java - 需要帮助在 2 个彼此重叠的 Jpanels 上绘画

Question

我正在为我 friend 正在制作的游戏创建 map 编辑器。游戏通过查看 png 文件来读取 map 。不同的十六进制颜色代码对应于不同的图 block 。现在，我让 map 编辑器按照游戏中显示的方式绘制 map (“预览”)。有没有一种方法可以将两个 JPanel 放在一起，这样只需单击一下即可在“预览”屏幕上绘制图 block ，并在第二个 JPanel 上绘制相应的颜色。我目前能够保存当前图像，我只想能够仅保存底部 JPanel(非预览)。

    package com.socialdonut.spriteworld_editor;

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Container;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Image;
import java.awt.RenderingHints;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;
import java.awt.geom.AffineTransform;
import java.awt.image.RenderedImage;
import java.io.File;
import java.io.IOException;

import javax.imageio.ImageIO;
import javax.swing.Icon;
import javax.swing.ImageIcon;
import javax.swing.JButton;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JPanel;


public class Main{

    public static void main(String[] args) throws IOException {
        Icon iconCT = new ImageIcon("cliffTop.png");
        Icon iconCM = new ImageIcon("cliffMid.png");
        Icon iconCB = new ImageIcon("cliffBot.png");
        Icon iconW = new ImageIcon("water.png");
        Icon iconG = new ImageIcon("grass.png");
        Icon iconP = new ImageIcon("water.png");

        JFrame frame = new JFrame("SpriteWorld Map Editor");

        Container content = frame.getContentPane();
        content.setLayout(new BorderLayout());

        final PadDraw drawPad = new PadDraw();

        content.add(drawPad, BorderLayout.CENTER);

        JPanel panel = new JPanel();
        panel.setPreferredSize(new Dimension(32, 68));
        panel.setMinimumSize(new Dimension(32, 68));
        panel.setMaximumSize(new Dimension(32, 68));

        JButton clearButton = new JButton("Clear");
        clearButton.addActionListener(new ActionListener(){
            public void actionPerformed(ActionEvent e){
                drawPad.clear();
            }
        });
        JButton saveButton = new JButton("Save");
        saveButton.addActionListener(new ActionListener(){
            public void actionPerformed(ActionEvent e){
                drawPad.save();
            }
        });

        JButton cliffBottomButton = new JButton(iconCB);
        cliffBottomButton.addActionListener(new ActionListener(){
            public void actionPerformed(ActionEvent e){
                drawPad.cliffBottom();
            }

        });

        JButton cliffMidButton = new JButton(iconCM);
        cliffMidButton.addActionListener(new ActionListener(){
            public void actionPerformed(ActionEvent e){
                drawPad.cliffMid();
            }
        });

        JButton cliffTopButton = new JButton(iconCT);
        cliffTopButton.addActionListener(new ActionListener(){
            public void actionPerformed(ActionEvent e){
                drawPad.cliffTop();
            }
        });

        JButton blueButton = new JButton(iconW);
        blueButton.addActionListener(new ActionListener(){
            public void actionPerformed(ActionEvent e){
                drawPad.blue();
            }
        });

        JButton greenButton = new JButton(iconG);
        greenButton.addActionListener(new ActionListener(){
            public void actionPerformed(ActionEvent e){
                drawPad.green();
            }
        });
        JButton pathButton = new JButton(iconP);
        pathButton.addActionListener(new ActionListener(){
            public void actionPerformed(ActionEvent e){
                drawPad.path();
            }
        });         
        cliffMidButton.setPreferredSize(new Dimension(16, 16));
        cliffTopButton.setPreferredSize(new Dimension(16, 16));
        cliffBottomButton.setPreferredSize(new Dimension(16, 16));
        blueButton.setPreferredSize(new Dimension(16, 16));
        greenButton.setPreferredSize(new Dimension(16,16));
        pathButton.setPreferredSize(new Dimension(16,16));

        panel.add(greenButton);
        panel.add(blueButton);
        panel.add(pathButton);
        panel.add(cliffTopButton);
        panel.add(cliffMidButton);
        panel.add(cliffBottomButton);
        panel.add(clearButton);
        panel.add(saveButton);

