bundles/org.eclipse.swt.win32.win32.x86_64/src/org/eclipse/swt/dnd/TreeDropTargetEffect.java

   1 /*******************************************************************************
   2  * Copyright (c) 2007, 2012 IBM Corporation and others.
   3  *
   4  * This program and the accompanying materials
   5  * are made available under the terms of the Eclipse Public License 2.0
   6  * which accompanies this distribution, and is available at
   7  * https://www.eclipse.org/legal/epl-2.0/
   8  *
   9  * SPDX-License-Identifier: EPL-2.0
  10  *
  11  * Contributors:
  12  *     IBM Corporation - initial API and implementation
  13  *******************************************************************************/
  14 package org.eclipse.swt.dnd;
  15
  16 import org.eclipse.swt.*;
  17 import org.eclipse.swt.graphics.*;
  18 import org.eclipse.swt.internal.*;
  19 import org.eclipse.swt.internal.win32.*;
  20 import org.eclipse.swt.widgets.*;
  21
  22 /**
  23  * This class provides a default drag under effect (eg. select, insert, scroll and expand)
  24  * when a drag occurs over a <code>Tree</code>.
  25  *
  26  * <p>Classes that wish to provide their own drag under effect for a <code>Tree</code>
  27  * can extend the <code>TreeDropTargetEffect</code> class and override any applicable methods
  28  * in <code>TreeDropTargetEffect</code> to display their own drag under effect.</p>
  29  *
  30  * Subclasses that override any methods of this class must call the corresponding
  31  * <code>super</code> method to get the default drag under effect implementation.
  32  *
  33  * <p>The feedback value is either one of the FEEDBACK constants defined in
  34  * class <code>DND</code> which is applicable to instances of this class,
  35  * or it must be built by <em>bitwise OR</em>'ing together
  36  * (that is, using the <code>int</code> "|" operator) two or more
  37  * of those <code>DND</code> effect constants.
  38  * </p>
  39  * <dl>
  40  * <dt><b>Feedback:</b></dt>
  41  * <dd>FEEDBACK_SELECT, FEEDBACK_INSERT_BEFORE, FEEDBACK_INSERT_AFTER, FEEDBACK_EXPAND, FEEDBACK_SCROLL</dd>
  42  * </dl>
  43  * <p>
  44  * Note: Only one of the styles FEEDBACK_SELECT, FEEDBACK_INSERT_BEFORE or
  45  * FEEDBACK_INSERT_AFTER may be specified.
  46  * </p>
  47  *
  48  * @see DropTargetAdapter
  49  * @see DropTargetEvent
  50  * @see <a href="http://www.eclipse.org/swt/">Sample code and further information</a>
  51  *
  52  * @since 3.3
  53  */
  54 public class TreeDropTargetEffect extends DropTargetEffect {
  55         static final int SCROLL_HYSTERESIS = 200; // milli seconds
  56         static final int EXPAND_HYSTERESIS = 1000; // milli seconds
  57
  58         long dropIndex;
  59         long scrollIndex;
  60         long scrollBeginTime;
  61         long expandIndex;
  62         long expandBeginTime;
  63         TreeItem insertItem;
  64         boolean insertBefore;
  65
  66         /**
  67          * Creates a new <code>TreeDropTargetEffect</code> to handle the drag under effect on the specified
  68          * <code>Tree</code>.
  69          *
  70          * @param tree the <code>Tree</code> over which the user positions the cursor to drop the data
  71          */
  72         public TreeDropTargetEffect(Tree tree) {
  73                 super(tree);
  74         }
  75
  76         int checkEffect(int effect) {
  77                 // Some effects are mutually exclusive.  Make sure that only one of the mutually exclusive effects has been specified.
  78                 if ((effect & DND.FEEDBACK_SELECT) != 0) effect = effect & ~DND.FEEDBACK_INSERT_AFTER & ~DND.FEEDBACK_INSERT_BEFORE;
  79                 if ((effect & DND.FEEDBACK_INSERT_BEFORE) != 0) effect = effect & ~DND.FEEDBACK_INSERT_AFTER;
  80                 return effect;
  81         }
  82
  83         /**
  84          * This implementation of <code>dragEnter</code> provides a default drag under effect
  85          * for the feedback specified in <code>event.feedback</code>.
  86          *
  87          * For additional information see <code>DropTargetAdapter.dragEnter</code>.
  88          *
  89          * Subclasses that override this method should call <code>super.dragEnter(event)</code>
  90          * to get the default drag under effect implementation.
