"turtle" --- Gráficos Turtle
****************************

**Código-fonte:** Lib/turtle.py

======================================================================


Introdução
==========

Gráficos turtle é uma forma popular de introduzir programação para
crianças. Era parte da linguagem de programação Logo desenvolvida por
Wally Feuzeig, Seymour Papert and Cynthia Solomon em 1967.

Imagine uma tartaruga robótica começando em (0, 0) no plano x-y.
Depois de um "import turtle", dê-lhe o comando "turtle.forward(15)", e
ela moverá (na tela!) 15 pixels na direção em que está virada (para
frente), desenhando uma linha à medida que ela se move. Digite o
comando "turtle.right(25)", e faça ela girar, no lugar, 25 graus no
sentido horário.


Turtle star
^^^^^^^^^^^

A tartaruga pode desenhar formas intrincadas usando programas que
repetem movimentos simples.

[imagem]

   from turtle import *
   color('red', 'yellow')
   begin_fill()
   while True:
       forward(200)
       left(170)
       if abs(pos()) < 1:
           break
   end_fill()
   done()

Ao combinar esses comandos similares, formas intrincadas e imagens
podem ser desenhadas facilmente.

O módulo "turtle" é uma reimplementação estendida de um módulo de
mesmo nome da distribuição padrão do Python até a versão Python 2.5.

Ele tenta manter as características do antigo módulo turtle e ser
(quase) 100% compatível com ele. Isso significa, em primeiro lugar,
permitir que o programador iniciante use todos os comandos, classes e
métodos interativamente ao usar o módulo de dentro do IDLE executado
com a chave "-n".

O módulo turtle fornece gráficos rudimentares, tanto para programação
orientada a objetos quanto procedural. Como ele usa o "tkinter" como
módulo gráfico, ele necessita de uma versão do instalada do Python que
suporta o Tk.

A interface orientada a objetos usa essencialmente duas classes (e
duas subclasses):

1. A classe "TurtleScreen" define as janelas gráficas como um parque
   de diversões para as tartarugas de desenho. Seu construtor precisa
   de um "tkinter.Canvas" ou um "ScrolledCanvas" como argumento. Deve
   ser usado quando "turtle" é usado como parte de algum aplicativo.

   A função "Screen()" retorna um objeto singleton de uma subclasse
   "TurtleScreen". Esta função deve ser usada quando "turtle" é usado
   como uma ferramenta autônoma para fazer gráficos. Como um objeto
   singleton, não é possível herdar de sua classe.

   Todos os métodos de TurtleScreen/Screen também existem como
   funções, ou seja, como parte da interface orientada a
   procedimentos.

2. "RawTurtle" (pedido: "RawPen") define objetos Turtle que desenham
   em uma "TurtleScreen". Seu construtor precisa de um Canvas,
   ScrolledCanvas ou TurtleScreen como argumento, para que os objetos
   RawTurtle saibam onde desenhar.

   Derivada de RawTurtle é a subclasse "Turtle" (alias: "Pen"), que se
   baseia "na" instância "Screen" que é criada automaticamente, se
   ainda não estiver presente.

   Todos os métodos de RawTurtle/Turtle também existem como funções,
   isto é, parte de uma interface procedural orientada à objeto.

A interface procedural fornece funções que são derivadas dos métodos
das classes "Screen" e "Turtle". Eles têm os mesmos nomes que os
métodos correspondentes. Um objeto de tela é criado automaticamente
sempre que uma função derivada de um método de tela é chamada. Um
objeto turtle (sem nome) é criado automaticamente sempre que qualquer
uma das funções derivadas de um método Turtle é chamada.

Para usar várias tartarugas em uma tela, é preciso usar a interface
orientada a objetos.

Nota:

  Na documentação a seguir, a lista de argumentos para funções é
  fornecida. Os métodos, é claro, têm o primeiro argumento adicional
  *self* que é omitido aqui.


Visão geral dos métodos Turtle e Screen disponíveis
===================================================


Métodos de Turtle
-----------------

Movimentos de Turtle
   Movimento e desenho
         "forward()" | "fd()"
         "backward()" | "bk()" | "back()"
         "right()" | "rt()"
         "left()" | "lt()"
         "goto()" | "setpos()" | "setposition()"
         "setx()"
         "sety()"
         "setheading()" | "seth()"
         "home()"
         "circle()"
         "dot()"
         "stamp()"
         "clearstamp()"
         "clearstamps()"
         "undo()"
         "speed()"

   Fala o estado de Turtle
         "position()" | "pos()"
         "towards()"
         "xcor()"
         "ycor()"
         "heading()"
         "distance()"

   Configuração e Medidas
         "degrees()"
         "radians()"

Controle da Caneta
   Estado do Desenho
         "pendown()" | "pd()" | "down()"
         "penup()" | "pu()" | "up()"
         "pensize()" | "width()"
         "pen()"
         "isdown()"

   Controle da Cor
         "color()"
         "pencolor()"
         "fillcolor()"

   Preenchimento
         "filling()"
         "begin_fill()"
         "end_fill()"

   Mais sobre o Controle do Desenho
         "reset()"
         "clear()"
         "write()"

Estado da Tartaruga
   Visibilidade
         "showturtle()" | "st()"
         "hideturtle()" | "ht()"
         "isvisible()"

   Aparência
         "shape()"
         "resizemode()"
         "shapesize()" | "turtlesize()"
         "shearfactor()"
         "settiltangle()"
         "tiltangle()"
         "tilt()"
         "shapetransform()"
         "get_shapepoly()"

Eventos Utilizados
      "onclick()"
      "onrelease()"
      "ondrag()"

Métodos Especiais da Tartaruga
      "begin_poly()"
      "end_poly()"
      "get_poly()"
      "clone()"
      "getturtle()" | "getpen()"
      "getscreen()"
      "setundobuffer()"
      "undobufferentries()"


Métodos de TurtleScreen/Screen
------------------------------

Controle da Janela
      "bgcolor()"
      "bgpic()"
      "clearscreen()"
      "resetscreen()"
      "screensize()"
      "setworldcoordinates()"

Controle da animação
      "delay()"
      "tracer()"
      "update()"

Usando os eventos de tela
      "listen()"
      "onkey()" | "onkeyrelease()"
      "onkeypress()"
      "onclick()" | "onscreenclick()"
      "ontimer()"
      "mainloop()" | "done()"

Configurações e métodos especiais
      "mode()"
      "colormode()"
      "getcanvas()"
      "getshapes()"
      "register_shape()" | "addshape()"
      "turtles()"
      "window_height()"
      "window_width()"

Métodos de entrada
      "textinput()"
      "numinput()"

Métodos específicos para Screen
      "bye()"
      "exitonclick()"
      "setup()"
      "title()"


Métodos de RawTurtle/Turtle e funções correspondentes
=====================================================

A maioria dos exemplos desta seção referem-se a uma instância Turtle
chamada "turtle".


Movimentos de Turtle
--------------------

turtle.forward(distance)
turtle.fd(distance)

   Parâmetros:
      **distance** -- um número (inteiro ou ponto flutuante)

   Move a tartaruga para frente pela *distance* especificada, na
   direção em que a tartaruga está indo.

      >>> turtle.position()
      (0.00,0.00)
      >>> turtle.forward(25)
      >>> turtle.position()
      (25.00,0.00)
      >>> turtle.forward(-75)
      >>> turtle.position()
      (-50.00,0.00)

turtle.back(distance)
turtle.bk(distance)
turtle.backward(distance)

   Parâmetros:
      **distance** -- um número

   Move a tartaruga para trás por *distance*, na direção oposta à
   direção em que a tartaruga está indo. Não muda o rumo da tartaruga.

