java-AffineTransform截断图像

我有一个图像,必须将其旋转45、90、135、180度.我在做什么：

try {
    BufferedImage src = ImageIO.read(new File("src.png"));
    double ang = Math.toRadians(90);

    AffineTransform t = new AffineTransform();
    t.setToRotation(ang, src.getWidth() / 2, src.getHeight() / 2);

    AffineTransformOp op = new AffineTransformOp(t, null);
    BufferedImage dst = new BufferedImage(src.getWidth(), src.getHeight(), src.getType());
    op.filter(src, dst);

    ImageIO.write(dst, "png", new File("output.png"));
} catch(Exception ex) { ex.printStackTrace();
}

问题是图像改变了位置并超出了目标图像的范围：

The problem http://img32.imageshack.us/img32/3328/resultcs.png

我已经对此进行了搜索,并找到了以下问题的解决方案：AffineTransform truncates image, what do I wrong?但是我不太理解,它仅适用于象限.我尝试将目的地的宽度和高度乘以两倍,但失败了：

Another fail http://img401.imageshack.us/img401/2417/result2a.png

如何解决这个问题？目标图像不应有任何多余的(对角线旋转除外)空白或截断的区域.角度问题(0 == 180或顺时针方向)并不重要.

谢谢你的帮助.

解决方法:

编辑：现在,它适用于一般情况.

围绕中心进行旋转,并将中心放置在目标图像中与源图像中相同的位置(正确行为).

我已经修改了您的代码以转换源图像矩形,以便我们可以轻松获得新的尺寸/图像偏移.这用于构造具有正确尺寸的目标BufferedImage,并将平移附加到AffineTransform,以便将图像中心放置在目标图像的中心.

        BufferedImage src = ImageIO.read(new File(INPUT));
        int w = src.getWidth();
        int h = src.getHeight();

        AffineTransform t = new AffineTransform();
        double ang = Math.toRadians(35);
        t.setToRotation(ang, w / 2d, h / 2d);

        // source image rectangle
        Point[] points = {
            new Point(0, 0),
            new Point(w, 0),
            new Point(w, h),
            new Point(0, h)
        };

        // transform to destination rectangle
        t.transform(points, 0, points, 0, 4);

        // get destination rectangle bounding box
        Point min = new Point(points[0]);
        Point max = new Point(points[0]);
        for (int i = 1, n = points.length; i < n; i ++) {
            Point p = points[i];
            double pX = p.getX(), pY = p.getY();

            // update min/max x
            if (pX < min.getX()) min.setLocation(pX, min.getY());
            if (pX > max.getX()) max.setLocation(pX, max.getY());

            // update min/max y
            if (pY < min.getY()) min.setLocation(min.getX(), pY);
            if (pY > max.getY()) max.setLocation(max.getX(), pY);
        }

        // determine new width, height
        w = (int) (max.getX() - min.getX());
        h = (int) (max.getY() - min.getY());

        // determine required translation
        double tx = min.getX();
        double ty = min.getY();

        // append required translation
        AffineTransform translation = new AffineTransform();
        translation.translate(-tx, -ty);
        t.preConcatenate(translation);

        AffineTransformOp op = new AffineTransformOp(t, null);
        BufferedImage dst = new BufferedImage(w, h, src.getType());
        op.filter(src, dst);

        ImageIO.write(dst, "png", new File(OUTPUT));

标签：affinetransform,java,image-processing,rotation,image-rotation
来源： https://codeday.me/bug/20191009/1880586.html