该程序读取数据文件并在文件中绘制数据点的图形。该图形绘制在具有三个部分的窗口中。第一部分包含三个按钮，用于启动程序的操作。动作也可以通过控制键启动。
第二部分显示要绘制图形的数据，并允许用户编辑图形数据。最后一部分显示图形。
package org.nhooo.example.geom;
import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.font.FontRenderContext;
import java.awt.font.LineMetrics;
import java.awt.geom.Ellipse2D;
import java.awt.geom.Line2D;
import java.awt.geom.Point2D;
import java.awt.geom.Rectangle2D;
import java.io.*;
public class Plot {
public static void main(String[] args) {
JFrame frame = new JFrame("Plot");
frame.getContentPane().setLayout(new BorderLayout());
frame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
String className = UIManager.getSystemLookAndFeelClassName();
UIManager.setLookAndFeel(className);
JPanel commandPanel = new JPanel(new FlowLayout());
JButton openButton = new JButton("Open Ctrl-O");
JButton plotButton = new JButton("Plot Ctrl-P");
JButton quitButton = new JButton("Quit Ctrl-Q");
quitButton.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
System.exit(0);
}
});
commandPanel.registerKeyboardAction(new ActionListener() {
public void actionPerformed(ActionEvent e) {
System.exit(0);
}
}, KeyStroke.getKeyStroke("control Q"), JComponent.WHEN_IN_FOCUSED_WINDOW);
commandPanel.add(openButton);
commandPanel.add(plotButton);
commandPanel.add(quitButton);
frame.getContentPane().add(commandPanel, "North");
GraphPanel graphpanel = new GraphPanel(frame);
plotButton.addActionListener(graphpanel);
commandPanel.registerKeyboardAction(graphpanel,
KeyStroke.getKeyStroke("control P"),
JComponent.WHEN_IN_FOCUSED_WINDOW);
openButton.addActionListener(graphpanel.getDataPanel());
commandPanel.registerKeyboardAction(graphpanel.getDataPanel(),
KeyStroke.getKeyStroke("control O"),
JComponent.WHEN_IN_FOCUSED_WINDOW);
frame.setVisible(true);
frame.pack();
}
}
class GraphPanel implements ActionListener {
private DataPanel datapanel;
private JFrame frame;
private GraphicPanel panel;
GraphPanel(JFrame newFrame) {
frame = newFrame;
panel = new GraphicPanel();
panel.setDisplayPlot(false);
datapanel = new DataPanel(frame);
panel.setDataPanel(datapanel);
frame.getContentPane().add(panel, "Center");
}
public void actionPerformed(ActionEvent e) {
if (!datapanel.isInitialized()) {
return;
}
datapanel.refreshData();
panel.setDisplayPlot(true);
panel.update(panel.getGraphics());
frame.setSize(700, 600);
frame.setVisible(true);
frame.pack();
}
ActionListener getDataPanel() {
return datapanel;
}
}
class GraphicPanel extends JPanel {
private boolean display_plot;
private DataPanel d;
public void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2d = (Graphics2D) g;
g2d.setPaint(Color.black);
g2d.setStroke(new BasicStroke());
g2d.setFont(new Font("Century Schoolbook", Font.PLAIN, 12));
if (d.isInitialized() && display_plot) {
d.refreshData();
Float xLower = d.getXLower();
Float xUpper = d.getXUpper();
Float xInterval = d.getXInterval();
Float yLower = d.getYLower();
Float yUpper = d.getYUpper();
Float yInterval = d.getYInterval();
Float dx = xUpper - xLower;
Float dy = yUpper - yLower;
drawCenteredString(g2d, d.getTitle(), 250, 25, (float) 0.);
drawCenteredString(g2d, d.getXTitle(), 250, 475, (float) 0.);
drawCenteredString(g2d, d.getYTitle(), 25, 250,
(float) -Math.PI / 2);
drawCenteredString(g2d, xLower.toString(), 50, 475, (float) 0);
drawCenteredString(g2d, xUpper.toString(), 450, 475, (float) 0);
drawCenteredString(g2d, yLower.toString(), 25, 450, (float) 0);
drawCenteredString(g2d, yUpper.toString(), 25, 50, (float) 0);
g2d.setPaint(Color.gray);
for (Float x = 50f; x <= 450; x += 400 * xInterval / dx)
g2d.draw(new Line2D.Float(x, 450, x, 50));
for (Float y = 50f; y <= 450; y += 400 * yInterval / dy)
