Mercurial > projects > dwt-mac
diff dwt/dnd/TableDropTargetEffect.d @ 0:380af2bdd8e5
Upload of whole dwt tree
author | Jacob Carlborg <doob@me.com> <jacob.carlborg@gmail.com> |
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date | Sat, 09 Aug 2008 17:00:02 +0200 |
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children | 1a8b3cb347e0 |
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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/dwt/dnd/TableDropTargetEffect.d Sat Aug 09 17:00:02 2008 +0200 @@ -0,0 +1,196 @@ +/******************************************************************************* + * Copyright (c) 2000, 2007 IBM Corporation and others. + * All rights reserved. This program and the accompanying materials + * are made available under the terms of the Eclipse Public License v1.0 + * which accompanies this distribution, and is available at + * http://www.eclipse.org/legal/epl-v10.html + * + * Contributors: + * IBM Corporation - initial API and implementation + *******************************************************************************/ +module dwt.dnd; + +import dwt.DWT; +import dwt.graphics.*; +import dwt.internal.Callback; +import dwt.internal.carbon.DataBrowserCallbacks; +import dwt.internal.carbon.OS; +import dwt.widgets.*; + +/** + * This class provides a default drag under effect (eg. select, insert and scroll) + * when a drag occurs over a <code>Table</code>. + * + * <p>Classes that wish to provide their own drag under effect for a <code>Table</code> + * can extend the <code>TableDropTargetEffect</code> and override any applicable methods + * in <code>TableDropTargetEffect</code> to display their own drag under effect.</p> + * + * Subclasses that override any methods of this class must call the corresponding + * <code>super</code> method to get the default drag under effect implementation. + * + * <p>The feedback value is either one of the FEEDBACK constants defined in + * class <code>DND</code> which is applicable to instances of this class, + * or it must be built by <em>bitwise OR</em>'ing together + * (that is, using the <code>int</code> "|" operator) two or more + * of those <code>DND</code> effect constants. + * </p> + * <p> + * <dl> + * <dt><b>Feedback:</b></dt> + * <dd>FEEDBACK_SELECT, FEEDBACK_SCROLL</dd> + * </dl> + * </p> + * + * @see DropTargetAdapter + * @see DropTargetEvent + * + * @since 3.3 + */ +public class TableDropTargetEffect : DropTargetEffect { + static final int SCROLL_HYSTERESIS = 150; // milli seconds + + TableItem scrollItem; + long scrollBeginTime; + DataBrowserCallbacks callbacks = null; + + static Callback AcceptDragProc; + static { + AcceptDragProc = new Callback(TableDropTargetEffect.class, "AcceptDragProc", 5); //$NON-NLS-1$ + int acceptDragProc = AcceptDragProc.getAddress(); + if (acceptDragProc is 0) DWT.error(DWT.ERROR_NO_MORE_CALLBACKS); + } + + static int AcceptDragProc(int theControl, int itemID, int property, int theRect, int theDrag) { + DropTarget target = FindDropTarget(theControl, theDrag); + if (target is null) return 0; + return (target.feedback & DND.FEEDBACK_SELECT) !is 0 ? 1 : 0; + } + + static DropTarget FindDropTarget(int theControl, int theDrag) { + if (theControl is 0) return null; + Display display = Display.findDisplay(Thread.currentThread()); + if (display is null || display.isDisposed()) return null; + Widget widget = display.findWidget(theControl); + if (widget is null) return null; + return (DropTarget)widget.getData(DND.DROP_TARGET_KEY); + } + + /** + * Creates a new <code>TableDropTargetEffect</code> to handle the drag under effect on the specified + * <code>Table</code>. + * + * @param table the <code>Table</code> over which the user positions the cursor to drop the data + */ + public TableDropTargetEffect(Table table) { + super(table); + } + + int checkEffect(int effect) { + // Some