也许你可以用这个作为起点。我使用了vector_math库中的Vector和Matrix4。我为矩形中的每个点使用了4个矢量，并对每个点应用了Matrix4转换矩阵。我不确定这是否正确，但它确实添加了旋转，但不是我预期的方式。它旋转了整个复制的图像，而不仅仅是旋转选区。

// initialize integers for initial points 
 // x2 is width ; y2 is height
 x1=0; y0=y; x2=100; y2=100;

// create 4 points of a rectangle for topLeft to bottomRight
  imglib.Point p1 = imglib.Point(x1, y1);
  imglib.Point p2 = imglib.Point(x2, y1);
  imglib.Point p3 = imglib.Point(x1, y2); 
  imglib.Point p4 = imglib.Point(x2, y2);

// put the 4 points in 4 vectors
  vector_math.Vector3 v1 = vector_math.Vector3(x1.toDouble() , y1.toDouble(), 1);
  vector_math.Vector3 v2 = vector_math.Vector3(x2.toDouble() , y1.toDouble(), 1);
  vector_math.Vector3 v3 = vector_math.Vector3(x1.toDouble() , y2.toDouble(), 1);
  vector_math.Vector3 v4 = vector_math.Vector3(x2.toDouble() , y2.toDouble(), 1);

// Create a matrix4, rotate it and apply it to all 4 points/vectors
 vector_math.Matrix4  T = vector_math.Matrix4.rotationZ(vector_math.radians(45));  
  v1 = T.transform3(v1);
  v2 = T.transform3(v2);
  v3 = T.transform3(v3);
  v4 = T.transform3(v4); 

// pull the new rotated point values out of the vectors: 
  p1.x = v1[0];
  p1.y =v1[1];
  p2.x = v2[0];
  p2.y =v2[1];
  p3.x = v3[0];
  p3.y =v3[1];
  p4.x = v4[0];
  p4.y =v4[1];

// copyRectify the source image with transformed points
imglib.Image angledSlice = imglib.copyRectify(
        srcImage, 
        topLeft: p1, 
        topRight: p2, 
        bottomLeft: p3, 
        bottomRight: p4,
         );