  91          *
  92          * @param event  the information associated with the drag enter event
  93          *
  94          * @see DropTargetAdapter
  95          * @see DropTargetEvent
  96          */
  97         @Override
  98         public void dragEnter(DropTargetEvent event) {
  99                 dropIndex = -1;
 100                 insertItem = null;
 101                 expandBeginTime = 0;
 102                 expandIndex = -1;
 103                 scrollBeginTime = 0;
 104                 scrollIndex = -1;
 105         }
 106
 107         /**
 108          * This implementation of <code>dragLeave</code> provides a default drag under effect
 109          * for the feedback specified in <code>event.feedback</code>.
 110          *
 111          * For additional information see <code>DropTargetAdapter.dragLeave</code>.
 112          *
 113          * Subclasses that override this method should call <code>super.dragLeave(event)</code>
 114          * to get the default drag under effect implementation.
 115          *
 116          * @param event  the information associated with the drag leave event
 117          *
 118          * @see DropTargetAdapter
 119          * @see DropTargetEvent
 120          */
 121         @Override
 122         public void dragLeave(DropTargetEvent event) {
 123                 Tree tree = (Tree) control;
 124                 long handle = tree.handle;
 125                 if (dropIndex != -1) {
 126                         TVITEM tvItem = new TVITEM ();
 127                         tvItem.hItem = dropIndex;
 128                         tvItem.mask = OS.TVIF_STATE;
 129                         tvItem.stateMask = OS.TVIS_DROPHILITED;
 130                         tvItem.state = 0;
 131                         OS.SendMessage (handle, OS.TVM_SETITEM, 0, tvItem);
 132                         dropIndex = -1;
 133                 }
 134                 if (insertItem != null) {
 135                         tree.setInsertMark(null, false);
 136                         insertItem = null;
 137                 }
 138                 expandBeginTime = 0;
 139                 expandIndex = -1;
 140                 scrollBeginTime = 0;
 141                 scrollIndex = -1;
 142         }
 143
 144         /**
 145          * This implementation of <code>dragOver</code> provides a default drag under effect
 146          * for the feedback specified in <code>event.feedback</code>.
 147          *
 148          * For additional information see <code>DropTargetAdapter.dragOver</code>.
 149          *
 150          * Subclasses that override this method should call <code>super.dragOver(event)</code>
 151          * to get the default drag under effect implementation.
 152          *
 153          * @param event  the information associated with the drag over event
 154          *
 155          * @see DropTargetAdapter
 156          * @see DropTargetEvent
 157          * @see DND#FEEDBACK_SELECT
 158          * @see DND#FEEDBACK_INSERT_BEFORE
 159          * @see DND#FEEDBACK_INSERT_AFTER
 160          * @see DND#FEEDBACK_SCROLL
 161          */
 162         @Override
 163         public void dragOver(DropTargetEvent event) {
 164                 Tree tree = (Tree) getControl();
 165                 int effect = checkEffect(event.feedback);
 166                 long handle = tree.handle;
 167                 Point coordinates = new Point(event.x, event.y);
 168                 coordinates = DPIUtil.autoScaleUp(tree.toControl(coordinates)); // To Pixels
 169                 TVHITTESTINFO lpht = new TVHITTESTINFO ();
 170                 lpht.x = coordinates.x;
 171                 lpht.y = coordinates.y;
 172                 OS.SendMessage (handle, OS.TVM_HITTEST, 0, lpht);
 173                 long hItem = lpht.hItem;
 174                 if ((effect & DND.FEEDBACK_SCROLL) == 0) {
 175                         scrollBeginTime = 0;
 176                         scrollIndex = -1;
 177                 } else {
 178                         if (hItem != -1 && scrollIndex == hItem && scrollBeginTime != 0) {
 179                                 if (System.currentTimeMillis() >= scrollBeginTime) {
 180                                         long topItem = OS.SendMessage(handle, OS.TVM_GETNEXTITEM, OS.TVGN_FIRSTVISIBLE, 0);
 181                                         long nextItem = OS.SendMessage(handle, OS.TVM_GETNEXTITEM, hItem == topItem ? OS.TVGN_PREVIOUSVISIBLE : OS.TVGN_NEXTVISIBLE, hItem);
 182                                         boolean scroll = true;
 183                                         if (hItem == topItem) {
 184                                                 scroll = nextItem != 0;
 185                                         } else {
 186                                                 RECT itemRect = new RECT ();
 187                                                 if (OS.TreeView_GetItemRect (handle, nextItem, itemRect, true)) {
 188                                                         RECT rect = new RECT ();
 189                                                         OS.GetClientRect (handle, rect);
 190                                                         POINT pt = new POINT ();
 191                                                         pt.x = itemRect.left;
 192                                                         pt.y = itemRect.top;
 193                                                         if (OS.PtInRect (rect, pt)) {
 194                                                                 pt.y = itemRect.bottom;
 195                                                                 if (OS.PtInRect (rect, pt)) scroll = false;
