001/* ===========================================================
002 * Orson Charts : a 3D chart library for the Java(tm) platform
003 * ===========================================================
004 * 
005 * (C)opyright 2013-2022, by David Gilbert.  All rights reserved.
006 * 
007 * https://github.com/jfree/orson-charts
008 * 
009 * This program is free software: you can redistribute it and/or modify
010 * it under the terms of the GNU General Public License as published by
011 * the Free Software Foundation, either version 3 of the License, or
012 * (at your option) any later version.
013 *
014 * This program is distributed in the hope that it will be useful,
015 * but WITHOUT ANY WARRANTY; without even the implied warranty of
016 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
017 * GNU General Public License for more details.
018 *
019 * You should have received a copy of the GNU General Public License
020 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
021 * 
022 * [Oracle and Java are registered trademarks of Oracle and/or its affiliates. 
023 * Other names may be trademarks of their respective owners.]
024 * 
025 * If you do not wish to be bound by the terms of the GPL, an alternative
026 * commercial license can be purchased.  For details, please see visit the
027 * Orson Charts home page:
028 * 
029 * http://www.object-refinery.com/orsoncharts/index.html
030 * 
031 */
032
033package org.jfree.chart3d.axis;
034
035import java.text.Format;
036
037/**
038 * <p>Provides standard tick sizes and formatting for numerical axes.  
039 * Conceptually, the selector maintains a list of standard tick sizes (ordered 
040 * by size), and a pointer to the current (selected) tick size.  Clients of
041 * the selector will initialise the pointer by calling the 
042 * {@link #select(double)} method with a reference value (a guess, based on 
043 * context, of the largest usable tick size - for example, one half of the
044 * axis length) then, as required, move the pointer to a smaller or larger
045 * tick size (using the {@link #next()} and {@link #previous()} methods) to 
046 * find the most appropriate standard size to use.</p>
047 * 
048 * <p>The {@link NumberTickSelector} class provides a standard implementation, 
049 * but you can create your own if necessary.</p>
050 */
051public interface TickSelector {
052    
053    /**
054     * Selects and returns a standard tick size that is greater than or equal to 
055     * the specified reference value and, ideally, as close to it as possible 
056     * (to minimise the number of iterations used by axes to determine the tick
057     * size to use).  After a call to this method, the 
058     * {@link #getCurrentTickSize()} method should return the selected tick 
059     * size (there is a "cursor" that points to this tick size), the 
060     * {@link #next()} method should move the pointer to the next (larger) 
061     * standard tick size, and the {@link #previous()} method should move the 
062     * pointer to the  previous (smaller) standard tick size.
063     * 
064     * @param reference  the reference value (must be positive and finite).
065     * 
066     * @return The selected tick size. 
067     */
068    double select(double reference);
069    
070    /**
071     * Move the cursor to the next (larger) tick size, if there is one.  
072     * Returns {@code true} in the case that the cursor is moved, and 
073     * {@code false} where there are a finite number of tick sizes and the
074     * current tick size is the largest available.
075     * 
076     * @return A boolean.
077     */
078    boolean next();
079    
080    /**
081     * Move the cursor to the previous (smaller) tick size, if there is one.  
082     * Returns {@code true} in the case that the cursor is moved, and 
083     * {@code false} where there are a finite number of tick sizes and the
084     * current tick size is the smallest available.
085     * 
086     * @return A boolean.
087     */
088    boolean previous();
089    
090    /**
091     * Returns the tick size that the cursor is currently referencing.
092     * 
093     * @return The tick size. 
094     */
095    double getCurrentTickSize();
096    
097    /**
098     * Returns the tick formatter associated with the tick size that the 
099     * cursor is currently referencing.
100     * 
101     * @return The formatter.
102     */
103    Format getCurrentTickLabelFormat();
104    
105}