needTrailingCells) { 1244 addTrailingCells(true); 1245 } 1246 1247 computeBarVisiblity(); 1248 updateScrollBarsAndCells(recreatedOrRebuilt); 1249 1250 lastWidth = getWidth(); 1251 lastHeight = getHeight(); 1252 lastCellCount = getCellCount(); 1253 lastVertical = isVertical(); 1254 lastPosition = getPosition(); 1255 1256 cleanPile(); 1257 } 1258 1259 /** {@inheritDoc} */ 1260 @Override protected void setWidth(double value) { 1261 if (value != lastWidth) { 1262 super.setWidth(value); 1263 sizeChanged = true; 1264 setNeedsLayout(true); 1265 requestLayout(); 1266 } 1267 } 1268 1269 /** {@inheritDoc} */ 1270 @Override protected void setHeight(double value) { 1271 if (value != lastHeight) { 1272 super.setHeight(value); 1273 sizeChanged = true; 1274 setNeedsLayout(true); 1275 requestLayout(); 1276 } 1277 } 1278 1279 /** 1280 * Get a cell which can be used in the layout. This function will reuse 1281 * cells from the pile where possible, and will create new cells when 1282 * necessary. 1283 */ 1284 protected T getAvailableCell(int prefIndex) { 1285 T cell = null; 1286 1287 // Fix for RT-12822. We try to retrieve the cell from the pile rather 1288 // than just grab a random cell from the pile (or create another cell). 1289 for (int i = 0, max = pile.size(); i < max; i++) { 1290 T _cell = pile.get(i); 1291 assert _cell != null; 1292 1293 if (getCellIndex(_cell) == prefIndex) { 1294 cell = _cell; 1295 pile.remove(i); 1296 break; 1297 } 1298 cell = null; 1299 } 1300 1301 if (cell == null) { 1302 if (pile.size() > 0) { 1303 // we try to get a cell with an index that is the same even/odd 1304 // as the prefIndex. This saves us from having to run so much 1305 // css on the cell as it will not change from even to odd, or 1306 // vice versa 1307 final boolean prefIndexIsEven = (prefIndex & 1) == 0; 1308 for (int i = 0, max = pile.size(); i < max; i++) { 1309 final T c = pile.get(i); 1310 final int cellIndex = getCellIndex(c); 1311 1312 if ((cellIndex & 1) == 0 && prefIndexIsEven) { 1313 cell = c; 1314 pile.remove(i); 1315 break; 1316 } else if ((cellIndex & 1) == 1 && ! prefIndexIsEven) { 1317 cell = c; 1318 pile.remove(i); 1319 break; 1320 } 1321 } 1322 1323 if (cell == null) { 1324 cell = pile.removeFirst(); 1325 } 1326 } else { 1327 cell = getCellFactory().call(this); 1328 cell.getProperties().put(NEW_CELL, null); 1329 } 1330 } 1331 1332 if (cell.getParent() == null) { 1333 sheetChildren.add(cell); 1334 } 1335 1336 return cell; 1337 } 1338 1339 /** 1340 * This method will remove all cells from the VirtualFlow and remove them, 1341 * adding them to the 'pile' (that is, a place from where cells can be used 1342 * at a later date). This method is protected to allow subclasses to clean up 1343 * appropriately. 1344 */ 1345 protected void addAllToPile() { 1346 for (int i = 0, max = cells.size(); i < max; i++) { 1347 addToPile(cells.removeFirst()); 1348 } 1349 } 1350 1351 /** 1352 * Gets a cell for the given index if the cell has been created and laid out. 1353 * "Visible" is a bit of a misnomer, the cell might not be visible in the 1354 * viewport (it may be clipped), but does distinguish between cells that 1355 * have been created and are in use vs. those that are in the pile or 1356 * not created. 1357 */ 1358 public T getVisibleCell(int index) { 1359 if (cells.isEmpty()) return null; 1360 1361 // check the last index 1362 T lastCell = cells.getLast(); 1363 int lastIndex = getCellIndex(lastCell); 1364 if (index == lastIndex) return lastCell; 1365 1366 // check the first index 1367 T firstCell = cells.getFirst(); 1368 int firstIndex = getCellIndex(firstCell); 1369 if (index == firstIndex) return firstCell; 1370 1371 // if index is > firstIndex and < lastIndex then we can get the index 1372 if (index > firstIndex && index < lastIndex) { 1373 T cell = cells.get(index - firstIndex); 1374 if (getCellIndex(cell) == index) return cell; 1375 } 1376 1377 // there is no visible cell for the specified index 1378 return null; 1379 } 1380 1381 /** 1382 * Locates and returns the last non-empty IndexedCell that is currently 1383 * partially or completely visible. This function may return null if there 1384 * are no cells, or if the viewport length is 0. 1385 */ 1386 public T getLastVisibleCell() { 1387 if (cells.isEmpty() || getViewportLength() <= 0) return null; 1388 1389 T cell; 1390 for (int i = cells.size() - 1; i >= 0; i--) { 1391 cell = cells.get(i); 1392 if (! cell.isEmpty()) { 1393 return cell; 1394 } 1395 } 1396 1397 return null; 1398 } 1399 1400 /** 1401 * Locates and returns the first non-empty IndexedCell that is partially or 1402 * completely visible. This really only ever returns null if there are no 1403 * cells or the viewport length is 0. 1404 */ 1405 public T getFirstVisibleCell() { 1406 if (cells.isEmpty() || getViewportLength() <= 0) return null; 1407 T cell = cells.getFirst(); 1408 return cell.isEmpty() ? null : cell; 1409 } 1410 1411 /** 1412 * Adjust the position of cells so that the specified cell 1413 * will be positioned at the start of the viewport. The given cell must 1414 * already be "live". 1415 */ 1416 public void scrollToTop(T firstCell) { 1417 if (firstCell != null) { 1418 scrollPixels(getCellPosition(firstCell)); 1419 } 1420 } 1421 1422 /** 1423 * Adjust the position of cells so that the specified cell 1424 * will be positioned at the end of the viewport. The given cell must 1425 * already be "live". 1426 */ 1427 public void scrollToBottom(T lastCell) { 1428 if (lastCell != null) { 1429 scrollPixels(getCellPosition(lastCell) + getCellLength(lastCell) - getViewportLength()); 1430 } 1431 } 1432 1433 /** 1434 * Adjusts the cells such that the selected cell will be fully visible in 1435 * the viewport (but only just). 1436 */ 1437 public void scrollTo(T cell) { 1438 if (cell != null) { 1439 final double start = getCellPosition(cell); 1440 final double length = getCellLength(cell); 1441 final double end = start + length; 1442 final double viewportLength = getViewportLength(); 1443 1444 if (start < 0) { 1445 scrollPixels(start); 1446 } else if (end > viewportLength) { 1447 scrollPixels(end - viewportLength); 1448 } 1449 } 1450 } 1451 1452 /** 1453 * Adjusts the cells such that the cell in the given index will be fully visible in 1454 * the viewport. 1455 */ 1456 public void scrollTo(int index) { 1457 T cell = getVisibleCell(index); 1458 if (cell != null) { 1459 scrollTo(cell); 1460 } else { 1461 adjustPositionToIndex(index); 1462 addAllToPile(); 1463 requestLayout(); 1464 } 1465 } 1466 1467 /** 1468 * Adjusts the cells such that the cell in the given index will be fully visible in 1469 * the viewport, and positioned at the very top of the viewport. 1470 */ 1471 public void scrollToTop(int index) { 1472 boolean posSet = false; 1473 1474 if (index >= getCellCount() - 1) { 1475 setPosition(1); 1476 posSet = true; 1477 } else if (index < 0) { 1478 setPosition(0); 1479 posSet = true; 1480 } 1481 1482 if (! posSet) { 1483 adjustPositionToIndex(index); 1484 double offset = - computeOffsetForCell(index); 1485 adjustByPixelAmount(offset); 1486 } 1487 1488 requestLayout(); 1489 } 1490 1491 // //TODO We assume all the cell have the same length. We will need to support 1492 // // cells of different lengths. 1493 // public void scrollToOffset(int offset) { 1494 // scrollPixels(offset * getCellLength(0)); 1495 // } 1496 1497 /** 1498 * Given a delta value representing a number of pixels, this method attempts 1499 * to move the VirtualFlow in the given direction (positive is down/right, 1500 * negative is up/left) the given number of pixels. It returns the number of 1501 * pixels actually moved. 