      >>> turtle.position()
      (0.00,0.00)
      >>> turtle.backward(30)
      >>> turtle.position()
      (-30.00,0.00)

turtle.right(angle)
turtle.rt(angle)

   Parâmetros:
      **angle** -- um número (inteiro ou ponto flutuante)

   Vira a tartaruga à direita por unidades de *angle*. (As unidades
   são por padrão graus, mas podem ser definidas através das funções
   "degrees()" e "radians()".) A orientação do ângulo depende do modo
   tartaruga, veja "mode()".

      >>> turtle.heading()
      22.0
      >>> turtle.right(45)
      >>> turtle.heading()
      337.0

turtle.left(angle)
turtle.lt(angle)

   Parâmetros:
      **angle** -- um número (inteiro ou ponto flutuante)

   Vira a tartaruga à esquerda por unidades de *angle*. (As unidades
   são por padrão graus, mas podem ser definidas através das funções
   "degrees()" e "radians()".) A orientação do ângulo depende do modo
   tartaruga, veja "mode()".

      >>> turtle.heading()
      22.0
      >>> turtle.left(45)
      >>> turtle.heading()
      67.0

turtle.goto(x, y=None)
turtle.setpos(x, y=None)
turtle.setposition(x, y=None)

   Parâmetros:
      * **x** -- um número ou um par/vetor de números

      * **y** -- um número ou "None"

   Se *y* for "None", *x* deve ser um par de coordenadas ou uma classe
   "Vec2D" (por exemplo, como retornado pela função "pos()").

   Move a tartaruga para uma posição absoluta. Caso a caneta esteja
   virada para baixo, traça a linha. Não altera a orientação da
   tartaruga.

       >>> tp = turtle.pos()
       >>> tp
       (0.00,0.00)
       >>> turtle.setpos(60,30)
       >>> turtle.pos()
       (60.00,30.00)
       >>> turtle.setpos((20,80))
       >>> turtle.pos()
       (20.00,80.00)
       >>> turtle.setpos(tp)
       >>> turtle.pos()
       (0.00,0.00)

turtle.setx(x)

   Parâmetros:
      **x** -- um número (inteiro ou ponto flutuante)

   Define a primeira coordenada da tartaruga para *x*, deixa a segunda
   coordenada inalterada.

      >>> turtle.position()
      (0.00,240.00)
      >>> turtle.setx(10)
      >>> turtle.position()
      (10.00,240.00)

turtle.sety(y)

   Parâmetros:
      **y** -- um número (inteiro ou ponto flutuante)

   Defina a segunda coordenada da tartaruga para *y*, deixa a primeira
   coordenada inalterada.

      >>> turtle.position()
      (0.00,40.00)
      >>> turtle.sety(-10)
      >>> turtle.position()
      (0.00,-10.00)

turtle.setheading(to_angle)
turtle.seth(to_angle)

   Parâmetros:
      **to_angle** -- um número (inteiro ou ponto flutuante)

   Define a orientação da tartaruga para  *to_angle*. Aqui estão
   algumas direções mais comuns em graus:

   +---------------------+----------------------+
   | modo padrão         | modo logo            |
   |=====================|======================|
   | 0 - leste           | 0 - norte            |
   +---------------------+----------------------+
   | 90 - norte          | 90 - leste           |
   +---------------------+----------------------+
   | 180 - oeste         | 180 - sul            |
   +---------------------+----------------------+
   | 270 - sul           | 270 - oeste          |
   +---------------------+----------------------+

      >>> turtle.setheading(90)
      >>> turtle.heading()
      90.0

turtle.home()

   Move a tartaruga para a origem -- coordenadas (0,0) -- e define seu
   rumo para sua orientação inicial (que depende do modo, veja
   "mode()").

      >>> turtle.heading()
      90.0
      >>> turtle.position()
      (0.00,-10.00)
      >>> turtle.home()
      >>> turtle.position()
      (0.00,0.00)
      >>> turtle.heading()
      0.0

turtle.circle(radius, extent=None, steps=None)

   Parâmetros:
      * **radius** -- um número

      * **extent** -- um número (ou "None")

      * **steps** -- um inteiro  (ou "None")

   Desenha um círculo com dado *radius*. O centro são as unidades de
   *radius* à esquerda da tartaruga; *extent* -- um ângulo --
   determina qual parte do círculo é desenhada. Se *extent* não for
   fornecida, desenha o círculo inteiro. Se *extent* não for um
   círculo completo, uma extremidade do arco será a posição atual da
   caneta. Desenha o arco no sentido anti-horário se *radius* for
   positivo, caso contrário, no sentido horário. Finalmente, a direção
   da tartaruga é alterada pela quantidade de *extent*.

   Como o círculo é aproximado por um polígono regular inscrito,
   *steps* determina o número de passos a serem usados. Caso não seja
   informado, será calculado automaticamente. Pode ser usado para
   desenhar polígonos regulares.

      >>> turtle.home()
      >>> turtle.position()
      (0.00,0.00)
      >>> turtle.heading()
      0.0
      >>> turtle.circle(50)
      >>> turtle.position()
      (-0.00,0.00)
      >>> turtle.heading()
      0.0
      >>> turtle.circle(120, 180)  # draw a semicircle
      >>> turtle.position()
      (0.00,240.00)
      >>> turtle.heading()
      180.0

turtle.dot(size=None, *color)

   Parâmetros:
      * **size** -- um inteiro >= 1  (caso seja fornecido)

      * **color** -- uma string de cores ou uma tupla de cores
        numéricas

   Desenha um ponto circular com diâmetro *size*, usando *color*. Se
   *size* não for fornecido, o máximo de pensize+4 e 2*pensize será
   usado.

      >>> turtle.home()
      >>> turtle.dot()
      >>> turtle.fd(50); turtle.dot(20, "blue"); turtle.fd(50)
      >>> turtle.position()
      (100.00,-0.00)
      >>> turtle.heading()
      0.0

turtle.stamp()

   Carimba uma cópia da forma da tartaruga na tela na posição atual da
   tartaruga. Retorna um stamp_id para esse carimbo, que pode ser
   usado para excluí-lo chamando "clearstamp(stamp_id)".

      >>> turtle.color("blue")
      >>> turtle.stamp()
      11
      >>> turtle.fd(50)

turtle.clearstamp(stampid)

   Parâmetros:
      **stampid** -- um inteiro, deve ser o valor de retorno da
      chamada de "stamp()" anterior

   Exclui o carimbo com o *stamp* fornecido.

      >>> turtle.position()
      (150.00,-0.00)
      >>> turtle.color("blue")
      >>> astamp = turtle.stamp()
      >>> turtle.fd(50)
      >>> turtle.position()
      (200.00,-0.00)
      >>> turtle.clearstamp(astamp)
      >>> turtle.position()
      (200.00,-0.00)

turtle.clearstamps(n=None)

   Parâmetros:
      **n** -- um inteiro  (ou "None")

   Exclui todos ou o primeiro/último *n* dos selos da tartaruga. Se
   *n* for "None", exclui todos os carimbos, se *n* > 0 exclui os
   primeiros *n* carimbos, senão se *n* < 0 exclui os últimos *n*
   carimbos.

      >>> for i in range(8):
      ...     turtle.stamp(); turtle.fd(30)
      13
      14
      15
      16
      17
      18
      19
      20
      >>> turtle.clearstamps(2)
      >>> turtle.clearstamps(-2)
      >>> turtle.clearstamps()

turtle.undo()

   Desfaz (repetidamente) a(s) última(s) ação(ões) da tartaruga. O
   número de ações de desfazer disponíveis é determinado pelo tamanho
   do buffer de desfazer.

      >>> for i in range(4):
      ...     turtle.fd(50); turtle.lt(80)
      ...
      >>> for i in range(8):
      ...     turtle.undo()

turtle.speed(speed=None)

   Parâmetros:
      **speed** -- um inteiro no intervalo 0..10 ou uma string de
      velocidade (veja abaixo)

   Define a velocidade da tartaruga para um valor inteiro no intervalo
   0..10. Se nenhum argumento for fornecido, retorna a velocidade
   atual.

