When the bounding box is affected by the pen width, then this width is scaled appropriately for the InkRenderer's view transform. To do this, the pen width is multiplied by the square root of the determinant of the view transform.
Note In Windows Vista and later versions, GetBoundingBox Method does not take the width of the stroke into account.
Note If you have not set the pen width explicitly, it is 53 by default. You must multiply the pen width by the square root of the determinant to yield the correct bounding box. The height and width of the bounding box are expanded by half this amount in each direction. For example, consider that the pen width is 53, the square root of the determinant is 50, and the bounding box is (0, 0, 1000, 1000). The pen width adjustment to the bounding box in each direction is calculated as (53 * 50) / 2, and the right and bottom sides are incremented by one. This results in a rendered bounding box of (-1325, -1325, 2326, 2326).