旋转缓冲图像实例

java rotation swing bufferedimage graphics2d

2022-09-02 02:26:56

我在旋转以显示时遇到问题。我认为旋转工作正常，但我实际上无法将其绘制到屏幕上。我的代码：BufferedImage

Class extends JPanel {
    BufferedImage img;
    int rotation = 0;

    public void paintComponent(Graphics g) {
        g.clearRect(0, 0, getWidth(), getHeight());
        img2d = img.createGraphics();
        img2d.rotate(Math.toRadians(rotation), img.getWidth() / 2, img.getHeight() / 2);
        g.drawImage(img, imgx, imgy, null);
        this.repaint();
    }
}

这对我不起作用。我找不到任何方法来绘制旋转到.img2dg

编辑：我有多个对象正在被绘制到，所以我不能旋转它。我需要能够单独旋转东西。g

答案 1

也许你应该尝试像这样使用：AffineTransform

AffineTransform transform = new AffineTransform();
transform.rotate(radians, bufferedImage.getWidth() / 2, bufferedImage.getHeight() / 2);
AffineTransformOp op = new AffineTransformOp(transform, AffineTransformOp.TYPE_BILINEAR);
bufferedImage = op.filter(bufferedImage, null);

希望这有帮助。

答案 2

我会使用Graphics2D.drawImage（image，affinetranform，imageobserver）。

下面的代码示例旋转图像并将其平移到组件的中心。这是结果的屏幕截图：

screenshot

public static void main(String[] args) throws IOException {
    JFrame frame = new JFrame("Test");

    frame.add(new JComponent() {
        BufferedImage image = ImageIO.read(
                new URL("http://upload.wikimedia.org/wikipedia/en/2/24/Lenna.png"));

        @Override
        protected void paintComponent(Graphics g) {
            super.paintComponent(g);

            // create the transform, note that the transformations happen
            // in reversed order (so check them backwards)
            AffineTransform at = new AffineTransform();

            // 4. translate it to the center of the component
            at.translate(getWidth() / 2, getHeight() / 2);

            // 3. do the actual rotation
            at.rotate(Math.PI / 4);

            // 2. just a scale because this image is big
            at.scale(0.5, 0.5);

            // 1. translate the object so that you rotate it around the 
            //    center (easier :))
            at.translate(-image.getWidth() / 2, -image.getHeight() / 2);

            // draw the image
            Graphics2D g2d = (Graphics2D) g;
            g2d.drawImage(image, at, null);

            // continue drawing other stuff (non-transformed)
            //...
        }
    });

    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.setSize(400, 400);
    frame.setVisible(true);
}