Constrain the move of a hotspot2 along a line ?

[Anonymous]

HI

With something like this, I can move a point C (editable hotspot2) on all directions :
!x
HOTSPOT2 Cx, 0, ID, Cy, 1+128 : ID=ID+1
HOTSPOT2 Cx, -1, ID, Cy, 3 : ID=ID+1
HOTSPOT2 Cx, Cy, ID, Cy, 2 : ID=ID+1
!y
HOTSPOT2 0, Cy, ID, Cx, 1+128 : ID=ID+1
HOTSPOT2 -1, Cy, ID, Cx, 3 : ID=ID+1
HOTSPOT2 Cx, Cy, ID, Cx, 2 : ID=ID+1



How can I force the displacement of the point C along the line D ?
C is halfway between A and B.

Thanks

[Anonymous]

This is done and it works (with ROT2).
Thanks to everyone.