Bitmap Rotation

The Win32 API provides a function to copy a bitmap into a parallelogram; this function, PlgBlt, performs a bit-block transfer from a rectangle in a source device context into a parallelogram in a destination device context. In order to rotate the bitmap, an application must provide the coordinates, in world units, to be used for the corners of the parallelogram. (For more information about rotation and world units, see Coordinate Spaces and Transformations.)