1502 */ 1503 public double scrollPixels(final double delta) { 1504 // Short cut this method for cases where nothing should be done 1505 if (delta == 0) return 0; 1506 1507 final boolean isVertical = isVertical(); 1508 if (((isVertical && (tempVisibility ? !needLengthBar : !vbar.isVisible())) || 1509 (! isVertical && (tempVisibility ? !needLengthBar : !hbar.isVisible())))) return 0; 1510 1511 double pos = getPosition(); 1512 if (pos == 0.0f && delta < 0) return 0; 1513 if (pos == 1.0f && delta > 0) return 0; 1514 1515 adjustByPixelAmount(delta); 1516 if (pos == getPosition()) { 1517 // The pos hasn't changed, there's nothing to do. This is likely 1518 // to occur when we hit either extremity 1519 return 0; 1520 } 1521 1522 // Now move stuff around. Translating by pixels fundamentally means 1523 // moving the cells by the delta. However, after having 1524 // done that, we need to go through the cells and see which cells, 1525 // after adding in the translation factor, now fall off the viewport. 1526 // Also, we need to add cells as appropriate to the end (or beginning, 1527 // depending on the direction of travel). 1528 // 1529 // One simplifying assumption (that had better be true!) is that we 1530 // will only make it this far in the function if the virtual scroll 1531 // bar is visible. Otherwise, we never will pixel scroll. So as we go, 1532 // if we find that the maxPrefBreadth exceeds the viewportBreadth, 1533 // then we will be sure to show the breadthBar and update it 1534 // accordingly. 1535 if (cells.size() > 0) { 1536 for (int i = 0; i < cells.size(); i++) { 1537 T cell = cells.get(i); 1538 assert cell != null; 1539 positionCell(cell, getCellPosition(cell) - delta); 1540 } 1541 1542 // Fix for RT-32908 1543 T firstCell = cells.getFirst(); 1544 double layoutY = firstCell == null ? 0 : getCellPosition(firstCell); 1545 for (int i = 0; i < cells.size(); i++) { 1546 T cell = cells.get(i); 1547 assert cell != null; 1548 double actualLayoutY = getCellPosition(cell); 1549 if (actualLayoutY != layoutY) { 1550 // we need to shift the cell to layoutY 1551 positionCell(cell, layoutY); 1552 } 1553 1554 layoutY += getCellLength(cell); 1555 } 1556 // end of fix for RT-32908 1557 cull(); 1558 firstCell = cells.getFirst(); 1559 1560 // Add any necessary leading cells 1561 if (firstCell != null) { 1562 int firstIndex = getCellIndex(firstCell); 1563 double prevIndexSize = getCellLength(firstIndex - 1); 1564 addLeadingCells(firstIndex - 1, getCellPosition(firstCell) - prevIndexSize); 1565 } else { 1566 int currentIndex = computeCurrentIndex(); 1567 1568 // The distance from the top of the viewport to the top of the 1569 // cell for the current index. 1570 double offset = -computeViewportOffset(getPosition()); 1571 1572 // Add all the leading and trailing cells (the call to add leading 1573 // cells will add the current cell as well -- that is, the one that 1574 // represents the current position on the mapper). 1575 addLeadingCells(currentIndex, offset); 1576 } 1577 1578 // Starting at the tail of the list, loop adding cells until 1579 // all the space on the table is filled up. We want to make 1580 // sure that we DO NOT add empty trailing cells (since we are 1581 // in the full virtual case and so there are no trailing empty 1582 // cells). 1583 if (! addTrailingCells(false)) { 1584 // Reached the end, but not enough cells to fill up to 1585 // the end. So, remove the trailing empty space, and translate 1586 // the cells down 1587 final T lastCell = getLastVisibleCell(); 1588 final double lastCellSize = getCellLength(lastCell); 1589 final double cellEnd = getCellPosition(lastCell) + lastCellSize; 1590 final double viewportLength = getViewportLength(); 1591 1592 if (cellEnd < viewportLength) { 1593 // Reposition the nodes 1594 double emptySize = viewportLength - cellEnd; 1595 for (int i = 0; i < cells.size(); i++) { 1596 T cell = cells.get(i); 1597 positionCell(cell, getCellPosition(cell) + emptySize); 1598 } 1599 setPosition(1.0f); 1600 // fill the leading empty space 1601 firstCell = cells.getFirst(); 1602 int firstIndex = getCellIndex(firstCell); 1603 double prevIndexSize = getCellLength(firstIndex - 1); 1604 addLeadingCells(firstIndex - 1, getCellPosition(firstCell) - prevIndexSize); 1605 } 1606 } 1607 } 1608 1609 // Now throw away any cells that don't fit 1610 cull(); 1611 1612 // Finally, update the scroll bars 1613 updateScrollBarsAndCells(false); 1614 lastPosition = getPosition(); 1615 1616 // notify 1617 return delta; // TODO fake 1618 } 1619 1620 /** {@inheritDoc} */ 1621 @Override protected double computePrefWidth(double height) { 1622 double w = isVertical() ? getPrefBreadth(height) : getPrefLength(); 1623 return w + vbar.prefWidth(-1); 1624 } 1625 1626 /** {@inheritDoc} */ 1627 @Override protected double computePrefHeight(double width) { 1628 double h = isVertical() ? getPrefLength() : getPrefBreadth(width); 1629 return h + hbar.prefHeight(-1); 1630 } 1631 1632 /** 1633 * Return a cell for the given index. This may be called for any cell, 1634 * including beyond the range defined by cellCount, in which case an 1635 * empty cell will be returned. The returned value should not be stored for 1636 * any reason. 1637 */ 1638 public T getCell(int index) { 1639 // If there are cells, then we will attempt to get an existing cell 1640 if (! cells.isEmpty()) { 1641 // First check the cells that have already been created and are 1642 // in use. If this call returns a value, then we can use it 1643 T cell = getVisibleCell(index); 1644 if (cell != null) return cell; 1645 } 1646 1647 // check the pile 1648 for (int i = 0; i < pile.size(); i++) { 1649 T cell = pile.get(i); 1650 if (getCellIndex(cell) == index) { 1651 // Note that we don't remove from the pile: if we do it leads 1652 // to a severe performance decrease. This seems to be OK, as 1653 // getCell() is only used for cell measurement purposes. 1654 // pile.remove(i); 1655 return cell; 1656 } 1657 } 1658 1659 if (pile.size() > 0) { 1660 return pile.get(0); 1661 } 1662 1663 // We need to use the accumCell and return that 1664 if (accumCell == null) { 1665 Callback<VirtualFlow<T>,T> cellFactory = getCellFactory(); 1666 if (cellFactory != null) { 1667 accumCell = cellFactory.call(this); 1668 accumCell.getProperties().put(NEW_CELL, null); 1669 accumCellParent.getChildren().setAll(accumCell); 1670 1671 // Note the screen reader will attempt to find all 1672 // the items inside the view to calculate the item count. 1673 // Having items under different parents (sheet and accumCellParent) 1674 // leads the screen reader to compute wrong values. 1675 // The regular scheme to provide items to the screen reader 1676 // uses getPrivateCell(), which places the item in the sheet. 1677 // The accumCell, and its children, should be ignored by the 1678 // screen reader. 1679 accumCell.setAccessibleRole(AccessibleRole.NODE); 1680 accumCell.getChildrenUnmodifiable().addListener((Observable c) -> { 1681 for (Node n : accumCell.getChildrenUnmodifiable()) { 1682 n.setAccessibleRole(AccessibleRole.NODE); 1683 } 1684 }); 1685 } 1686 } 1687 setCellIndex(accumCell, index); 1688 resizeCellSize(accumCell); 1689 return accumCell; 1690 } 1691 1692 /** 1693 * The VirtualFlow uses this method to set a cells index (rather than calling 1694 * {@link IndexedCell#updateIndex(int)} directly), so it is a perfect place 1695 * for subclasses to override if this if of interest. 