   Se a entrada for um número maior que 10 ou menor que 0,5, a
   velocidade é definida como 0. As strings de velocidade são mapeadas
   para valores de velocidade da seguinte forma:

   * "fastest": 0

   * "fast": 10

   * "normal": 6

   * "slow": 3

   * "slowest": 1

   Velocidades de 1 a 10  tornam a animação cada vez mais rápida,
   tanto para o desenho da linha  como para a rotação da tartaruga.

   Atenção: *speed* = 0 significa que *nenhuma* animação ocorre. Para
   frente/trás faz a tartaruga pular e da mesma forma para
   esquerda/direita faz a tartaruga girar instantaneamente.

      >>> turtle.speed()
      3
      >>> turtle.speed('normal')
      >>> turtle.speed()
      6
      >>> turtle.speed(9)
      >>> turtle.speed()
      9


Fala o estado de Turtle
-----------------------

turtle.position()
turtle.pos()

   Retorna a localização atual da tartaruga (x,y) (como um vetor
   "Vec2D").

      >>> turtle.pos()
      (440.00,-0.00)

turtle.towards(x, y=None)

   Parâmetros:
      * **x** -- um número ou um par/vetor de números ou uma instância
        de tartaruga

      * **y** -- um número caso *x* seja um número, senão "None"

   Retorna o ângulo entre a linha da posição da tartaruga para a
   posição especificada por (x,y), o vetor ou a outra tartaruga. Isso
   depende da orientação inicial da tartaruga, que depende do modo -
   "standard"/"world" ou "logo".

      >>> turtle.goto(10, 10)
      >>> turtle.towards(0,0)
      225.0

turtle.xcor()

   Retorna a coordenada X da tartaruga.

      >>> turtle.home()
      >>> turtle.left(50)
      >>> turtle.forward(100)
      >>> turtle.pos()
      (64.28,76.60)
      >>> print(round(turtle.xcor(), 5))
      64.27876

turtle.ycor()

   Retorna a coordenada Y da tartaruga.

      >>> turtle.home()
      >>> turtle.left(60)
      >>> turtle.forward(100)
      >>> print(turtle.pos())
      (50.00,86.60)
      >>> print(round(turtle.ycor(), 5))
      86.60254

turtle.heading()

   Retorna o título atual da tartaruga (o valor depende do modo da
   tartaruga, veja "mode()").

      >>> turtle.home()
      >>> turtle.left(67)
      >>> turtle.heading()
      67.0

turtle.distance(x, y=None)

   Parâmetros:
      * **x** -- um número ou um par/vetor de números ou uma instância
        de tartaruga

      * **y** -- um número caso *x* seja um número, senão "None"

   Retorna a distância da tartaruga para (x,y), o vetor dado, ou a
   outra tartaruga dada, em unidades de passo de tartaruga.

      >>> turtle.home()
      >>> turtle.distance(30,40)
      50.0
      >>> turtle.distance((30,40))
      50.0
      >>> joe = Turtle()
      >>> joe.forward(77)
      >>> turtle.distance(joe)
      77.0


Configurações de medida
-----------------------

turtle.degrees(fullcircle=360.0)

   Parâmetros:
      **fullcircle** -- um número

   Define as unidades de medição do ângulo, ou seja, defina o número
   de "graus" para um círculo completo. O valor padrão é 360 graus.

      >>> turtle.home()
      >>> turtle.left(90)
      >>> turtle.heading()
      90.0

      Change angle measurement unit to grad (also known as gon,
      grade, or gradian and equals 1/100-th of the right angle.)
      >>> turtle.degrees(400.0)
      >>> turtle.heading()
      100.0
      >>> turtle.degrees(360)
      >>> turtle.heading()
      90.0

turtle.radians()

   Define as unidades de medida de ângulo para radianos. Equivalente a
   "degrees(2*math.pi)".

      >>> turtle.home()
      >>> turtle.left(90)
      >>> turtle.heading()
      90.0
      >>> turtle.radians()
      >>> turtle.heading()
      1.5707963267948966


Controle da Caneta
------------------


Estado do Desenho
~~~~~~~~~~~~~~~~~

turtle.pendown()
turtle.pd()
turtle.down()

   Desce a caneta - desenha ao se mover.

turtle.penup()
turtle.pu()
turtle.up()

   Levanta a caneta -- sem qualquer desenho ao se mover.

turtle.pensize(width=None)
turtle.width(width=None)

   Parâmetros:
      **width** -- um número positivo

   Define a espessura da linha para *width* ou retorne-a. Se
   resizemode estiver definido como "auto" e a forma de tartaruga for
   um polígono, esse polígono será desenhado com a mesma espessura de
   linha. Se nenhum argumento for fornecido, o tamanho da pena atual
   será retornado.

      >>> turtle.pensize()
      1
      >>> turtle.pensize(10)   # from here on lines of width 10 are drawn

turtle.pen(pen=None, **pendict)

   Parâmetros:
      * **pen** -- um dicionário com algumas ou todas as chaves
        listadas abaixo

      * **pendict** -- um ou mais argumentos nomeados com as chaves
        listadas abaixo como palavras-chave

   Retorna ou define os atributos da caneta em um "dicionário da
   caneta" com os seguintes pares de chave/valor:

   * "shown": True/False

   * "pendown": True/False

   * "pencolor": string de cores ou tupla de cores

   * "fillcolor": string de cores ou tupla de cores

   * "pensize": número positivo

   * "speed": número na faixa de 0..10

   * "resizemode": "auto", "user" ou "noresize"

   * "stretchfactor": (número positivo, número positivo)

   * "outline": número positivo

   * "tilt": número

   Este dicionário pode ser usado como argumento para uma chamada
   subsequente para "pen()" para restaurar o estado da caneta
   anterior. Além disso, um ou mais desses atributos podem ser
   fornecidos como argumentos nomeados. Isso pode ser usado para
   definir vários atributos de caneta em uma instrução.

      >>> turtle.pen(fillcolor="black", pencolor="red", pensize=10)
      >>> sorted(turtle.pen().items())
      [('fillcolor', 'black'), ('outline', 1), ('pencolor', 'red'),
       ('pendown', True), ('pensize', 10), ('resizemode', 'noresize'),
       ('shearfactor', 0.0), ('shown', True), ('speed', 9),
       ('stretchfactor', (1.0, 1.0)), ('tilt', 0.0)]
      >>> penstate=turtle.pen()
      >>> turtle.color("yellow", "")
      >>> turtle.penup()
      >>> sorted(turtle.pen().items())[:3]
      [('fillcolor', ''), ('outline', 1), ('pencolor', 'yellow')]
      >>> turtle.pen(penstate, fillcolor="green")
      >>> sorted(turtle.pen().items())[:3]
      [('fillcolor', 'green'), ('outline', 1), ('pencolor', 'red')]

turtle.isdown()

   Retorna "True" se a caneta estiver abaixada, "False" se estiver
   levantada.

      >>> turtle.penup()
      >>> turtle.isdown()
      False
      >>> turtle.pendown()
      >>> turtle.isdown()
      True


Controle da Cor
~~~~~~~~~~~~~~~

turtle.pencolor(*args)

   Retorna ou define a cor da caneta ou pencolor.

   São permitidos quatro formatos de entrada:

   "pencolor()"
      Retorna a cor da caneta atual como string de especificação de
      cor ou como uma tupla (veja o exemplo). Pode ser usado como
      entrada para outra chamada color/pencolor/fillcolor.

   "pencolor(colorstring)"
      Define pencolor como *colorstring*, que é uma string de
      especificação de cor Tk, como ""red"", ""yellow"" ou
      ""#33cc8c"".

