我一直在尝试使用for循环旋转图像。我的代码确实有效,但是此方法似乎不必要,并且图像在旋转时会丢失像素。有没有更简单的方法可以做到这一点?
//rotates image around center a degrees
public void drawRotatedImage(Graphics g, BufferedImage image, double a, int x, int y, int pixelSize) {
//origin point for rotation
int rX = image.getWidth() / 2;
int rY = image.getHeight() / 2;
for(int x1 = 0; x1 < image.getWidth(); x1++) {
for(int y1 = 0; y1 < image.getHeight(); y1++) {
int c = image.getRGB(x1, y1);
//rotating point
int nX = (int) (((x1-rX) * Math.cos(a)) - ((y1-rY) * Math.sin(a)));
int nY = (int) (((x1-rX) * Math.sin(a)) + ((y1-rY) * Math.cos(a)));
g.setColor(new Color(c));
//drawing each pixel
g.fillRect((nX*pixelSize) + x, (nY*pixelSize) + y, pixelSize, pixelSize);
}
}
}
我创建了一个简单的示例程序(改编自Rotating BufferedImage instances)
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.geom.AffineTransform;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.net.URL;
import javax.imageio.ImageIO;
import javax.swing.JComponent;
import javax.swing.JFrame;
public class Main {
public static void main(String[] args) throws IOException {
JFrame frame = new JFrame("Test");
frame.add(new JComponent() {
BufferedImage image = ImageIO.read(new URL(
"https://upload.wikimedia.org/wikipedia/commons/thumb/9/9e/%D0%9D%D0%B5%D1%80%D0%BF%D0%B8%D1%87%D0%B8%D0%B9_%D0%B2%D0%B7%D0%B3%D0%BB%D1%8F%D0%B4.jpg/500px-%D0%9D%D0%B5%D1%80%D0%BF%D0%B8%D1%87%D0%B8%D0%B9_%D0%B2%D0%B7%D0%B3%D0%BB%D1%8F%D0%B4.jpg"));
@Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
AffineTransform at = new AffineTransform();
at.translate(getWidth() / 2, getHeight() / 2); // draw image in center of frame
// at.scale(0.5, 0.5);
at.rotate(Math.toRadians(180));
at.translate(-image.getWidth() / 2, -image.getHeight() / 2); // rotate around the center
Graphics2D g2d = (Graphics2D) g;
g2d.drawImage(image, at, null);
}
});
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(800, 800);
frame.setVisible(true);
}
}
尝试使用AffineTransform
获取旋转的实例
static void rotate(BufferedImage from, BufferedImage to, double rotate)
{
double x = from.getWidth() /2;
double y = from.getHeight() /2;
// rotate around the center
double f = rotate; // 6.284 is full turn
AffineTransform trans = AffineTransform.getRotateInstance(f, x, y);
AffineTransformOp op = new AffineTransformOp(trans,
AffineTransformOp.TYPE_BILINEAR);
op.filter(from, to);
}
或如果您只想显示它
static void rotate(Graphics2d g2d, BufferedImage img, double rotate)
{
double x = from.getWidth() /2;
double y = from.getHeight() /2;
// rotate around the center
double f = rotate; // 6.284 is full turn
AffineTransform trans = AffineTransform.getRotateInstance(f, x, y);
g2d.drawImage(img, trans, null);
}