This was the content of this Q&A from the old FAQ:
In PDF the image can be rotated by any degree. The image can also be stretched, skewed, etc. The transformation is specified using the Current Transformation Matrix (CTM) which can be accessed using the Element.GetCTM() method.
Use the following code snippet (pseudocode) to calculate image rotation angle (in radians):
double GetRotation(Matrix2D& mtx) { double x1=0, y1=0, x2=1, y2=0; mtx.Mult(x1, y1); mtx.Mult(x2, y2); return atan2(y2-y1, x2-x1); }
The position of the image on the page is given using the translation component of the matrix (i.e mtx.m_h, mtx.m_v).