   "pencolor((r, g, b))"
      Define a cor da caneta como a cor RGB representada pela tupla
      *r*, *g*, e *b*. Os valores de *r*, *g*, and *b* precisam estar
      na faixa 0..colormode, onde colormode é 1.0 ou 255 (ver
      "colormode()").

   "pencolor(r, g, b)"
      Define a cor da caneta como a cor RGB representada por *r*, *g*,
      e *b*. Os valores de *r*, *g*, and *b* precisam estar na faixa
      0..colormode, onde colormode é 1.0 ou 255 (ver "colormode()").

   Se a forma da tartaruga for um polígono, o contorno desse polígono
   será desenhado com a nova cor de caneta definida.

       >>> colormode()
       1.0
       >>> turtle.pencolor()
       'red'
       >>> turtle.pencolor("brown")
       >>> turtle.pencolor()
       'brown'
       >>> tup = (0.2, 0.8, 0.55)
       >>> turtle.pencolor(tup)
       >>> turtle.pencolor()
       (0.2, 0.8, 0.5490196078431373)
       >>> colormode(255)
       >>> turtle.pencolor()
       (51.0, 204.0, 140.0)
       >>> turtle.pencolor('#32c18f')
       >>> turtle.pencolor()
       (50.0, 193.0, 143.0)

turtle.fillcolor(*args)

   Retorna ou define o fillcolor.

   São permitidos quatro formatos de entrada:

   "fillcolor()"
      Return the current fillcolor as color specification string,
      possibly in tuple format (see example).  May be used as input to
      another color/pencolor/fillcolor call.

   "fillcolor(colorstring)"
      Set fillcolor to *colorstring*, which is a Tk color
      specification string, such as ""red"", ""yellow"", or
      ""#33cc8c"".

   "fillcolor((r, g, b))"
      Set fillcolor to the RGB color represented by the tuple of *r*,
      *g*, and *b*.  Each of *r*, *g*, and *b* must be in the range
      0..colormode, where colormode is either 1.0 or 255 (see
      "colormode()").

   "fillcolor(r, g, b)"
      Set fillcolor to the RGB color represented by *r*, *g*, and *b*.
      Each of *r*, *g*, and *b* must be in the range 0..colormode.

   If turtleshape is a polygon, the interior of that polygon is drawn
   with the newly set fillcolor.

       >>> turtle.fillcolor("violet")
       >>> turtle.fillcolor()
       'violet'
       >>> turtle.pencolor()
       (50.0, 193.0, 143.0)
       >>> turtle.fillcolor((50, 193, 143))  # Integers, not floats
       >>> turtle.fillcolor()
       (50.0, 193.0, 143.0)
       >>> turtle.fillcolor('#ffffff')
       >>> turtle.fillcolor()
       (255.0, 255.0, 255.0)

turtle.color(*args)

   Return or set pencolor and fillcolor.

   Several input formats are allowed.  They use 0 to 3 arguments as
   follows:

   "color()"
      Return the current pencolor and the current fillcolor as a pair
      of color specification strings or tuples as returned by
      "pencolor()" and "fillcolor()".

   "color(colorstring)", "color((r,g,b))", "color(r,g,b)"
      Inputs as in "pencolor()", set both, fillcolor and pencolor, to
      the given value.

   "color(colorstring1, colorstring2)", "color((r1,g1,b1),
   (r2,g2,b2))"
      Equivalent to "pencolor(colorstring1)" and
      "fillcolor(colorstring2)" and analogously if the other input
      format is used.

   If turtleshape is a polygon, outline and interior of that polygon
   is drawn with the newly set colors.

       >>> turtle.color("red", "green")
       >>> turtle.color()
       ('red', 'green')
       >>> color("#285078", "#a0c8f0")
       >>> color()
       ((40.0, 80.0, 120.0), (160.0, 200.0, 240.0))

Veja também: Método da tela "colormode()".


Preenchimento
~~~~~~~~~~~~~

turtle.filling()

   Retorna fillstate ("True" se estiver preenchido, "False" caso
   contrário).

       >>> turtle.begin_fill()
       >>> if turtle.filling():
       ...    turtle.pensize(5)
       ... else:
       ...    turtle.pensize(3)

turtle.begin_fill()

   To be called just before drawing a shape to be filled.

turtle.end_fill()

   Fill the shape drawn after the last call to "begin_fill()".

   Whether or not overlap regions for self-intersecting polygons or
   multiple shapes are filled depends on the operating system
   graphics, type of overlap, and number of overlaps.  For example,
   the Turtle star above may be either all yellow or have some white
   regions.

      >>> turtle.color("black", "red")
      >>> turtle.begin_fill()
      >>> turtle.circle(80)
      >>> turtle.end_fill()


Mais sobre o Controle do Desenho
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

turtle.reset()

   Delete the turtle's drawings from the screen, re-center the turtle
   and set variables to the default values.

      >>> turtle.goto(0,-22)
      >>> turtle.left(100)
      >>> turtle.position()
      (0.00,-22.00)
      >>> turtle.heading()
      100.0
      >>> turtle.reset()
      >>> turtle.position()
      (0.00,0.00)
      >>> turtle.heading()
      0.0

turtle.clear()

   Delete the turtle's drawings from the screen.  Do not move turtle.
   State and position of the turtle as well as drawings of other
   turtles are not affected.

turtle.write(arg, move=False, align="left", font=("Arial", 8, "normal"))

   Parâmetros:
      * **arg** -- object to be written to the TurtleScreen

      * **move** -- True/False

      * **align** -- uma das Strings "left", "center" ou right"

      * **font** -- a triple (fontname, fontsize, fonttype)

   Write text - the string representation of *arg* - at the current
   turtle position according to *align* ("left", "center" or "right")
   and with the given font.  If *move* is true, the pen is moved to
   the bottom-right corner of the text.  By default, *move* is
   "False".

   >>> turtle.write("Home = ", True, align="center")
   >>> turtle.write((0,0), True)


Estado da Tartaruga
-------------------


Visibilidade
~~~~~~~~~~~~

turtle.hideturtle()
turtle.ht()

   Make the turtle invisible.  It's a good idea to do this while
   you're in the middle of doing some complex drawing, because hiding
   the turtle speeds up the drawing observably.

      >>> turtle.hideturtle()

turtle.showturtle()
turtle.st()

   Tornar a tartaruga visível.

      >>> turtle.showturtle()

turtle.isvisible()

   Return "True" if the Turtle is shown, "False" if it's hidden.

   >>> turtle.hideturtle()
   >>> turtle.isvisible()
   False
   >>> turtle.showturtle()
   >>> turtle.isvisible()
   True


