org.eclipse.osbp.vaadin.addons.absolutelayout/src/org/eclipse/osbp/vaadin/addons/absolutelayout/client/OAlignmentManager.java - gerrit/osbp/org.eclipse.osbp.vaadin.addons - Git at Google

 /**
  *
  * Copyright (c) 2011, 2016 - Loetz GmbH&Co.KG (69115 Heidelberg, Germany)
  *
  * 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:
  * Florian Pirchner <florian.pirchner@gmail.com> - Initial implementation
  */
 package org.eclipse.osbp.vaadin.addons.absolutelayout.client;

 import java.util.HashSet;
 import java.util.Map;
 import java.util.Set;

 import org.eclipse.osbp.vaadin.addons.absolutelayout.client.OAlignmentOverlay.AlignmentsLocation;

 import com.google.gwt.core.client.Scheduler;
 import com.google.gwt.dom.client.Element;
 import com.google.gwt.dom.client.Style.Unit;
 import com.google.gwt.user.client.ui.Widget;
 import com.vaadin.client.ui.dd.VDragEvent;

 import fi.jasoft.dragdroplayouts.client.ui.Constants;

 // TODO: Auto-generated Javadoc
 /**
  * This class handles alignments for drag and drop and resize operations.
  */
 public class OAlignmentManager {

 	/** The manager. */
 	private static OAlignmentManager manager;

 	/** The alignments. */
 	protected Set<OAlignmentOverlay> alignments = new HashSet<>();

 	/** The snap. */
 	protected int snap = 4;

 	/** The layout. */
 	private OAbsoluteLayoutWidget layout;

 	/** The snap info. */
 	private OAlignmentSnapInfo snapInfo;

 	/** The resizing widget. */
 	private OAbsoluteLayoutWidget.ResizableAbsoluteWrapper resizingWidget;

 	/** The resizing overlay. */
 	private Element resizingOverlay;

 	/** The resize location. */
 	private OResizeLocation resizeLocation;

 	/** The use alignments. */
 	private boolean useAlignments;

 	/**
 	 * Instantiates a new o alignment manager.
 	 */
 	private OAlignmentManager() {

 	}

 	/**
 	 * Gets the.
 	 *
 	 * @return the o alignment manager
 	 */
 	public static OAlignmentManager get() {
 		if (manager == null) {
 			manager = new OAlignmentManager();
 		}
 		return manager;
 	}

 	/**
 	 * Start.
 	 *
 	 * @param layout the layout
 	 */
 	protected void start(OAbsoluteLayoutWidget layout) {
 		this.layout = layout;
 	}

 	/**
 	 * Start drag and drop.
 	 *
 	 * @param layout the layout
 	 */
 	public void startDragAndDrop(OAbsoluteLayoutWidget layout) {
 		start(layout);
 	}

 	/**
 	 * Start resize.
 	 *
 	 * @param layout the layout
 	 * @param resizingWidget the resizing widget
 	 * @param resizeLocation the resize location
 	 * @param resizingOverlay the resizing overlay
 	 */
 	public void startResize(OAbsoluteLayoutWidget layout, OAbsoluteLayoutWidget.ResizableAbsoluteWrapper resizingWidget,
 			OResizeLocation resizeLocation, Element resizingOverlay) {
 		this.layout = layout;
 		this.resizingWidget = resizingWidget;
 		this.resizeLocation = resizeLocation;
 		this.resizingOverlay = resizingOverlay;

 		start(layout);
 	}

 	/**
 	 * Checks if is active.
 	 *
 	 * @return true, if is active
 	 */
 	public boolean isActive() {
 		return layout != null;
 	}

 	/**
 	 * Stop.
 	 */
 	public void stop() {
 		resetAlignments();
 		layout = null;
 		alignments.clear();
 		resizeLocation = null;
 		resizingWidget = null;
 		snapInfo = null;
 	}

 	/**
 	 * Update alignments for drop.
 	 *
 	 * @param drag the drag
 	 */
 	public void updateAlignmentsForDrop(final VDragEvent drag) {
 		if (!useAlignments) {
 			return;
 		}

 		Scheduler.get().scheduleDeferred(new Scheduler.ScheduledCommand() {
 			@Override
 			public void execute() {
 				resetSnap();
 				resetAlignments();

 				Map<String, Object> dropDetail = drag.getDropDetails();
 				if (!dropDetail.containsKey(Constants.DROP_DETAIL_RELATIVE_TOP)) {
 					return;
 				}
 				int top = (int) dropDetail.get(Constants.DROP_DETAIL_RELATIVE_TOP);
 				int left = (int) dropDetail.get(Constants.DROP_DETAIL_RELATIVE_LEFT);
 				int width = (int) dropDetail.get(Constants.DROP_DETAIL_COMPONENT_WIDTH);
 				int height = (int) dropDetail.get(Constants.DROP_DETAIL_COMPONENT_HEIGHT);

 				int topEdgeY = top;
 				int leftEdgeX = left;
 				int rightEdgeX = left + width;
 				int bottomEdgeY = top + height;

 				int snapCount = 0;
 				for (Widget child : layout.getChildren()) {
 					int childTop = child.getElement().getOffsetTop();
 					int childLeft = child.getElement().getOffsetLeft();
 					int childWidth = child.getElement().getOffsetWidth();
 					int childHeight = child.getElement().getOffsetHeight();

