def rotate_by(obj, angle):
vecs = vecs_from_coords(_canvas.coords(obj))
anchorPos = Vec2d.getAverage(vecs)
newVecs = []
for vec in vecs:
vec -= anchorPos
vec.rotate(angle)
vec += anchorPos
newVecs.append(vec)
newCoords = coords_from_vecs(newVecs)
_canvas.coords(obj, *newCoords)
def rotate_by(obj, angle):
vecs = vecs_from_coords(_canvas.coords(obj))
anchorPos = Vec2d.getAverage(vecs)
newVecs = []
for vec in vecs:
vec -= anchorPos
vec.rotate(angle)
vec += anchorPos
newVecs.append(vec)
newCoords = coords_from_vecs(newVecs)
_canvas.coords(obj, *newCoords)