1696 * 1697 * @param cell The cell whose index will be updated. 1698 * @param index The new index for the cell. 1699 */ 1700 protected void setCellIndex(T cell, int index) { 1701 assert cell != null; 1702 1703 cell.updateIndex(index); 1704 1705 // make sure the cell is sized correctly. This is important for both 1706 // general layout of cells in a VirtualFlow, but also in cases such as 1707 // RT-34333, where the sizes were being reported incorrectly to the 1708 // ComboBox popup. 1709 if ((cell.isNeedsLayout() && cell.getScene() != null) || cell.getProperties().containsKey(NEW_CELL)) { 1710 cell.applyCss(); 1711 cell.getProperties().remove(NEW_CELL); 1712 } 1713 } 1714 1715 /** 1716 * Return the index for a given cell. This allows subclasses to customise 1717 * how cell indices are retrieved. 1718 */ 1719 protected int getCellIndex(T cell){ 1720 return cell.getIndex(); 1721 } 1722 1723 1724 1725 /*************************************************************************** 1726 * * 1727 * Private implementation * 1728 * * 1729 **************************************************************************/ 1730 1731 final VirtualScrollBar getHbar() { 1732 return hbar; 1733 } 1734 final VirtualScrollBar getVbar() { 1735 return vbar; 1736 } 1737 1738 /** 1739 * The maximum preferred size in the non-virtual direction. For example, 1740 * if vertical, then this is the max pref width of all cells encountered. 1741 * <p> 1742 * In general, this is the largest preferred size in the non-virtual 1743 * direction that we have ever encountered. We don't reduce this size 1744 * unless instructed to do so, so as to reduce the amount of scroll bar 1745 * jitter. The access on this variable is package ONLY FOR TESTING. 1746 */ 1747 private double maxPrefBreadth; 1748 private final void setMaxPrefBreadth(double value) { 1749 this.maxPrefBreadth = value; 1750 } 1751 final double getMaxPrefBreadth() { 1752 return maxPrefBreadth; 1753 } 1754 1755 /** 1756 * The breadth of the viewport portion of the VirtualFlow as computed during 1757 * the layout pass. In a vertical flow this would be the same as the clip 1758 * view width. In a horizontal flow this is the clip view height. 1759 * The access on this variable is package ONLY FOR TESTING. 1760 */ 1761 private double viewportBreadth; 1762 private final void setViewportBreadth(double value) { 1763 this.viewportBreadth = value; 1764 } 1765 private final double getViewportBreadth() { 1766 return viewportBreadth; 1767 } 1768 1769 /** 1770 * The length of the viewport portion of the VirtualFlow as computed 1771 * during the layout pass. In a vertical flow this would be the same as the 1772 * clip view height. In a horizontal flow this is the clip view width. 1773 * The access on this variable is package ONLY FOR TESTING. 1774 */ 1775 private double viewportLength; 1776 void setViewportLength(double value) { 1777 this.viewportLength = value; 1778 } 1779 double getViewportLength() { 1780 return viewportLength; 1781 } 1782 1783 /** 1784 * Compute and return the length of the cell for the given index. This is 1785 * called both internally when adjusting by pixels, and also at times 1786 * by PositionMapper (see the getItemSize callback). When called by 1787 * PositionMapper, it is possible that it will be called for some index 1788 * which is not associated with any cell, so we have to do a bit of work 1789 * to use a cell as a helper for computing cell size in some cases. 1790 */ 1791 double getCellLength(int index) { 1792 if (fixedCellSizeEnabled) return getFixedCellSize(); 1793 1794 T cell = getCell(index); 1795 double length = getCellLength(cell); 1796 releaseCell(cell); 1797 return length; 1798 } 1799 1800 /** 1801 */ 1802 double getCellBreadth(int index) { 1803 T cell = getCell(index); 1804 double b = getCellBreadth(cell); 1805 releaseCell(cell); 1806 return b; 1807 } 1808 1809 /** 1810 * Gets the length of a specific cell 1811 */ 1812 double getCellLength(T cell) { 1813 if (cell == null) return 0; 1814 if (fixedCellSizeEnabled) return getFixedCellSize(); 1815 1816 return isVertical() ? 1817 cell.getLayoutBounds().getHeight() 1818 : cell.getLayoutBounds().getWidth(); 1819 } 1820 1821 /** 1822 * Gets the breadth of a specific cell 1823 */ 1824 double getCellBreadth(Cell cell) { 1825 return isVertical() ? 1826 cell.prefWidth(-1) 1827 : cell.prefHeight(-1); 1828 } 1829 1830 /** 1831 * Gets the layout position of the cell along the length axis 1832 */ 1833 double getCellPosition(T cell) { 1834 if (cell == null) return 0; 1835 1836 return isVertical() ? 1837 cell.getLayoutY() 1838 : cell.getLayoutX(); 1839 } 1840 1841 private void positionCell(T cell, double position) { 1842 if (isVertical()) { 1843 cell.setLayoutX(0); 1844 cell.setLayoutY(snapSize(position)); 1845 } else { 1846 cell.setLayoutX(snapSize(position)); 1847 cell.setLayoutY(0); 1848 } 1849 } 1850 1851 private void resizeCellSize(T cell) { 1852 if (cell == null) return; 1853 1854 if (isVertical()) { 1855 double width = Math.max(getMaxPrefBreadth(), getViewportBreadth()); 1856 cell.resize(width, fixedCellSizeEnabled ? getFixedCellSize() : Utils.boundedSize(cell.prefHeight(width), cell.minHeight(width), cell.maxHeight(width))); 1857 } else { 1858 double height = Math.max(getMaxPrefBreadth(), getViewportBreadth()); 1859 cell.resize(fixedCellSizeEnabled ? getFixedCellSize() : Utils.boundedSize(cell.prefWidth(height), cell.minWidth(height), cell.maxWidth(height)), height); 1860 } 1861 } 1862 1863 private List<T> getCells() { 1864 return cells; 1865 } 1866 1867 // Returns last visible cell whose bounds are entirely within the viewport 1868 T getLastVisibleCellWithinViewPort() { 1869 if (cells.isEmpty() || getViewportLength() <= 0) return null; 1870 1871 T cell; 1872 final double max = getViewportLength(); 1873 for (int i = cells.size() - 1; i >= 0; i--) { 1874 cell = cells.get(i); 1875 if (cell.isEmpty()) continue; 1876 1877 final double cellStart = getCellPosition(cell); 1878 final double cellEnd = cellStart + getCellLength(cell); 1879 1880 // we use the magic +2 to allow for a little bit of fuzziness, 1881 // this is to help in situations such as RT-34407 1882 if (cellEnd <= (max + 2)) { 1883 return cell; 1884 } 1885 } 1886 1887 return null; 1888 } 1889 1890 // Returns first visible cell whose bounds are entirely within the viewport 1891 T getFirstVisibleCellWithinViewPort() { 1892 if (cells.isEmpty() || getViewportLength() <= 0) return null; 1893 1894 T cell; 1895 for (int i = 0; i < cells.size(); i++) { 1896 cell = cells.get(i); 1897 if (cell.isEmpty()) continue; 1898 1899 final double cellStart = getCellPosition(cell); 1900 if (cellStart >= 0) { 1901 return cell; 1902 } 1903 } 1904 1905 return null; 1906 } 1907 1908 /** 1909 * Adds all the cells prior to and including the given currentIndex, until 1910 * no more can be added without falling off the flow. The startOffset 1911 * indicates the distance from the leading edge (top) of the viewport to 1912 * the leading edge (top) of the currentIndex. 1913 */ 1914 void addLeadingCells(int currentIndex, double startOffset) { 1915 // The offset will keep track of the distance from the top of the 1916 // viewport to the top of the current index. We will increment it 1917 // as we lay out leading cells. 