01: /*
02: * The Unified Mapping Platform (JUMP) is an extensible, interactive GUI
03: * for visualizing and manipulating spatial features with geometry and attributes.
04: *
05: * Copyright (C) 2003 Vivid Solutions
06: *
07: * This program is free software; you can redistribute it and/or
08: * modify it under the terms of the GNU General Public License
09: * as published by the Free Software Foundation; either version 2
10: * of the License, or (at your option) any later version.
11: *
12: * This program is distributed in the hope that it will be useful,
13: * but WITHOUT ANY WARRANTY; without even the implied warranty of
14: * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15: * GNU General Public License for more details.
16: *
17: * You should have received a copy of the GNU General Public License
18: * along with this program; if not, write to the Free Software
19: * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
20: *
21: * For more information, contact:
22: *
23: * Vivid Solutions
24: * Suite #1A
25: * 2328 Government Street
26: * Victoria BC V8T 5G5
27: * Canada
28: *
29: * (250)385-6040
30: * www.vividsolutions.com
31: */
32: package com.vividsolutions.jump.workbench.ui.snap;
33:
34: import com.vividsolutions.jts.geom.Coordinate;
35:
36: import com.vividsolutions.jump.util.Blackboard;
37: import com.vividsolutions.jump.workbench.ui.LayerViewPanel;
38:
39: public class SnapToGridPolicy implements SnapPolicy {
40: public static final String ENABLED_KEY = SnapToGridPolicy.class
41: .getName()
42: + " - ENABLED";
43: public static final String GRID_SIZE_KEY = SnapToGridPolicy.class
44: .getName()
45: + " - GRID_SIZE";
46: private Blackboard blackboard;
47:
48: public SnapToGridPolicy(Blackboard blackboard) {
49: this .blackboard = blackboard;
50: }
51:
52: public Coordinate snap(LayerViewPanel panel,
53: Coordinate originalCoordinate) {
54: if (!blackboard.get(ENABLED_KEY, false)) {
55: return null;
56: }
57:
58: double gridSize = blackboard.get(GRID_SIZE_KEY, 20d);
59:
60: Coordinate gridCoordinate = new Coordinate(Math
61: .round(originalCoordinate.x / gridSize)
62: * gridSize, Math.round(originalCoordinate.y / gridSize)
63: * gridSize);
64:
65: return (gridCoordinate.distance(originalCoordinate) <= (SnapManager
66: .getToleranceInPixels(blackboard) / panel.getViewport()
67: .getScale())) ? gridCoordinate : originalCoordinate;
68: }
69: }
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