如何在java中编辑曲线

Question

我正在制作一个能够在鼠标事件上在JPanel上绘制曲线的Java程序。

现在我想在绘制该曲线后询问，如何编辑该曲线？

这是我的Java程序：

import java.awt.*;
import java.awt.event.*;
import java.awt.geom.QuadCurve2D;
import java.awt.image.BufferedImage;
import java.util.ArrayList;
import java.util.List;
import java.util.Random;
import java.util.Vector;

import javax.swing.*;

public class MouseTestHovercraft extends JPanel {
    private static final int PREF_W = 600;
    private static final int PREF_H = PREF_W;
    private static final int MAX_CLR = 5;
    private static final Color CURRENT_LIST_COLOR = new Color(190, 190, 255);
    private List<Color> colors = new ArrayList<Color>();
    private boolean tracking = false;
    private List<Point> currentList = null;
    private BufferedImage bufferedImage = new BufferedImage(PREF_W, PREF_H,
            BufferedImage.TYPE_INT_ARGB);
    private Random random = new Random();

这个构造函数用于在释放鼠标后立即改变曲线的颜色。

    public MouseTestHovercraft() {
        for (int redIndex = 0; redIndex < MAX_CLR; redIndex++) {
            int r = (redIndex * 256) / (MAX_CLR - 1);
            r = (r == 256) ? 255 : r;
            for (int greenIndex = 0; greenIndex < MAX_CLR; greenIndex++) {
                int g = (greenIndex * 256) / (MAX_CLR - 1);
                g = (g == 256) ? 255 : g;
                for (int blueIndex = 0; blueIndex < MAX_CLR; blueIndex++) {
                    int b = (blueIndex * 256) / (MAX_CLR - 1);
                    b = (b == 256) ? 255 : b;
                    Color c = new Color(r, g, b);
                    colors.add(c);
                }
            }
        }

        add(new JToggleButton(new AbstractAction("TrackMouse") {
            public void actionPerformed(ActionEvent ae) {
                trackMouse(ae);
            }
        }));
        add(new JButton(new AbstractAction("Clear Image") {
            public void actionPerformed(ActionEvent e) {
                bufferedImage = new BufferedImage(getWidth(), getHeight(),
                        BufferedImage.TYPE_INT_ARGB);
                repaint();
            }
        }));

        MyMouseAdapter myMA = new MyMouseAdapter();
        addMouseListener(myMA);
        addMouseMotionListener(myMA);
    }

这用于监听跟踪按钮的事件。

    private void trackMouse(ActionEvent ae) {
        JToggleButton toggleBtn = (JToggleButton) ae.getSource();
        tracking = toggleBtn.isSelected();
    }

    @Override
    public Dimension getPreferredSize() {
        return new Dimension(PREF_W, PREF_H);
    }

    public void msg(String message) {
        System.out.println(message);
    }

    @Override
    protected void paintComponent(Graphics g) {
        super.paintComponent(g);
        g.drawImage(bufferedImage, 0, 0, null);
        if (currentList != null) {
            drawList(g, currentList, CURRENT_LIST_COLOR, 1f);
        }
    }

这将使用quadcurve

在jpanel上绘制曲线

    private void drawList(Graphics g, List<Point> ptList, Color color,
            float strokeWidth) {
        if (ptList.size() > 1) {
            Graphics2D g2 = (Graphics2D) g.create();
            //        Graphics2D g2 = (Graphics2D) g;
            g2.setColor(color);
            //         g2.setStroke(new BasicStroke(strokeWidth));
            QuadCurve2D selectedCurve = null;
            for (int j = 0; j < ptList.size() - 1; j++) {
                int x1 = ptList.get(j).x;
                int y1 = ptList.get(j).y;
                int x2 = ptList.get(j + 1).x;
                int y2 = ptList.get(j + 1).y;

                selectedCurve =new QuadCurve2D.Float(x1, y1, 5, 5, x2,y2);

                g2.draw(selectedCurve);

            }
            g2.dispose();
        }
    }

在鼠标按下时，此代码将首先将起点添加到当前列表列表中，然后在释放鼠标之前将所有点添加到当前列表中。

    private class MyMouseAdapter extends MouseAdapter {



        @Override
        public void mousePressed(MouseEvent e) {
            if (tracking && e.getButton() == MouseEvent.BUTTON1) {
                currentList = new ArrayList<Point>();


                currentList.add(e.getPoint());
            }
        }

        @Override
        public void mouseReleased(MouseEvent e) {
            if (tracking && e.getButton() == MouseEvent.BUTTON1) {
                currentList.add(e.getPoint());
                Graphics2D g2 = bufferedImage.createGraphics();
                Color color = colors.get(random.nextInt(colors.size()));
                drawList(g2, currentList, color, 3f);
                currentList = null;
                repaint();
            }
        }

        @Override
        public void mouseDragged(MouseEvent e) {
            if (tracking && currentList != null) {
                currentList.add(e.getPoint());
                repaint();
            }
        }
    }

    private static void createAndShowGui() {
        MouseTestHovercraft mainPanel = new MouseTestHovercraft();

        JFrame frame = new JFrame("MouseMotion Eg");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.getContentPane().add(mainPanel);
        frame.setResizable(false);
        frame.pack();
        frame.setLocationByPlatform(true);
        frame.setVisible(true);
    }

    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                createAndShowGui();
            }
        });
    }
}