effects are mutually exclusive. Make sure that only one of the mutually exclusive effects has been specified. + if ((effect & DND.FEEDBACK_SELECT) !is 0) effect = effect & ~DND.FEEDBACK_INSERT_AFTER & ~DND.FEEDBACK_INSERT_BEFORE; + if ((effect & DND.FEEDBACK_INSERT_BEFORE) !is 0) effect = effect & ~DND.FEEDBACK_INSERT_AFTER; + return effect; + } + + /** + * This implementation of <code>dragEnter</code> provides a default drag under effect + * for the feedback specified in <code>event.feedback</code>. + * + * For additional information see <code>DropTargetAdapter.dragEnter</code>. + * + * Subclasses that override this method should call <code>super.dragEnter(event)</code> + * to get the default drag under effect implementation. + * + * @param event the information associated with the drag enter event + * + * @see DropTargetAdapter + * @see DropTargetEvent + */ + public void dragEnter(DropTargetEvent event) { + if (callbacks is null) { + Table table = (Table) control; + DataBrowserCallbacks callbacks = new DataBrowserCallbacks (); + OS.GetDataBrowserCallbacks (table.handle, callbacks); + callbacks.v1_acceptDragCallback = AcceptDragProc.getAddress(); + OS.SetDataBrowserCallbacks(table.handle, callbacks); + } + scrollBeginTime = 0; + scrollItem = null; + } + + /** + * This implementation of <code>dragLeave</code> provides a default drag under effect + * for the feedback specified in <code>event.feedback</code>. + * + * For additional information see <code>DropTargetAdapter.dragLeave</code>. + * + * Subclasses that override this method should call <code>super.dragLeave(event)</code> + * to get the default drag under effect implementation. + * + * @param event the information associated with the drag leave event + * + * @see DropTargetAdapter + * @see DropTargetEvent + */ + public void dragLeave(DropTargetEvent event) { + scrollBeginTime = 0; + scrollItem = null; + } + + /** + * This implementation of <code>dragOver</code> provides a default drag under effect + * for the feedback specified in <code>event.feedback</code>. The class description + * lists the FEEDBACK constants that are applicable to the class. + * + * For additional information see <code>DropTargetAdapter.dragOver</code>. + * + * Subclasses that override this method should call <code>super.dragOver(event)</code> + * to get the default drag under effect implementation. + * + * @param event the information associated with the drag over event + * + * @see DropTargetAdapter + * @see DropTargetEvent + * @see DND#FEEDBACK_SELECT + * @see DND#FEEDBACK_SCROLL + */ + public void dragOver(DropTargetEvent event) { + Table table = (Table) control; + int effect = checkEffect(event.feedback); + + TableItem item = (TableItem)getItem(table, event.x, event.y); + + if ((effect & DND.FEEDBACK_SCROLL) is 0) { + scrollBeginTime = 0; + scrollItem = null; + } else { + if (item !is null && item.opEquals(scrollItem) && scrollBeginTime !is 0) { + if (System.currentTimeMillis() >= scrollBeginTime) { + Rectangle area = table.getClientArea(); + int headerHeight = table.getHeaderHeight(); + int itemHeight= table.getItemHeight(); + Point pt = new Point(event.x, event.y); + pt = table.getDisplay().map(null, table, pt); + TableItem nextItem = null; + if (pt.y < area.y + headerHeight + 2 * itemHeight) { + int index = Math.max(0, table.indexOf(item)-1); + nextItem = table.getItem(index); + } + if (pt.y > area.y + area.height - 2 * itemHeight) { + int index = Math.min(table.getItemCount()-1, table.indexOf(item)+1); + nextItem = table.getItem(index); + } + if (nextItem !is null) table.showItem(nextItem); + scrollBeginTime = 0; + scrollItem = null; + } + } else { + scrollBeginTime = System.currentTimeMillis() + SCROLL_HYSTERESIS; + scrollItem = item; + } + } + + // store current effect for selection feedback + ((DropTarget)event.widget).feedback = effect; + } +}