Aparência
~~~~~~~~~

turtle.shape(name=None)

   Parâmetros:
      **name** -- a string which is a valid shapename

   Set turtle shape to shape with given *name* or, if name is not
   given, return name of current shape.  Shape with *name* must exist
   in the TurtleScreen's shape dictionary.  Initially there are the
   following polygon shapes: "arrow", "turtle", "circle", "square",
   "triangle", "classic".  To learn about how to deal with shapes see
   Screen method "register_shape()".

      >>> turtle.shape()
      'classic'
      >>> turtle.shape("turtle")
      >>> turtle.shape()
      'turtle'

turtle.resizemode(rmode=None)

   Parâmetros:
      **rmode** -- uma das Strings "auto", "user", "noresize"

   Set resizemode to one of the values: "auto", "user", "noresize".
   If *rmode* is not given, return current resizemode.  Different
   resizemodes have the following effects:

   * "auto": adapta a aparência da tartaruga correspondente ao valor
     do pensize.

   * "user": adapts the appearance of the turtle according to the
     values of stretchfactor and outlinewidth (outline), which are set
     by "shapesize()".

   * "noresize": no adaption of the turtle's appearance takes place.

   "resizemode("user")" is called by "shapesize()" when used with
   arguments.

      >>> turtle.resizemode()
      'noresize'
      >>> turtle.resizemode("auto")
      >>> turtle.resizemode()
      'auto'

turtle.shapesize(stretch_wid=None, stretch_len=None, outline=None)
turtle.turtlesize(stretch_wid=None, stretch_len=None, outline=None)

   Parâmetros:
      * **stretch_wid** -- número positivo

      * **stretch_len** -- número positivo

      * **outline** -- número positivo

   Return or set the pen's attributes x/y-stretchfactors and/or
   outline.  Set resizemode to "user".  If and only if resizemode is
   set to "user", the turtle will be displayed stretched according to
   its stretchfactors: *stretch_wid* is stretchfactor perpendicular to
   its orientation, *stretch_len* is stretchfactor in direction of its
   orientation, *outline* determines the width of the shapes's
   outline.

      >>> turtle.shapesize()
      (1.0, 1.0, 1)
      >>> turtle.resizemode("user")
      >>> turtle.shapesize(5, 5, 12)
      >>> turtle.shapesize()
      (5, 5, 12)
      >>> turtle.shapesize(outline=8)
      >>> turtle.shapesize()
      (5, 5, 8)

turtle.shearfactor(shear=None)

   Parâmetros:
      **shear** -- número (opcional)

   Set or return the current shearfactor. Shear the turtleshape
   according to the given shearfactor shear, which is the tangent of
   the shear angle. Do *not* change the turtle's heading (direction of
   movement). If shear is not given: return the current shearfactor,
   i. e. the tangent of the shear angle, by which lines parallel to
   the heading of the turtle are sheared.

       >>> turtle.shape("circle")
       >>> turtle.shapesize(5,2)
       >>> turtle.shearfactor(0.5)
       >>> turtle.shearfactor()
       0.5

turtle.tilt(angle)

   Parâmetros:
      **angle** -- um número

   Rotate the turtleshape by *angle* from its current tilt-angle, but
   do *not* change the turtle's heading (direction of movement).

      >>> turtle.reset()
      >>> turtle.shape("circle")
      >>> turtle.shapesize(5,2)
      >>> turtle.tilt(30)
      >>> turtle.fd(50)
      >>> turtle.tilt(30)
      >>> turtle.fd(50)

turtle.settiltangle(angle)

   Parâmetros:
      **angle** -- um número

   Rotate the turtleshape to point in the direction specified by
   *angle*, regardless of its current tilt-angle.  *Do not* change the
   turtle's heading (direction of movement).

      >>> turtle.reset()
      >>> turtle.shape("circle")
      >>> turtle.shapesize(5,2)
      >>> turtle.settiltangle(45)
      >>> turtle.fd(50)
      >>> turtle.settiltangle(-45)
      >>> turtle.fd(50)

   Obsoleto desde a versão 3.1.

turtle.tiltangle(angle=None)

   Parâmetros:
      **angle** -- um número (opcional)

   Set or return the current tilt-angle. If angle is given, rotate the
   turtleshape to point in the direction specified by angle,
   regardless of its current tilt-angle. Do *not* change the turtle's
   heading (direction of movement). If angle is not given: return the
   current tilt-angle, i. e. the angle between the orientation of the
   turtleshape and the heading of the turtle (its direction of
   movement).

      >>> turtle.reset()
      >>> turtle.shape("circle")
      >>> turtle.shapesize(5,2)
      >>> turtle.tilt(45)
      >>> turtle.tiltangle()
      45.0

turtle.shapetransform(t11=None, t12=None, t21=None, t22=None)

   Parâmetros:
      * **t11** -- um número (opcional)

      * **t12** -- um número (opcional)

      * **t21** -- um número (opcional)

      * **t12** -- um número (opcional)

   Set or return the current transformation matrix of the turtle
   shape.

   If none of the matrix elements are given, return the transformation
   matrix as a tuple of 4 elements. Otherwise set the given elements
   and transform the turtleshape according to the matrix consisting of
   first row t11, t12 and second row t21, t22. The determinant t11 *
   t22 - t12 * t21 must not be zero, otherwise an error is raised.
   Modify stretchfactor, shearfactor and tiltangle according to the
   given matrix.

      >>> turtle = Turtle()
      >>> turtle.shape("square")
      >>> turtle.shapesize(4,2)
      >>> turtle.shearfactor(-0.5)
      >>> turtle.shapetransform()
      (4.0, -1.0, -0.0, 2.0)

turtle.get_shapepoly()

   Return the current shape polygon as tuple of coordinate pairs. This
   can be used to define a new shape or components of a compound
   shape.

      >>> turtle.shape("square")
      >>> turtle.shapetransform(4, -1, 0, 2)
      >>> turtle.get_shapepoly()
      ((50, -20), (30, 20), (-50, 20), (-30, -20))


Eventos Utilizados
------------------

turtle.onclick(fun, btn=1, add=None)

   Parâmetros:
      * **fun** -- a function with two arguments which will be called
        with the coordinates of the clicked point on the canvas

      * **btn** -- number of the mouse-button, defaults to 1 (left
        mouse button)

      * **add** -- "True" or "False" -- if "True", a new binding will
        be added, otherwise it will replace a former binding

   Bind *fun* to mouse-click events on this turtle.  If *fun* is
   "None", existing bindings are removed.  Example for the anonymous
   turtle, i.e. the procedural way:

      >>> def turn(x, y):
      ...     left(180)
      ...
      >>> onclick(turn)  # Now clicking into the turtle will turn it.
      >>> onclick(None)  # event-binding will be removed

turtle.onrelease(fun, btn=1, add=None)

   Parâmetros:
      * **fun** -- a function with two arguments which will be called
        with the coordinates of the clicked point on the canvas

      * **btn** -- number of the mouse-button, defaults to 1 (left
        mouse button)

      * **add** -- "True" or "False" -- if "True", a new binding will
        be added, otherwise it will replace a former binding

   Bind *fun* to mouse-button-release events on this turtle.  If *fun*
   is "None", existing bindings are removed.

      >>> class MyTurtle(Turtle):
      ...     def glow(self,x,y):
      ...         self.fillcolor("red")
      ...     def unglow(self,x,y):
      ...         self.fillcolor("")
      ...
      >>> turtle = MyTurtle()
      >>> turtle.onclick(turtle.glow)     # clicking on turtle turns fillcolor red,
      >>> turtle.onrelease(turtle.unglow) # releasing turns it to transparent.

turtle.ondrag(fun, btn=1, add=None)

   Parâmetros:
      * **fun** -- a function with two arguments which will be called
        with the coordinates of the clicked point on the canvas

      * **btn** -- number of the mouse-button, defaults to 1 (left
        mouse button)

      * **add** -- "True" or "False" -- if "True", a new binding will
        be added, otherwise it will replace a former binding

   Bind *fun* to mouse-move events on this turtle.  If *fun* is
   "None", existing bindings are removed.

   Remark: Every sequence of mouse-move-events on a turtle is preceded
   by a mouse-click event on that turtle.

      >>> turtle.ondrag(turtle.goto)

   Subsequently, clicking and dragging the Turtle will move it across
   the screen thereby producing handdrawings (if pen is down).


Métodos Especiais da Tartaruga
------------------------------

turtle.begin_poly()

   Start recording the vertices of a polygon.  Current turtle position
   is first vertex of polygon.

turtle.end_poly()

   Stop recording the vertices of a polygon.  Current turtle position
