JFreeChart大數值

Question

你好，我有一個小問題。

得到這樣的圖表有點大的價值。有沒有簡單的方法來解決這個問題？我希望看到 數字的東西作爲1e15。

Answer 1

即將在1.0.18版本是一個新的TickUnitSource的實現，來解決該問題：

/* =========================================================== 
* JFreeChart : a free chart library for the Java(tm) platform 
* =========================================================== 
* 
* (C) Copyright 2000-2014, by Object Refinery Limited and Contributors. 
* 
* Project Info: http://www.jfree.org/jfreechart/index.html 
* 
* This library is free software; you can redistribute it and/or modify it 
* under the terms of the GNU Lesser General Public License as published by 
* the Free Software Foundation; either version 2.1 of the License, or 
* (at your option) any later version. 
* 
* This library is distributed in the hope that it will be useful, but 
* WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY 
* or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public 
* License for more details. 
* 
* You should have received a copy of the GNU Lesser General Public 
* License along with this library; if not, write to the Free Software 
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, 
* USA. 
* 
* [Oracle and Java are registered trademarks of Oracle and/or its affiliates. 
* Other names may be trademarks of their respective owners.] 
* 
* ------------------------- 
* NumberTickUnitSource.java 
* ------------------------- 
* (C) Copyright 2014, by Object Refinery Limited. 
* 
* Original Author: David Gilbert (for Object Refinery Limited); 
* Contributor(s): -; 
* 
* Changes 
* ------- 
* 18-Mar-2014 : Version 1 (DG); 
* 
*/ 

package org.jfree.chart.axis; 

import java.io.Serializable; 
import java.text.DecimalFormat; 
import java.text.NumberFormat; 

/** 
* A tick unit source implementation that returns NumberTickUnit instances 
* that are multiples of 1 or 5 times some power of 10. 
* 
* @since 1.0.18 
*/ 
public class NumberTickUnitSource implements TickUnitSource, Serializable { 

    private int power = 0; 

    private int factor = 1; 

    /** 
    * Creates a new instance. 
    */ 
    public NumberTickUnitSource() { 
     this.power = 0; 
     this.factor = 1; 
    } 

    @Override 
    public TickUnit getLargerTickUnit(TickUnit unit) { 
     TickUnit t = getCeilingTickUnit(unit); 
     if (t.equals(unit)) { 
      next(); 
      t = new NumberTickUnit(getTickSize(), getTickLabelFormat(), 
        getMinorTickCount()); 
     } 
     return t; 
    } 

    @Override 
    public TickUnit getCeilingTickUnit(TickUnit unit) { 
     return getCeilingTickUnit(unit.getSize()); 
    } 

    @Override 
    public TickUnit getCeilingTickUnit(double size) { 
     this.power = (int) Math.ceil(Math.log10(size)); 
     this.factor = 1; 
     return new NumberTickUnit(getTickSize(), getTickLabelFormat(), 
       getMinorTickCount()); 
    } 

    private boolean next() { 
     if (factor == 1) { 
      factor = 5; 
      return true; 
     } 
     if (factor == 5) { 
      power++; 
      factor = 1; 
      return true; 
     } 
     throw new IllegalStateException("We should never get here."); 
    } 

    private boolean previous() { 
     if (factor == 1) { 
      factor = 5; 
      power--; 
      return true; 
     } 
     if (factor == 5) { 
      factor = 1; 
      return true; 
     } 
     throw new IllegalStateException("We should never get here."); 
    } 

    private double getTickSize() { 
     return this.factor * Math.pow(10.0, this.power); 
    } 

    private DecimalFormat dfNeg4 = new DecimalFormat("0.0000"); 
    private DecimalFormat dfNeg3 = new DecimalFormat("0.000"); 
    private DecimalFormat dfNeg2 = new DecimalFormat("0.00"); 
    private DecimalFormat dfNeg1 = new DecimalFormat("0.0"); 
    private DecimalFormat df0 = new DecimalFormat("#,##0"); 

    private NumberFormat getTickLabelFormat() { 
     if (power == -4) { 
      return dfNeg4; 
     } 
     if (power == -3) { 
      return dfNeg3; 
     } 
     if (power == -2) { 
      return dfNeg2; 
     } 
     if (power == -1) { 
      return dfNeg1; 
     } 
     if (power >= 0 && power <= 6) { 
      return df0; 
     } 
     return new DecimalFormat("0.#E0"); 
    } 

    private int getMinorTickCount() { 
     if (factor == 1) { 
      return 10; 
     } else if (factor == 5) { 
      return 5; 
     } 
     return 0; 
    } 

    @Override 
    public boolean equals(Object obj) { 
     return (obj instanceof NumberTickUnitSource); 
    } 
} 

添加到您的代碼：

NumberAxis rangeAxis = (NumberAxis) plot.getRangeAxis(); 
    rangeAxis.setStandardTickUnits(new NumberTickUnitSource());