--- a/src/panotools-wrappers/pttransform.h
+++ b/src/panotools-wrappers/pttransform.h
@@ -33,7 +33,11 @@
 #include <pano13/filter.h>
 
 
-/** state of a transform */
+/** state of a transform.
+ *
+ *  Internal data structure, do not access directly
+ *
+ */
 typedef struct
 {
     struct 	MakeParams	mp;
@@ -71,7 +75,7 @@
 pt_transform * panoTransformCreate(pt_script * script, int imgNr);
 
 
-/** Transform coordinates
+/** Transform coordinates (inverse transform)
  *
  *  @param x_dest x (input) coordinate in destination (panorama) image
  *  @param y_dest y (input) coordinate in destination (panorama) image
@@ -85,11 +89,11 @@
  *          1: inside src image, x_src, y_src valid.
  *
  */
-int panoTransformApply(pt_transform *transform,
+int panoTransformInverse(pt_transform *transform,
             double x_dest, double y_dest, double *x_src, double *y_src );
 
 
-/** Transform coordinates (inverse transform)
+/** Transform coordinates (forward transform)
  *
  *  @param x_src x (input) coordinate in source (input) image
  *  @param y_src y (input) coordinate in source (input) image
@@ -101,7 +105,7 @@
  *          1: inside src image, x_dest, y_dest valid.
  *
  */
-int panoTransformInvApply(pt_transform *transform,
+int panoTransformForward(pt_transform *transform,
             double x_src, double y_src, double *x_dest, double *y_dest );