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/*******************************************************************************
 * 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, scroll and expand)
 * when a drag occurs over a Tree.
 *
 * 

Classes that wish to provide their own drag under effect for a Tree * can extend the TreeDropTargetEffect class and override any applicable methods * in TreeDropTargetEffect 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_INSERT_BEFORE, FEEDBACK_INSERT_AFTER, FEEDBACK_EXPAND, FEEDBACK_SCROLL
*
*

* Note: Only one of the styles FEEDBACK_SELECT, FEEDBACK_INSERT_BEFORE or * FEEDBACK_INSERT_AFTER may be specified. *

* * @see DropTargetAdapter * @see DropTargetEvent * @see Sample code and further information * * @since 3.3 */ public class TreeDropTargetEffect extends DropTargetEffect { static final int SCROLL_HYSTERESIS = 150; // milli seconds static final int EXPAND_HYSTERESIS = 1000; // milli seconds int scrollIndex = -1; long scrollBeginTime; int expandIndex = -1; long expandBeginTime; /** * Creates a new TreeDropTargetEffect to handle the drag under effect on the specified * Tree. * * @param tree the Tree over which the user positions the cursor to drop the data */ public TreeDropTargetEffect(Tree tree) { super(tree); } 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) { expandBeginTime = 0; expandIndex = -1; 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) { Tree tree = (Tree) control; long handle = tree.handle; GTK.gtk_tree_view_set_drag_dest_row(handle, 0, GTK.GTK_TREE_VIEW_DROP_BEFORE); scrollBeginTime = 0; scrollIndex = -1; expandBeginTime = 0; expandIndex = -1; } /** * This implementation of dragOver provides a default drag under effect * for the feedback specified in event.feedback. * * 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_INSERT_BEFORE * @see DND#FEEDBACK_INSERT_AFTER * @see DND#FEEDBACK_SCROLL */ @Override public void dragOver(DropTargetEvent event) { Tree tree = (Tree) control; int effect = checkEffect(event.feedback); long handle = tree.handle; Point coordinates = new Point(event.x, event.y); coordinates = DPIUtil.autoScaleUp(tree.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 depth = GTK.gtk_tree_path_get_depth(path[0]); int[] temp = new int[depth]; C.memmove (temp, indices, temp.length * 4); index = temp[temp.length - 1]; } } if ((effect & DND.FEEDBACK_SCROLL) == 0) { scrollBeginTime = 0; scrollIndex = -1; } else { if (index != -1 && scrollIndex == index && scrollBeginTime != 0) { if (System.currentTimeMillis() >= scrollBeginTime) { GdkRectangle cellRect = new GdkRectangle (); GTK.gtk_tree_view_get_cell_area (handle, path[0], 0, cellRect); if (cellRect.y < cellRect.height) { int[] tx = new int[1], ty = new int[1]; GTK.gtk_tree_view_convert_bin_window_to_tree_coords(handle, cellRect.x, cellRect.y - cellRect.height, tx, ty); GTK.gtk_tree_view_scroll_to_point (handle, -1, ty[0]); } else { //scroll down GTK.gtk_tree_view_get_path_at_pos (handle, coordinates.x, coordinates.y + cellRect.height, path, null, null, null); 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 ((effect & DND.FEEDBACK_EXPAND) == 0) { expandBeginTime = 0; expandIndex = -1; } else { if (index != -1 && expandIndex == index && expandBeginTime != 0) { if (System.currentTimeMillis() >= expandBeginTime) { GTK.gtk_tree_view_expand_row (handle, path[0], false); expandBeginTime = 0; expandIndex = -1; } } else { expandBeginTime = System.currentTimeMillis() + EXPAND_HYSTERESIS; expandIndex = 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]); } }




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