1918 double offset = startOffset; 1919 // The index is the absolute index of the cell being laid out 1920 int index = currentIndex; 1921 1922 // Offset should really be the bottom of the current index 1923 boolean first = true; // first time in, we just fudge the offset and let 1924 // it be the top of the current index then redefine 1925 // it as the bottom of the current index thereafter 1926 // while we have not yet laid out so many cells that they would fall 1927 // off the flow, we will continue to create and add cells. The 1928 // offset is our indication of whether we can lay out additional 1929 // cells. If the offset is ever < 0, except in the case of the very 1930 // first cell, then we must quit. 1931 T cell = null; 1932 1933 // special case for the position == 1.0, skip adding last invisible cell 1934 if (index == getCellCount() && offset == getViewportLength()) { 1935 index--; 1936 first = false; 1937 } 1938 while (index >= 0 && (offset > 0 || first)) { 1939 cell = getAvailableCell(index); 1940 setCellIndex(cell, index); 1941 resizeCellSize(cell); // resize must be after config 1942 cells.addFirst(cell); 1943 1944 // A little gross but better than alternatives because it reduces 1945 // the number of times we have to update a cell or compute its 1946 // size. The first time into this loop "offset" is actually the 1947 // top of the current index. On all subsequent visits, it is the 1948 // bottom of the current index. 1949 if (first) { 1950 first = false; 1951 } else { 1952 offset -= getCellLength(cell); 1953 } 1954 1955 // Position the cell, and update the maxPrefBreadth variable as we go. 1956 positionCell(cell, offset); 1957 setMaxPrefBreadth(Math.max(getMaxPrefBreadth(), getCellBreadth(cell))); 1958 cell.setVisible(true); 1959 --index; 1960 } 1961 1962 // There are times when after laying out the cells we discover that 1963 // the top of the first cell which represents index 0 is below the top 1964 // of the viewport. In these cases, we have to adjust the cells up 1965 // and reset the mapper position. This might happen when items got 1966 // removed at the top or when the viewport size increased. 1967 if (cells.size() > 0) { 1968 cell = cells.getFirst(); 1969 int firstIndex = getCellIndex(cell); 1970 double firstCellPos = getCellPosition(cell); 1971 if (firstIndex == 0 && firstCellPos > 0) { 1972 setPosition(0.0f); 1973 offset = 0; 1974 for (int i = 0; i < cells.size(); i++) { 1975 cell = cells.get(i); 1976 positionCell(cell, offset); 1977 offset += getCellLength(cell); 1978 } 1979 } 1980 } else { 1981 // reset scrollbar to top, so if the flow sees cells again it starts at the top 1982 vbar.setValue(0); 1983 hbar.setValue(0); 1984 } 1985 } 1986 1987 /** 1988 * Adds all the trailing cells that come <em>after</em> the last index in 1989 * the cells ObservableList. 1990 */ 1991 boolean addTrailingCells(boolean fillEmptyCells) { 1992 // If cells is empty then addLeadingCells bailed for some reason and 1993 // we're hosed, so just punt 1994 if (cells.isEmpty()) return false; 1995 1996 // While we have not yet laid out so many cells that they would fall 1997 // off the flow, so we will continue to create and add cells. When the 1998 // offset becomes greater than the width/height of the flow, then we 1999 // know we cannot add any more cells. 2000 T startCell = cells.getLast(); 2001 double offset = getCellPosition(startCell) + getCellLength(startCell); 2002 int index = getCellIndex(startCell) + 1; 2003 final int cellCount = getCellCount(); 2004 boolean filledWithNonEmpty = index <= cellCount; 2005 2006 final double viewportLength = getViewportLength(); 2007 2008 // Fix for RT-37421, which was a regression caused by RT-36556 2009 if (offset < 0 && !fillEmptyCells) { 2010 return false; 2011 } 2012 2013 // 2014 // RT-36507: viewportLength - offset gives the maximum number of 2015 // additional cells that should ever be able to fit in the viewport if 2016 // every cell had a height of 1. If index ever exceeds this count, 2017 // then offset is not incrementing fast enough, or at all, which means 2018 // there is something wrong with the cell size calculation. 2019 // 2020 final double maxCellCount = viewportLength - offset; 2021 while (offset < viewportLength) { 2022 if (index >= cellCount) { 2023 if (offset < viewportLength) filledWithNonEmpty = false; 2024 if (! fillEmptyCells) return filledWithNonEmpty; 2025 // RT-36507 - return if we've exceeded the maximum 2026 if (index > maxCellCount) { 2027 final PlatformLogger logger = Logging.getControlsLogger(); 2028 if (logger.isLoggable(PlatformLogger.Level.INFO)) { 2029 if (startCell != null) { 2030 logger.info("index exceeds maxCellCount. Check size calculations for " + startCell.getClass()); 2031 } else { 2032 logger.info("index exceeds maxCellCount"); 2033 } 2034 } 2035 return filledWithNonEmpty; 2036 } 2037 } 2038 T cell = getAvailableCell(index); 2039 setCellIndex(cell, index); 2040 resizeCellSize(cell); // resize happens after config! 2041 cells.addLast(cell); 2042 2043 // Position the cell and update the max pref 2044 positionCell(cell, offset); 2045 setMaxPrefBreadth(Math.max(getMaxPrefBreadth(), getCellBreadth(cell))); 2046 2047 offset += getCellLength(cell); 2048 cell.setVisible(true); 2049 ++index; 2050 } 2051 2052 // Discover whether the first cell coincides with index #0. If after 2053 // adding all the trailing cells we find that a) the first cell was 2054 // not index #0 and b) there are trailing cells, then we have a 2055 // problem. We need to shift all the cells down and add leading cells, 2056 // one at a time, until either the very last non-empty cells is aligned 2057 // with the bottom OR we have laid out cell index #0 at the first 2058 // position. 2059 T firstCell = cells.getFirst(); 2060 index = getCellIndex(firstCell); 2061 T lastNonEmptyCell = getLastVisibleCell(); 2062 double start = getCellPosition(firstCell); 2063 double end = getCellPosition(lastNonEmptyCell) + getCellLength(lastNonEmptyCell); 2064 if ((index != 0 || (index == 0 && start < 0)) && fillEmptyCells && 2065 lastNonEmptyCell != null && getCellIndex(lastNonEmptyCell) == cellCount - 1 && end < viewportLength) { 2066 2067 double prospectiveEnd = end; 2068 double distance = viewportLength - end; 2069 while (prospectiveEnd < viewportLength && index != 0 && (-start) < distance) { 2070 index--; 2071 T cell = getAvailableCell(index); 2072 setCellIndex(cell, index); 2073 resizeCellSize(cell); // resize must be after config 2074 cells.addFirst(cell); 2075 double cellLength = getCellLength(cell); 2076 start -= cellLength; 2077 prospectiveEnd += cellLength; 2078 positionCell(cell, start); 2079 setMaxPrefBreadth(Math.max(getMaxPrefBreadth(), getCellBreadth(cell))); 2080 cell.setVisible(true); 2081 } 2082 2083 // The amount by which to translate the cells down 2084 firstCell = cells.getFirst(); 2085 start = getCellPosition(firstCell); 2086 double delta = viewportLength - end; 2087 if (getCellIndex(firstCell) == 0 && delta > (-start)) { 2088 delta = (-start); 2089 } 2090 // Move things 2091 for (int i = 0; i < cells.size(); i++) { 2092 T cell = cells.get(i); 2093 positionCell(cell, getCellPosition(cell) + delta); 2094 } 2095 2096 // Check whether the first cell, subsequent to our adjustments, is 2097 // now index #0 and aligned with the top. If so, change the position 2098 // to be at 0 instead of 1. 