Actionscript:

// from http://codebase.dbpsite.com/code/finddifferencebetweentwoangles25

function angleDifference(angle0:Number, angle1:Number):Number{

return Math.abs((angle0 + 180  angle1) % 360  180);

}


trace("get the angle between:");

trace("350 and 10 =", angleDifference(350, 10));

trace("180 and 1 =", angleDifference(180, 1));

trace("10 and 5 =", angleDifference(10, 5));

trace("725 and 45 =", angleDifference(725, 45));

/* outputs:

get the angle between:

350 and 10 = 20

180 and 1 = 179

10 and 5 = 15

725 and 45 = 50

*/
This snippet shows an easy way to find the difference between two angles. The tricky part about doing this is finding the difference between something like 350 and 1 (which should be 11).
Over the years I have done this a few different ways  I needed it for something today and realized that my way was a tad clunky (had a little redundant logic)  So with a quick google search I found a more elegant solution.
9 Comments
This is the best solution I have found. The next best is:
abs = abs(angle0  angle1);
return min((2 * PI)  abs, abs);
In PHP, it is about 2.5 slower compared to yours.
NOTE: the solution I posted uses radians from pi to pi.
I don’t think your solution works for all inputs. If I put in 57 and 328 (so it is 57  328) I get 271 where the answer should be 89.
yeah I think your right, I’ve been meaning to fix this post.
Thank you for this post, works nice for the most values.
I found the same error like Robert.
I fixed it with an if clause:
public static double angleDifference(double firstAngle, double secondAngle) {
if (firstAngle < secondAngle) {
double tmpAngle = firstAngle;
firstAngle = secondAngle;
secondAngle = tmpAngle;
}
return Math.abs((firstAngle + 180  secondAngle) % 360  180);
}
WARNING!!!
This solution and the alternate found in the comments are both incorrect. They can be used to find the angle difference assuming only one direction of rotation. Which is usually not what people mean when they say difference between angles.
Unfortunately this page is currently the first result on google for the search term “Difference between angles”. A correct solution is
double difference = secondAngle  firstAngle;
while (difference 180) difference = 360;
return difference
see the following link for an explanation.
http://www.codeproject.com/Articles/59789/Calculatetherealdifferencebetweentwoanglesk.aspx
Hey Xavier… at some point a few months ago I realized this post was wrong. I’ve meaning to update it for ages but haven’t gotten around to it. I’ll update the post later today with your link and information. Thanks for pointing this out.
How about this:
def angleDif(a1,a2):
return min((a1a2)%360,(a2a1)%360)
Hey zevan, is this formula correct now?
how input angle cnc turning programmr.