Talk:Rotating calipers

Algorithm

I think it is necessary to say that the given algorithm needs the points to be in counter-clockwise order, and that clockwise order can also be used (as suggested in some algorithms by http://cgm.cs.mcgill.ca/~orm/rotcal.html) if the caliper vectors are swapped in the begining:

 VECTOR caliper_a(-1,0);    // Caliper A points along the negative x-axis
 VECTOR caliper_b(1,0);     // Caliper B points along the positive x-axis

--155.210.155.136 (talk) 15:30, 3 April 2009 (UTC)

Shouldn't these lines:

 width = caliper_a.distance(points[p_b]);
 width = caliper_b.distance(points[p_a]);

actually be:

 width = points[p_a].distance(points[p_b]);
 width = points[p_b].distance(points[p_a]);

?

207.67.82.250 (talk) 20:02, 13 June 2011 (UTC)

In the monotone chain algorithm, shouldn't the function calls

 dir(U[k-1], U[k], p’[k])
 dir(L[k-1], L[k], p’[k])

actually be

 dir(U[U.size - 1], U[U.size], p’[k])
 dir(L[L.size - 1], L[L.size], p’[k])

? It seems that at step k there is no guarantee that either stack has size precisely k.

5.2.158.243 (talk) 13:46, 31 July 2018 (UTC)

A piece of mathematical humor

A Toussaint's webpage contains the following list of links:

• The rotating caliper graph.
• Updating the width and diameter of a point set with the rotating caliper graph.
• Measuring the diameter of a tree with the rotating calipers.
• Digital Electronic Calipers for only $139.

I guess he makes lots of dime from the ad :-) Lorem Ip (talk) 16:09, 8 September 2010 (UTC)