 					int childTopEdgeY = childTop;
 					int childLeftEdgeX = childLeft;
 					int childRightEdgeX = childLeft + childWidth;
 					int childBottomEdgeY = childTop + childHeight;

 					boolean isDraggedLeftOf = false;
 					boolean isDraggedToOf = false;
 					if (left < child.getAbsoluteLeft()) {
 						isDraggedLeftOf = true;
 					}

 					if (top < child.getAbsoluteTop()) {
 						isDraggedToOf = true;
 					}

 					AlignmentsLocation location = null;
 					// paired sides -> left to left,...
 					int top_top_EdgeYDelta = topEdgeY - childTopEdgeY;
 					int bottom_bottom_EdgeYDelta = bottomEdgeY - childBottomEdgeY;
 					int left_left_EdgeXDelta = leftEdgeX - childLeftEdgeX;
 					int right_right_EdgeXDelta = rightEdgeX - childRightEdgeX;
 					int top_bottom_EdgeYDelta = topEdgeY - childBottomEdgeY;
 					int bottom_top_EdgeYDelta = bottomEdgeY - childTopEdgeY;
 					int left_right_EdgeXDelta = leftEdgeX - childRightEdgeX;
 					int right_left_EdgeXDelta = rightEdgeX - childLeftEdgeX;

 					OAlignmentSnapInfo snapInfo = null;
 					if (isInsideSnapBounds(top_top_EdgeYDelta)) {
 						snapInfo = new OAlignmentSnapInfo(0, top_top_EdgeYDelta);
 						location = isDraggedLeftOf ? AlignmentsLocation.TOP_EDGE_TOLEFT
 								: AlignmentsLocation.TOP_EDGE_TORIGHT;
 					} else if (isInsideSnapBounds(left_left_EdgeXDelta)) {
 						snapInfo = new OAlignmentSnapInfo(left_left_EdgeXDelta, 0);
 						location = isDraggedToOf ? AlignmentsLocation.LEFT_EDGE_TOTOP
 								: AlignmentsLocation.LEFT_EDGE_TOBOTTOM;
 					} else if (isInsideSnapBounds(right_right_EdgeXDelta)) {
 						snapInfo = new OAlignmentSnapInfo(right_right_EdgeXDelta, 0);
 						location = isDraggedToOf ? AlignmentsLocation.RIGHT_EDGE_TOTOP
 								: AlignmentsLocation.RIGHT_EDGE_TOBOTTOM;
 					} else if (isInsideSnapBounds(bottom_bottom_EdgeYDelta)) {
 						snapInfo = new OAlignmentSnapInfo(0, bottom_bottom_EdgeYDelta);
 						location = isDraggedLeftOf ? AlignmentsLocation.BOTTOM_EDGE_TOLEFT
 								: AlignmentsLocation.BOTTOM_EDGE_TORIGHT;
 						// unpaired sides
 					} else if (isInsideSnapBounds(top_bottom_EdgeYDelta)) {
 						snapInfo = new OAlignmentSnapInfo(0, top_bottom_EdgeYDelta);
 						location = isDraggedLeftOf ? AlignmentsLocation.BOTTOM_EDGE_TOLEFT
 								: AlignmentsLocation.BOTTOM_EDGE_TORIGHT;
 					} else if (isInsideSnapBounds(left_right_EdgeXDelta)) {
 						snapInfo = new OAlignmentSnapInfo(left_right_EdgeXDelta, 0);
 						location = isDraggedToOf ? AlignmentsLocation.RIGHT_EDGE_TOTOP
 								: AlignmentsLocation.RIGHT_EDGE_TOBOTTOM;
 					} else if (isInsideSnapBounds(right_left_EdgeXDelta)) {
 						snapInfo = new OAlignmentSnapInfo(right_left_EdgeXDelta, 0);
 						location = isDraggedToOf ? AlignmentsLocation.LEFT_EDGE_TOTOP
 								: AlignmentsLocation.LEFT_EDGE_TOBOTTOM;
 					} else if (isInsideSnapBounds(bottom_top_EdgeYDelta)) {
 						snapInfo = new OAlignmentSnapInfo(0, bottom_top_EdgeYDelta);
 						location = isDraggedLeftOf ? AlignmentsLocation.TOP_EDGE_TOLEFT
 								: AlignmentsLocation.TOP_EDGE_TORIGHT;
 					}

 					if (location != null) {
 						snapCount++;

 						if (isFirstSnap(snapCount)) {
 							registerSnap(snapInfo);
 						}

 						OAlignmentOverlay overlay = new OAlignmentOverlay(child, drag.getDragImage(), location,
 								snapInfo, false, snapCount == 1);
 						alignments.add(overlay);
 						overlay.show();
 					}
 				}
 			}
 		});
 	}

