在java中旋转图像

Rotate an image in java

提问by user489041

I am looking to rotate an image. I have a JInternalFramewhich contains a JLabel. The label contains the image. After the image has been rotated, I need to resize the internal frame. The code I have currently rotates the image, but there is black around the edges of the image and it is off centered. Any suggestions on how to fix this?

我正在寻找旋转图像。我有一个JInternalFrame包含JLabel. 标签包含图像。旋转图像后，我需要调整内部框架的大小。我目前使用的代码旋转图像，但图像边缘有黑色，并且偏离中心。对于如何解决这个问题，有任何的建议吗？

public void rotateIcon(int angle)
{
        int w = theLabel.getIcon().getIconWidth();
        int h = theLabel.getIcon().getIconHeight();
        int type = BufferedImage.TYPE_INT_RGB;  // other options, see api

        BufferedImage DaImage = new BufferedImage(h, w, type);
        Graphics2D g2 = DaImage.createGraphics();

        double x = (h - w)/2.0;
        double y = (w - h)/2.0;
        AffineTransform at = AffineTransform.getTranslateInstance(x, y);

        at.rotate(Math.toRadians(angle), w/2.0, h/2.0);
        g2.drawImage(new ImageIcon(getData()).getImage(), at, theLabel);
        g2.dispose();

        theLabel.setIcon(new ImageIcon(DaImage));
        this.setSize(DaImage.getWidth(),DaImage.getHeight()); //resize the frame
}

采纳答案by Reverend Gonzo

You need to be using trigonometry to determine the correct width/height, using transparency to prevent the black area, and I think the Transform is wrong, which is making it off center.

您需要使用三角函数来确定正确的宽度/高度，使用透明度来防止黑色区域，我认为变换是错误的，这使它偏离了中心。

Try this:

尝试这个：

public static BufferedImage rotate(BufferedImage image, double angle) {
    double sin = Math.abs(Math.sin(angle)), cos = Math.abs(Math.cos(angle));
    int w = image.getWidth(), h = image.getHeight();
    int neww = (int)Math.floor(w*cos+h*sin), newh = (int) Math.floor(h * cos + w * sin);
    GraphicsConfiguration gc = getDefaultConfiguration();
    BufferedImage result = gc.createCompatibleImage(neww, newh, Transparency.TRANSLUCENT);
    Graphics2D g = result.createGraphics();
    g.translate((neww - w) / 2, (newh - h) / 2);
    g.rotate(angle, w / 2, h / 2);
    g.drawRenderedImage(image, null);
    g.dispose();
    return result;
}

private static GraphicsConfiguration getDefaultConfiguration() {
    GraphicsEnvironment ge = GraphicsEnvironment.getLocalGraphicsEnvironment();
    GraphicsDevice gd = ge.getDefaultScreenDevice();
    return gd.getDefaultConfiguration();
}

from http://flyingdogz.wordpress.com/2008/02/11/image-rotate-in-java-2-easier-to-use/

来自http://flyingdogz.wordpress.com/2008/02/11/image-rotate-in-java-2-easier-to-use/

回答by camickr

You could try using a Rotated Icon.

您可以尝试使用Rotated Icon。

回答by bjoernz

Does it help if you change:

如果你改变它是否有帮助：

BufferedImage DaImage = new BufferedImage(height, width, type);

BufferedImage DaImage = new BufferedImage(height, width, type);

to:

到：

BufferedImage DaImage = new BufferedImage(**width, height**, type);?

BufferedImage DaImage = new BufferedImage(**width, height**, type);?

回答by user1050755

Based on a previous example, but actually working with recent JDKs and in headless mode:

基于前面的示例，但实际上使用最新的 JDK 和无头模式：

public static BufferedImage rotate(BufferedImage image, double angle) {
    double sin = Math.abs(Math.sin(angle)), cos = Math.abs(Math.cos(angle));
    int w = image.getWidth(), h = image.getHeight();
    int neww = (int)Math.floor(w*cos+h*sin), newh = (int) Math.floor(h * cos + w * sin);
    BufferedImage result = deepCopy(image, false);
    Graphics2D g = result.createGraphics();
    g.translate((neww - w) / 2, (newh - h) / 2);
    g.rotate(angle, w / 2, h / 2);
    g.drawRenderedImage(image, null);
    g.dispose();
    return result;
}

public static BufferedImage deepCopy(BufferedImage bi, boolean copyPixels) {
    ColorModel cm = bi.getColorModel();
    boolean isAlphaPremultiplied = cm.isAlphaPremultiplied();
    WritableRaster raster = bi.getRaster().createCompatibleWritableRaster();
    if (copyPixels) {
        bi.copyData(raster);
    }
    return new BufferedImage(cm, raster, isAlphaPremultiplied, null);
}