Full 360 degree circular sector?

johnbmaths shared this question 2 years ago

Answered

In order to attach a point so it can't move outside a circular area i need a circular disc i.e. circle plus interior. The circular sector command requires 3 points but if 2 are collinear then you don't get anything! Placing two points as close as possible is OK except for those of us with severe OCD when such a fudge just won't do.

Is there a way I've missed? apart from gluing together 2 half discs which would be tedious for such a simple task.

Thanks.

John B

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Comments (4)

Michael Borcherds ● 2 years ago

I think the best solution is to draw a circle and use https://wiki.geogebra.org/e...

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johnbmaths ● 2 years ago

Thanks for suggestion Michael but it is not simply a visibility issue. The point is linked to a slider on update by its distance from a fixed point and alters the slider value and vice versa. Consequently if the point is allowed to wander anywhere there is an issue with the Max value of the slider being exceeded and things get messy. If I have a circular region with radius = slider Max there is no problem.

Disappointing that there is no command for circular sectors with (centre, radius, angle) parameters with angle = 360 allowed.

Looks like I will have to settle for 359.9 or closer. Doesn't really restrict the point.

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johnbmaths ● 2 years ago

I just found a reference to attaching point to a circle/interior. It suggests increasing opacity of fill from 0. This seems to work OK but more than that when I set opacity back to 0 to see what happens it still restricts the point to movement within and on the circle.

Not sure if this is an intended result or how future reliable it might be. A more general sector command would still be welcome nevertheless.

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Ramchandra ● 2 years ago

I usually draw two adjacent consecutive sectors and readjust opacity (and of course the end points) to cover full circle from 0 to 360 degrees.

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