g2d.draw(new Line2D.Float(45, y, 450, y));
g2d.setPaint(Color.red);
Float diam = 8f;
int num_points = d.getNumberOfPoints();
for (int i = 0; i < num_points; i++) {
Float ex = 400 * (d.getPoint(i).x - xLower) / dx + 50;
ex -= diam / 2;
Float ey = -400 * (d.getPoint(i).y - yLower) / dy + 450;
ey -= diam / 2;
g2d.fill(new Ellipse2D.Float(ex, ey, diam, diam));
}
}
}
void setDataPanel(DataPanel new_d) {
d = new_d;
}
void setDisplayPlot(boolean new_display) {
display_plot = new_display;
}
private void drawCenteredString(Graphics2D g2d, String string,
int x0, int y0, float angle) {
FontRenderContext frc = g2d.getFontRenderContext();
Rectangle2D bounds = g2d.getFont().getStringBounds(string, frc);
LineMetrics metrics = g2d.getFont().getLineMetrics(string, frc);
if (angle == 0) {
g2d.drawString(string, x0 - (float) bounds.getWidth() / 2,
y0 + metrics.getHeight() / 2);
} else {
g2d.rotate(angle, x0, y0);
g2d.drawString(string, x0 - (float) bounds.getWidth() / 2,
y0 + metrics.getHeight() / 2);
g2d.rotate(-angle, x0, y0);
}
}
}
class DataPanel implements ActionListener {
private boolean initialized;
private int titleIndex, xTitleIndex, yTitleIndex;
private int xLowerIndex, xUpperIndex, xIntervalIndex;
private int yLowerIndex, yUpperIndex, yIntervalIndex;
private JFrame frame;
private JPanel panel;
private String title;
private String xTitle;
private String yTitle;
private float xLower, xUpper, xInterval;
private float yLower, yUpper, yInterval;
private Point2D.Float[] points;
private JLabel[] paramLabels;
private JTextField[] paramFields;
private JTextField[] dataFields;
DataPanel(JFrame newFrame) {
initialized = false;
titleIndex = 0;
xTitleIndex = 1;
xLowerIndex = 2;
xUpperIndex = 3;
xIntervalIndex = 4;
yTitleIndex = 5;
yLowerIndex = 6;
yUpperIndex = 7;
yIntervalIndex = 8;
paramLabels = new JLabel[9];
paramLabels[titleIndex] = new JLabel("Title");
paramLabels[xTitleIndex] = new JLabel("X Axis Title");
paramLabels[yTitleIndex] = new JLabel("Y Axis Title");
paramLabels[xLowerIndex] = new JLabel("X lower bound");
paramLabels[xUpperIndex] = new JLabel("X upper bound");
paramLabels[xIntervalIndex] = new JLabel("X tick interval");
paramLabels[yLowerIndex] = new JLabel("Y lower bound");
paramLabels[yUpperIndex] = new JLabel("Y upper bound");
paramLabels[yIntervalIndex] = new JLabel("Y tick interval");
paramFields = new JTextField[9];
paramFields[titleIndex] = new JTextField("Test Title");
paramFields[xTitleIndex] = new JTextField("X");
paramFields[yTitleIndex] = new JTextField("Y");
paramFields[xLowerIndex] = new JTextField("0");
paramFields[xUpperIndex] = new JTextField("10");
paramFields[xIntervalIndex] = new JTextField("1");
paramFields[yLowerIndex] = new JTextField("0");
paramFields[yUpperIndex] = new JTextField("10");
paramFields[yIntervalIndex] = new JTextField("1");
frame = newFrame;
panel = new JPanel(new FlowLayout());
frame.getContentPane().add(panel, "West");
}
public void actionPerformed(ActionEvent e) {
JFrame fileFrame = new JFrame();
JPanel filePanel = new JPanel();
JFileChooser fileChooser = new JFileChooser();
fileFrame.getContentPane().add(filePanel);
filePanel.add(fileChooser);
fileChooser.setFileSelectionMode(JFileChooser.FILES_ONLY);
int result = fileChooser.showOpenDialog(filePanel);
if (result != JFileChooser.APPROVE_OPTION) {
JLabel msg = new JLabel("No file selected");
panel.add(msg);
return;
}
File datafile = fileChooser.getSelectedFile();
initialized = readFile(datafile);
panel.update(panel.getGraphics());
frame.pack();
frame.setVisible(true);
}
// 数据文件包含两个部分。
// 第一部分包含用于配置图形的参数。
// 每行以单个单词标识符开头，后跟一个空格。
// 该行的其余部分是值。
// 它由包含单词“ Data”的行终止。"Data".