        content.add(panel, BorderLayout.WEST);

        frame.setSize(1366, 768);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setVisible(true);
    }
}


class PadDraw extends JComponent{

    Image image;
    Image img;
    Graphics2D graphics2D;
    int currentX, currentY, oldX, oldY;

    public PadDraw(){
        setDoubleBuffered(false);
        addMouseListener(new MouseAdapter(){
            public void mousePressed(MouseEvent e){
                oldX = e.getX();
                oldY = e.getY();
            }
        });
        addMouseListener(new MouseListener(){

            @Override
            public void mouseClicked(MouseEvent e) {
                currentX = e.getX();
                currentY = e.getY();
                if(graphics2D != null) {
                    int displayX = (int) currentX/10, displayY = (int)currentY/10;
                    if (displayX%2 == 1)
                        displayX--;
                    if (displayY%2 == 1)
                        displayY--;
                    //graphics2D.fill(new Rectangle2D.Double(displayX, displayY, 2, 2));
                    graphics2D.drawImage(img, displayX, displayY, 2, 2, null);
                }
                repaint();
                oldX = currentX;
                oldY = currentY;
            }

            @Override
            public void mouseEntered(MouseEvent arg0) {

            }

            @Override
            public void mouseExited(MouseEvent arg0) {

            }

            @Override
            public void mousePressed(MouseEvent arg0) {

            }

            @Override
            public void mouseReleased(MouseEvent arg0) {

            }
        });
    }
public void save() {
    try {
        ImageIO.write((RenderedImage) image, "PNG", new File("map1_back.png"));
    } catch (IOException e) {
        e.printStackTrace();
    }
}
public void paintComponent(Graphics g){
        if(image == null){
            image = createImage(getSize().width, getSize().height);
            graphics2D = (Graphics2D)image.getGraphics();
            graphics2D.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
            AffineTransform tx1 = new AffineTransform();
            tx1.scale(10, 10);
            graphics2D.setTransform(tx1);
            clear();

        }
        g.drawImage(image, 0, 0, null);
    }

    public void clear(){
        graphics2D.setPaint(new Color(Integer.parseInt("000000", 16)));
        graphics2D.fillRect(0, 0, getSize().width, getSize().height);
        repaint();
    }
    public void cliffBottom(){
        //graphics2D.setPaint(new Color(Integer.parseInt("ca8e0c", 16)));
        try {
            img = ImageIO.read(new File("cliffBot.png"));
        } catch (IOException e1) {
            e1.printStackTrace();
        }
        repaint();
    }
    public void cliffMid(){
        //graphics2D.setPaint(new Color(Integer.parseInt("ac790b", 16)));
        try {
            img = ImageIO.read(new File("cliffMid.png"));
        } catch (IOException e1) {
        e1.printStackTrace();
        }
        repaint();
    }
    public void cliffTop(){
        //graphics2D.setPaint(new Color(Integer.parseInt("725006", 16)));
        try {
            img = ImageIO.read(new File("cliffTop.png"));
        } catch (IOException e1) {
            e1.printStackTrace();
        }
        repaint();
    }
    public void blue(){
        //graphics2D.setPaint(new Color(Integer.parseInt("0000ff", 16)));
        try {
            img = ImageIO.read(new File("water.png"));
        } catch (IOException e1) {
            e1.printStackTrace();
        }
        repaint();
    }
    public void green(){
        //graphics2D.setPaint(new Color(Integer.parseInt("00ff00", 16)));
        try {
            img = ImageIO.read(new File("grass.png"));
        } catch (IOException e1) {
            e1.printStackTrace();
        }
        repaint();
    }
    public void path(){
        try {
            img = ImageIO.read(new File("water.png"));
        } catch (IOException e1) {
            e1.printStackTrace();
        }
    repaint();
    }
}   

Answer 1

要执行您所描述的操作，有多种方法，其他答案涵盖了这一点。

有一种更好的方法，即使用单个面板来显示然后在该面板中渲染多个图像。您会发现这更加灵活并且性能更好。