 	/**
 	 * Update alignments for resize.
 	 *
 	 * @param draggedElement            the resize preview element
 	 * @param dragOverlayElement the drag overlay element
 	 */
 	public void updateAlignmentsForResize(final Element draggedElement, final Element dragOverlayElement) {
 		if (dragOverlayElement == null || !useAlignments) {
 			return;
 		}
 		Scheduler.get().scheduleDeferred(new Scheduler.ScheduledCommand() {
 			@Override
 			public void execute() {
 				resetSnap();
 				resetAlignments();

 				int top = (int) dragOverlayElement.getAbsoluteTop();
 				int left = (int) dragOverlayElement.getAbsoluteLeft();
 				int width = (int) dragOverlayElement.getOffsetWidth();
 				int height = (int) dragOverlayElement.getOffsetHeight();

 				int topEdgeY = top;
 				int leftEdgeX = left;
 				int rightEdgeX = left + width;
 				int bottomEdgeY = top + height;

 				int snapCount = 0;

 				for (Widget child : layout.getChildren()) {
 					if (child == getResizingWidget()) {
 						continue;
 					}

 					int childTop = child.getElement().getAbsoluteTop();
 					int childLeft = child.getElement().getAbsoluteLeft();
 					int childWidth = child.getElement().getOffsetWidth();
 					int childHeight = child.getElement().getOffsetHeight();

 					int childTopEdgeY = childTop;
 					int childLeftEdgeX = childLeft;
 					int childRightEdgeX = childLeft + childWidth;
 					int childBottomEdgeY = childTop + childHeight;

 					boolean isDraggedLeftOf = false;
 					boolean isDraggedToOf = false;
 					if (left < child.getAbsoluteLeft()) {
 						isDraggedLeftOf = true;
 					}

 					if (top < child.getAbsoluteTop()) {
 						isDraggedToOf = true;
 					}

 					AlignmentsLocation location = null;
 					// paired sides -> left to left,...
 					int top_top_EdgeYDelta = topEdgeY - childTopEdgeY;
 					int bottom_bottom_EdgeYDelta = bottomEdgeY - childBottomEdgeY;
 					int left_left_EdgeXDelta = leftEdgeX - childLeftEdgeX;
 					int right_right_EdgeXDelta = rightEdgeX - childRightEdgeX;
 					int top_bottom_EdgeYDelta = topEdgeY - childBottomEdgeY;
 					int bottom_top_EdgeYDelta = bottomEdgeY - childTopEdgeY;
 					int left_right_EdgeXDelta = leftEdgeX - childRightEdgeX;
 					int right_left_EdgeXDelta = rightEdgeX - childLeftEdgeX;

 					OAlignmentSnapInfo snapInfo = null;
 					OResizeLocation resizeLoc = getResizeLocation();
 					if (resizeLoc.isTop() && isInsideSnapBounds(top_top_EdgeYDelta)) {
 						snapInfo = new OAlignmentSnapInfo(0, top_top_EdgeYDelta, resizeLoc);
 						location = isDraggedLeftOf ? AlignmentsLocation.TOP_EDGE_TOLEFT
 								: AlignmentsLocation.TOP_EDGE_TORIGHT;
 					} else if (resizeLoc.isLeft() && isInsideSnapBounds(left_left_EdgeXDelta)) {
 						snapInfo = new OAlignmentSnapInfo(left_left_EdgeXDelta, 0, resizeLoc);
 						location = isDraggedToOf ? AlignmentsLocation.LEFT_EDGE_TOTOP
 								: AlignmentsLocation.LEFT_EDGE_TOBOTTOM;
 					} else if (resizeLoc.isRight() && isInsideSnapBounds(right_right_EdgeXDelta)) {
 						snapInfo = new OAlignmentSnapInfo(right_right_EdgeXDelta, 0, resizeLoc);
 						location = isDraggedToOf ? AlignmentsLocation.RIGHT_EDGE_TOTOP
 								: AlignmentsLocation.RIGHT_EDGE_TOBOTTOM;
 					} else if (resizeLoc.isBottom() && isInsideSnapBounds(bottom_bottom_EdgeYDelta)) {
 						snapInfo = new OAlignmentSnapInfo(0, bottom_bottom_EdgeYDelta, resizeLoc);
 						location = isDraggedLeftOf ? AlignmentsLocation.BOTTOM_EDGE_TOLEFT
 								: AlignmentsLocation.BOTTOM_EDGE_TORIGHT;
 						// unpaired sides
 					} else if (resizeLoc.isTop() && isInsideSnapBounds(top_bottom_EdgeYDelta)) {
 						snapInfo = new OAlignmentSnapInfo(0, top_bottom_EdgeYDelta, resizeLoc);
 						location = isDraggedLeftOf ? AlignmentsLocation.BOTTOM_EDGE_TOLEFT
 								: AlignmentsLocation.BOTTOM_EDGE_TORIGHT;
 					} else if (resizeLoc.isLeft() && isInsideSnapBounds(left_right_EdgeXDelta)) {
 						snapInfo = new OAlignmentSnapInfo(left_right_EdgeXDelta, 0, resizeLoc);
 						location = isDraggedToOf ? AlignmentsLocation.RIGHT_EDGE_TOTOP
 								: AlignmentsLocation.RIGHT_EDGE_TOBOTTOM;
 					} else if (resizeLoc.isRight() && isInsideSnapBounds(right_left_EdgeXDelta)) {
 						snapInfo = new OAlignmentSnapInfo(right_left_EdgeXDelta, 0, resizeLoc);
 						location = isDraggedToOf ? AlignmentsLocation.LEFT_EDGE_TOTOP
 								: AlignmentsLocation.LEFT_EDGE_TOBOTTOM;
 					} else if (resizeLoc.isBottom() && isInsideSnapBounds(bottom_top_EdgeYDelta)) {
 						snapInfo = new OAlignmentSnapInfo(0, bottom_top_EdgeYDelta, resizeLoc);
 						location = isDraggedLeftOf ? AlignmentsLocation.TOP_EDGE_TOLEFT
 								: AlignmentsLocation.TOP_EDGE_TORIGHT;
 					}

