旋转图像对象

因此，基于此答案中的示例，您应该能够设计一种旋转方法，该方法可以将源图像旋转给定的度数，例如…

  // Make sure you actually load some image and assign it to this  // variable, otherwise you will have a NullPointerException to   // deal with  private BufferedImage source;  public Image rotateBy(double degrees) {    // The size of the original image    int w = source.getWidth();    int h = source.getHeight();    // The angel of the rotation in radians    double rads = Math.toRadians(degrees);    // Some nice math which demonstrates I have no idea what I'm talking about    // Okay, this calculates the amount of space the image will need in    // order not be clipped when it's rotated    double sin = Math.abs(Math.sin(rads));    double cos = Math.abs(Math.cos(rads));    int newWidth = (int) Math.floor(w * cos + h * sin);    int newHeight = (int) Math.floor(h * cos + w * sin);    // A new image, into which the original can be painted    BufferedImage rotated = new BufferedImage(newWidth, newHeight, BufferedImage.TYPE_INT_ARGB);    Graphics2D g2d = rotated.createGraphics();    // The transformation which will be used to actually rotate the image    // The translation, actually makes sure that the image is positioned onto    // the viewable area of the image    AffineTransform at = new AffineTransform();    at.translate((newWidth - w) / 2, (newHeight - h) / 2);    // And we rotate about the center of the image...    int x = w / 2;    int y = h / 2;    at.rotate(rads, x, y);    g2d.setTransform(at);    // And we paint the original image onto the new image    g2d.drawImage(source, 0, 0, null);    g2d.dispose();    return rotated;  }