   is last vertex of polygon.  This will be connected with the first
   vertex.

turtle.get_poly()

   Return the last recorded polygon.

      >>> turtle.home()
      >>> turtle.begin_poly()
      >>> turtle.fd(100)
      >>> turtle.left(20)
      >>> turtle.fd(30)
      >>> turtle.left(60)
      >>> turtle.fd(50)
      >>> turtle.end_poly()
      >>> p = turtle.get_poly()
      >>> register_shape("myFavouriteShape", p)

turtle.clone()

   Create and return a clone of the turtle with same position, heading
   and turtle properties.

      >>> mick = Turtle()
      >>> joe = mick.clone()

turtle.getturtle()
turtle.getpen()

   Return the Turtle object itself.  Only reasonable use: as a
   function to return the "anonymous turtle":

      >>> pet = getturtle()
      >>> pet.fd(50)
      >>> pet
      <turtle.Turtle object at 0x...>

turtle.getscreen()

   Return the "TurtleScreen" object the turtle is drawing on.
   TurtleScreen methods can then be called for that object.

      >>> ts = turtle.getscreen()
      >>> ts
      <turtle._Screen object at 0x...>
      >>> ts.bgcolor("pink")

turtle.setundobuffer(size)

   Parâmetros:
      **size** -- um inteiro ou "None"

   Set or disable undobuffer.  If *size* is an integer, an empty
   undobuffer of given size is installed.  *size* gives the maximum
   number of turtle actions that can be undone by the "undo()"
   method/function.  If *size* is "None", the undobuffer is disabled.

      >>> turtle.setundobuffer(42)

turtle.undobufferentries()

   Return number of entries in the undobuffer.

      >>> while undobufferentries():
      ...     undo()


Formas compostas
----------------

To use compound turtle shapes, which consist of several polygons of
different color, you must use the helper class "Shape" explicitly as
described below:

1. Create an empty Shape object of type "compound".

2. Add as many components to this object as desired, using the
   "addcomponent()" method.

   Por exemplo:

      >>> s = Shape("compound")
      >>> poly1 = ((0,0),(10,-5),(0,10),(-10,-5))
      >>> s.addcomponent(poly1, "red", "blue")
      >>> poly2 = ((0,0),(10,-5),(-10,-5))
      >>> s.addcomponent(poly2, "blue", "red")

3. Now add the Shape to the Screen's shapelist and use it:

      >>> register_shape("myshape", s)
      >>> shape("myshape")

Nota:

  The "Shape" class is used internally by the "register_shape()"
  method in different ways.  The application programmer has to deal
  with the Shape class *only* when using compound shapes like shown
  above!


Methods of TurtleScreen/Screen and corresponding functions
==========================================================

Most of the examples in this section refer to a TurtleScreen instance
called "screen".


Controle da Janela
------------------

turtle.bgcolor(*args)

   Parâmetros:
      **args** -- a color string or three numbers in the range
      0..colormode or a 3-tuple of such numbers

   Set or return background color of the TurtleScreen.

      >>> screen.bgcolor("orange")
      >>> screen.bgcolor()
      'orange'
      >>> screen.bgcolor("#800080")
      >>> screen.bgcolor()
      (128.0, 0.0, 128.0)

turtle.bgpic(picname=None)

   Parâmetros:
      **picname** -- a string, name of a gif-file or ""nopic"", or
      "None"

   Set background image or return name of current backgroundimage.  If
   *picname* is a filename, set the corresponding image as background.
   If *picname* is ""nopic"", delete background image, if present.  If
   *picname* is "None", return the filename of the current
   backgroundimage.

      >>> screen.bgpic()
      'nopic'
      >>> screen.bgpic("landscape.gif")
      >>> screen.bgpic()
      "landscape.gif"

turtle.clear()

   Nota:

     This TurtleScreen method is available as a global function only
     under the name "clearscreen".  The global function "clear" is a
     different one derived from the Turtle method "clear".

turtle.clearscreen()

   Delete all drawings and all turtles from the TurtleScreen.  Reset
   the now empty TurtleScreen to its initial state: white background,
   no background image, no event bindings and tracing on.

turtle.reset()

   Nota:

     This TurtleScreen method is available as a global function only
     under the name "resetscreen".  The global function "reset" is
     another one derived from the Turtle method "reset".

turtle.resetscreen()

   Reset all Turtles on the Screen to their initial state.

turtle.screensize(canvwidth=None, canvheight=None, bg=None)

   Parâmetros:
      * **canvwidth** -- positive integer, new width of canvas in
        pixels

      * **canvheight** -- positive integer, new height of canvas in
        pixels

      * **bg** -- colorstring or color-tuple, new background color

   If no arguments are given, return current (canvaswidth,
   canvasheight).  Else resize the canvas the turtles are drawing on.
   Do not alter the drawing window.  To observe hidden parts of the
   canvas, use the scrollbars. With this method, one can make visible
   those parts of a drawing which were outside the canvas before.

   >>> screen.screensize()
   (400, 300)
   >>> screen.screensize(2000,1500)
   >>> screen.screensize()
   (2000, 1500)

   e.g. to search for an erroneously escaped turtle ;-)

turtle.setworldcoordinates(llx, lly, urx, ury)

   Parâmetros:
      * **llx** -- a number, x-coordinate of lower left corner of
        canvas

      * **lly** -- a number, y-coordinate of lower left corner of
        canvas

      * **urx** -- a number, x-coordinate of upper right corner of
        canvas

      * **ury** -- a number, y-coordinate of upper right corner of
        canvas

   Set up user-defined coordinate system and switch to mode "world" if
   necessary.  This performs a "screen.reset()".  If mode "world" is
   already active, all drawings are redrawn according to the new
   coordinates.

   **ATTENTION**: in user-defined coordinate systems angles may appear
   distorted.

      >>> screen.reset()
      >>> screen.setworldcoordinates(-50,-7.5,50,7.5)
      >>> for _ in range(72):
      ...     left(10)
      ...
      >>> for _ in range(8):
      ...     left(45); fd(2)   # a regular octagon


Controle da animação
--------------------

turtle.delay(delay=None)

   Parâmetros:
      **delay** -- positive integer

   Set or return the drawing *delay* in milliseconds.  (This is
   approximately the time interval between two consecutive canvas
   updates.)  The longer the drawing delay, the slower the animation.

   Argumentos opcionais:

      >>> screen.delay()
      10
      >>> screen.delay(5)
      >>> screen.delay()
      5

turtle.tracer(n=None, delay=None)

   Parâmetros:
      * **n** -- inteiro não-negativo

      * **delay** -- inteiro não-negativo

   Turn turtle animation on/off and set delay for update drawings.  If
   *n* is given, only each n-th regular screen update is really
   performed.  (Can be used to accelerate the drawing of complex
   graphics.)  When called without arguments, returns the currently
   stored value of n. Second argument sets delay value (see
   "delay()").

      >>> screen.tracer(8, 25)
      >>> dist = 2
      >>> for i in range(200):
      ...     fd(dist)
      ...     rt(90)
      ...     dist += 2

turtle.update()

   Perform a TurtleScreen update. To be used when tracer is turned
   off.

Veja também o método RawTurtle/Turtle "speed()".


Usando os eventos de tela
-------------------------

turtle.listen(xdummy=None, ydummy=None)

   Set focus on TurtleScreen (in order to collect key-events).  Dummy
   arguments are provided in order to be able to pass "listen()" to
   the onclick method.

turtle.onkey(fun, key)
turtle.onkeyrelease(fun, key)

   Parâmetros:
      * **fun** -- a function with no arguments or "None"

      * **key** -- a string: key (e.g. "a") or key-symbol (e.g.
        "space")

   Bind *fun* to key-release event of key.  If *fun* is "None", event
   bindings are removed. Remark: in order to be able to register key-
   events, TurtleScreen must have the focus. (See method "listen()".)

      >>> def f():
      ...     fd(50)
      ...     lt(60)
      ...
      >>> screen.onkey(f, "Up")
      >>> screen.listen()

turtle.onkeypress(fun, key=None)

   Parâmetros:
      * **fun** -- a function with no arguments or "None"

      * **key** -- a string: key (e.g. "a") or key-symbol (e.g.
        "space")

   Bind *fun* to key-press event of key if key is given, or to any
   key-press-event if no key is given. Remark: in order to be able to
   register key-events, TurtleScreen must have focus. (See method
   "listen()".)

      >>> def f():