 					if (location != null) {
 						snapCount++;

 						if (isFirstSnap(snapCount)) {
 							registerSnap(snapInfo);
 						}

 						OAlignmentOverlay overlay = new OAlignmentOverlay(child, dragOverlayElement, location, snapInfo,
 								true, isFirstSnap(snapCount));
 						alignments.add(overlay);
 						overlay.show();
 					}
 				}
 			}
 		});
 	}

 	/**
 	 * Checks if is first snap.
 	 *
 	 * @param snapCount the snap count
 	 * @return true, if is first snap
 	 */
 	private boolean isFirstSnap(int snapCount) {
 		return snapCount == 1;
 	}

 	/**
 	 * Resets all alignments.
 	 */
 	protected void resetAlignments() {
 		for (OAlignmentOverlay alignment : alignments) {
 			alignment.hide();
 		}
 		alignments.clear();
 	}

 	/**
 	 * Checks if is inside snap bounds.
 	 *
 	 * @param value the value
 	 * @return true, if is inside snap bounds
 	 */
 	protected boolean isInsideSnapBounds(int value) {
 		int snap = getSnapFromCSS();
 		return value <= snap && value >= -snap;
 	}

 	/**
 	 * Reads the snap in pixels from the elements style.
 	 *
 	 * @return the snap from css
 	 */
 	protected int getSnapFromCSS() {
 		String snapStr = layout.getElement().getStyle().getProperty(IOConstants.CSS_SNAP_PROPERTY);
 		if (snapStr != null) {
 			return Integer.valueOf(snapStr);
 		} else {
 			return snap;
 		}
 	}

 	/**
 	 * Registers the current snap. Only one snap definition can be active at a
 	 * time.
 	 *
 	 * @param snapInfo the snap info
 	 */
 	protected void registerSnap(OAlignmentSnapInfo snapInfo) {
 		this.snapInfo = snapInfo;
 	}

 	/**
 	 * Resets the snap info.
 	 */
 	protected void resetSnap() {
 		this.snapInfo = null;
 	}

 	/**
 	 * Gets the snap.
 	 *
 	 * @return the snap
 	 */
 	protected OAlignmentSnapInfo getSnap() {
 		return snapInfo != null ? snapInfo : new OAlignmentSnapInfo(0, 0);
 	}

 	/**
 	 * Updates the dropDetails after drop event.
 	 *
 	 * @param drag the drag
 	 */
 	public void updateDropDetails(VDragEvent drag) {
 		if (snapInfo != null) {
 			Map<String, Object> dropDetail = drag.getDropDetails();
 			int rTop = (int) dropDetail.get(Constants.DROP_DETAIL_RELATIVE_TOP);
 			int aTop = (int) dropDetail.get(Constants.DROP_DETAIL_ABSOLUTE_TOP);
 			int rLeft = (int) dropDetail.get(Constants.DROP_DETAIL_RELATIVE_LEFT);
 			int aLeft = (int) dropDetail.get(Constants.DROP_DETAIL_ABSOLUTE_LEFT);

 			rTop -= snapInfo.getY();
 			aTop -= snapInfo.getY();
 			rLeft -= snapInfo.getX();
 			aLeft -= snapInfo.getX();

 			dropDetail.put(Constants.DROP_DETAIL_RELATIVE_TOP, rTop);
 			dropDetail.put(Constants.DROP_DETAIL_ABSOLUTE_TOP, aTop);
 			dropDetail.put(Constants.DROP_DETAIL_RELATIVE_LEFT, rLeft);
 			dropDetail.put(Constants.DROP_DETAIL_ABSOLUTE_LEFT, aLeft);
 		}
 	}

 	/**
 	 * Updates the resized widget after the resizing was finished.
 	 *
 	 * @param accept the accept
 	 * @param oldWidth the old width
 	 * @param oldHeight the old height
 	 */
 	public void updateResizedWidget(boolean accept, int oldWidth, int oldHeight) {
 		if (accept) {
 			int width = resizingOverlay.getOffsetWidth();
 			int height = resizingOverlay.getOffsetHeight();

 			resizingWidget.getElement().getStyle().setWidth(width, Unit.PX);
 			resizingWidget.getElement().getStyle().setHeight(height, Unit.PX);

 			resizingWidget.notifyResized(width, height, oldWidth, oldHeight, resizeLocation);
 		} else {
 			resizingWidget.notifyResizingCancel();
 		}
 	}

 	/**
 	 * Returns the widget that is currently resized.
 	 *
 	 * @return the resizing widget
 	 */
 	public Widget getResizingWidget() {
 		return resizingWidget;
 	}

 	/**
 	 * Returns the resizing operation currently performed.
 	 *
 	 * @return the resize location
 	 */
 	public OResizeLocation getResizeLocation() {
 		return resizeLocation;
 	}