2099 start = getCellPosition(firstCell); 2100 if (getCellIndex(firstCell) == 0 && start == 0) { 2101 setPosition(0); 2102 } else if (getPosition() != 1) { 2103 setPosition(1); 2104 } 2105 } 2106 2107 return filledWithNonEmpty; 2108 } 2109 2110 void reconfigureCells() { 2111 needsReconfigureCells = true; 2112 requestLayout(); 2113 } 2114 2115 void recreateCells() { 2116 needsRecreateCells = true; 2117 requestLayout(); 2118 } 2119 2120 void rebuildCells() { 2121 needsRebuildCells = true; 2122 requestLayout(); 2123 } 2124 2125 void requestCellLayout() { 2126 needsCellsLayout = true; 2127 requestLayout(); 2128 } 2129 2130 void setCellDirty(int index) { 2131 dirtyCells.set(index); 2132 requestLayout(); 2133 } 2134 2135 private void startSBReleasedAnimation() { 2136 if (sbTouchTimeline == null) { 2137 /* 2138 ** timeline to leave the scrollbars visible for a short 2139 ** while after a scroll/drag 2140 */ 2141 sbTouchTimeline = new Timeline(); 2142 sbTouchKF1 = new KeyFrame(Duration.millis(0), event -> { 2143 tempVisibility = true; 2144 requestLayout(); 2145 }); 2146 2147 sbTouchKF2 = new KeyFrame(Duration.millis(1000), event -> { 2148 if (touchDetected == false && mouseDown == false) { 2149 tempVisibility = false; 2150 requestLayout(); 2151 } 2152 }); 2153 sbTouchTimeline.getKeyFrames().addAll(sbTouchKF1, sbTouchKF2); 2154 } 2155 sbTouchTimeline.playFromStart(); 2156 } 2157 2158 private void scrollBarOn() { 2159 tempVisibility = true; 2160 requestLayout(); 2161 } 2162 2163 void updateHbar() { 2164 // Bring the clipView.clipX back to 0 if control is vertical or 2165 // the hbar isn't visible (fix for RT-11666) 2166 if (! isVisible() || getScene() == null) return; 2167 2168 if (isVertical()) { 2169 if (hbar.isVisible()) { 2170 clipView.setClipX(hbar.getValue()); 2171 } else { 2172 // all cells are now less than the width of the flow, 2173 // so we should shift the hbar/clip such that 2174 // everything is visible in the viewport. 2175 clipView.setClipX(0); 2176 hbar.setValue(0); 2177 } 2178 } 2179 } 2180 2181 /** 2182 * @return true if bar visibility changed 2183 */ 2184 private boolean computeBarVisiblity() { 2185 if (cells.isEmpty()) { 2186 // In case no cells are set yet, we assume no bars are needed 2187 needLengthBar = false; 2188 needBreadthBar = false; 2189 return true; 2190 } 2191 2192 final boolean isVertical = isVertical(); 2193 boolean barVisibilityChanged = false; 2194 2195 VirtualScrollBar breadthBar = isVertical ? hbar : vbar; 2196 VirtualScrollBar lengthBar = isVertical ? vbar : hbar; 2197 2198 final double viewportBreadth = getViewportBreadth(); 2199 2200 final int cellsSize = cells.size(); 2201 final int cellCount = getCellCount(); 2202 for (int i = 0; i < 2; i++) { 2203 final boolean lengthBarVisible = getPosition() > 0 2204 || cellCount > cellsSize 2205 || (cellCount == cellsSize && (getCellPosition(cells.getLast()) + getCellLength(cells.getLast())) > getViewportLength()) 2206 || (cellCount == cellsSize - 1 && barVisibilityChanged && needBreadthBar); 2207 2208 if (lengthBarVisible ^ needLengthBar) { 2209 needLengthBar = lengthBarVisible; 2210 barVisibilityChanged = true; 2211 } 2212 2213 // second conditional removed for RT-36669. 2214 final boolean breadthBarVisible = (maxPrefBreadth > viewportBreadth);// || (needLengthBar && maxPrefBreadth > (viewportBreadth - lengthBarBreadth)); 2215 if (breadthBarVisible ^ needBreadthBar) { 2216 needBreadthBar = breadthBarVisible; 2217 barVisibilityChanged = true; 2218 } 2219 } 2220 2221 // Start by optimistically deciding whether the length bar and 2222 // breadth bar are needed and adjust the viewport dimensions 2223 // accordingly. If during layout we find that one or the other of the 2224 // bars actually is needed, then we will perform a cleanup pass 2225 2226 if (!Properties.IS_TOUCH_SUPPORTED) { 2227 updateViewportDimensions(); 2228 breadthBar.setVisible(needBreadthBar); 2229 lengthBar.setVisible(needLengthBar); 2230 } else { 2231 breadthBar.setVisible(needBreadthBar && tempVisibility); 2232 lengthBar.setVisible(needLengthBar && tempVisibility); 2233 } 2234 2235 return barVisibilityChanged; 2236 } 2237 2238 private void updateViewportDimensions() { 2239 final boolean isVertical = isVertical(); 2240 final double breadthBarLength = snapSize(isVertical ? hbar.prefHeight(-1) : vbar.prefWidth(-1)); 2241 final double lengthBarBreadth = snapSize(isVertical ? vbar.prefWidth(-1) : hbar.prefHeight(-1)); 2242 2243 setViewportBreadth((isVertical ? getWidth() : getHeight()) - (needLengthBar ? lengthBarBreadth : 0)); 2244 setViewportLength((isVertical ? getHeight() : getWidth()) - (needBreadthBar ? breadthBarLength : 0)); 2245 } 2246 2247 private void initViewport() { 2248 // Initialize the viewportLength and viewportBreadth to match the 2249 // width/height of the flow 2250 final boolean isVertical = isVertical(); 2251 2252 updateViewportDimensions(); 2253 2254 VirtualScrollBar breadthBar = isVertical ? hbar : vbar; 2255 VirtualScrollBar lengthBar = isVertical ? vbar : hbar; 2256 2257 // If there has been a switch between the virtualized bar, then we 2258 // will want to do some stuff TODO. 2259 breadthBar.setVirtual(false); 2260 lengthBar.setVirtual(true); 2261 } 2262 2263 private void updateScrollBarsAndCells(boolean recreate) { 2264 // Assign the hbar and vbar to the breadthBar and lengthBar so as 2265 // to make some subsequent calculations easier. 2266 final boolean isVertical = isVertical(); 2267 VirtualScrollBar breadthBar = isVertical ? hbar : vbar; 2268 VirtualScrollBar lengthBar = isVertical ? vbar : hbar; 2269 2270 // We may have adjusted the viewport length and breadth after the 2271 // layout due to scroll bars becoming visible. So we need to perform 2272 // a follow up pass and resize and shift all the cells to fit the 2273 // viewport. Note that the prospective viewport size is always >= the 2274 // final viewport size, so we don't have to worry about adding 2275 // cells during this cleanup phase. 2276 fitCells(); 2277 2278 // Update cell positions. 2279 // When rebuilding the cells, we add the cells and along the way compute 2280 // the maxPrefBreadth. Based on the computed value, we may add 2281 // the breadth scrollbar which changes viewport length, so we need 2282 // to re-position the cells. 2283 if (!cells.isEmpty()) { 2284 final double currOffset = -computeViewportOffset(getPosition()); 2285 final int currIndex = computeCurrentIndex() - cells.getFirst().getIndex(); 2286 final int size = cells.size(); 2287 2288 // position leading cells 2289 double offset = currOffset; 2290 2291 for (int i = currIndex - 1; i >= 0 && i < size; i--) { 2292 final T cell = cells.get(i); 2293 2294 offset -= getCellLength(cell); 2295 2296 positionCell(cell, offset); 2297 } 2298 2299 // position trailing cells 2300 offset = currOffset; 2301 for (int i = currIndex; i >= 0 && i < size; i++) { 2302 final T cell = cells.get(i); 2303 positionCell(cell, offset); 2304 2305 offset += getCellLength(cell); 2306 } 2307 } 2308 2309 // Toggle visibility on the corner 2310 corner.setVisible(breadthBar.isVisible() && lengthBar.isVisible()); 2311 2312 double sumCellLength = 0; 2313 double flowLength = (isVertical ? getHeight() : getWidth()) - 2314 (breadthBar.isVisible() ? breadthBar.prefHeight(-1) : 0); 2315 2316 final double viewportBreadth = getViewportBreadth(); 2317 final double viewportLength = getViewportLength(); 2318 2319 // Now position and update the scroll bars 2320 if (breadthBar.isVisible()) { 2321 /* 2322 ** Positioning the ScrollBar 2323 */ 2324 if (!Properties.IS_TOUCH_SUPPORTED) { 2325 if (isVertical) { 2326 hbar.resizeRelocate(0, viewportLength, 