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:
33: package com.vividsolutions.jump.workbench.ui.snap;
34:
35: import java.util.ArrayList;
36: import java.util.Iterator;
37:
38: import com.vividsolutions.jts.geom.Coordinate;
39: import com.vividsolutions.jts.geom.Geometry;
40: import com.vividsolutions.jts.geom.GeometryFactory;
41: import com.vividsolutions.jump.geom.CoordUtil;
42: import com.vividsolutions.jump.util.Blackboard;
43: import com.vividsolutions.jump.workbench.ui.LayerViewPanel;
44: import com.vividsolutions.jump.workbench.ui.plugin.VerticesInFencePlugIn;
45:
46: public class SnapToVerticesPolicy implements SnapPolicy {
47: private GeometryFactory factory = new GeometryFactory();
48: //On-screen features are cached. The cache is built lazily. [Jon Aquino]
49:
50: private Blackboard blackboard;
51:
52: public SnapToVerticesPolicy(Blackboard blackboard) {
53: this .blackboard = blackboard;
54: }
55:
56: public static final String ENABLED_KEY = SnapToVerticesPolicy.class
57: .getName()
58: + " - ENABLED";
59:
60: public Coordinate snap(LayerViewPanel panel,
61: Coordinate originalPoint) {
62: if (!blackboard.get(ENABLED_KEY, false)) {
63: return null;
64: }
65: Geometry bufferedTransformedCursorLocation;
66: bufferedTransformedCursorLocation = factory.createPoint(
67: originalPoint).buffer(
68: SnapManager.getToleranceInPixels(blackboard)
69: / panel.getViewport().getScale());
70: ArrayList vertices = new ArrayList();
71: for (Iterator i = VisiblePointsAndLinesCache.instance(panel)
72: .getTree().query(
73: bufferedTransformedCursorLocation
74: .getEnvelopeInternal()).iterator(); i
75: .hasNext();) {
76: Geometry pointsAndLines = (Geometry) i.next();
77: vertices.addAll(VerticesInFencePlugIn.verticesInFence(
78: pointsAndLines, bufferedTransformedCursorLocation,
79: true).getCoordinates());
80: }
81: if (vertices.isEmpty()) {
82: return null;
83: }
84: return CoordUtil.closest(vertices, originalPoint);
85: }
86: }
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