 	/**
 	 * Returns true, if alignments should be used.
 	 *
 	 * @return true, if is use alignments
 	 */
 	public boolean isUseAlignments() {
 		return useAlignments;
 	}

 	/**
 	 * Sets the use alignments.
 	 *
 	 * @param useAlignments the new use alignments
 	 */
 	public void setUseAlignments(boolean useAlignments) {
 		// if alignments switched off, ensure that pending alignments are being
 		// removed.
 		if (this.useAlignments == true && useAlignments == false) {
 			Scheduler.get().scheduleDeferred(new Scheduler.ScheduledCommand() {
 				@Override
 				public void execute() {
 					resetSnap();
 					resetAlignments();
 				}
 			});
 		}
 		this.useAlignments = useAlignments;
 	}

 }
	/**
	*
	* Copyright (c) 2011, 2016 - Loetz GmbH&Co.KG (69115 Heidelberg, Germany)
	*
	* 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:
	* Florian Pirchner <florian.pirchner@gmail.com> - Initial implementation
	*/
	package org.eclipse.osbp.vaadin.addons.absolutelayout.client;

	import java.util.HashSet;
	import java.util.Map;
	import java.util.Set;

	import org.eclipse.osbp.vaadin.addons.absolutelayout.client.OAlignmentOverlay.AlignmentsLocation;

	import com.google.gwt.core.client.Scheduler;
	import com.google.gwt.dom.client.Element;
	import com.google.gwt.dom.client.Style.Unit;
	import com.google.gwt.user.client.ui.Widget;
	import com.vaadin.client.ui.dd.VDragEvent;

	import fi.jasoft.dragdroplayouts.client.ui.Constants;

	// TODO: Auto-generated Javadoc
	/**
	* This class handles alignments for drag and drop and resize operations.
	*/
	public class OAlignmentManager {

	/** The manager. */
	private static OAlignmentManager manager;

	/** The alignments. */
	protected Set<OAlignmentOverlay> alignments = new HashSet<>();

	/** The snap. */
	protected int snap = 4;

	/** The layout. */
	private OAbsoluteLayoutWidget layout;

	/** The snap info. */
	private OAlignmentSnapInfo snapInfo;

	/** The resizing widget. */
	private OAbsoluteLayoutWidget.ResizableAbsoluteWrapper resizingWidget;

	/** The resizing overlay. */
	private Element resizingOverlay;

	/** The resize location. */
	private OResizeLocation resizeLocation;

	/** The use alignments. */
	private boolean useAlignments;

	/**
	* Instantiates a new o alignment manager.
	*/
	private OAlignmentManager() {

	}

	/**
	* Gets the.
	*
	* @return the o alignment manager
	*/
	public static OAlignmentManager get() {
	if (manager == null) {
	manager = new OAlignmentManager();
	}
	return manager;
	}

	/**
	* Start.
	*
	* @param layout the layout
	*/
	protected void start(OAbsoluteLayoutWidget layout) {
	this.layout = layout;
	}

	/**
	* Start drag and drop.
	*
	* @param layout the layout
	*/
	public void startDragAndDrop(OAbsoluteLayoutWidget layout) {
	start(layout);
	}

	/**
	* Start resize.
	*
	* @param layout the layout
	* @param resizingWidget the resizing widget
	* @param resizeLocation the resize location
	* @param resizingOverlay the resizing overlay
	*/
	public void startResize(OAbsoluteLayoutWidget layout, OAbsoluteLayoutWidget.ResizableAbsoluteWrapper resizingWidget,
	OResizeLocation resizeLocation, Element resizingOverlay) {
	this.layout = layout;
	this.resizingWidget = resizingWidget;
	this.resizeLocation = resizeLocation;
	this.resizingOverlay = resizingOverlay;

	start(layout);
	}

	/**
	* Checks if is active.
	*
	* @return true, if is active
	*/
	public boolean isActive() {
	return layout != null;
	}

	/**
	* Stop.
	*/
	public void stop() {
	resetAlignments();
	layout = null;
	alignments.clear();
	resizeLocation = null;
	resizingWidget = null;
	snapInfo = null;
	}

	/**
	* Update alignments for drop.
	*
	* @param drag the drag
	*/
	public void updateAlignmentsForDrop(final VDragEvent drag) {
	if (!useAlignments) {
	return;
	}

	Scheduler.get().scheduleDeferred(new Scheduler.ScheduledCommand() {
	@Override
	public void execute() {
	resetSnap();
	resetAlignments();

	Map<String, Object> dropDetail = drag.getDropDetails();
	if (!dropDetail.containsKey(Constants.DROP_DETAIL_RELATIVE_TOP)) {
	return;
	}
	int top = (int) dropDetail.get(Constants.DROP_DETAIL_RELATIVE_TOP);
	int left = (int) dropDetail.get(Constants.DROP_DETAIL_RELATIVE_LEFT);
	int width = (int) dropDetail.get(Constants.DROP_DETAIL_COMPONENT_WIDTH);
	int height = (int) dropDetail.get(Constants.DROP_DETAIL_COMPONENT_HEIGHT);

	int topEdgeY = top;
	int leftEdgeX = left;
	int rightEdgeX = left + width;
	int bottomEdgeY = top + height;

