01: /* ===========================================================
02: * JFreeChart : a free chart library for the Java(tm) platform
03: * ===========================================================
04: *
05: * (C) Copyright 2000-2005, by Object Refinery Limited and Contributors.
06: *
07: * Project Info: http://www.jfree.org/jfreechart/index.html
08: *
09: * This library is free software; you can redistribute it and/or modify it
10: * under the terms of the GNU Lesser General Public License as published by
11: * the Free Software Foundation; either version 2.1 of the License, or
12: * (at your option) any later version.
13: *
14: * This library is distributed in the hope that it will be useful, but
15: * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
16: * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
17: * License for more details.
18: *
19: * You should have received a copy of the GNU Lesser General Public
20: * License along with this library; if not, write to the Free Software
21: * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
22: * USA.
23: *
24: * [Java is a trademark or registered trademark of Sun Microsystems, Inc.
25: * in the United States and other countries.]
26: *
27: * ---------------------------
28: * StandardTickUnitSource.java
29: * ---------------------------
30: * (C) Copyright 2003, 2004, by Object Refinery Limited.
31: *
32: * Original Author: David Gilbert (for Object Refinery Limited);
33: * Contributor(s): -;
34: *
35: * $Id: StandardTickUnitSource.java,v 1.2.2.2 2006/01/27 13:53:28 mungady Exp $
36: *
37: * Changes
38: * -------
39: * 23-Sep-2003 : Version 1 (DG);
40: *
41: */
42:
43: package org.jfree.chart.axis;
44:
45: import java.text.DecimalFormat;
46:
47: /**
48: * A source that can used by the {@link NumberAxis} class to obtain a
49: * suitable {@link TickUnit}.
50: */
51: public class StandardTickUnitSource implements TickUnitSource {
52:
53: /** Constant for log(10.0). */
54: private static final double LOG_10_VALUE = Math.log(10.0);
55:
56: /**
57: * Returns a tick unit that is larger than the supplied unit.
58: *
59: * @param unit the unit (<code>null</code> not permitted).
60: *
61: * @return A tick unit that is larger than the supplied unit.
62: */
63: public TickUnit getLargerTickUnit(TickUnit unit) {
64: double x = unit.getSize();
65: double log = Math.log(x) / LOG_10_VALUE;
66: double higher = Math.ceil(log);
67: return new NumberTickUnit(Math.pow(10, higher),
68: new DecimalFormat("0.0E0"));
69: }
70:
71: /**
72: * Returns the tick unit in the collection that is greater than or equal
73: * to (in size) the specified unit.
74: *
75: * @param unit the unit (<code>null</code> not permitted).
76: *
77: * @return A unit from the collection.
78: */
79: public TickUnit getCeilingTickUnit(TickUnit unit) {
80: return getLargerTickUnit(unit);
81: }
82:
83: /**
84: * Returns the tick unit in the collection that is greater than or equal
85: * to the specified size.
86: *
87: * @param size the size.
88: *
89: * @return A unit from the collection.
90: */
91: public TickUnit getCeilingTickUnit(double size) {
92: double log = Math.log(size) / LOG_10_VALUE;
93: double higher = Math.ceil(log);
94: return new NumberTickUnit(Math.pow(10, higher),
95: new DecimalFormat("0.0E0"));
96: }
97:
98: }
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