      ...     fd(50)
      ...
      >>> screen.onkey(f, "Up")
      >>> screen.listen()

turtle.onclick(fun, btn=1, add=None)
turtle.onscreenclick(fun, btn=1, add=None)

   Parâmetros:
      * **fun** -- a function with two arguments which will be called
        with the coordinates of the clicked point on the canvas

      * **btn** -- number of the mouse-button, defaults to 1 (left
        mouse button)

      * **add** -- "True" or "False" -- if "True", a new binding will
        be added, otherwise it will replace a former binding

   Bind *fun* to mouse-click events on this screen.  If *fun* is
   "None", existing bindings are removed.

   Example for a TurtleScreen instance named "screen" and a Turtle
   instance named "turtle":

      >>> screen.onclick(turtle.goto) # Subsequently clicking into the TurtleScreen will
      >>>                             # make the turtle move to the clicked point.
      >>> screen.onclick(None)        # remove event binding again

   Nota:

     This TurtleScreen method is available as a global function only
     under the name "onscreenclick".  The global function "onclick" is
     another one derived from the Turtle method "onclick".

turtle.ontimer(fun, t=0)

   Parâmetros:
      * **fun** -- um função sem nenhum argumento

      * **t** -- um número >= 0

   Install a timer that calls *fun* after *t* milliseconds.

      >>> running = True
      >>> def f():
      ...     if running:
      ...         fd(50)
      ...         lt(60)
      ...         screen.ontimer(f, 250)
      >>> f()   ### makes the turtle march around
      >>> running = False

turtle.mainloop()
turtle.done()

   Starts event loop - calling Tkinter's mainloop function. Must be
   the last statement in a turtle graphics program. Must *not* be used
   if a script is run from within IDLE in -n mode (No subprocess) -
   for interactive use of turtle graphics.

      >>> screen.mainloop()


Métodos de entrada
------------------

turtle.textinput(title, prompt)

   Parâmetros:
      * **title** -- string

      * **prompt** -- string

   Pop up a dialog window for input of a string. Parameter title is
   the title of the dialog window, prompt is a text mostly describing
   what information to input. Return the string input. If the dialog
   is canceled, return "None".

      >>> screen.textinput("NIM", "Name of first player:")

turtle.numinput(title, prompt, default=None, minval=None, maxval=None)

   Parâmetros:
      * **title** -- string

      * **prompt** -- string

      * **default** -- número (opcional)

      * **minval** -- número (opcional)

      * **maxval** -- número (opcional)

   Pop up a dialog window for input of a number. title is the title of
   the dialog window, prompt is a text mostly describing what
   numerical information to input. default: default value, minval:
   minimum value for input, maxval: maximum value for input The number
   input must be in the range minval .. maxval if these are given. If
   not, a hint is issued and the dialog remains open for correction.
   Return the number input. If the dialog is canceled,  return "None".

      >>> screen.numinput("Poker", "Your stakes:", 1000, minval=10, maxval=10000)


Configurações e métodos especiais
---------------------------------

turtle.mode(mode=None)

   Parâmetros:
      **mode** -- one of the strings "standard", "logo" or "world"

   Set turtle mode ("standard", "logo" or "world") and perform reset.
   If mode is not given, current mode is returned.

   Mode "standard" is compatible with old "turtle".  Mode "logo" is
   compatible with most Logo turtle graphics.  Mode "world" uses user-
   defined "world coordinates". **Attention**: in this mode angles
   appear distorted if "x/y" unit-ratio doesn't equal 1.

   +--------------+---------------------------+---------------------+
   | Modo         | Título inicial da         | ângulos positivos   |
   |              | tartaruga                 |                     |
   |==============|===========================|=====================|
   | "standard"   | para a direita (east)     | counterclockwise    |
   +--------------+---------------------------+---------------------+
   | "logo"       | upward (north)            | sentido horário     |
   +--------------+---------------------------+---------------------+

      >>> mode("logo")   # resets turtle heading to north
      >>> mode()
      'logo'

turtle.colormode(cmode=None)

   Parâmetros:
      **cmode** -- um dos valroes 1.0 ou 255

   Return the colormode or set it to 1.0 or 255.  Subsequently *r*,
   *g*, *b* values of color triples have to be in the range
   0..*cmode*.

      >>> screen.colormode(1)
      >>> turtle.pencolor(240, 160, 80)
      Traceback (most recent call last):
           ...
      TurtleGraphicsError: bad color sequence: (240, 160, 80)
      >>> screen.colormode()
      1.0
      >>> screen.colormode(255)
      >>> screen.colormode()
      255
      >>> turtle.pencolor(240,160,80)

turtle.getcanvas()

   Return the Canvas of this TurtleScreen.  Useful for insiders who
   know what to do with a Tkinter Canvas.

      >>> cv = screen.getcanvas()
      >>> cv
      <turtle.ScrolledCanvas object ...>

turtle.getshapes()

   Retorna uma lista dos nomes de todas as formas de tartarugas
   disponíveis no momento.

      >>> screen.getshapes()
      ['arrow', 'blank', 'circle', ..., 'turtle']

turtle.register_shape(name, shape=None)
turtle.addshape(name, shape=None)

   Há três maneiras diferentes de chamar essa função:

   1. *name* is the name of a gif-file and *shape* is "None": Install
      the corresponding image shape.

         >>> screen.register_shape("turtle.gif")

      Nota:

        Image shapes *do not* rotate when turning the turtle, so they
        do not display the heading of the turtle!

   2. *name* is an arbitrary string and *shape* is a tuple of pairs of
      coordinates: Install the corresponding polygon shape.

         >>> screen.register_shape("triangle", ((5,-3), (0,5), (-5,-3)))

   3. *name* is an arbitrary string and shape is a (compound) "Shape"
      object: Install the corresponding compound shape.

   Add a turtle shape to TurtleScreen's shapelist.  Only thusly
   registered shapes can be used by issuing the command
   "shape(shapename)".

turtle.turtles()

   Retorne uma lista de tartarugas na tela.

      >>> for turtle in screen.turtles():
      ...     turtle.color("red")

turtle.window_height()

   Retorna a altura da janela da tartaruga.

      >>> screen.window_height()
      480

turtle.window_width()

   Retorna a largura da janela da tartaruga.

      >>> screen.window_width()
      640


Methods specific to Screen, not inherited from TurtleScreen
-----------------------------------------------------------

turtle.bye()

   Shut the turtlegraphics window.

turtle.exitonclick()

   Bind "bye()" method to mouse clicks on the Screen.

   If the value "using_IDLE" in the configuration dictionary is
   "False" (default value), also enter mainloop.  Remark: If IDLE with
   the "-n" switch (no subprocess) is used, this value should be set
   to "True" in "turtle.cfg".  In this case IDLE's own mainloop is
   active also for the client script.

turtle.setup(width=_CFG["width"], height=_CFG["height"], startx=_CFG["leftright"], starty=_CFG["topbottom"])

   Set the size and position of the main window.  Default values of
   arguments are stored in the configuration dictionary and can be
   changed via a "turtle.cfg" file.

   Parâmetros:
      * **width** -- if an integer, a size in pixels, if a float, a
        fraction of the screen; default is 50% of screen

      * **height** -- if an integer, the height in pixels, if a float,
        a fraction of the screen; default is 75% of screen

      * **startx** -- if positive, starting position in pixels from
        the left edge of the screen, if negative from the right edge,
        if "None", center window horizontally

      * **starty** -- if positive, starting position in pixels from
        the top edge of the screen, if negative from the bottom edge,
        if "None", center window vertically

      >>> screen.setup (width=200, height=200, startx=0, starty=0)
      >>>              # sets window to 200x200 pixels, in upper left of screen
      >>> screen.setup(width=.75, height=0.5, startx=None, starty=None)
      >>>              # sets window to 75% of screen by 50% of screen and centers

turtle.title(titlestring)

   Parâmetros:
      **titlestring** -- a string that is shown in the titlebar of the
      turtle graphics window

   Set title of turtle window to *titlestring*.

