Python turtle.back函数代码示例

def draw_demo(turtle):
    width = turtle.window_width()
    height = turtle.window_height()
    cell_size = min(width/8.5, height/7)
    turtle.up()
    turtle.back(width*.475)
    turtle.left(90)
    turtle.forward(height*0.4)
    turtle.right(90)
    turtle.down()

    state1 = """\
3|6 2|0 2
        -
5 3 1|2 3
- -
3 1 4|3 6
        -
5|5 6|6 1
"""
    draw_diagram(turtle, state1, cell_size, solution=True)

    turtle.right(90)
    turtle.forward(cell_size*7)
    turtle.left(90)

def B(distance):
    '''
    This function defines a function B(distance) that moves the turtle backwards "distance"
    Inputs: Distance
    Distance: can be any float
    '''
    turtle.back(distance) 

def sig(x,y):
    '''
    This function adds my signiture to the turtle drawing in a location x,y
    pre-conditions: the turtle is somwhere on the board
    post-conditions: the turtle is at the base fo my signiture
    '''
    turtle.up()
    turtle.goto(x,y)
    turtle.down()
    turtle.setheading(0)
    turtle.left(90)
    turtle.forward(20)
    turtle.left(90)
    turtle.left(60)
    turtle.forward(23)
    turtle.left(180)
    turtle.forward(23)
    turtle.right(60)
    turtle.right(90)
    turtle.left(45)
    turtle.forward(27)
    turtle.left(135)
    turtle.forward(20)
    turtle.up()
    turtle.right(90)
    turtle.forward(15)
    turtle.down()
    turtle.right(90)
    turtle.forward(20)
    turtle.forward(-10)
    turtle.right(90)
    turtle.back(5)
    turtle.forward(60)

def newSnow(size,n):
	x=size/2
	y=.4
	if n<=0 or size<10:
		return
	else:
		for i in range(2):
			if n%2==0:
				turtle.color("#0099CC")
			elif n%3==0:
				turtle.color("#B2DFEE")
			else:
				turtle.color("#00B2EE")
			turtle.forward(y*size/2)
			turtle.left(60)
			newSnow(x,n-1)
			turtle.right(120)
			newSnow(x,n-1)
			turtle.left(60)
			x/=2
			y+=.2
		if n%2==0:
				turtle.color("#0099CC")
		elif n%3==0:
			turtle.color("#B2DFEE")
		else:
			turtle.color("#00B2EE")
		turtle.forward(.4*size/2)
		turtle.up()
		turtle.back(1.4*size/2)
		turtle.down()
	return

def treeSimpleVerbose(length, angle, minlength=10, level=0):
    recursionPrint("level: {} | length: {} | angle: {}".format(level, length, angle), level)

    if length < minlength:
        recursionPrint("length < {}, returning\n".format(minlength), level)
        return

    recursionPrint("forward({})".format(length), level)
    t.forward(length)
    recursionPrint("left({})".format(angle), level)
    t.left(angle)

    recursionPrint("calling first tree({}, {}, {})\n".format(length * 0.75, angle, level+1), level)
    treeSimpleVerbose(length * 0.75, angle, minlength=minlength,  level=level+1)

    recursionPrint("right({})".format(2 * angle), level)
    t.right(2 * angle)

    recursionPrint("calling second tree({}, {}, {})\n".format(length * 0.75, angle, level+1), level)
    treeSimpleVerbose(length * 0.75, angle, minlength=minlength, level=level+1)

    recursionPrint("left({})".format(angle), level)
    t.left(angle)
    recursionPrint("back({})".format(length), level)
    t.back(length)

def drawA(length):
    """
    Draw A.
    :pre: (relative) pos (0,0), heading (east), up
    :post: (relative) pos (length,0), heading (east), up
    :return: None
    """

    turtle.down()
    turtle.left(90)
    turtle.forward(length)
    turtle.right(90)
    turtle.forward(length)
    turtle.right(90)
    turtle.forward(length)
    turtle.up()
    turtle.back(length/2)
    turtle.right(90)
    turtle.down()
    turtle.forward(length)
    turtle.up()
    turtle.back(length)
    turtle.left(90)
    turtle.forward(length/2)
    turtle.left(90)