	int snapCount = 0;
	for (Widget child : layout.getChildren()) {
	int childTop = child.getElement().getOffsetTop();
	int childLeft = child.getElement().getOffsetLeft();
	int childWidth = child.getElement().getOffsetWidth();
	int childHeight = child.getElement().getOffsetHeight();

	int childTopEdgeY = childTop;
	int childLeftEdgeX = childLeft;
	int childRightEdgeX = childLeft + childWidth;
	int childBottomEdgeY = childTop + childHeight;

	boolean isDraggedLeftOf = false;
	boolean isDraggedToOf = false;
	if (left < child.getAbsoluteLeft()) {
	isDraggedLeftOf = true;
	}

	if (top < child.getAbsoluteTop()) {
	isDraggedToOf = true;
	}

	AlignmentsLocation location = null;
	// paired sides -> left to left,...
	int top_top_EdgeYDelta = topEdgeY - childTopEdgeY;
	int bottom_bottom_EdgeYDelta = bottomEdgeY - childBottomEdgeY;
	int left_left_EdgeXDelta = leftEdgeX - childLeftEdgeX;
	int right_right_EdgeXDelta = rightEdgeX - childRightEdgeX;
	int top_bottom_EdgeYDelta = topEdgeY - childBottomEdgeY;
	int bottom_top_EdgeYDelta = bottomEdgeY - childTopEdgeY;
	int left_right_EdgeXDelta = leftEdgeX - childRightEdgeX;
	int right_left_EdgeXDelta = rightEdgeX - childLeftEdgeX;

	OAlignmentSnapInfo snapInfo = null;
	if (isInsideSnapBounds(top_top_EdgeYDelta)) {
	snapInfo = new OAlignmentSnapInfo(0, top_top_EdgeYDelta);
	location = isDraggedLeftOf ? AlignmentsLocation.TOP_EDGE_TOLEFT
	: AlignmentsLocation.TOP_EDGE_TORIGHT;
	} else if (isInsideSnapBounds(left_left_EdgeXDelta)) {
	snapInfo = new OAlignmentSnapInfo(left_left_EdgeXDelta, 0);
	location = isDraggedToOf ? AlignmentsLocation.LEFT_EDGE_TOTOP
	: AlignmentsLocation.LEFT_EDGE_TOBOTTOM;
	} else if (isInsideSnapBounds(right_right_EdgeXDelta)) {
	snapInfo = new OAlignmentSnapInfo(right_right_EdgeXDelta, 0);
	location = isDraggedToOf ? AlignmentsLocation.RIGHT_EDGE_TOTOP
	: AlignmentsLocation.RIGHT_EDGE_TOBOTTOM;
	} else if (isInsideSnapBounds(bottom_bottom_EdgeYDelta)) {
	snapInfo = new OAlignmentSnapInfo(0, bottom_bottom_EdgeYDelta);
	location = isDraggedLeftOf ? AlignmentsLocation.BOTTOM_EDGE_TOLEFT
	: AlignmentsLocation.BOTTOM_EDGE_TORIGHT;
	// unpaired sides
	} else if (isInsideSnapBounds(top_bottom_EdgeYDelta)) {
	snapInfo = new OAlignmentSnapInfo(0, top_bottom_EdgeYDelta);
	location = isDraggedLeftOf ? AlignmentsLocation.BOTTOM_EDGE_TOLEFT
	: AlignmentsLocation.BOTTOM_EDGE_TORIGHT;
	} else if (isInsideSnapBounds(left_right_EdgeXDelta)) {
	snapInfo = new OAlignmentSnapInfo(left_right_EdgeXDelta, 0);
	location = isDraggedToOf ? AlignmentsLocation.RIGHT_EDGE_TOTOP
	: AlignmentsLocation.RIGHT_EDGE_TOBOTTOM;
	} else if (isInsideSnapBounds(right_left_EdgeXDelta)) {
	snapInfo = new OAlignmentSnapInfo(right_left_EdgeXDelta, 0);
	location = isDraggedToOf ? AlignmentsLocation.LEFT_EDGE_TOTOP
	: AlignmentsLocation.LEFT_EDGE_TOBOTTOM;
	} else if (isInsideSnapBounds(bottom_top_EdgeYDelta)) {
	snapInfo = new OAlignmentSnapInfo(0, bottom_top_EdgeYDelta);
	location = isDraggedLeftOf ? AlignmentsLocation.TOP_EDGE_TOLEFT
	: AlignmentsLocation.TOP_EDGE_TORIGHT;
	}

	if (location != null) {
	snapCount++;

	if (isFirstSnap(snapCount)) {
	registerSnap(snapInfo);
	}

	OAlignmentOverlay overlay = new OAlignmentOverlay(child, drag.getDragImage(), location,
	snapInfo, false, snapCount == 1);
	alignments.add(overlay);
	overlay.show();
	}
	}
	}
	});
	}

