bool polygon_c::outline_vertex(polygon_c* newpoly, doublePair prev, doublePair cur, doublePair next, double distance){	
	//Get vectors representing the lines
	doublePair A = cur-prev;
	doublePair B = next-cur;
 
	//Calculate the offset vectors for the lines (rotate by 90degrees, divide by length to get unit perp vector, multiply by 'distance')
	doublePair offsetA=doublePair(-A.y,A.x).unit()*distance;
	doublePair offsetB=doublePair(-B.y,B.x).unit()*distance;
 
	//Determine if the angle made by A-B is convex, concave, straight or reverse
	double ang=A.angle(B);
 
	//Clamp really small angles to zero
	(abs(ang)<10e-5) && (ang=0);
 
	//Straight, convex or concave?
	if ((ang<0) || (prev==next)){			//Concave - return arc at 'distance' around cur starting from cur+offsetA, ending at cur+offsetB
		//TODO : Draw arc		
		double incAng=PI2/18;
		double angle;
		double endAng;
		
		//Add arc startpoints
		newpoly->verts.push_back(cur+offsetA);
 
		//For straight lines (IE prev==next), 'fix' the angle to account for lack of 'clockwiseness' in doubleback nodes
		if (prev==next){ang=-PI;}
 
		//Determine start and end angles
		angle=atan2(offsetA.y, offsetA.x)-incAng;
		endAng=(angle+ang)+incAng;
 
		double points=ceil((endAng-angle)/incAng);
		incAng=(endAng-angle)/points;
 
		//Add arc
		while (angle>endAng){
			newpoly->verts.push_back(cur+doublePair(cos(angle)*distance,sin(angle)*distance));
			angle-=incAng;
		}
 
		//Add the arc endpoint
		newpoly->verts.push_back(cur+offsetB);
 
	}else if (ang>0){	//Convex - return intersect(prev+offsetA->cur+offsetA, cur+offsetB->next+offsetB)
		doublePair intersect=doublePair::line_intersect(prev+offsetA,cur+offsetA,  cur+offsetB,next+offsetB);
		newpoly->verts.push_back(intersect);
	}else{				//Straigh line - return cur+offsetA		
		//Comment out to simplify the polygon
		//newpoly->verts.push_back(cur+offsetA);
	}
 
	return true;
}