How to make dots and get its coordinate along countour ?

[PULSE.Wannabe]

I want to get the coordinates of a contour.

- What it should look like :

- What I did (It's too much, it counts every x pixel): 

- Is it possible to get the yellow boxes' coordinate? (I'm using Clamp(Rake) function.

Thanks in advance 

[altenbach]

continued here.