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我試圖繪製平滑的曲線，其中點靠得很近（-4.0,0.01），（-4.1，.02）等等。該圖將有多條線，我想爲每條曲線使用虛線。我正在使用JFreeChart並編寫了一個自定義的XYLineAndShapeRenderer來創建虛線。但是，破折號並不總是出現。看起來，數據集中的點越接近我獲得的破折號越少。有誰知道我可以如何使用靠近在一起的點並仍然是虛線？下面的代碼演示了這個問題。所有這些行應該有破折號。我認爲這個問題與Java使用BasicStroke繪製線條的方式有關，但我不確定。感謝您的幫助！JFreeChart如何繪製與間隔很近的點的虛線
import org.jfree.chart.ChartFactory;
import org.jfree.chart.ChartPanel;
import org.jfree.chart.JFreeChart;
import org.jfree.chart.plot.PlotOrientation;
import org.jfree.chart.plot.XYPlot;
import org.jfree.chart.renderer.xy.XYLineAndShapeRenderer;
import org.jfree.data.xy.XYSeries;
import org.jfree.data.xy.XYSeriesCollection;
import org.jfree.ui.ApplicationFrame;
import javax.swing.*;
import java.awt.*;
public class IccGraph extends ApplicationFrame {
public IccGraph(String title){
super(title);
JPanel chartPanel = createPanel();
chartPanel.setPreferredSize(new Dimension(450, 400));
setContentPane(chartPanel);
}
private double probability(double x, double b){
double top = Math.exp(x-b);
double prob = top/(1+top);
return prob;
}
public XYSeriesCollection createData(){
XYSeriesCollection dataset = new XYSeriesCollection();
XYSeries series1 = new XYSeries("Wide Points");
XYSeries series2 = new XYSeries("Close Points");
XYSeries series3 = new XYSeries("Very Close Points");
double maxValue = 4.0;
double value = -4.0;
double prob = 0.0;
//create series where x-axis values use increments of .5
//will produce graph with dashes as expected
while(value<maxValue){
prob = probability(value, -1.0);
series1.add(value, prob);
value += .5;
}
//create series where x-axis values use increments of .1
//will produce line with some dashes
value = -4.0;
while(value<maxValue){
prob = probability(value, 0.0);
series2.add(value, prob);
value += .1;
}
//create series where x-axis values use increments of .01
//will produce straight lines in graph
value = -4.0;
while(value<maxValue){
prob = probability(value, 1.0);
series3.add(value, prob);
value += .01;
}
dataset.addSeries(series1);
dataset.addSeries(series2);
dataset.addSeries(series3);
return dataset;
}
public JPanel createPanel(){
JFreeChart chart = createChart(createData());
ChartPanel panel = new ChartPanel(chart);
return panel;
}
public JFreeChart createChart(XYSeriesCollection dataset){
JFreeChart chart = ChartFactory.createXYLineChart(
"", // chart title
"Theta", // x axis label
"Probability", // y axis label
dataset, // data
PlotOrientation.VERTICAL,
true, // include legend
true, // tooltips
false // urls
);
XYLineAndShapeRenderer renderer = new XYLineAndShapeRenderer(){
@Override
public Stroke getItemStroke(int row, int col){
Stroke dash1 = new BasicStroke(1.0f,
BasicStroke.CAP_SQUARE,
BasicStroke.JOIN_MITER,
10.0f,
new float[] {5.0f,5.0f},
0.0f);
return dash1;
}
};
renderer.setBaseShapesFilled(false);
renderer.setDrawOutlines(false);
XYPlot plot = (XYPlot)chart.getPlot();
plot.setRenderer(renderer);
return chart;
}
public static void main(String[] args) {
IccGraph graph = new IccGraph("Line Dash Problem");
graph.pack();
graph.setVisible(true);
}