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Java > Open Source Codes > org > eclipse > ui > internal > DragCursors


1 /*******************************************************************************
2  * Copyright (c) 2004, 2006 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  *******************************************************************************/
11 package org.eclipse.ui.internal;
12
13 import org.eclipse.jface.resource.ImageDescriptor;
14 import org.eclipse.swt.SWT;
15 import org.eclipse.swt.graphics.Cursor;
16 import org.eclipse.swt.widgets.Display;
17
18 /**
19  * Provides the set of cursors used for drag-and-drop.
20  */
21 public class DragCursors {
22     public static final int INVALID = 0;
23
24     public static final int LEFT = 1;
25
26     public static final int RIGHT = 2;
27
28     public static final int TOP = 3;
29
30     public static final int BOTTOM = 4;
31
32     public static final int CENTER = 5;
33
34     public static final int OFFSCREEN = 6;
35
36     public static final int FASTVIEW = 7;
37
38     private final static Cursor cursors[] = new Cursor[8];
39
40     public static int positionToDragCursor(int swtPositionConstant) {
41         switch (swtPositionConstant) {
42         case SWT.LEFT:
43             return LEFT;
44         case SWT.RIGHT:
45             return RIGHT;
46         case SWT.TOP:
47             return TOP;
48         case SWT.BOTTOM:
49             return BOTTOM;
50         case SWT.CENTER:
51             return CENTER;
52         }
53
54         return INVALID;
55     }
56
57     /**
58      * Converts a drag cursor (LEFT, RIGHT, TOP, BOTTOM, CENTER) into an SWT constant
59      * (SWT.LEFT, SWT.RIGHT, SWT.TOP, SWT.BOTTOM, SWT.CENTER)
60      *
61      * @param dragCursorId
62      * @return an SWT.* constant
63      */
64     public static int dragCursorToSwtConstant(int dragCursorId) {
65         switch (dragCursorId) {
66         case LEFT:
67             return SWT.LEFT;
68         case RIGHT:
69             return SWT.RIGHT;
70         case TOP:
71             return SWT.TOP;
72         case BOTTOM:
73             return SWT.BOTTOM;
74         case CENTER:
75             return SWT.CENTER;
76         }
77
78         return SWT.DEFAULT;
79     }
80
81     /**
82      * Return the cursor for a drop scenario, as identified by code.
83      * Code must be one of INVALID, LEFT, RIGHT, TOP, etc.
84      * If the code is not found default to INVALID.
85      */
86     public static Cursor getCursor(int code) {
87         Display display = Display.getCurrent();
88         if (cursors[code] == null) {
89             ImageDescriptor source = null;
90             ImageDescriptor mask = null;
91             switch (code) {
92             case LEFT:
93                 source = WorkbenchImages
94                         .getImageDescriptor(IWorkbenchGraphicConstants.IMG_OBJS_DND_LEFT_SOURCE);
95                 mask = WorkbenchImages
96                         .getImageDescriptor(IWorkbenchGraphicConstants.IMG_OBJS_DND_LEFT_MASK);
97                 cursors[LEFT] = new Cursor(display, source.getImageData(), mask
98                         .getImageData(), 16, 16);
99                 break;
100             case RIGHT:
101                 source = WorkbenchImages
102                         .getImageDescriptor(IWorkbenchGraphicConstants.IMG_OBJS_DND_RIGHT_SOURCE);
103                 mask = WorkbenchImages
104                         .getImageDescriptor(IWorkbenchGraphicConstants.IMG_OBJS_DND_RIGHT_MASK);
105                 cursors[RIGHT] = new Cursor(display, source.getImageData(),
106                         mask.getImageData(), 16, 16);
107                 break;
108             case TOP:
109                 source = WorkbenchImages
110                         .getImageDescriptor(IWorkbenchGraphicConstants.IMG_OBJS_DND_TOP_SOURCE);
111                 mask = WorkbenchImages
112                         .getImageDescriptor(IWorkbenchGraphicConstants.IMG_OBJS_DND_TOP_MASK);
113                 cursors[TOP] = new Cursor(display, source.getImageData(), mask
114                         .getImageData(), 16, 16);
115                 break;
116             case BOTTOM:
117                 source = WorkbenchImages
118                         .getImageDescriptor(IWorkbenchGraphicConstants.IMG_OBJS_DND_BOTTOM_SOURCE);
119                 mask = WorkbenchImages
120                         .getImageDescriptor(IWorkbenchGraphicConstants.IMG_OBJS_DND_BOTTOM_MASK);
121                 cursors[BOTTOM] = new Cursor(display, source.getImageData(),
122                         mask.getImageData(), 16, 16);
123                 break;
124             case CENTER:
125                 source = WorkbenchImages
126                         .getImageDescriptor(IWorkbenchGraphicConstants.IMG_OBJS_DND_STACK_SOURCE);
127                 mask = WorkbenchImages
128                         .getImageDescriptor(IWorkbenchGraphicConstants.IMG_OBJS_DND_STACK_MASK);
129                 cursors[CENTER] = new Cursor(display, source.getImageData(),
130                         mask.getImageData(), 16, 16);
131                 break;
132             case OFFSCREEN:
133                 source = WorkbenchImages
134                         .getImageDescriptor(IWorkbenchGraphicConstants.IMG_OBJS_DND_OFFSCREEN_SOURCE);
135                 mask = WorkbenchImages
136                         .getImageDescriptor(IWorkbenchGraphicConstants.IMG_OBJS_DND_OFFSCREEN_MASK);
137                 cursors[OFFSCREEN] = new Cursor(display, source.getImageData(),
138                         mask.getImageData(), 16, 16);
139                 break;
140             case FASTVIEW:
141                 source = WorkbenchImages
142                         .getImageDescriptor(IWorkbenchGraphicConstants.IMG_OBJS_DND_TOFASTVIEW_SOURCE);
143                 mask = WorkbenchImages
144                         .getImageDescriptor(IWorkbenchGraphicConstants.IMG_OBJS_DND_TOFASTVIEW_MASK);
145                 cursors[FASTVIEW] = new Cursor(Display.getCurrent(), source
146                         .getImageData(), mask.getImageData(), 16, 16);
147             default:
148             case INVALID:
149                 source = WorkbenchImages
150                         .getImageDescriptor(IWorkbenchGraphicConstants.IMG_OBJS_DND_INVALID_SOURCE);
151                 mask = WorkbenchImages
152                         .getImageDescriptor(IWorkbenchGraphicConstants.IMG_OBJS_DND_INVALID_MASK);
153                 cursors[INVALID] = new Cursor(display, source.getImageData(),
154                         mask.getImageData(), 16, 16);
155                 break;
156             }
157         }
158         return cursors[code];
159     }
160
161     /**
162      * Disposes all drag-and-drop cursors.
163      */
164     public static void dispose() {
165         for (int idx = 0; idx < cursors.length; idx++) {
166             cursors[idx].dispose();
167             cursors[idx] = null;
168         }
169     }
170 }
171
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