org.eclipse.swt.dnd.TableDropTargetEffect Maven / Gradle / Ivy

Go to download
Show more of this group Show more artifacts with this name
Show all versions of org.eclipse.swt.gtk.linux.ppc64le Show documentation
Standard Widget Toolkit for GTK on ppc64le
The newest version!
/*******************************************************************************
 * Copyright (c) 2000, 2017 IBM Corporation and others.
 *
 * This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License 2.0
 * which accompanies this distribution, and is available at
 * https://www.eclipse.org/legal/epl-2.0/
 *
 * SPDX-License-Identifier: EPL-2.0
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.swt.dnd;

import org.eclipse.swt.graphics.*;
import org.eclipse.swt.internal.*;
import org.eclipse.swt.internal.gtk.*;
import org.eclipse.swt.widgets.*;

/**
 * This class provides a default drag under effect (eg. select, insert and scroll)
 * when a drag occurs over a Table.
 *
 * Classes that wish to provide their own drag under effect for a Table
 * can extend the TableDropTargetEffect and override any applicable methods
 * in TableDropTargetEffect to display their own drag under effect.
 *
 * Subclasses that override any methods of this class must call the corresponding
 * super method to get the default drag under effect implementation.
 *
 * The feedback value is either one of the FEEDBACK constants defined in
 * class DND which is applicable to instances of this class,
 * or it must be built by bitwise OR'ing together
 * (that is, using the int "|" operator) two or more
 * of those DND effect constants.
 * 
 * 
 * Feedback:
 * FEEDBACK_SELECT, FEEDBACK_SCROLL
 * 
 *
 * @see DropTargetAdapter
 * @see DropTargetEvent
 * @see Sample code and further information
 *
 * @since 3.3
 */
public class TableDropTargetEffect extends DropTargetEffect {
	static final int SCROLL_HYSTERESIS = 150; // milli seconds

	int scrollIndex;
	long scrollBeginTime;

	/**
	 * Creates a new TableDropTargetEffect to handle the drag under effect on the specified
	 * Table.
	 *
	 * @param table the Table 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) != 0) effect = effect & ~DND.FEEDBACK_INSERT_AFTER & ~DND.FEEDBACK_INSERT_BEFORE;
		if ((effect & DND.FEEDBACK_INSERT_BEFORE) != 0) effect = effect & ~DND.FEEDBACK_INSERT_AFTER;
		return effect;
	}

	/**
	 * This implementation of dragEnter provides a default drag under effect
	 * for the feedback specified in event.feedback.
	 *
	 * For additional information see DropTargetAdapter.dragEnter.
	 *
	 * Subclasses that override this method should call super.dragEnter(event)
	 * to get the default drag under effect implementation.
	 *
	 * @param event  the information associated with the drag enter event
	 *
	 * @see DropTargetAdapter
	 * @see DropTargetEvent
	 */
	@Override
	public void dragEnter(DropTargetEvent event) {
		scrollBeginTime = 0;
		scrollIndex = -1;
	}

	/**
	 * This implementation of dragLeave provides a default drag under effect
	 * for the feedback specified in event.feedback.
	 *
	 * For additional information see DropTargetAdapter.dragLeave.
	 *
	 * Subclasses that override this method should call super.dragLeave(event)
	 * to get the default drag under effect implementation.
	 *
	 * @param event  the information associated with the drag leave event
	 *
	 * @see DropTargetAdapter
	 * @see DropTargetEvent
	 */
	@Override
	public void dragLeave(DropTargetEvent event) {
		Table table = (Table) control;
		long handle = table.handle;
		GTK.gtk_tree_view_set_drag_dest_row(handle, 0, GTK.GTK_TREE_VIEW_DROP_BEFORE);

		scrollBeginTime = 0;
		scrollIndex = -1;
	}

	/**
	 * This implementation of dragOver provides a default drag under effect
	 * for the feedback specified in event.feedback. The class description
	 * lists the FEEDBACK constants that are applicable to the class.
	 *
	 * For additional information see DropTargetAdapter.dragOver.
	 *
	 * Subclasses that override this method should call super.dragOver(event)
	 * 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
	 */
	@Override
	public void dragOver(DropTargetEvent event) {
		Table table = (Table) control;
		long handle = table.handle;
		int effect = checkEffect(event.feedback);
		Point coordinates = new Point(event.x, event.y);
		coordinates = DPIUtil.autoScaleUp(table.toControl(coordinates));
		long [] path = new long [1];
		GTK.gtk_tree_view_get_path_at_pos (handle, coordinates.x, coordinates.y, path, null, null, null);
		int index = -1;
		if (path[0] != 0) {
			long indices = GTK.gtk_tree_path_get_indices (path[0]);
			if (indices != 0) {
				int[] temp = new int[1];
				C.memmove (temp, indices, 4);
				index = temp[0];
			}
		}
		if ((effect & DND.FEEDBACK_SCROLL) == 0) {
			scrollBeginTime = 0;
			scrollIndex = -1;
		} else {
			if (index != -1 && scrollIndex == index && scrollBeginTime != 0) {
				if (System.currentTimeMillis() >= scrollBeginTime) {
					if (coordinates.y < DPIUtil.autoScaleUp(table.getItemHeight())) {
						GTK.gtk_tree_path_prev(path[0]);
					} else {
						GTK.gtk_tree_path_next(path[0]);
					}
					if (path[0] != 0) {
						GTK.gtk_tree_view_scroll_to_cell(handle, path[0], 0, false, 0, 0);
						GTK.gtk_tree_path_free(path[0]);
						path[0] = 0;
						GTK.gtk_tree_view_get_path_at_pos (handle, coordinates.x, coordinates.y, path, null, null, null);
					}
					scrollBeginTime = 0;
					scrollIndex = -1;
				}
			} else {
				scrollBeginTime = System.currentTimeMillis() + SCROLL_HYSTERESIS;
				scrollIndex = index;
			}
		}
		if (path[0] != 0) {
			int position = -1;
			if ((effect & DND.FEEDBACK_SELECT) != 0) position = GTK.GTK_TREE_VIEW_DROP_INTO_OR_BEFORE;
			if ((effect & DND.FEEDBACK_INSERT_BEFORE) != 0) position = GTK.GTK_TREE_VIEW_DROP_BEFORE;
			if ((effect & DND.FEEDBACK_INSERT_AFTER) != 0) position = GTK.GTK_TREE_VIEW_DROP_AFTER;
			if (position != -1) {
				GTK.gtk_tree_view_set_drag_dest_row(handle, path[0], position);
			} else {
				GTK.gtk_tree_view_set_drag_dest_row(handle, 0, GTK.GTK_TREE_VIEW_DROP_BEFORE);
			}
		} else {
			GTK.gtk_tree_view_set_drag_dest_row(handle, 0, GTK.GTK_TREE_VIEW_DROP_BEFORE);
		}
		if (path[0] != 0) GTK.gtk_tree_path_free (path [0]);
	}
}