def draw_arrow(turtle, cell_size, rotation=0):
    pos = turtle.pos()
    turtle.left(rotation)
    turtle.back(cell_size*.2)
    turtle.down()
    turtle.left(90)
    turtle.begin_fill()
    turtle.forward(cell_size*.05)
    turtle.right(90)
    turtle.forward(cell_size*.3)
    turtle.left(90)
    turtle.forward(cell_size*.1)
    turtle.right(120)
    turtle.forward(cell_size*.3)
    turtle.right(120)
    turtle.forward(cell_size*.3)
    turtle.right(120)
    turtle.forward(cell_size*.1)
    turtle.left(90)
    turtle.forward(cell_size*.3)
    turtle.right(90)
    turtle.forward(cell_size*.05)
    turtle.right(90)
    turtle.forward(cell_size*.2)
    turtle.end_fill()
    turtle.up()
    turtle.setpos(pos)
    turtle.right(rotation)

def joonista_puu(tyve_pikkus, min_haru_pikkus):
    """
    Joonistab puu.
    Puu on fraktaalne/rekursiivne kujund,
    mille tüve küljes on kaks lühema tüvega alampuud:
    puu haru. Kui tyve_pikkus < min_haru_pikkus,
    siis puu koosneb ainult tüvest.
    Funktsioon taastab kilpkonna algse oleku.
    """
    # Joonista tüvi
    turtle.forward(tyve_pikkus)
    # Kui tyve_pikkus > min_haru pikkus
    if tyve_pikkus > min_haru_pikkus:
        # Keera kilpkonna 45 kraadi vasakule
        turtle.left(45)
        # Joonista esimene alampuu 0.6*tyve_pikkus
        joonista_puu(0.6*tyve_pikkus, min_haru_pikkus)
        # Keera kilpkonna 90 kraadi paremale
        turtle.right(90)
        # Joonista teine alampuu
        joonista_puu(0.6*tyve_pikkus, min_haru_pikkus)
        # Taasta algne suund
        turtle.left(45)
    # Taasta algne olek
    turtle.back(tyve_pikkus)

def draw_tree(n, b, l, size):
	if n < 0:						#base-case
		return
	elif n == 0:					#Draw Leaves
		turtle.color("green")							#Color of leaves
		turtle.width(1)
		numberOfLeaves = random.randint(5, 15)			#Random number of leaves ranging from 5 to 15
		angle = int(270 / numberOfLeaves)				#Angle Range between leaves determined by number of leaves
		for i in range(numberOfLeaves):
			if (randomB(l)):
				angle2 = random.randint(0 + (i * angle), 0 + ((i + 1) * angle))	#Angle between different leaves can be different given the Angle Range
				angle2-=135
				turtle.right(angle2)
				turtle.forward(5)
				turtle.back(5)
				turtle.left(angle2)
		return
	else:							#Draw Tree
		turtle.color("brown")						#Color of Tree
		turtle.forward(size)
		b1 = math.floor(5 * b)						#Using Bushiness to calculate number of branches: Max branchess are 5
		angle = int(270 / b1);						#Angle Range between branches determined by Number of Branches
		for i in range(b1):
			if randomB(b1):
				angle2 = random.randint(0 + (i * angle), 0 + ((i + 1) * angle))	#Angle between different branches can be different given the Angle Range
				angle2-=135
				turtle.right(angle2)
				draw_tree(n - 1, b, l, size * random.uniform(0.4, 0.7))			#Recursion step: size of sub-tree is random
				turtle.left(angle2)
		turtle.color("brown")
		turtle.back(size)
	return

def nextSlice():
	"""
	Moves the turtle to the next slice.
	"""
	turtle.back(100)
	turtle.right(90)
	turtle.forward(1)
	turtle.left(90)

