public CachedLine arrowForEnd(CachedLine c, float distanceBack, float size, float width) {
Cursor cc = new Cursor(c).end();
cc.forwardD(-distanceBack);
Vector2 p = cc.position();
Vector2 t = cc.tangentForward();
if (t == null || t.mag() == 0 || t.isNaN()) t = cc.tangentBackward();
Vector2 n = t.normalize();
n.scale(size);
return triangleAt(p, n, width);
}
public CachedLine arrowFor(CachedLine c, float along, float size, float width) {
Cursor cc = new Cursor(c);
float len = cc.length();
cc.forwardD(len * along);
Vector2 p = cc.position();
Vector2 t = cc.tangentForward();
if (t == null || t.mag() == 0 || t.isNaN() || along == 1) t = cc.tangentBackward();
Vector2 n = t.normalize();
n.scale(size);
return triangleAt(p, n, width);
}