我正在制作一个类似于 MS Paint 的简单程序。我创建了一个空白的自定义图像作为我的“画布”。但是，每当我放大窗口时，图像都会保持相同的大小。当我调整窗口大小时，如何才能使图像适合？
我的代码是：
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Container;
import java.awt.Cursor;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Image;
import java.awt.Point;
import java.awt.RenderingHints;
import java.awt.Toolkit;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.awt.event.MouseMotionAdapter;
import java.awt.image.BufferedImage;
import javax.swing.BorderFactory;
import javax.swing.JButton;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JPanel;
public class ScribblePad extends JFrame {
// Setting GUI variables...
public static int WIDTH = 800;
public static int HEIGHT = 800;
public static int X = 10;
public static int Y = 10;
public static String TITLE = "ScribblePad";
// Create GUI components...
PaintPanel paintPanel = new PaintPanel();
JPanel buttonPanel = new JPanel();
Container mainContainer = getContentPane();
JButton clearButton = new JButton("Clear");
JButton buttonBlack = new JButton();
JButton buttonRed = new JButton();
JButton buttonBlue = new JButton();
JButton buttonYellow = new JButton();
JButton buttonGreen = new JButton();
Cursor crosshairCursor = Cursor.getPredefinedCursor(Cursor.CROSSHAIR_CURSOR);
// Run the entire program...
public static void main(String []args) {
new ScribblePad();
}
// Create ScribblePad constructor...
public ScribblePad() {
// Setting JFrame properties...
super(TITLE);
setVisible(true);
setSize(WIDTH, HEIGHT);
setLocation(X, Y);
setDefaultCloseOperation(EXIT_ON_CLOSE);
// Setting properties of other components...
paintPanel.setCursor(crosshairCursor);
buttonPanel.setBackground(Color.WHITE);
buttonPanel.setBorder(BorderFactory.createMatteBorder(0, 0, 1, 0, Color.BLACK));
// Adding the components...
mainContainer.add(paintPanel, BorderLayout.CENTER);
mainContainer.add(buttonPanel, BorderLayout.NORTH);
// Adding ActionListeners and setting properties of the buttons..
buttonBlack.setBackground(Color.BLACK);
buttonBlack.setForeground(Color.BLACK);
buttonBlack.setPreferredSize(new Dimension(32, 32));
buttonRed.setBackground(Color.RED);
buttonRed.setForeground(Color.RED);
buttonRed.setPreferredSize(new Dimension(32, 32));
buttonGreen.setBackground(Color.GREEN);
buttonGreen.setForeground(Color.GREEN);
buttonGreen.setPreferredSize(new Dimension(32, 32));
buttonBlue.setBackground(Color.BLUE);
buttonBlue.setForeground(Color.BLUE);
buttonBlue.setPreferredSize(new Dimension(32, 32));
buttonYellow.setBackground(Color.YELLOW);
buttonYellow.setForeground(Color.YELLOW);
buttonYellow.setPreferredSize(new Dimension(32, 32));
clearButton.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent e){
paintPanel.clearCanvas();
}
});
buttonBlack.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent e){
paintPanel.setBlack();
}
});
buttonGreen.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent e){
paintPanel.setGreen();
}
});
buttonRed.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent e){
paintPanel.setRed();
}
});
buttonYellow.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent e){
paintPanel.setYellow();
}
});
buttonBlue.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent e){
paintPanel.setBlue();
}
});
// Adding buttons to the buttonPanel...
buttonPanel.add(buttonBlack);
buttonPanel.add(buttonRed);
buttonPanel.add(buttonGreen);
buttonPanel.add(buttonBlue);
buttonPanel.add(buttonYellow);
buttonPanel.add(clearButton);
}
public class PaintPanel extends JComponent {
Image blankCanvas;
Graphics2D g2D;
int mouseX, mouseY, oldX, oldY;
String currentColour = "BLACK";
public PaintPanel() {
setDoubleBuffered(true);
addMouseListener(new MouseAdapter() {
public void mousePressed(MouseEvent e) {
oldX = e.getX();
oldY = e.getY();
g2D.drawOval(oldX, oldY, 1, 1);
System.out.println("[Debug] Point drawn at (" + oldX + ", " + oldY + ").");
repaint();
}
});
addMouseMotionListener(new MouseMotionAdapter(){
public void mouseDragged(MouseEvent e){
mouseX = e.getX();
mouseY = e.getY();
if(g2D != null)
g2D.drawLine(oldX, oldY, mouseX, mouseY);
repaint();
System.out.println("[Debug] Line drawn from (" + oldX + ", " + oldY + ") to (" + mouseX + ", " + mouseY + ").");
oldX = mouseX;
oldY = mouseY;
}
});
}
public void paintComponent(Graphics g) {
if (blankCanvas == null) {
blankCanvas = this.createImage(getWidth(), getHeight());
g2D = (Graphics2D)blankCanvas.getGraphics();
g2D.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
clearCanvas();
}
g.drawImage(blankCanvas, 0, 0, null);
}
public void clearCanvas() {
g2D.setPaint(Color.WHITE);
g2D.fillRect(0, 0, getSize().width, getSize().height);
switch(currentColour) {
case "BLACK": g2D.setColor(Color.BLACK); break;
case "RED": g2D.setColor(Color.RED); break;
case "GREEN": g2D.setColor(Color.GREEN); break;
case "BLUE": g2D.setColor(Color.BLUE); break;
case "YELLOW": g2D.setColor(Color.YELLOW); break;
}
System.out.println("[Debug] Canvas cleared.");
repaint();
}
public void setBlack() {
g2D.setColor(Color.BLACK);
System.out.println("[Debug] Colour changed to black.");
currentColour = "BLACK";
}
public void setRed() {
g2D.setColor(Color.RED);
System.out.println("[Debug] Colour changed to red.");
currentColour = "RED";
}
public void setBlue() {
g2D.setColor(Color.BLUE);
System.out.println("[Debug] Colour changed to blue.");
currentColour = "BLUE";
}
public void setYellow() {
g2D.setColor(Color.YELLOW);
System.out.println("[Debug] Colour changed to yellow.");
currentColour = "YELLOW";
}
public void setGreen() {
g2D.setColor(Color.GREEN);
System.out.println("[Debug] Colour changed to green.");
currentColour = "GREEN";
}
}
}