Java在中心旋转图像

Question

How do i rotate an image in the center if itself? this code works, but it rotates the image in the top-left corner of the screen:

    AffineTransform oldtrans = new AffineTransform();
    AffineTransform trans = new AffineTransform();

    trans.setToIdentity();
    trans.rotate(Math.toRadians(angle));
    trans.translate(_x-(width/2), _y-(height/2));
    g.setTransform(trans);
    g.drawImage(this.getImage(), (int)_x, (int)_y, (int)width, (int)height, null);
    trans.setToIdentity();
    g.setTransform(oldtrans);

Please help!!!

Answer 1

你应该在rotate（）调用中再给出两个参数：

affineTransform.rotate(Math.toRadians(angle), m_imageWidth/2, m_imageHeight/2); 

Answer 2

You're halfway there, literally. What you have to do is two translations. Something along the lines of:

1. Translate the image to its centre (tanslate(x-width/2, y-width/2).
2. Rotate the image by angle radians (like you have).
3. Translate the image back to its original position (tanslate(x+width/2, y+width/2).

Hope this works for you.