bisector -- Angle bisector of two lines

i1 : circ=Circle{Radius=>0.1,"fill"=>"red","stroke"=>"black"};

i2 : (a,b,c)=apply(([-1,-1],[2,0],[0,2]),coord -> gNode(coord,circ,Draggable=>true))

o2 = (a, b, c)

o2 : Sequence

i3 : p=bisector(a,b,c); q=bisector(b,c,a); r=bisector(c,a,b); o=crossing(p,a,q,b);

i7 : gList(Line{a,b},Line{a,c},Line{b,c},Line{p,a},Line{q,b},Line{r,c},Circle{o,projection(o,a,b)},a,b,c)

o7 = GraphicsList{cache => CacheTable{}                                                                                                                                                                                                                                                                                                                  }
                  Contents => {Line{cache => CacheTable{}         }, Line{cache => CacheTable{}         }, Line{cache => CacheTable{}         }, Line{cache => CacheTable{}         }, Line{cache => CacheTable{}         }, Line{cache => CacheTable{}         }, Circle{cache => CacheTable{}                                               }, a, b, c}
                                    Point1 => GraphicsCoordinate a        Point1 => GraphicsCoordinate a        Point1 => GraphicsCoordinate b        Point1 => p                           Point1 => q                           Point1 => r                             Center => o
                                    Point2 => GraphicsCoordinate b        Point2 => GraphicsCoordinate c        Point2 => GraphicsCoordinate c        Point2 => GraphicsCoordinate a        Point2 => GraphicsCoordinate b        Point2 => GraphicsCoordinate c          Radius => projection (o, GraphicsCoordinate a, GraphicsCoordinate b)
                                    style => MutableHashTable{}           style => MutableHashTable{}           style => MutableHashTable{}           style => MutableHashTable{}           style => MutableHashTable{}           style => MutableHashTable{}             style => MutableHashTable{}
                  style => MutableHashTable{}

o7 : GraphicsList