[ Java 代碼範本 ] JFreeChart : 3D BarChart - Demo 3 (多維度的3D 長條圖)

前言 : 
這裡要展示的是多維的 3D BarChart, 因為是多維所以資料的容器使用類別 DefaultCategoryDataset, 而因為是 3D 的 Bar Chart, 所以透過 ChartFactory 的工廠方法createBarChart3D() 建立圖表. 而接著透過取出建立圖表的 CategoryAxis 進行顯示 Label 的旋轉 : 

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1. CategoryPlot plot = chart.getCategoryPlot();  
2. // 設定 Label(Category1, Category2) 轉動角度 360度/8=45度  
3. CategoryAxis axis = plot.getDomainAxis();  
4. axis.setCategoryLabelPositions(  
5.     CategoryLabelPositions.createUpRotationLabelPositions(Math.PI / 8.0)  
6. );  

接著透過 BarRenderer 設定 Bar 的寬度 : 

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1. CategoryItemRenderer renderer = plot.getRenderer();  
2. renderer.setBaseItemLabelsVisible(true);  
3. BarRenderer r = (BarRenderer) renderer;  
4. r.setMaximumBarWidth(0.06); // 設定 Single Bar width 佔 所有 Space 的百分比  

範例代碼 : 
顯示 3D 多維的 Bar Chart. 

- BarChart3DDemo3.java :

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1. package john.jfreechart.barchart;  
2.   
3. import org.jfree.chart.ChartFactory;  
4. import org.jfree.chart.ChartPanel;  
5. import org.jfree.chart.JFreeChart;  
6. import org.jfree.chart.axis.CategoryAxis;  
7. import org.jfree.chart.axis.CategoryLabelPositions;  
8. import org.jfree.chart.plot.CategoryPlot;  
9. import org.jfree.chart.plot.PlotOrientation;  
10. import org.jfree.chart.renderer.category.BarRenderer;  
11. import org.jfree.chart.renderer.category.CategoryItemRenderer;  
12. import org.jfree.data.category.CategoryDataset;  
13. import org.jfree.data.category.DefaultCategoryDataset;  
14. import org.jfree.ui.ApplicationFrame;  
15. import org.jfree.ui.RefineryUtilities;  
16.   
17. /** 
18. * This demonstration shows a 3D bar chart with item labels displayed. 
19. * Source : http://www.koders.com/java/fid106C050FCFFD2D4A9174E48FA06ED1902C2D2E15.aspx 
20. * @author John-Lee 
21. */  
22. public class BarChart3DDemo3 extends ApplicationFrame{  
23.     /** 
24.      * Creates a new demo. 
25.      * 
26.      * @param title  the frame title. 
27.      */  
28.     public BarChart3DDemo3(String title) {  
29.         super(title);          
30.         CategoryDataset dataset = createDataset();  
31.         JFreeChart chart = createChart(dataset);  
32.         ChartPanel chartPanel = new ChartPanel(chart);  
33.         chartPanel.setPreferredSize(new java.awt.Dimension(500, 270));  
34.         setContentPane(chartPanel);  
35.     }  
36.       
37.     /** 
38.      * Creates a sample dataset. 
39.      * 
40.      * @return a sample dataset. 
41.      */  
42.    private CategoryDataset createDataset() {  
43.         DefaultCategoryDataset dataset = new DefaultCategoryDataset();  
44.         dataset.addValue(25.0, "Series 1", "Category 1");     
45.         dataset.addValue(34.0, "Series 1", "Category 2");     
46.         dataset.addValue(19.0, "Series 2", "Category 1");     
47.         dataset.addValue(29.0, "Series 2", "Category 2");     
48.         dataset.addValue(41.0, "Series 3", "Category 1");     
49.         dataset.addValue(33.0, "Series 3", "Category 2");     
50.         return dataset;  
51.     }  
52.       
53.     /** 
54.      * Creates a chart. 
55.      *  
56.      * @param dataset  the dataset. 
57.      *  
58.      * @return The chart. 
59.      */  
60.     private JFreeChart createChart(CategoryDataset dataset) {          
61.         JFreeChart chart = ChartFactory.createBarChart3D(  
62.             "3D Bar Chart Demo",      // chart title  
63.             "Category",               // domain axis label  
64.             "Value",                  // range axis label  
65.             dataset,                  // data  
66.             PlotOrientation.VERTICAL, // orientation  
67.             true,                     // include legend  
68.             true,                     // tooltips  
69.             false                     // urls  
70.         );  
71.   
72.         CategoryPlot plot = chart.getCategoryPlot();  
73.         // 設定 Label(Category1, Category2) 轉動角度 360度/8=45度  
74.         CategoryAxis axis = plot.getDomainAxis();  
75.         axis.setCategoryLabelPositions(  
76.             CategoryLabelPositions.createUpRotationLabelPositions(Math.PI / 8.0)  
77.         );  
78.           
79.         CategoryItemRenderer renderer = plot.getRenderer();  
80.         renderer.setBaseItemLabelsVisible(true);  
81.         BarRenderer r = (BarRenderer) renderer;  
82.         r.setMaximumBarWidth(0.06); // 設定 Single Bar width 佔 所有 Space 的百分比  
83.           
84.         return chart;  
85.     }  
86.           
87.     /** 
88.      * Starting point for the demonstration application. 
89.      * 
90.      * @param args  ignored. 
91.      */  
92.     public static void main(String[] args) {  
93.         BarChart3DDemo3 demo = new BarChart3DDemo3("3D Bar Chart Demo 3");  
94.         demo.pack();  
95.         RefineryUtilities.centerFrameOnScreen(demo);  
96.         demo.setVisible(true);  
97.     }  
98. }  

執行結果 :