如何从Jfree图表的图像中获取图像映射

Question

在条形图中，我想为每种颜色（或段）使用超链接。为此，我需要使用Image MAP（使用Jfree图表）。我的代码是通过 Jfree 图表创建图像，但我也想要每个颜色代码的单独超链接。您能否建议我如何根据颜色代码或行键或列键从 Jfree 图表的图像中获取坐标。

公共类演示{

public static void main(String arg[]) throws IOException{
    DefaultCategoryDataset result = new DefaultCategoryDataset();
     result.addValue(20.3, "Apraisal Forms", "Dtest");
        result.addValue(19.4, "Resignation  Form", "Dtest");
        result.addValue(16.5, "HES forms", "Dtest");
        result.addValue(8, "Feedback forms", "Dtest");
        result.addValue(27.2, "Apraisal Forms", "HR Dept");
        result.addValue(5.9, "Resignation  Form", "HR Dept");
        result.addValue(14.4, "Feedback forms", "HR Dept");
        result.addValue(4, "HES forms", "HR Dept");
    JFreeChart chart = ChartFactory.createStackedBarChart3D("overview by Departments", "x label", "Message Count", result, PlotOrientation.VERTICAL, true, true, true);
    ChartUtilities.saveChartAsJPEG(new File("D:\chart.jpg"), chart, 500, 300);
      }
    }

Answer 1

我通过实现ToolTipTagFragmentGenerator和URLTagFragmentGenerator来完成它。以下是完整的代码：

public class Demo {
    public static void main(String arg[]) throws IOException {
        DefaultCategoryDataset result = new DefaultCategoryDataset();
        result.addValue(20.3, "Apraisal Forms", "Dtest");
        result.addValue(19.4, "Resignation  Form", "Dtest");
        result.addValue(16.5, "HES forms", "Dtest");
        result.addValue(8, "Feedback forms", "Dtest");
        result.addValue(27.2, "Apraisal Forms", "HR Dept");
        result.addValue(5.9, "Resignation  Form", "HR Dept");
        result.addValue(14.4, "Feedback forms", "HR Dept");
        result.addValue(4, "HES forms", "HR Dept");
        result.addValue(18.4, "Resignation  Form", "Admin Dept");
        result.addValue(16.1, "HES forms", "Admin Dept");
        result.addValue(13.7, "Feedback forms", "Admin Dept");
        JFreeChart chart = ChartFactory.createStackedBarChart3D(
            "overview by Departments", "x label", "Message Count", result,
            PlotOrientation.VERTICAL, true, true, true);
        SubCategoryAxis domainAxis = new SubCategoryAxis("Name of Department");
        domainAxis.setCategoryMargin(0.60);
        CategoryPlot plot = chart.getCategoryPlot();
        plot.setDomainAxis(domainAxis);
        String map = "";
        ChartRenderingInfo info = new ChartRenderingInfo(
            new StandardEntityCollection());
        try {
            ByteArrayOutputStream out = new ByteArrayOutputStream();
            ChartUtilities.writeChartAsPNG(out, chart, 600, 400, info);
            ToolTipTagFragmentGenerator tooltipConstructor = new ToolTipTagFragmentGenerator() {
                public String generateToolTipFragment(String arg0) {
                    String toolTip = " title = "value" + arg0 + """;
                    return (toolTip);
                }
            };
            URLTagFragmentGenerator urlConstructor = new URLTagFragmentGenerator() {
                public String generateURLFragment(String arg0) {
                    String address = " href="ControllerAddress\methodName?"
                        + arg0 + """;
                    return (address);
                }
            };
            map = ChartUtilities.getImageMap("chart", info, tooltipConstructor,
                urlConstructor);
            out.close();
        } catch (IOException e) {
            System.out.println(e);
        }
        System.out.println(map);
        ChartFrame frame1 = new ChartFrame("Bar Chart", chart);
        frame1.setVisible(true);
        frame1.setSize(600, 350);
    }
}