// 第二部分包含将要绘制图形的数据对。
private boolean readFile(File datafile) {
int numAllocated = 10;
int numRead = 0;
int numDataPoints = 0;
String[] dataStrings = new String[numAllocated];
BufferedReader reader = null;
try {
reader = new BufferedReader(new FileReader(datafile));
String text;
while ((text = reader.readLine()) != null) {
if (numRead >= numAllocated) {
numAllocated = 2 * numAllocated;
String[] temp = dataStrings;
dataStrings = new String[numAllocated];
System.arraycopy(temp, 0, dataStrings, 0, numRead);
}
dataStrings[numRead] = text;
numRead = numRead + 1;
}
} catch (FileNotFoundException e) {
System.out.println("File not found");
} catch (IOException e) {
System.out.println("IO Exception");
}
try {
if (reader != null)
reader.close();
} catch (IOException e) {
System.out.println("IO Exception on close");
}
int thisCase = -2;
int thisDataPoint = 0;
for (int i = 0; i < numRead; i++) {
String[] segments = dataStrings[i].split(" ");
if (segments[0].equals("Title")) {
thisCase = titleIndex;
} else if (segments[0].equals("xTitle")) {
thisCase = xTitleIndex;
} else if (segments[0].equals("yTitle")) {
thisCase = yTitleIndex;
} else if (segments[0].equals("xLower")) {
thisCase = xLowerIndex;
} else if (segments[0].equals("xUpper")) {
thisCase = xUpperIndex;
} else if (segments[0].equals("xInterval")) {
thisCase = xIntervalIndex;
} else if (segments[0].equals("yLower")) {
thisCase = yLowerIndex;
} else if (segments[0].equals("yUpper")) {
thisCase = yUpperIndex;
} else if (segments[0].equals("yInterval")) {
thisCase = yIntervalIndex;
} else if (segments[0].equals("Data")) {
thisCase = -1;
numDataPoints = numRead - i - 1;
dataFields = new JTextField[2 * numDataPoints];
points = new Point2D.Float[numDataPoints];
} else if (thisCase != -1) {
thisCase = -2;
}
if (thisCase >= 0 && segments.length > 1) {
StringBuilder temp = new StringBuilder(segments[1]);
for (int j = 2; j < segments.length; j++)
temp.append(" ").append(segments[j]);
paramFields[thisCase].setText(temp.toString());
thisCase = -2;
} else if (thisCase == -1 && !segments[0].equals("Data")
&& thisDataPoint < numDataPoints) {
dataFields[2 * thisDataPoint] = new JTextField(segments[0]);
dataFields[2 * thisDataPoint + 1] = new JTextField(segments[1]);
thisDataPoint++;
}
}
frame.getContentPane().remove(panel);
panel = new JPanel(new GridLayout(9 + numDataPoints, 2));
for (int i = 0; i < 9; i++) {
panel.add(paramLabels[i]);
panel.add(paramFields[i]);
}
for (int i = 0; i < numDataPoints; i++) {
panel.add(dataFields[2 * i]);
panel.add(dataFields[2 * i + 1]);
}
frame.getContentPane().add(panel, "West");
return true;
}
// 从面板读取数据，以防用户进行任何更改
void refreshData() {
if (!initialized) {
return;
}
title = paramFields[titleIndex].getText();
xTitle = paramFields[xTitleIndex].getText();
yTitle = paramFields[yTitleIndex].getText();
xLower = Float.parseFloat(paramFields[xLowerIndex].getText());
xUpper = Float.parseFloat(paramFields[xUpperIndex].getText());
xInterval = Float.parseFloat(paramFields[xIntervalIndex].getText());
yLower = Float.parseFloat(paramFields[yLowerIndex].getText());
yUpper = Float.parseFloat(paramFields[yUpperIndex].getText());
yInterval = Float.parseFloat(paramFields[yIntervalIndex].getText());
for (int i = 0; i < points.length; i++) {
Float x = Float.parseFloat(dataFields[2 * i].getText());
Float y = Float.parseFloat(dataFields[2 * i + 1].getText());
points[i] = new Point2D.Float(x, y);
}
}
boolean isInitialized() {
return initialized;
}
String getTitle() {
return title;
}
String getXTitle() {
return xTitle;
}
String getYTitle() {
return yTitle;
}
float getXLower() {
return xLower;
}
float getXUpper() {
return xUpper;
}
float getXInterval() {
return xInterval;
}
float getYLower() {
return yLower;
}
float getYUpper() {
return yUpper;
}
float getYInterval() {
return yInterval;
}
int getNumberOfPoints() {
return points.length;
}
Point2D.Float getPoint(int i) {
if (i < 0) {
i = 0;
} else if (i >= points.length) {
i = points.length - 1;
}
return points[i];
}
}这是数据文件示例，您可以将其另存为test.txt。
Title Test String Xtitle X axis Ytitle Y axis Xlower 0 Xupper 10 Xinterval 1.0 Ylower 0 Yupper 10 Yinterval 1 Data 0 0 0.25 0.0625 0.5 0.25 0.75 0.5625 1 1 1.25 1.5625 1.5 2.25 1.75 3.0625 2 4 2.25 5.0625 2.5 6.25 2.75 7.5625 3 9 3.25 7.5625 3.5 6.25 3.75 5.0625 4.0 4 4.25 3.0625 4.5 2.25 4.75 1.5625 5.0 1 5.25 0.5625 5.5 0.25 5.75 0.0625 6 0
运行程序显示结果。