org.eclipse.swt.dnd.TreeDropTargetEffect source code

1 /*******************************************************************************
2  * Copyright (c) 2000, 2008 IBM Corporation and others.
3  * All rights reserved. This program and the accompanying materials
4  * are made available under the terms of the Eclipse Public License v1.0
5  * which accompanies this distribution, and is available at
6  * http://www.eclipse.org/legal/epl-v10.html
7  *
8  * Contributors:
9  *     IBM Corporation - initial API and implementation
10  * Port to the D programming language:
11  *     Frank Benoit <benoit@tionex.de>
12  *******************************************************************************/
13 module org.eclipse.swt.dnd.TreeDropTargetEffect;
14 
15 import java.lang.all;
16 
17 
18 import org.eclipse.swt.graphics.Point;
19 import org.eclipse.swt.internal.gtk.OS;
20 import org.eclipse.swt.widgets.Tree;
21 import org.eclipse.swt.dnd.DropTargetEffect;
22 import org.eclipse.swt.dnd.DropTargetEvent;
23 import org.eclipse.swt.dnd.DND;
24 
25 /**
26  * This class provides a default drag under effect (eg. select, insert, scroll and expand)
27  * when a drag occurs over a <code>Tree</code>.
28  *
29  * <p>Classes that wish to provide their own drag under effect for a <code>Tree</code>
30  * can extend the <code>TreeDropTargetEffect</code> class and override any applicable methods
31  * in <code>TreeDropTargetEffect</code> to display their own drag under effect.</p>
32  *
33  * Subclasses that override any methods of this class must call the corresponding
34  * <code>super</code> method to get the default drag under effect implementation.
35  *
36  * <p>The feedback value is either one of the FEEDBACK constants defined in
37  * class <code>DND</code> which is applicable to instances of this class,
38  * or it must be built by <em>bitwise OR</em>'ing together
39  * (that is, using the <code>int</code> "|" operator) two or more
40  * of those <code>DND</code> effect constants.
41  * </p>
42  * <p>
43  * <dl>
44  * <dt><b>Feedback:</b></dt>
45  * <dd>FEEDBACK_SELECT, FEEDBACK_INSERT_BEFORE, FEEDBACK_INSERT_AFTER, FEEDBACK_EXPAND, FEEDBACK_SCROLL</dd>
46  * </dl>
47  * </p><p>
48  * Note: Only one of the styles FEEDBACK_SELECT, FEEDBACK_INSERT_BEFORE or
49  * FEEDBACK_INSERT_AFTER may be specified.
50  * </p>
51  *
52  * @see DropTargetAdapter
53  * @see DropTargetEvent
54  * @see <a href="http://www.eclipse.org/swt/">Sample code and further information</a>
55  *
56  * @since 3.3
57  */
58 public class TreeDropTargetEffect : DropTargetEffect {
59     static const int SCROLL_HYSTERESIS = 150; // milli seconds
60     static const int EXPAND_HYSTERESIS = 1000; // milli seconds
61 
62     int scrollIndex = -1;
63     long scrollBeginTime;
64 
65     int expandIndex = -1;
66     long expandBeginTime;
67 
68     /**
69      * Creates a new <code>TreeDropTargetEffect</code> to handle the drag under effect on the specified
70      * <code>Tree</code>.
71      *
72      * @param tree the <code>Tree</code> over which the user positions the cursor to drop the data
73      */
74     public this(Tree tree) {
75         super(tree);
76     }
77 
78     int checkEffect(int effect) {
79         // Some effects are mutually exclusive.  Make sure that only one of the mutually exclusive effects has been specified.
80         if ((effect & DND.FEEDBACK_SELECT) !is 0) effect = effect & ~DND.FEEDBACK_INSERT_AFTER & ~DND.FEEDBACK_INSERT_BEFORE;
81         if ((effect & DND.FEEDBACK_INSERT_BEFORE) !is 0) effect = effect & ~DND.FEEDBACK_INSERT_AFTER;
82         return effect;
83     }
84 
85     /**
86      * This implementation of <code>dragEnter</code> provides a default drag under effect
87      * for the feedback specified in <code>event.feedback</code>.
88      *
89      * For additional information see <code>DropTargetAdapter.dragEnter</code>.
90      *
91      * Subclasses that override this method should call <code>super.dragEnter(event)</code>
92      * to get the default drag under effect implementation.
93      *
94      * @param event  the information associated with the drag enter event
95      *
96      * @see DropTargetAdapter
97      * @see DropTargetEvent
98      */
99     public override void dragEnter(DropTargetEvent event) {
100         expandBeginTime = 0;
101         expandIndex = -1;
102         scrollBeginTime = 0;
103         scrollIndex = -1;
104     }
105 
106     /**
107      * This implementation of <code>dragLeave</code> provides a default drag under effect
108      * for the feedback specified in <code>event.feedback</code>.
109      *
110      * For additional information see <code>DropTargetAdapter.dragLeave</code>.
111      *
112      * Subclasses that override this method should call <code>super.dragLeave(event)</code>
113      * to get the default drag under effect implementation.