	/**
	* Update alignments for resize.
	*
	* @param draggedElement the resize preview element
	* @param dragOverlayElement the drag overlay element
	*/
	public void updateAlignmentsForResize(final Element draggedElement, final Element dragOverlayElement) {
	if (dragOverlayElement == null \|\| !useAlignments) {
	return;
	}
	Scheduler.get().scheduleDeferred(new Scheduler.ScheduledCommand() {
	@Override
	public void execute() {
	resetSnap();
	resetAlignments();

	int top = (int) dragOverlayElement.getAbsoluteTop();
	int left = (int) dragOverlayElement.getAbsoluteLeft();
	int width = (int) dragOverlayElement.getOffsetWidth();
	int height = (int) dragOverlayElement.getOffsetHeight();

	int topEdgeY = top;
	int leftEdgeX = left;
	int rightEdgeX = left + width;
	int bottomEdgeY = top + height;

	int snapCount = 0;

	for (Widget child : layout.getChildren()) {
	if (child == getResizingWidget()) {
	continue;
	}

	int childTop = child.getElement().getAbsoluteTop();
	int childLeft = child.getElement().getAbsoluteLeft();
	int childWidth = child.getElement().getOffsetWidth();
	int childHeight = child.getElement().getOffsetHeight();

	int childTopEdgeY = childTop;
	int childLeftEdgeX = childLeft;
	int childRightEdgeX = childLeft + childWidth;
	int childBottomEdgeY = childTop + childHeight;

	boolean isDraggedLeftOf = false;
	boolean isDraggedToOf = false;
	if (left < child.getAbsoluteLeft()) {
	isDraggedLeftOf = true;
	}

	if (top < child.getAbsoluteTop()) {
	isDraggedToOf = true;
	}

	AlignmentsLocation location = null;
	// paired sides -> left to left,...
	int top_top_EdgeYDelta = topEdgeY - childTopEdgeY;
	int bottom_bottom_EdgeYDelta = bottomEdgeY - childBottomEdgeY;
	int left_left_EdgeXDelta = leftEdgeX - childLeftEdgeX;
	int right_right_EdgeXDelta = rightEdgeX - childRightEdgeX;
	int top_bottom_EdgeYDelta = topEdgeY - childBottomEdgeY;
	int bottom_top_EdgeYDelta = bottomEdgeY - childTopEdgeY;
	int left_right_EdgeXDelta = leftEdgeX - childRightEdgeX;
	int right_left_EdgeXDelta = rightEdgeX - childLeftEdgeX;

	OAlignmentSnapInfo snapInfo = null;
	OResizeLocation resizeLoc = getResizeLocation();
	if (resizeLoc.isTop() && isInsideSnapBounds(top_top_EdgeYDelta)) {
	snapInfo = new OAlignmentSnapInfo(0, top_top_EdgeYDelta, resizeLoc);
	location = isDraggedLeftOf ? AlignmentsLocation.TOP_EDGE_TOLEFT
	: AlignmentsLocation.TOP_EDGE_TORIGHT;
	} else if (resizeLoc.isLeft() && isInsideSnapBounds(left_left_EdgeXDelta)) {
	snapInfo = new OAlignmentSnapInfo(left_left_EdgeXDelta, 0, resizeLoc);
	location = isDraggedToOf ? AlignmentsLocation.LEFT_EDGE_TOTOP
	: AlignmentsLocation.LEFT_EDGE_TOBOTTOM;
	} else if (resizeLoc.isRight() && isInsideSnapBounds(right_right_EdgeXDelta)) {
	snapInfo = new OAlignmentSnapInfo(right_right_EdgeXDelta, 0, resizeLoc);
	location = isDraggedToOf ? AlignmentsLocation.RIGHT_EDGE_TOTOP
	: AlignmentsLocation.RIGHT_EDGE_TOBOTTOM;
	} else if (resizeLoc.isBottom() && isInsideSnapBounds(bottom_bottom_EdgeYDelta)) {
	snapInfo = new OAlignmentSnapInfo(0, bottom_bottom_EdgeYDelta, resizeLoc);
	location = isDraggedLeftOf ? AlignmentsLocation.BOTTOM_EDGE_TOLEFT
	: AlignmentsLocation.BOTTOM_EDGE_TORIGHT;
	// unpaired sides
	} else if (resizeLoc.isTop() && isInsideSnapBounds(top_bottom_EdgeYDelta)) {
	snapInfo = new OAlignmentSnapInfo(0, top_bottom_EdgeYDelta, resizeLoc);
	location = isDraggedLeftOf ? AlignmentsLocation.BOTTOM_EDGE_TOLEFT
	: AlignmentsLocation.BOTTOM_EDGE_TORIGHT;
	} else if (resizeLoc.isLeft() && isInsideSnapBounds(left_right_EdgeXDelta)) {
	snapInfo = new OAlignmentSnapInfo(left_right_EdgeXDelta, 0, resizeLoc);
	location = isDraggedToOf ? AlignmentsLocation.RIGHT_EDGE_TOTOP
	: AlignmentsLocation.RIGHT_EDGE_TOBOTTOM;
	} else if (resizeLoc.isRight() && isInsideSnapBounds(right_left_EdgeXDelta)) {
	snapInfo = new OAlignmentSnapInfo(right_left_EdgeXDelta, 0, resizeLoc);
	location = isDraggedToOf ? AlignmentsLocation.LEFT_EDGE_TOTOP
	: AlignmentsLocation.LEFT_EDGE_TOBOTTOM;
	} else if (resizeLoc.isBottom() && isInsideSnapBounds(bottom_top_EdgeYDelta)) {
	snapInfo = new OAlignmentSnapInfo(0, bottom_top_EdgeYDelta, resizeLoc);
	location = isDraggedLeftOf ? AlignmentsLocation.TOP_EDGE_TOLEFT
	: AlignmentsLocation.TOP_EDGE_TORIGHT;
	}

	if (location != null) {
	snapCount++;

	if (isFirstSnap(snapCount)) {
	registerSnap(snapInfo);
	}

	OAlignmentOverlay overlay = new OAlignmentOverlay(child, dragOverlayElement, location, snapInfo,
	true, isFirstSnap(snapCount));
	alignments.add(overlay);
	overlay.show();
	}
	}
	}
	});
	}

