java - 在java中将图像旋转90度

Question

我已经设法旋转图像180 degrees，但希望旋转它90 degrees clockwise可以有人编辑我的代码，以便它通过解释来做到这一点。谢谢。

 private void rotateClockwise()
    {
        if(currentImage != null){
            int width = currentImage.getWidth();
            int height = currentImage.getHeight();
            OFImage newImage = new OFImage(width, height);
            for(int y = 0; y < height; y++) {
                for(int x = 0; x < width; x++) {
                    newImage.setPixel( x, height-y-1, currentImage.getPixel(x, y));
                }
        }
            currentImage = newImage;
            imagePanel.setImage(currentImage);
            frame.pack();
    }
    }

Answer 1

使用此方法。

/**
 * Rotates an image. Actually rotates a new copy of the image.
 * 
 * @param img The image to be rotated
 * @param angle The angle in degrees
 * @return The rotated image
 */
public static Image rotate(Image img, double angle)
{
    double sin = Math.abs(Math.sin(Math.toRadians(angle))),
           cos = Math.abs(Math.cos(Math.toRadians(angle)));

    int w = img.getWidth(null), h = img.getHeight(null);

    int neww = (int) Math.floor(w*cos + h*sin),
        newh = (int) Math.floor(h*cos + w*sin);

    BufferedImage bimg = toBufferedImage(getEmptyImage(neww, newh));
    Graphics2D g = bimg.createGraphics();

    g.translate((neww-w)/2, (newh-h)/2);
    g.rotate(Math.toRadians(angle), w/2, h/2);
    g.drawRenderedImage(toBufferedImage(img), null);
    g.dispose();

    return toImage(bimg);
}

取自我的ImageTool类。

希望能帮助到你。

Answer 2

看看http://docs.oracle.com/javase/tutorial/2d/index.html和http://docs.oracle.com/javase/6/docs/api/java/awt/Graphics2D.html# rotate%28double%29以及这篇文章Rotate an image in java