Circle shape - Aftereffects Expression

circleshape.js

seg = Math.floor( Math.max(effect("Segments")("Slider"), 2) );
radius = effect("Radius")("Slider");
angle_param = clamp(effect("Angle Control")("Angle"), -360, 360);
close = effect("Close")("Checkbox") > 0;

angle = degreesToRadians(angle_param) * 1 / seg;
tangent = [0, 4  / 3 * Math.tan(angle/4) ] * radius;

firsttangent = [0,0];
numiterations = seg + 1;
 if( close && (angle_param >= 360 || angle_param <= -360) )
{
	firsttangent = -tangent;
	numiterations -= 1;
}

points = [];
intan = [];
outtan = [];

points.push( [radius, 0] );
intan.push(firsttangent);
outtan.push(tangent);

for(var i = 1; i < numiterations; i++){
	points.push( [Math.cos(angle * i), Math.sin(angle * i)] * radius);
	
	tanx = tangent[0] * Math.cos(angle) - tangent[1] * Math.sin(angle);
	tany = tangent[0] * Math.sin(angle) + tangent[1] * Math.cos(angle);
	tangent = [tanx, tany];
	intan.push(-tangent);
	if( close && i == numiterations-1 && angle_param < 360 && angle_param > -360 )
		outtan.push( [0,0] );
	else
		outtan.push(tangent);
}

if( close && angle_param < 360 && angle_param > -360 )
{
	points.push( [0, 0] );
	intan.push( [0,0] );
	outtan.push( [0,0] );
}

createPath(points, intan, outtan, close);