2327 viewportBreadth, hbar.prefHeight(viewportBreadth)); 2328 } else { 2329 vbar.resizeRelocate(viewportLength, 0, 2330 vbar.prefWidth(viewportBreadth), viewportBreadth); 2331 } 2332 } 2333 else { 2334 if (isVertical) { 2335 hbar.resizeRelocate(0, (viewportLength-hbar.getHeight()), 2336 viewportBreadth, hbar.prefHeight(viewportBreadth)); 2337 } else { 2338 vbar.resizeRelocate((viewportLength-vbar.getWidth()), 0, 2339 vbar.prefWidth(viewportBreadth), viewportBreadth); 2340 } 2341 } 2342 2343 if (getMaxPrefBreadth() != -1) { 2344 double newMax = Math.max(1, getMaxPrefBreadth() - viewportBreadth); 2345 if (newMax != breadthBar.getMax()) { 2346 breadthBar.setMax(newMax); 2347 2348 double breadthBarValue = breadthBar.getValue(); 2349 boolean maxed = breadthBarValue != 0 && newMax == breadthBarValue; 2350 if (maxed || breadthBarValue > newMax) { 2351 breadthBar.setValue(newMax); 2352 } 2353 2354 breadthBar.setVisibleAmount((viewportBreadth / getMaxPrefBreadth()) * newMax); 2355 } 2356 } 2357 } 2358 2359 // determine how many cells there are on screen so that the scrollbar 2360 // thumb can be appropriately sized 2361 if (recreate && (lengthBar.isVisible() || Properties.IS_TOUCH_SUPPORTED)) { 2362 final int cellCount = getCellCount(); 2363 int numCellsVisibleOnScreen = 0; 2364 for (int i = 0, max = cells.size(); i < max; i++) { 2365 T cell = cells.get(i); 2366 if (cell != null && !cell.isEmpty()) { 2367 sumCellLength += (isVertical ? cell.getHeight() : cell.getWidth()); 2368 if (sumCellLength > flowLength) { 2369 break; 2370 } 2371 2372 numCellsVisibleOnScreen++; 2373 } 2374 } 2375 2376 lengthBar.setMax(1); 2377 if (numCellsVisibleOnScreen == 0 && cellCount == 1) { 2378 // special case to help resolve RT-17701 and the case where we have 2379 // only a single row and it is bigger than the viewport 2380 lengthBar.setVisibleAmount(flowLength / sumCellLength); 2381 } else { 2382 lengthBar.setVisibleAmount(numCellsVisibleOnScreen / (float) cellCount); 2383 } 2384 } 2385 2386 if (lengthBar.isVisible()) { 2387 // Fix for RT-11873. If this isn't here, we can have a situation where 2388 // the scrollbar scrolls endlessly. This is possible when the cell 2389 // count grows as the user hits the maximal position on the scrollbar 2390 // (i.e. the list size dynamically grows as the user needs more). 2391 // 2392 // This code was commented out to resolve RT-14477 after testing 2393 // whether RT-11873 can be recreated. It could not, and therefore 2394 // for now this code will remained uncommented until it is deleted 2395 // following further testing. 2396 // if (lengthBar.getValue() == 1.0 && lastCellCount != cellCount) { 2397 // lengthBar.setValue(0.99); 2398 // } 2399 2400 /* 2401 ** Positioning the ScrollBar 2402 */ 2403 if (!Properties.IS_TOUCH_SUPPORTED) { 2404 if (isVertical) { 2405 vbar.resizeRelocate(viewportBreadth, 0, vbar.prefWidth(viewportLength), viewportLength); 2406 } else { 2407 hbar.resizeRelocate(0, viewportBreadth, viewportLength, hbar.prefHeight(-1)); 2408 } 2409 } 2410 else { 2411 if (isVertical) { 2412 vbar.resizeRelocate((viewportBreadth-vbar.getWidth()), 0, vbar.prefWidth(viewportLength), viewportLength); 2413 } else { 2414 hbar.resizeRelocate(0, (viewportBreadth-hbar.getHeight()), viewportLength, hbar.prefHeight(-1)); 2415 } 2416 } 2417 } 2418 2419 if (corner.isVisible()) { 2420 if (!Properties.IS_TOUCH_SUPPORTED) { 2421 corner.resize(vbar.getWidth(), hbar.getHeight()); 2422 corner.relocate(hbar.getLayoutX() + hbar.getWidth(), vbar.getLayoutY() + vbar.getHeight()); 2423 } 2424 else { 2425 corner.resize(vbar.getWidth(), hbar.getHeight()); 2426 corner.relocate(hbar.getLayoutX() + (hbar.getWidth()-vbar.getWidth()), vbar.getLayoutY() + (vbar.getHeight()-hbar.getHeight())); 2427 hbar.resize(hbar.getWidth()-vbar.getWidth(), hbar.getHeight()); 2428 vbar.resize(vbar.getWidth(), vbar.getHeight()-hbar.getHeight()); 2429 } 2430 } 2431 2432 clipView.resize(snapSize(isVertical ? viewportBreadth : viewportLength), 2433 snapSize(isVertical ? viewportLength : viewportBreadth)); 2434 2435 // If the viewportLength becomes large enough that all cells fit 2436 // within the viewport, then we want to update the value to match. 2437 if (getPosition() != lengthBar.getValue()) { 2438 lengthBar.setValue(getPosition()); 2439 } 2440 } 2441 2442 /** 2443 * Adjusts the cells location and size if necessary. The breadths of all 2444 * cells will be adjusted to fit the viewportWidth or maxPrefBreadth, and 2445 * the layout position will be updated if necessary based on index and 2446 * offset. 2447 */ 2448 private void fitCells() { 2449 double size = Math.max(getMaxPrefBreadth(), getViewportBreadth()); 2450 boolean isVertical = isVertical(); 2451 2452 // Note: Do not optimise this loop by pre-calculating the cells size and 2453 // storing that into a int value - this can lead to RT-32828 2454 for (int i = 0; i < cells.size(); i++) { 2455 Cell<?> cell = cells.get(i); 2456 if (isVertical) { 2457 cell.resize(size, cell.prefHeight(size)); 2458 } else { 2459 cell.resize(cell.prefWidth(size), size); 2460 } 2461 } 2462 } 2463 2464 private void cull() { 2465 final double viewportLength = getViewportLength(); 2466 for (int i = cells.size() - 1; i >= 0; i--) { 2467 T cell = cells.get(i); 2468 double cellSize = getCellLength(cell); 2469 double cellStart = getCellPosition(cell); 2470 double cellEnd = cellStart + cellSize; 2471 if (cellStart >= viewportLength || cellEnd < 0) { 2472 addToPile(cells.remove(i)); 2473 } 2474 } 2475 } 2476 2477 /** 2478 * After using the accum cell, it needs to be released! 2479 */ 2480 private void releaseCell(T cell) { 2481 if (accumCell != null && cell == accumCell) { 2482 accumCell.updateIndex(-1); 2483 } 2484 } 2485 2486 /** 2487 * This method is an experts-only method - if the requested index is not 2488 * already an existing visible cell, it will create a cell for the 2489 * given index and insert it into the sheet. From that point on it will be 2490 * unmanaged, and is up to the caller of this method to manage it. 2491 */ 2492 T getPrivateCell(int index) { 2493 T cell = null; 2494 2495 // If there are cells, then we will attempt to get an existing cell 2496 if (! cells.isEmpty()) { 2497 // First check the cells that have already been created and are 2498 // in use. If this call returns a value, then we can use it 2499 cell = getVisibleCell(index); 2500 if (cell != null) { 2501 // Force the underlying text inside the cell to be updated 2502 // so that when the screen reader runs, it will match the 2503 // text in the cell (force updateDisplayedText()) 2504 cell.layout(); 2505 return cell; 2506 } 2507 } 2508 2509 // check the existing sheet children 2510 if (cell == null) { 2511 for (int i = 0; i < sheetChildren.size(); i++) { 2512 T _cell = (T) sheetChildren.get(i); 2513 if (getCellIndex(_cell) == index) { 2514 return _cell; 2515 } 2516 } 2517 } 2518 2519 if (cell == null) { 2520 Callback<VirtualFlow<T>, T> cellFactory = getCellFactory(); 2521 if (cellFactory != null) { 2522 cell = cellFactory.call(this); 2523 } 2524 } 2525 2526 if (cell != null) { 2527 setCellIndex(cell, index); 2528 resizeCellSize(cell); 2529 cell.setVisible(false); 2530 sheetChildren.add(cell); 2531 privateCells.add(cell); 2532 } 2533 2534 return cell; 2535 } 2536 2537 private final List<T> privateCells = new ArrayList<>(); 2538 2539 private void releaseAllPrivateCells() { 2540 sheetChildren.removeAll(privateCells); 2541 } 2542 2543 /** 2544 * Puts the given cell onto the pile. This is called whenever a cell has 2545 * fallen off the flow's start. 