我正试图简单地在for循环中旋转图像,如下所示:
class MyCanvas extends JComponent {
AffineTransform identity = new AffineTransform();
Image arrow;
Double angle = -180.0;
public void spin() {
angle += 10.0;
for(int i = 0; i < 10; i++) {
repaint();
System.out.println(i);
try {
Thread.sleep(1000);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
public void paint(Graphics g) {
Graphics2D g2 = (Graphics2D) g;
arrow = Toolkit.getDefaultToolkit().getImage("red-arrow-right-th.png");
// Rotate + translate
AffineTransform trans = new AffineTransform();
trans.setTransform(identity);
trans.translate(getWidth()/2, getHeight()/2);
trans.rotate(Math.toRadians(angle));
System.out.println(trans);
g2.drawImage(arrow, trans, this);
g2.finalize();
}
}
然而,当我在main中运行调用spin()
时,它似乎只应用了一次旋转,同时仍然正确地打印出循环。我在俯瞰什么?
我已经使用MadProgrammer的推荐转换了您的代码:
- 不要覆盖
paint
,要覆盖paintComponent
- 在执行任何自定义绘制之前,请调用CCD_ 4
- 永远不要在任何事情上调用
finalize
,尤其不要在你自己没有创建的对象上 - 使用摆动计时器
注意以下
-
限定的this用于从ActionListener内部类访问ImageRotationView实例。
-
AffineTransform.getRotateInstance
返回围绕锚点旋转坐标的变换。 - 速度可以优化,但它可以像这样正常工作
- 这个类作为一个独立的应用程序工作
- 基本目录中应该存在一个名为
dice.png
的文件
import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Image;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.geom.AffineTransform;
import java.io.File;
import java.io.IOException;
import javax.imageio.ImageIO;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.Timer;
public class ImageRotationFrame {
public static void main(String[] args) {
new ImageRotationFrame();
}
public ImageRotationFrame() {
EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
JFrame frame = new JFrame("Testing");
frame.setSize(400, 400);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.add(new ImageRotationComponent());
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
private class ImageRotationComponent extends JComponent {
Image arrow;
double angle = 0.0;
@Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
angle += 0.4;
AffineTransform trans = AffineTransform.getRotateInstance(angle, getWidth() / 2, getHeight() / 2);
((Graphics2D) g).drawImage(arrow, trans, this);
}
public ImageRotationComponent() {
try {
arrow = ImageIO.read(new File("dice.png"));
} catch (IOException e) {
e.printStackTrace();
}
int delay = 500; //milliseconds
ActionListener taskPerformer = new ActionListener() {
@Override
public void actionPerformed(ActionEvent evt) {
ImageRotationComponent.this.repaint();
}
};
new Timer(delay, taskPerformer).start();
}
}
}