	/**
	* Checks if is first snap.
	*
	* @param snapCount the snap count
	* @return true, if is first snap
	*/
	private boolean isFirstSnap(int snapCount) {
	return snapCount == 1;
	}

	/**
	* Resets all alignments.
	*/
	protected void resetAlignments() {
	for (OAlignmentOverlay alignment : alignments) {
	alignment.hide();
	}
	alignments.clear();
	}

	/**
	* Checks if is inside snap bounds.
	*
	* @param value the value
	* @return true, if is inside snap bounds
	*/
	protected boolean isInsideSnapBounds(int value) {
	int snap = getSnapFromCSS();
	return value <= snap && value >= -snap;
	}

	/**
	* Reads the snap in pixels from the elements style.
	*
	* @return the snap from css
	*/
	protected int getSnapFromCSS() {
	String snapStr = layout.getElement().getStyle().getProperty(IOConstants.CSS_SNAP_PROPERTY);
	if (snapStr != null) {
	return Integer.valueOf(snapStr);
	} else {
	return snap;
	}
	}

	/**
	* Registers the current snap. Only one snap definition can be active at a
	* time.
	*
	* @param snapInfo the snap info
	*/
	protected void registerSnap(OAlignmentSnapInfo snapInfo) {
	this.snapInfo = snapInfo;
	}

	/**
	* Resets the snap info.
	*/
	protected void resetSnap() {
	this.snapInfo = null;
	}

	/**
	* Gets the snap.
	*
	* @return the snap
	*/
	protected OAlignmentSnapInfo getSnap() {
	return snapInfo != null ? snapInfo : new OAlignmentSnapInfo(0, 0);
	}

	/**
	* Updates the dropDetails after drop event.
	*
	* @param drag the drag
	*/
	public void updateDropDetails(VDragEvent drag) {
	if (snapInfo != null) {
	Map<String, Object> dropDetail = drag.getDropDetails();
	int rTop = (int) dropDetail.get(Constants.DROP_DETAIL_RELATIVE_TOP);
	int aTop = (int) dropDetail.get(Constants.DROP_DETAIL_ABSOLUTE_TOP);
	int rLeft = (int) dropDetail.get(Constants.DROP_DETAIL_RELATIVE_LEFT);
	int aLeft = (int) dropDetail.get(Constants.DROP_DETAIL_ABSOLUTE_LEFT);

	rTop -= snapInfo.getY();
	aTop -= snapInfo.getY();
	rLeft -= snapInfo.getX();
	aLeft -= snapInfo.getX();

	dropDetail.put(Constants.DROP_DETAIL_RELATIVE_TOP, rTop);
	dropDetail.put(Constants.DROP_DETAIL_ABSOLUTE_TOP, aTop);
	dropDetail.put(Constants.DROP_DETAIL_RELATIVE_LEFT, rLeft);
	dropDetail.put(Constants.DROP_DETAIL_ABSOLUTE_LEFT, aLeft);
	}
	}

	/**
	* Updates the resized widget after the resizing was finished.
	*
	* @param accept the accept
	* @param oldWidth the old width
	* @param oldHeight the old height
	*/
	public void updateResizedWidget(boolean accept, int oldWidth, int oldHeight) {
	if (accept) {
	int width = resizingOverlay.getOffsetWidth();
	int height = resizingOverlay.getOffsetHeight();

	resizingWidget.getElement().getStyle().setWidth(width, Unit.PX);
	resizingWidget.getElement().getStyle().setHeight(height, Unit.PX);

	resizingWidget.notifyResized(width, height, oldWidth, oldHeight, resizeLocation);
	} else {
	resizingWidget.notifyResizingCancel();
	}
	}

	/**
	* Returns the widget that is currently resized.
	*
	* @return the resizing widget
	*/
	public Widget getResizingWidget() {
	return resizingWidget;
	}

	/**
	* Returns the resizing operation currently performed.
	*
	* @return the resize location
	*/
	public OResizeLocation getResizeLocation() {
	return resizeLocation;
	}

	/**
	* Returns true, if alignments should be used.
	*
	* @return true, if is use alignments
	*/
	public boolean isUseAlignments() {
	return useAlignments;
	}

	/**
	* Sets the use alignments.
	*
	* @param useAlignments the new use alignments
	*/
	public void setUseAlignments(boolean useAlignments) {
	// if alignments switched off, ensure that pending alignments are being
	// removed.
	if (this.useAlignments == true && useAlignments == false) {
	Scheduler.get().scheduleDeferred(new Scheduler.ScheduledCommand() {
	@Override
	public void execute() {
	resetSnap();
	resetAlignments();
	}
	});
	}
	this.useAlignments = useAlignments;
	}

	}