Java如何绘制/绘制图形？

2024-04-16 10:35:04 262

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。

Java如何绘制/绘制图形？

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