我需要在每个切片中放置标签和颜色。所以它应该是“全球 - 20％”的颜色。 我还是初学者，请帮帮我!!
import java.awt.*;
import java.awt.event.*;
import java.awt.font.*;
import java.awt.geom.*;
import java.awt.image.*;
import java.text.*;
import javax.swing.*;
public class PieChart
{
public static void main(String[] args)
{
JFrame f = new JFrame("CMIS242 PieChart");
f.getContentPane().add(new PieChartPanel());
f.setSize(400,400);
f.setLocationRelativeTo(null);
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.setVisible(true);
}
}
class PieChartPanel extends JPanel
{
BufferedImage image;
final int PAD = 30;
Font font;
NumberFormat numberFormat;
public PieChartPanel()
{
font = new Font("Comic Sans", Font.BOLD, 18);
numberFormat = NumberFormat.getPercentInstance();
addMouseListener(new Visibility(this));
addComponentListener(new ComponentAdapter()
{});
}
protected void paintComponent(Graphics graphics)
{
super.paintComponent(graphics);
Graphics2D graphics2d = (Graphics2D)graphics;
graphics2d.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
RenderingHints.VALUE_ANTIALIAS_ON);
createChartImage();
graphics2d.drawImage(image, 0, 0, this);
}
private void createChartImage()
{
int[] marks = {10, 24, 30, 36};
int width = getWidth();
int height = getHeight();
int cp = width/2;
int cq = height/2;
image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
Graphics2D g2 = image.createGraphics();
g2.setPaint(Color.white);
g2.fillRect(0, 0, width, height);
g2.setPaint(Color.black);
int pie = Math.min(width,height) - 2*PAD;
g2.draw(new Ellipse2D.Double(cp - pie/2, cq - pie/2, pie, pie));
double total = 0;
for(int j = 0; j < marks.length; j++)
total += marks[j];
double theta = 0, phi = 0;
double p, q;
for(int j = 0; j < marks.length; j++)
{
p = cp + (pie/2) * Math.cos(theta);
q = cq + (pie/2) * Math.sin(theta);
g2.draw(new Line2D.Double(cp, cq, p, q));
phi = (marks[j]/total) * 2 * Math.PI;
p = cp + (9*pie/24) * Math.cos(theta + phi/2);
q = cq + (9*pie/24) * Math.sin(theta + phi/2);
g2.setFont(font);
String st = String.valueOf(marks[j]);
FontRenderContext frc = g2.getFontRenderContext();
float textWidth = (float)font.getStringBounds(st, frc).getWidth();
LineMetrics lm = font.getLineMetrics(st, frc);
float sp = (float)(p - textWidth/2);
float sq = (float)(q + lm.getAscent()/2);
p = cp + (pie/2 + 4*PAD/5) * Math.cos(theta + phi/2);
q = cq + (pie/2 + 4*PAD/5) * Math.sin(theta+ phi/2);
st = numberFormat.format(marks[j]/total);
textWidth = (float)font.getStringBounds(st, frc).getWidth();
lm = font.getLineMetrics(st, frc);
sp = (float)(p - textWidth/2);
sq = (float)(q + lm.getAscent()/2);
g2.drawString(st, sp, sq);
theta += phi;
}
//g2.dispose();
}
public void toggleVisibility()
{
repaint();
}
}
class Visibility extends MouseAdapter
{
PieChartPanel piechart;
public Visibility(PieChartPanel pc)
{
piechart = pc;
}
public void mousePressed(MouseEvent event)
{
if(event.getClickCount() > 1)
piechart.toggleVisibility();
}
}
答案 0 :(得分：0)
使用此功能在饼图中显示标签。
private PieDataset createSampleDataset()
{
final DefaultPieDataset result = new DefaultPieDataset();
result.setValue("Java", new Double(20));
result.setValue("Visual Basic", new Double(20));
result.setValue("C/C++", new Double(20));
result.setValue("PHP", new Double(20));
result.setValue("Perl", new Double(20));
return result;
}
看看这个例子：
package piechart3D;
import java.text.AttributedString;
import org.jfree.chart.ChartFactory;
import org.jfree.chart.ChartPanel;
import org.jfree.chart.JFreeChart;
import org.jfree.chart.labels.PieSectionLabelGenerator;
import org.jfree.chart.plot.PiePlot3D;
import org.jfree.data.general.DefaultPieDataset;
import org.jfree.data.general.PieDataset;
import org.jfree.ui.ApplicationFrame;
import org.jfree.ui.RefineryUtilities;
import org.jfree.util.Rotation;
public class Piechart3D extends ApplicationFrame
{
public Piechart3D(final String title)
{
super(title);
final PieDataset dataset = createSampleDataset();
final JFreeChart chart = createChart(dataset);
final ChartPanel chartPanel = new ChartPanel(chart);
chartPanel.setPreferredSize(new java.awt.Dimension(500, 270));
setContentPane(chartPanel);
}
private PieDataset createSampleDataset()
{
final DefaultPieDataset result = new DefaultPieDataset();
result.setValue("Java", new Double(20));
result.setValue("Visual Basic", new Double(20));
result.setValue("C/C++", new Double(20));
result.setValue("PHP", new Double(20));
result.setValue("Perl", new Double(20));
return result;
}
private JFreeChart createChart(final PieDataset dataset)
{
final JFreeChart chart = ChartFactory.createPieChart3D(
"3D Pie Chart", // chart title
dataset, // data
true, // include legend
true,
false
);
final PiePlot3D plot = (PiePlot3D) chart.getPlot();
plot.setStartAngle(290);
plot.setDirection(Rotation.CLOCKWISE);
plot.setForegroundAlpha(0.5f);
plot.setNoDataMessage("No data to display");
plot.setLabelGenerator(new CustomLabelGenerator() {
@Override
public AttributedString generateAttributedSectionLabel(PieDataset pd, Comparable cmprbl) {
throw new UnsupportedOperationException("Not supported yet.");
}
});
return chart;
}
/**
* Starting point for the demonstration application.
*
* @param args ignored.
*/
public static void main(final String[] args) {
final Piechart3D demo = new Piechart3D("3D Pie Chart");
demo.pack();
RefineryUtilities.centerFrameOnScreen(demo);
demo.setVisible(true);
}
/**
* A custom label generator (returns null for one item as a test).
*/
static abstract class CustomLabelGenerator implements PieSectionLabelGenerator {
/**
* Generates a label for a pie section.
*
* @param dataset the dataset (<code>null</code> not permitted).
* @param key the section key (<code>null</code> not permitted).
*
* @return the label (possibly <code>null</code>).
*/
@Override
public String generateSectionLabel(final PieDataset dataset, final Comparable key) {
String result = null;
if (dataset != null) {
if (!key.equals("I-Phone"))
{
result = key.toString();
}
}
return result;
}
}
}
谢谢..