2546 */ 2547 private void addToPile(T cell) { 2548 assert cell != null; 2549 pile.addLast(cell); 2550 } 2551 2552 private void cleanPile() { 2553 boolean wasFocusOwner = false; 2554 2555 for (int i = 0, max = pile.size(); i < max; i++) { 2556 T cell = pile.get(i); 2557 wasFocusOwner = wasFocusOwner || doesCellContainFocus(cell); 2558 cell.setVisible(false); 2559 } 2560 2561 // Fix for RT-35876: Rather than have the cells do weird things with 2562 // focus (in particular, have focus jump between cells), we return focus 2563 // to the VirtualFlow itself. 2564 if (wasFocusOwner) { 2565 requestFocus(); 2566 } 2567 } 2568 2569 private boolean doesCellContainFocus(Cell<?> c) { 2570 Scene scene = c.getScene(); 2571 final Node focusOwner = scene == null ? null : scene.getFocusOwner(); 2572 2573 if (focusOwner != null) { 2574 if (c.equals(focusOwner)) { 2575 return true; 2576 } 2577 2578 Parent p = focusOwner.getParent(); 2579 while (p != null && ! (p instanceof VirtualFlow)) { 2580 if (c.equals(p)) { 2581 return true; 2582 } 2583 p = p.getParent(); 2584 } 2585 } 2586 2587 return false; 2588 } 2589 2590 private double getPrefBreadth(double oppDimension) { 2591 double max = getMaxCellWidth(10); 2592 2593 // This primarily exists for the case where we do not want the breadth 2594 // to grow to ensure a golden ratio between width and height (for example, 2595 // when a ListView is used in a ComboBox - the width should not grow 2596 // just because items are being added to the ListView) 2597 if (oppDimension > -1) { 2598 double prefLength = getPrefLength(); 2599 max = Math.max(max, prefLength * GOLDEN_RATIO_MULTIPLIER); 2600 } 2601 2602 return max; 2603 } 2604 2605 private double getPrefLength() { 2606 double sum = 0.0; 2607 int rows = Math.min(10, getCellCount()); 2608 for (int i = 0; i < rows; i++) { 2609 sum += getCellLength(i); 2610 } 2611 return sum; 2612 } 2613 2614 double getMaxCellWidth(int rowsToCount) { 2615 double max = 0.0; 2616 2617 // we always measure at least one row 2618 int rows = Math.max(1, rowsToCount == -1 ? getCellCount() : rowsToCount); 2619 for (int i = 0; i < rows; i++) { 2620 max = Math.max(max, getCellBreadth(i)); 2621 } 2622 return max; 2623 } 2624 2625 // Old PositionMapper 2626 /** 2627 * Given a position value between 0 and 1, compute and return the viewport 2628 * offset from the "current" cell associated with that position value. 2629 * That is, if the return value of this function where used as a translation 2630 * factor for a sheet that contained all the items, then the current 2631 * item would end up positioned correctly. 2632 */ 2633 private double computeViewportOffset(double position) { 2634 double p = com.sun.javafx.util.Utils.clamp(0, position, 1); 2635 double fractionalPosition = p * getCellCount(); 2636 int cellIndex = (int) fractionalPosition; 2637 double fraction = fractionalPosition - cellIndex; 2638 double cellSize = getCellLength(cellIndex); 2639 double pixelOffset = cellSize * fraction; 2640 double viewportOffset = getViewportLength() * p; 2641 return pixelOffset - viewportOffset; 2642 } 2643 2644 private void adjustPositionToIndex(int index) { 2645 int cellCount = getCellCount(); 2646 if (cellCount <= 0) { 2647 setPosition(0.0f); 2648 } else { 2649 setPosition(((double)index) / cellCount); 2650 } 2651 } 2652 2653 /** 2654 * Adjust the position based on a delta of pixels. If negative, then the 2655 * position will be adjusted negatively. If positive, then the position will 2656 * be adjusted positively. If the pixel amount is too great for the range of 2657 * the position, then it will be clamped such that position is always 2658 * strictly between 0 and 1 2659 */ 2660 private void adjustByPixelAmount(double numPixels) { 2661 if (numPixels == 0) return; 2662 // Starting from the current cell, we move in the direction indicated 2663 // by numPixels one cell at a team. For each cell, we discover how many 2664 // pixels the "position" line would move within that cell, and adjust 2665 // our count of numPixels accordingly. When we come to the "final" cell, 2666 // then we can take the remaining number of pixels and multiply it by 2667 // the "travel rate" of "p" within that cell to get the delta. Add 2668 // the delta to "p" to get position. 2669 2670 // get some basic info about the list and the current cell 2671 boolean forward = numPixels > 0; 2672 int cellCount = getCellCount(); 2673 double fractionalPosition = getPosition() * cellCount; 2674 int cellIndex = (int) fractionalPosition; 2675 if (forward && cellIndex == cellCount) return; 2676 double cellSize = getCellLength(cellIndex); 2677 double fraction = fractionalPosition - cellIndex; 2678 double pixelOffset = cellSize * fraction; 2679 2680 // compute the percentage of "position" that represents each cell 2681 double cellPercent = 1.0 / cellCount; 2682 2683 // To help simplify the algorithm, we pretend as though the current 2684 // position is at the beginning of the current cell. This reduces some 2685 // of the corner cases and provides a simpler algorithm without adding 2686 // any overhead to performance. 2687 double start = computeOffsetForCell(cellIndex); 2688 double end = cellSize + computeOffsetForCell(cellIndex + 1); 2689 2690 // We need to discover the distance that the fictional "position line" 2691 // would travel within this cell, from its current position to the end. 2692 double remaining = end - start; 2693 2694 // Keep track of the number of pixels left to travel 2695 double n = forward ? 2696 numPixels + pixelOffset - (getViewportLength() * getPosition()) - start 2697 : -numPixels + end - (pixelOffset - (getViewportLength() * getPosition())); 2698 2699 // "p" represents the most recent value for position. This is always 2700 // based on the edge between two cells, except at the very end of the 2701 // algorithm where it is added to the computed "p" offset for the final 2702 // value of Position. 2703 double p = cellPercent * cellIndex; 2704 2705 // Loop over the cells one at a time until either we reach the end of 2706 // the cells, or we find that the "n" will fall within the cell we're on 2707 while (n > remaining && ((forward && cellIndex < cellCount - 1) || (! forward && cellIndex > 0))) { 2708 if (forward) cellIndex++; else cellIndex--; 2709 n -= remaining; 2710 cellSize = getCellLength(cellIndex); 2711 start = computeOffsetForCell(cellIndex); 2712 end = cellSize + computeOffsetForCell(cellIndex + 1); 2713 remaining = end - start; 2714 p = cellPercent * cellIndex; 2715 } 2716 2717 // if remaining is < n, then we must have hit an end, so as a 2718 // fast path, we can just set position to 1.0 or 0.0 and return 2719 // because we know we hit the end 2720 if (n > remaining) { 2721 setPosition(forward ? 1.0f : 0.0f); 2722 } else if (forward) { 2723 double rate = cellPercent / Math.abs(end - start); 2724 setPosition(p + (rate * n)); 2725 } else { 2726 double rate = cellPercent / Math.abs(end - start); 2727 setPosition((p + cellPercent) - (rate * n)); 2728 } 2729 } 2730 2731 private int computeCurrentIndex() { 2732 return (int) (getPosition() * getCellCount()); 2733 } 2734 2735 /** 2736 * Given an item index, this function will compute and return the viewport 2737 * offset from the beginning of the specified item. Notice that because each 2738 * item has the same percentage of the position dedicated to it, and since 2739 * we are measuring from the start of each item, this is a very simple 2740 * calculation. 