001 /* =========================================================== 002 * JFreeChart : a free chart library for the Java(tm) platform 003 * =========================================================== 004 * 005 * (C) Copyright 2000-2005, by Object Refinery Limited and Contributors. 006 * 007 * Project Info: http://www.jfree.org/jfreechart/index.html 008 * 009 * This library is free software; you can redistribute it and/or modify it 010 * under the terms of the GNU Lesser General Public License as published by 011 * the Free Software Foundation; either version 2.1 of the License, or 012 * (at your option) any later version. 013 * 014 * This library is distributed in the hope that it will be useful, but 015 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY 016 * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public 017 * License for more details. 018 * 019 * You should have received a copy of the GNU Lesser General Public 020 * License along with this library; if not, write to the Free Software 021 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, 022 * USA. 023 * 024 * [Java is a trademark or registered trademark of Sun Microsystems, Inc. 025 * in the United States and other countries.] 026 * 027 * --------------------------- 028 * StandardTickUnitSource.java 029 * --------------------------- 030 * (C) Copyright 2003, 2004, by Object Refinery Limited. 031 * 032 * Original Author: David Gilbert (for Object Refinery Limited); 033 * Contributor(s): -; 034 * 035 * $Id: StandardTickUnitSource.java,v 1.2.2.2 2006/01/27 13:53:28 mungady Exp $ 036 * 037 * Changes 038 * ------- 039 * 23-Sep-2003 : Version 1 (DG); 040 * 041 */ 042 043 package org.jfree.chart.axis; 044 045 import java.text.DecimalFormat; 046 047 /** 048 * A source that can used by the {@link NumberAxis} class to obtain a 049 * suitable {@link TickUnit}. 050 */ 051 public class StandardTickUnitSource implements TickUnitSource { 052 053 /** Constant for log(10.0). */ 054 private static final double LOG_10_VALUE = Math.log(10.0); 055 056 /** 057 * Returns a tick unit that is larger than the supplied unit. 058 * 059 * @param unit the unit (<code>null</code> not permitted). 060 * 061 * @return A tick unit that is larger than the supplied unit. 062 */ 063 public TickUnit getLargerTickUnit(TickUnit unit) { 064 double x = unit.getSize(); 065 double log = Math.log(x) / LOG_10_VALUE; 066 double higher = Math.ceil(log); 067 return new NumberTickUnit(Math.pow(10, higher), 068 new DecimalFormat("0.0E0")); 069 } 070 071 /** 072 * Returns the tick unit in the collection that is greater than or equal 073 * to (in size) the specified unit. 074 * 075 * @param unit the unit (<code>null</code> not permitted). 076 * 077 * @return A unit from the collection. 078 */ 079 public TickUnit getCeilingTickUnit(TickUnit unit) { 080 return getLargerTickUnit(unit); 081 } 082 083 /** 084 * Returns the tick unit in the collection that is greater than or equal 085 * to the specified size. 086 * 087 * @param size the size. 088 * 089 * @return A unit from the collection. 090 */ 091 public TickUnit getCeilingTickUnit(double size) { 092 double log = Math.log(size) / LOG_10_VALUE; 093 double higher = Math.ceil(log); 094 return new NumberTickUnit(Math.pow(10, higher), 095 new DecimalFormat("0.0E0")); 096 } 097 098 }