除了@tulskiy的有益观察之外,我还要补充两点:
始终在事件分发线程上构造GUI ,如下所示。
一个sscce应该是一个简短的,自包含的,正确的(可编译的)示例。为方便起见,不要要求其他人重新创建多个公共类。使用顶级(package-private)或嵌套类。由于这是图形问题,因此请使用反映您问题的公共或合成图像。
在下面的示例中,
paintComponent()更改图形上下文的变换以实现旋转。请注意,操作是以声明顺序的(明显)相反的顺序执行的:首先,将图像的中心平移到原点;第二,旋转图像。第三,将图像的中心平移到面板的中心。您可以通过调整面板大小来查看效果。
附录:另请参见使用的另一种方法
AffineTransform。
package overflow;import java.awt.*;import java.awt.event.*;import java.awt.image.BufferedImage;import java.util.Random;import javax.swing.*;public class RotateApp { private static final int N = 3; public static void main(String[] args) { EventQueue.invokeLater(new Runnable() { @Override public void run() { Jframe frame = new Jframe(); frame.setLayout(new GridLayout(N, N, N, N)); frame.setDefaultCloseOperation(Jframe.EXIT_ON_CLOSE); for (int i = 0; i < N * N; i++) { frame.add(new RotatePanel()); } frame.pack(); frame.setVisible(true); } }); }}class RotatePanel extends JPanel implements ActionListener { private static final int SIZE = 256; private static double DELTA_THETA = Math.PI / 90; private final Timer timer = new Timer(25, this); private Image image = RotatableImage.getImage(SIZE); private double dt = DELTA_THETA; private double theta; public RotatePanel() { this.setBackground(Color.lightGray); this.setPreferredSize(new Dimension( image.getWidth(null), image.getHeight(null))); this.addMouseListener(new MouseAdapter() { @Override public void mousePressed(MouseEvent e) { image = RotatableImage.getImage(SIZE); dt = -dt; } }); timer.start(); } @Override public void paintComponent(Graphics g) { super.paintComponent(g); Graphics2D g2d = (Graphics2D) g; g2d.translate(this.getWidth() / 2, this.getHeight() / 2); g2d.rotate(theta); g2d.translate(-image.getWidth(this) / 2, -image.getHeight(this) / 2); g2d.drawImage(image, 0, 0, null); } @Override public void actionPerformed(ActionEvent e) { theta += dt; repaint(); } @Override public Dimension getPreferredSize() { return new Dimension(SIZE, SIZE); }}class RotatableImage { private static final Random r = new Random(); static public Image getImage(int size) { BufferedImage bi = new BufferedImage( size, size, BufferedImage.TYPE_INT_ARGB); Graphics2D g2d = bi.createGraphics(); g2d.setRenderingHint( RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON); g2d.setPaint(Color.getHSBColor(r.nextFloat(), 1, 1)); g2d.setStroke(new BasicStroke(size / 8)); g2d.drawLine(0, size / 2, size, size / 2); g2d.drawLine(size / 2, 0, size / 2, size); g2d.dispose(); return bi; }}


