我有两个问题
1)我正在尝试使用形状注释在XYplot上绘制弧。我使用XYLine注释绘制一条线,我希望弧线从线条结束处开始。我对参数有一些问题。我希望弧的高度为17,宽度为44,并从图的点(3.0,17)开始(这是线结束的地方)。但是下面的代码不起作用。有人可以告诉我代码有什么问题吗?
Arc2D.Double arc = new Arc2D.Double(3.0,
16.9,
44.0,
17.04,
180.0,
180.0,
Arc2D.OPEN
);
plot.addAnnotation(new XYShapeAnnotation(arc,
new BasicStroke(2.0f), Color.white));
XYLineAnnotation a1 = new XYLineAnnotation(3.0, 0.0, 3.0,
16.9, new BasicStroke(2.0f), Color.white);
2)如何在极坐标图上绘制类似的图形?
由于
答案 0 :(得分:3)
关于Arc2D
的关键是边界矩形。要使半弧H
单位为高,边界必须为2 * H
单位高。
AFAIK,PolarPlot
不支持注释。
import java.awt.BasicStroke;
import java.awt.Color;
import java.awt.geom.Arc2D;
import java.util.Random;
import org.jfree.chart.ChartFactory;
import org.jfree.chart.ChartFrame;
import org.jfree.chart.JFreeChart;
import org.jfree.chart.annotations.XYLineAnnotation;
import org.jfree.chart.annotations.XYShapeAnnotation;
import org.jfree.chart.plot.PlotOrientation;
import org.jfree.chart.plot.XYPlot;
import org.jfree.data.xy.XYDataset;
import org.jfree.data.xy.XYSeries;
import org.jfree.data.xy.XYSeriesCollection;
/** @see http://stackoverflow.com/questions/6604211 */
public class ArcTest {
private static final Random r = new Random();
private static final double PI = 180d;
private static final int X = 3;
private static final int Y = 0;
private static final int W = 44;
private static final int H = 17;
public static void main(String[] args) {
JFreeChart chart = ChartFactory.createXYLineChart(
"ArcTest", "X", "Y", createDataset(),
PlotOrientation.VERTICAL, true, true, false);
XYPlot plot = chart.getXYPlot();
XYLineAnnotation line = new XYLineAnnotation(
X, Y, X, H, new BasicStroke(2f), Color.blue);
plot.addAnnotation(line);
Arc2D.Double arc = new Arc2D.Double(
X, Y, W, 2 * H, PI, PI, Arc2D.OPEN);
plot.addAnnotation(new XYShapeAnnotation(arc,
new BasicStroke(2.0f), Color.blue));
ChartFrame frame = new ChartFrame("First", chart);
frame.pack();
frame.setVisible(true);
}
private static XYDataset createDataset() {
XYSeriesCollection result = new XYSeriesCollection();
XYSeries series = new XYSeries("ArcTest");
series.add(0, 0);
series.add(W, W);
result.addSeries(series);
return result;
}
}