def draw_pips(turtle, pips, cell_size):
    PIP_PATTERNS = """\
---+
   |
   |
   |
---+
   |
 O |
   |
---+
O  |
   |
  O|
---+
O  |
 O |
  O|
---+
O O|
   |
O O|
---+
O O|
 O |
O O|
---+
OOO|
   |
OOO|
---+
"""
    pip_pattern = PIP_PATTERNS.splitlines()[pips*4+1:pips*4+4]
    pip_radius = cell_size*0.09
    turtle.up()
    pos = turtle.pos()
    turtle.back(pip_radius*5)
    turtle.left(90)
    turtle.forward(pip_radius*5)
    turtle.right(90)
    for i in range(3):
        turtle.forward(pip_radius*2)
        turtle.right(90)
        turtle.forward(pip_radius)
        turtle.left(90)
        for j in range(3):
            if pip_pattern[i][j] == 'O':
                turtle.down()
                turtle.begin_fill()
                turtle.circle(-pip_radius)
                turtle.end_fill()
                turtle.up()
            turtle.forward(pip_radius*3)
        turtle.back(pip_radius*11)
        turtle.right(90)
        turtle.forward(pip_radius*2)
        turtle.left(90)
    turtle.setpos(pos)

def radar_chart(data):
    # Some "typical" test data
    #print "Hello"
    length=len(data) # stores the length of the data provided
    turtle.home()   # Sets the turtle to position (0,0)
    division=360/length #what angle is needed for invidual lines
    poslist=[] #list to store current position
    valpos=[]   #list to store position
    j=0
    turtle.hideturtle() #hides the arrow
        #Draw the foundation of the Radar Chart
    for i in range(length): # Loop until all the given data is plotted
        turtle.forward(200) #move turtle forward
        turtle.dot(10,"black") # Draw the black dot at the end of each data
        nowpos=turtle.pos() # store the current position
        poslist.append(nowpos) #append the current position to list
        #turtle.hideturtle()
        turtle.setpos(nowpos[0]+10,nowpos[1]) #get the turtle to new postion to write data
        turtle.write(data[i], True, align="center") # Write the label of data
        turtle.setpos(nowpos[0],nowpos[1]) #return to the previous position
        turtle.back(200) #return home
        turtle.left(division) # rotate by the specific angle
    turtle.home()    # return to turtle home
    #Connect the ends points of the radar chart
    for i in poslist: #
        turtle.setpos(i[0],i[1])
        #turtle.setpos(i[j],i[j+1])
        #turtle.forward(100)
        #turtle.home()
        #turtle.degree(division)
        #turtle.heading()
        #turtle.forward(100)
    turtle.setpos(poslist[0][0],poslist[0][1])
    turtle.home()
    #Draw green Dots 
    for i in range(length):
        incval=data[i]
        turtle.forward(incval*2)
        turtle.dot(15,"green")
        nowpos=turtle.pos()
        valpos.append(nowpos) 
        turtle.back(incval*2)
        turtle.left(division)
    turtle.begin_poly()
    turtle.fill(True)
    #Fill the green Dots
    for i in valpos:
        turtle.setpos(int(i[0]),int(i[1]))
    turtle.setpos(valpos[0][0],valpos[0][1])
    turtle.end_poly()
    p = turtle.get_poly()
    turtle.register_shape("jpt", p)
    turtle.color("Green", "Green")
    turtle.begin_fill()
    #turtle.p(80)
    turtle.end_fill()
    turtle.fill(False)

def draw_whole_tree(x,y):
    size = 10
    draw_tree(x,y)
    draw_star(size,x,y)
    for i in coords:
        turtle.goto(i)
        #draw_bauble()
    turtle.back(100)
    draw_pot()

def drawTree(n,size):
    if(n>0):
        turtle.forward(size)
        turtle.left(45)
        drawTree(n-1,size/2)
        turtle.right(90)
        drawTree(n-1,size/2)
        turtle.left(45)
        turtle.back(size)

def draw_wall(x, y):
    goto(x, y)
    turtle.color("red")
    if y % 2 == 0:
        turtle.seth(0)
    else:
        turtle.seth(90)
    turtle.forward(5)
    turtle.back(10)