 196                                                         }
 197                                                 }
 198                                         }
 199                                         if (scroll) {
 200                                                 OS.SendMessage (handle, OS.TVM_ENSUREVISIBLE, 0, nextItem);
 201                                                 tree.redraw();
 202                                         }
 203                                         scrollBeginTime = 0;
 204                                         scrollIndex = -1;
 205                                 }
 206                         } else {
 207                                 scrollBeginTime = System.currentTimeMillis() + SCROLL_HYSTERESIS;
 208                                 scrollIndex = hItem;
 209                         }
 210                 }
 211                 if ((effect & DND.FEEDBACK_EXPAND) == 0) {
 212                         expandBeginTime = 0;
 213                         expandIndex = -1;
 214                 } else {
 215                         if (hItem != -1 && expandIndex == hItem && expandBeginTime != 0) {
 216                                 if (System.currentTimeMillis() >= expandBeginTime) {
 217                                         if (OS.SendMessage (handle, OS.TVM_GETNEXTITEM, OS.TVGN_CHILD, hItem) != 0) {
 218                                                 TreeItem item = (TreeItem)tree.getDisplay().findWidget(tree.handle, hItem);
 219                                                 if (item != null && !item.getExpanded()) {
 220                                                         item.setExpanded(true);
 221                                                         tree.redraw();
 222                                                         Event expandEvent = new Event ();
 223                                                         expandEvent.item = item;
 224                                                         tree.notifyListeners(SWT.Expand, expandEvent);
 225                                                 }
 226                                         }
 227                                         expandBeginTime = 0;
 228                                         expandIndex = -1;
 229                                 }
 230                         } else {
 231                                 expandBeginTime = System.currentTimeMillis() + EXPAND_HYSTERESIS;
 232                                 expandIndex = hItem;
 233                         }
 234                 }
 235                 if (dropIndex != -1 && (dropIndex != hItem || (effect & DND.FEEDBACK_SELECT) == 0)) {
 236                         TVITEM tvItem = new TVITEM ();
 237                         tvItem.hItem = dropIndex;
 238                         tvItem.mask = OS.TVIF_STATE;
 239                         tvItem.stateMask = OS.TVIS_DROPHILITED;
 240                         tvItem.state = 0;
 241                         OS.SendMessage (handle, OS.TVM_SETITEM, 0, tvItem);
 242                         dropIndex = -1;
 243                 }
 244                 if (hItem != -1 && hItem != dropIndex && (effect & DND.FEEDBACK_SELECT) != 0) {
 245                         TVITEM tvItem = new TVITEM ();
 246                         tvItem.hItem = hItem;
 247                         tvItem.mask = OS.TVIF_STATE;
 248                         tvItem.stateMask = OS.TVIS_DROPHILITED;
 249                         tvItem.state = OS.TVIS_DROPHILITED;
 250                         OS.SendMessage (handle, OS.TVM_SETITEM, 0, tvItem);
 251                         dropIndex = hItem;
 252                 }
 253                 if ((effect & DND.FEEDBACK_INSERT_BEFORE) != 0 || (effect & DND.FEEDBACK_INSERT_AFTER) != 0) {
 254                         boolean before = (effect & DND.FEEDBACK_INSERT_BEFORE) != 0;
 255                         /*
 256                         * Bug in Windows.  When TVM_SETINSERTMARK is used to set
 257                         * an insert mark for a tree and an item is expanded or
 258                         * collapsed near the insert mark, the tree does not redraw
 259                         * the insert mark properly.  The fix is to hide and show
 260                         * the insert mark whenever an item is expanded or collapsed.
 261                         * Since the insert mark can not be queried from the tree,
 262                         * use the Tree API rather than calling the OS directly.
 263                         */
 264                         TreeItem item = (TreeItem)tree.getDisplay().findWidget(tree.handle, hItem);
 265                         if (item != null) {
 266                                 if (item != insertItem || before != insertBefore) {
 267                                         tree.setInsertMark(item, before);
 268                                 }
 269                                 insertItem = item;
 270                                 insertBefore = before;
 271                         } else {
 272                                 if (insertItem != null) {
 273                                         tree.setInsertMark(null, false);
 274                                 }
 275                                 insertItem = null;
 276                         }
 277                 } else {
 278                         if (insertItem != null) {
 279                                 tree.setInsertMark(null, false);
 280                         }
 281                         insertItem = null;
 282                 }
 283         }
 284 }