114      *
115      * @param event  the information associated with the drag leave event
116      *
117      * @see DropTargetAdapter
118      * @see DropTargetEvent
119      */
120     public override void dragLeave(DropTargetEvent event) {
121         Tree tree = cast(Tree) control;
122         auto handle = tree.handle;
123         OS.gtk_tree_view_set_drag_dest_row(handle, null, OS.GTK_TREE_VIEW_DROP_BEFORE);
124 
125         scrollBeginTime = 0;
126         scrollIndex = -1;
127         expandBeginTime = 0;
128         expandIndex = -1;
129     }
130 
131     /**
132      * This implementation of <code>dragOver</code> provides a default drag under effect
133      * for the feedback specified in <code>event.feedback</code>.
134      *
135      * For additional information see <code>DropTargetAdapter.dragOver</code>.
136      *
137      * Subclasses that override this method should call <code>super.dragOver(event)</code>
138      * to get the default drag under effect implementation.
139      *
140      * @param event  the information associated with the drag over event
141      *
142      * @see DropTargetAdapter
143      * @see DropTargetEvent
144      * @see DND#FEEDBACK_SELECT
145      * @see DND#FEEDBACK_INSERT_BEFORE
146      * @see DND#FEEDBACK_INSERT_AFTER
147      * @see DND#FEEDBACK_SCROLL
148      */
149     public override void dragOver(DropTargetEvent event) {
150         Tree tree = cast(Tree) control;
151         int effect = checkEffect(event.feedback);
152 
153         auto handle = tree.handle;
154         Point coordinates = new Point(event.x, event.y);
155         coordinates = tree.toControl(coordinates);
156         void* path;
157         OS.gtk_tree_view_get_path_at_pos (handle, coordinates.x, coordinates.y, &path, null, null, null);
158         int index = -1;
159         if (path !is null) {
160             auto indices = OS.gtk_tree_path_get_indices(path);
161             if (indices !is null) {
162                 ptrdiff_t depth = OS.gtk_tree_path_get_depth(path);
163                 index = indices[depth - 1];
164             }
165         }
166         if ((effect & DND.FEEDBACK_SCROLL) is 0) {
167             scrollBeginTime = 0;
168             scrollIndex = -1;
169         } else {
170             if (index !is -1 && scrollIndex is index && scrollBeginTime !is 0) {
171                 if (System.currentTimeMillis() >= scrollBeginTime) {
172                     GdkRectangle cellRect;
173                     OS.gtk_tree_view_get_cell_area (handle, path, null, &cellRect);
174                     if (cellRect.y < cellRect.height) {
175                         int tx, ty;
176                         OS.gtk_tree_view_widget_to_tree_coords(handle, cellRect.x, cellRect.y - cellRect.height, &tx, &ty);
177                         OS.gtk_tree_view_scroll_to_point (handle, -1, ty);
178                     } else {
179                         //scroll down
180                         OS.gtk_tree_view_get_path_at_pos (handle, coordinates.x, coordinates.y + cellRect.height, &path, null, null, null);
181                         if (path !is null) {
182                             OS.gtk_tree_view_scroll_to_cell(handle, path, null, false, 0, 0);
183                             OS.gtk_tree_path_free(path);
184                             path = null;
185                         }
186                         OS.gtk_tree_view_get_path_at_pos (handle, coordinates.x, coordinates.y, &path, null, null, null);
187                     }
188                     scrollBeginTime = 0;
189                     scrollIndex = -1;
190                 }
191             } else {
192                 scrollBeginTime = System.currentTimeMillis() + SCROLL_HYSTERESIS;
193                 scrollIndex = index;
194             }
195         }
196         if ((effect & DND.FEEDBACK_EXPAND) is 0) {
197             expandBeginTime = 0;
198             expandIndex = -1;
199         } else {
200             if (index !is -1 && expandIndex is index && expandBeginTime !is 0) {
201                 if (System.currentTimeMillis() >= expandBeginTime) {
202                     OS.gtk_tree_view_expand_row (handle, path, false);
203                     expandBeginTime = 0;
204                     expandIndex = -1;
205                 }
206             } else {
207                 expandBeginTime = System.currentTimeMillis() + EXPAND_HYSTERESIS;
208                 expandIndex = index;
209             }
210         }
211         if (path !is null) {
212             int position = -1;
213             if ((effect & DND.FEEDBACK_SELECT) !is 0) position = OS.GTK_TREE_VIEW_DROP_INTO_OR_BEFORE;
214             if ((effect & DND.FEEDBACK_INSERT_BEFORE) !is 0) position = OS.GTK_TREE_VIEW_DROP_BEFORE;
215             if ((effect & DND.FEEDBACK_INSERT_AFTER) !is 0) position = OS.GTK_TREE_VIEW_DROP_AFTER;
216             if (position !is -1) {
217                 OS.gtk_tree_view_set_drag_dest_row(handle, path, position);
218             } else {
219                 OS.gtk_tree_view_set_drag_dest_row(handle, null, OS.GTK_TREE_VIEW_DROP_BEFORE);
220             }
221         } else {
222             OS.gtk_tree_view_set_drag_dest_row(handle, null, OS.GTK_TREE_VIEW_DROP_BEFORE);
223         }
224 
225         if (path !is null) OS.gtk_tree_path_free (path );
226     }
227 
228 }