关于java：AffineTransform截断图像

AffineTransform truncates image

我有一个图像，必须将其旋转45、90、135、180度。我在做什么：

1
2
3
4
5
6
7
8
9
10
11
12
13
14

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

相关讨论

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。这用于构造尺寸正确的目标BufferedImage，并将平移附加到您的AffineTransform，以便将图像中心放置在目标图像的中心。

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53

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));