Python turtle 模块，goto() 实例源码

def draw_canvas(state):
    '''Draw all the cities in the current state in a canvas. Indicate the start
       city with a description and the current city by the turtle pointer head
    '''
    turtle.clear()
    turtle.hideturtle()
    turtle.up()
    turtle.pencolor("blue")
    current_city = state.current_city
    for city in state.cities:
        x = city.position[0]
        y = city.position[1]
        turtle.goto(x, y)

        if city.is_start:
            turtle.write('{}, Start'.format(city.name), align="center", font=("Arial", 12, "bold"))
        elif city == current_city:
            turtle.write('{}, Current'.format(city.name), align="center", font=("Arial", 12, "bold"))            
        else:
            turtle.write('{}'.format(city.name), align="center", font=("Arial", 12, "bold"))

    turtle.goto(current_city.position[0], current_city.position[1])

def draw(self):
        "draws the lsystem on the screen"
        stack = []
        tt.penup()
        tt.setpos(0, -200)
        tt.seth(90)
        tt.pendown()

        print "Drawing the lsystem ..."
        for i, codebit in enumerate(self.generation[-1]):

            if codebit in ['F', 'A', 'B']:
                tt.forward(self.length)
                print '[ FRWD ] ', codebit
            elif codebit == '+':
                tt.right(self.angle)
                print '[ RGHT ] ', codebit
            elif codebit == '-':
                tt.left(self.angle)
                print '[ LEFT ] ', codebit
            elif codebit == '[':
                stack.append((tt.pos(), tt.heading()))
                print '[ PUSH ] ', (tt.pos(), tt.heading())
            elif codebit == ']':
                position,heading = stack.pop()
                print '[ POP  ] ', (position, heading)
                tt.penup()
                tt.goto(position)
                tt.seth(heading)
                tt.pendown()
            else:
                print '[ NOP  ] ', codebit

            if self.save_every_frame:
                self.save(frame=i)

        print "Done drawing"
        print "Saving file as %s.jpg" % self.name,
        self.save()
        print "Done"

def line(x1, y1, x2, y2):
    t.up()
    t.setx(x1)
    t.sety(y1)
    t.down()
    t.goto(x2, y2)
    # print ("Line drawn from (",x1,", ",y1,") to (",x2,", ",y2,").")

def line(x1, y1, x2, y2):
    t.up()
    t.setx(x1)
    t.sety(y1)
    t.down()
    t.goto(x2, y2)
    # print ("Line drawn from (",x1,", ",y1,") to (",x2,", ",y2,").")

def draw_final_path(state):
    '''Draw the TSP path given the cities in the correct order'''
    if not state:
        return None

    states = []
    while state:
        states.append(state)
        state = state.parent    

    cities = [state.current_city for state in states]
    rest = deepcopy(cities)
    rest = rest[1:]
    rest.reverse()
    cities = [cities[0]] + rest

    turtle.clear()
    turtle.hideturtle()
    turtle.up()
    turtle.pensize(1)

    for city in cities:
        x = city.position[0]
        y = city.position[1]
        turtle.pencolor("red")
        turtle.goto(x, y)
        turtle.pencolor("black")

        if city.is_start:
            turtle.write('{}-Start'.format(city.name), align="center", font=("Arial", 11, "bold"))
        else:
            turtle.write('{}'.format(city.name), align="center",  font=("Arial", 11, "bold"))

        turtle.down()

    turtle.pencolor("red")
    turtle.goto(cities[0].position[0], cities[0].position[1])

def draw_star(x, y, side):
    star_angle = 360.0/6
    left_angle = star_angle * 2
    tu.penup()
    tu.goto(x, y)
    tu.pendown()
    for i in range(6):
        tu.forward(side)
        tu.right(star_angle)
        tu.forward(side)
        tu.left(left_angle)

def draw_flat_world():
    init()
    turtle.goto(-300, 0)

    draw_world()

def draw_round_world():
    init()
    turtle.goto(0, 300)
    turtle.hideturtle()

    draw_world(5)

def draw_floor(floornum: int):
    global current_floor
    current_floor = floornum

    node_coords = utils.get_node_coords(utils.Direction.left) 

    if floornum == len(full_floors):
        rooms = []
        # All edges with rooms
        print('Showing everything')
        edges = chain.from_iterable(chain(((True, e) for e in edges[0]), ((False, e) for e in edges[1])) for _, edges in full_floors)
        # Edges with elevation changes
        #edges = set(chain.from_iterable((edge(v, n) for n in b.values() if set(['u', 'd']) & set(utils.get_graph().edgedata[edge(v, n)]['rooms'])) for v, b in enumerate(utils.get_graph().branches)))
        # All edges
        #...
    elif floornum >= 0 and floornum < len(full_floors):
        rooms, edges = full_floors[floornum]
        print(edges)
        edges = chain(((True, e) for e in edges[0]), ((False, e) for e in edges[1]))
        print(rooms)
    else:
        return

    turtle.showturtle()
    turtle.speed(0)
    turtle.clear()

    written_nodes = set()

    for edge_dir, (a, b) in edges:
        turtle.penup()
        x, y, _ = node_coords[a]
        turtle.goto(x / SHRINK + X_OFFSET, y / SHRINK + Y_OFFSET)
        if a not in written_nodes:
            turtle.write(a)
            written_nodes.add(a)

        turtle.pendown()

        if edge_dir:
            if edge_lengths[edge(a, b)] <= 0:
                turtle.pencolor('red')
            else:
                turtle.pencolor('black')
        else:
            if edge_lengths[edge(a, b)] <= 0:
                turtle.pencolor('blue')
            else:
                turtle.pencolor('green')

        x, y, _ = node_coords[b]
        turtle.goto(x / SHRINK + X_OFFSET, y / SHRINK + Y_OFFSET)
        turtle.pencolor('black')
        if b not in written_nodes:
            turtle.write(b)
            written_nodes.add(b)

    turtle.hideturtle()
    turtle.done()