2741 */ 2742 private double computeOffsetForCell(int itemIndex) { 2743 double cellCount = getCellCount(); 2744 double p = com.sun.javafx.util.Utils.clamp(0, itemIndex, cellCount) / cellCount; 2745 return -(getViewportLength() * p); 2746 } 2747 2748 // /** 2749 // * Adjust the position based on a chunk of pixels. The position is based 2750 // * on the start of the scrollbar position. 2751 // */ 2752 // private void adjustByPixelChunk(double numPixels) { 2753 // setPosition(0); 2754 // adjustByPixelAmount(numPixels); 2755 // } 2756 // end of old PositionMapper code 2757 2758 2759 2760 2761 /*************************************************************************** 2762 * * 2763 * Support classes * 2764 * * 2765 **************************************************************************/ 2766 2767 /** 2768 * A simple extension to Region that ensures that anything wanting to flow 2769 * outside of the bounds of the Region is clipped. 2770 */ 2771 static class ClippedContainer extends Region { 2772 2773 /** 2774 * The Node which is embedded within this {@code ClipView}. 2775 */ 2776 private Node node; 2777 public Node getNode() { return this.node; } 2778 public void setNode(Node n) { 2779 this.node = n; 2780 2781 getChildren().clear(); 2782 getChildren().add(node); 2783 } 2784 2785 public void setClipX(double clipX) { 2786 setLayoutX(-clipX); 2787 clipRect.setLayoutX(clipX); 2788 } 2789 2790 public void setClipY(double clipY) { 2791 setLayoutY(-clipY); 2792 clipRect.setLayoutY(clipY); 2793 } 2794 2795 private final Rectangle clipRect; 2796 2797 public ClippedContainer(final VirtualFlow<?> flow) { 2798 if (flow == null) { 2799 throw new IllegalArgumentException("VirtualFlow can not be null"); 2800 } 2801 2802 getStyleClass().add("clipped-container"); 2803 2804 // clipping 2805 clipRect = new Rectangle(); 2806 clipRect.setSmooth(false); 2807 setClip(clipRect); 2808 // --- clipping 2809 2810 super.widthProperty().addListener(valueModel -> { 2811 clipRect.setWidth(getWidth()); 2812 }); 2813 super.heightProperty().addListener(valueModel -> { 2814 clipRect.setHeight(getHeight()); 2815 }); 2816 } 2817 } 2818 2819 /** 2820 * A List-like implementation that is exceedingly efficient for the purposes 2821 * of the VirtualFlow. Typically there is not much variance in the number of 2822 * cells -- it is always some reasonably consistent number. Yet for efficiency 2823 * in code, we like to use a linked list implementation so as to append to 2824 * start or append to end. However, at times when we need to iterate, LinkedList 2825 * is expensive computationally as well as requiring the construction of 2826 * temporary iterators. 2827 * <p> 2828 * This linked list like implementation is done using an array. It begins by 2829 * putting the first item in the center of the allocated array, and then grows 2830 * outward (either towards the first or last of the array depending on whether 2831 * we are inserting at the head or tail). It maintains an index to the start 2832 * and end of the array, so that it can efficiently expose iteration. 2833 * <p> 2834 * This class is package private solely for the sake of testing. 2835 */ 2836 static class ArrayLinkedList<T> extends AbstractList<T> { 2837 /** 2838 * The array list backing this class. We default the size of the array 2839 * list to be fairly large so as not to require resizing during normal 2840 * use, and since that many ArrayLinkedLists won't be created it isn't 2841 * very painful to do so. 2842 */ 2843 private final ArrayList<T> array; 2844 2845 private int firstIndex = -1; 2846 private int lastIndex = -1; 2847 2848 public ArrayLinkedList() { 2849 array = new ArrayList<T>(50); 2850 2851 for (int i = 0; i < 50; i++) { 2852 array.add(null); 2853 } 2854 } 2855 2856 public T getFirst() { 2857 return firstIndex == -1 ? null : array.get(firstIndex); 2858 } 2859 2860 public T getLast() { 2861 return lastIndex == -1 ? null : array.get(lastIndex); 2862 } 2863 2864 public void addFirst(T cell) { 2865 // if firstIndex == -1 then that means this is the first item in the 2866 // list and we need to initialize firstIndex and lastIndex 2867 if (firstIndex == -1) { 2868 firstIndex = lastIndex = array.size() / 2; 2869 array.set(firstIndex, cell); 2870 } else if (firstIndex == 0) { 2871 // we're already at the head of the array, so insert at position 2872 // 0 and then increment the lastIndex to compensate 2873 array.add(0, cell); 2874 lastIndex++; 2875 } else { 2876 // we're not yet at the head of the array, so insert at the 2877 // firstIndex - 1 position and decrement first position 2878 array.set(--firstIndex, cell); 2879 } 2880 } 2881 2882 public void addLast(T cell) { 2883 // if lastIndex == -1 then that means this is the first item in the 2884 // list and we need to initialize the firstIndex and lastIndex 2885 if (firstIndex == -1) { 2886 firstIndex = lastIndex = array.size() / 2; 2887 array.set(lastIndex, cell); 2888 } else if (lastIndex == array.size() - 1) { 2889 // we're at the end of the array so need to "add" so as to force 2890 // the array to be expanded in size 2891 array.add(++lastIndex, cell); 2892 } else { 2893 array.set(++lastIndex, cell); 2894 } 2895 } 2896 2897 public int size() { 2898 return firstIndex == -1 ? 0 : lastIndex - firstIndex + 1; 2899 } 2900 2901 public boolean isEmpty() { 2902 return firstIndex == -1; 2903 } 2904 2905 public T get(int index) { 2906 if (index > (lastIndex - firstIndex) || index < 0) { 2907 // Commented out exception due to RT-29111 2908 // throw new java.lang.ArrayIndexOutOfBoundsException(); 2909 return null; 2910 } 2911 2912 return array.get(firstIndex + index); 2913 } 2914 2915 public void clear() { 2916 for (int i = 0; i < array.size(); i++) { 2917 array.set(i, null); 2918 } 2919 2920 firstIndex = lastIndex = -1; 2921 } 2922 2923 public T removeFirst() { 2924 if (isEmpty()) return null; 2925 return remove(0); 2926 } 2927 2928 public T removeLast() { 2929 if (isEmpty()) return null; 2930 return remove(lastIndex - firstIndex); 2931 } 2932 2933 public T remove(int index) { 2934 if (index > lastIndex - firstIndex || index < 0) { 2935 throw new ArrayIndexOutOfBoundsException(); 2936 } 2937 2938 // if the index == 0, then we're removing the first 2939 // item and can simply set it to null in the array and increment 2940 // the firstIndex unless there is only one item, in which case 2941 // we have to also set first & last index to -1. 2942 if (index == 0) { 2943 T cell = array.get(firstIndex); 2944 array.set(firstIndex, null); 2945 if (firstIndex == lastIndex) { 2946 firstIndex = lastIndex = -1; 2947 } else { 2948 firstIndex++; 2949 } 2950 return cell; 2951 } else if (index == lastIndex - firstIndex) { 2952 // if the index == lastIndex - firstIndex, then we're removing the 2953 // last item and can simply set it to null in the array and 2954 // decrement the lastIndex 2955 T cell = array.get(lastIndex); 2956 array.set(lastIndex--, null); 2957 return cell; 2958 } else { 2959 // if the index is somewhere in between, then we have to remove the 2960 // item and decrement the lastIndex 2961 T cell = array.get(firstIndex + index); 2962 array.set(firstIndex + index, null); 2963 for (int i = (firstIndex + index + 1); i <= lastIndex; i++) { 2964 array.set(i - 1, array.get(i)); 2965 } 2966 array.set(lastIndex--, null); 2967 return cell; 2968 } 2969 } 2970 } 2971 }