* @param dstH the height of the destination image
* @param dstFormat the destination image format
* @param flags specify which algorithm and options to use for rescaling
+ * @param param extra parameters to tune the used scaler
+ * For SWS_BICUBIC param[0] and [1] tune the shape of the basis
+ * function, param[0] tunes f(1) and param[1] f´(1)
+ * For SWS_GAUSS param[0] tunes the exponent and thus cutoff
+ * frequency
+ * For SWS_LANCZOS param[0] tunes the width of the window function
* @return a pointer to an allocated context, or NULL in case of error
* @note this function is to be removed after a saner alternative is
* written