      >>> screen.title("Welcome to the turtle zoo!")


Classes Públicas
================

class turtle.RawTurtle(canvas)
class turtle.RawPen(canvas)

   Parâmetros:
      **canvas** -- a "tkinter.Canvas", a "ScrolledCanvas" or a
      "TurtleScreen"

   Create a turtle.  The turtle has all methods described above as
   "methods of Turtle/RawTurtle".

class turtle.Turtle

   Subclass of RawTurtle, has the same interface but draws on a
   default "Screen" object created automatically when needed for the
   first time.

class turtle.TurtleScreen(cv)

   Parâmetros:
      **cv** -- uma "tkinter.Canvas"

   Provides screen oriented methods like "setbg()" etc. that are
   described above.

class turtle.Screen

   Subclass of TurtleScreen, with four methods added.

class turtle.ScrolledCanvas(master)

   Parâmetros:
      **master** -- some Tkinter widget to contain the ScrolledCanvas,
      i.e. a Tkinter-canvas with scrollbars added

   Used by class Screen, which thus automatically provides a
   ScrolledCanvas as playground for the turtles.

class turtle.Shape(type_, data)

   Parâmetros:
      **type_** -- one of the strings "polygon", "image", "compound"

   Data structure modeling shapes.  The pair "(type_, data)" must
   follow this specification:

   +-------------+------------------------------------------------------------+
   | *type_*     | *data*                                                     |
   |=============|============================================================|
   | "polygon"   | a polygon-tuple, i.e. a tuple of pairs of coordinates      |
   +-------------+------------------------------------------------------------+
   | "image"     | an image  (in this form only used internally!)             |
   +-------------+------------------------------------------------------------+
   | "compound"  | "None" (a compound shape has to be constructed using the   |
   |             | "addcomponent()" method)                                   |
   +-------------+------------------------------------------------------------+

   addcomponent(poly, fill, outline=None)

      Parâmetros:
         * **poly** -- a polygon, i.e. a tuple of pairs of numbers

         * **fill** -- a color the *poly* will be filled with

         * **outline** -- a color for the poly's outline (if given)

      Exemplo:

         >>> poly = ((0,0),(10,-5),(0,10),(-10,-5))
         >>> s = Shape("compound")
         >>> s.addcomponent(poly, "red", "blue")
         >>> # ... add more components and then use register_shape()

      See Formas compostas.

class turtle.Vec2D(x, y)

   A two-dimensional vector class, used as a helper class for
   implementing turtle graphics.  May be useful for turtle graphics
   programs too.  Derived from tuple, so a vector is a tuple!

   Provides (for *a*, *b* vectors, *k* number):

   * "a + b" vetor adicional

   * "a - b" subtração de vetor

   * "a * b" produto interno

   * "k * a" e "a * k" multiplicação com escalar

   * "abs(a)" valor absoluto de um

   * rotação "a.rotate(angle)"


Ajuda e Configuração
====================


Como usar a Ajuda
-----------------

The public methods of the Screen and Turtle classes are documented
extensively via docstrings.  So these can be used as online-help via
the Python help facilities:

* When using IDLE, tooltips show the signatures and first lines of the
  docstrings of typed in function-/method calls.

* Calling "help()" on methods or functions displays the docstrings:

     >>> help(Screen.bgcolor)
     Help on method bgcolor in module turtle:

     bgcolor(self, *args) unbound turtle.Screen method
         Set or return backgroundcolor of the TurtleScreen.

         Arguments (if given): a color string or three numbers
         in the range 0..colormode or a 3-tuple of such numbers.


           >>> screen.bgcolor("orange")
           >>> screen.bgcolor()
           "orange"
           >>> screen.bgcolor(0.5,0,0.5)
           >>> screen.bgcolor()
           "#800080"

     >>> help(Turtle.penup)
     Help on method penup in module turtle:

     penup(self) unbound turtle.Turtle method
         Pull the pen up -- no drawing when moving.

         Aliases: penup | pu | up

         No argument

         >>> turtle.penup()

* The docstrings of the functions which are derived from methods have
  a modified form:

     >>> help(bgcolor)
     Help on function bgcolor in module turtle:

     bgcolor(*args)
         Set or return backgroundcolor of the TurtleScreen.

         Arguments (if given): a color string or three numbers
         in the range 0..colormode or a 3-tuple of such numbers.

         Example::

           >>> bgcolor("orange")
           >>> bgcolor()
           "orange"
           >>> bgcolor(0.5,0,0.5)
           >>> bgcolor()
           "#800080"

     >>> help(penup)
     Help on function penup in module turtle:

     penup()
         Pull the pen up -- no drawing when moving.

         Aliases: penup | pu | up

         No argument

         Example:
         >>> penup()

These modified docstrings are created automatically together with the
function definitions that are derived from the methods at import time.


Translation of docstrings into different languages
--------------------------------------------------

There is a utility to create a dictionary the keys of which are the
method names and the values of which are the docstrings of the public
methods of the classes Screen and Turtle.

turtle.write_docstringdict(filename="turtle_docstringdict")

   Parâmetros:
      **filename** -- a string, used as filename

   Create and write docstring-dictionary to a Python script with the
   given filename.  This function has to be called explicitly (it is
   not used by the turtle graphics classes).  The docstring dictionary
   will be written to the Python script "*filename*.py".  It is
   intended to serve as a template for translation of the docstrings
   into different languages.

If you (or your students) want to use "turtle" with online help in
your native language, you have to translate the docstrings and save
the resulting file as e.g. "turtle_docstringdict_german.py".

If you have an appropriate entry in your "turtle.cfg" file this
dictionary will be read in at import time and will replace the
original English docstrings.

At the time of this writing there are docstring dictionaries in German
and in Italian.  (Requests please to glingl@aon.at.)


How to configure Screen and Turtles
-----------------------------------

The built-in default configuration mimics the appearance and behaviour
of the old turtle module in order to retain best possible
compatibility with it.

If you want to use a different configuration which better reflects the
features of this module or which better fits to your needs, e.g. for
use in a classroom, you can prepare a configuration file "turtle.cfg"
which will be read at import time and modify the configuration
according to its settings.

The built in configuration would correspond to the following
turtle.cfg:

   width = 0.5
   height = 0.75
   leftright = None
   topbottom = None
   canvwidth = 400
   canvheight = 300
   mode = standard
   colormode = 1.0
   delay = 10
   undobuffersize = 1000
   shape = classic
   pencolor = black
   fillcolor = black
   resizemode = noresize
   visible = True
   language = english
   exampleturtle = turtle
   examplescreen = screen
   title = Python Turtle Graphics
   using_IDLE = False

Breve explicação das entradas selecionadas:

* The first four lines correspond to the arguments of the
  "Screen.setup()" method.

* Line 5 and 6 correspond to the arguments of the method
  "Screen.screensize()".

* *shape* can be any of the built-in shapes, e.g: arrow, turtle, etc.
  For more info try "help(shape)".

* If you want to use no fillcolor (i.e. make the turtle transparent),
  you have to write "fillcolor = """ (but all nonempty strings must
  not have quotes in the cfg-file).

* If you want to reflect the turtle its state, you have to use
  "resizemode = auto".

* If you set e.g. "language = italian" the docstringdict
  "turtle_docstringdict_italian.py" will be loaded at import time (if
  present on the import path, e.g. in the same directory as "turtle".

* The entries *exampleturtle* and *examplescreen* define the names of
  these objects as they occur in the docstrings.  The transformation
  of method-docstrings to function-docstrings will delete these names
  from the docstrings.

* *using_IDLE*: Set this to "True" if you regularly work with IDLE and
  its -n switch ("no subprocess").  This will prevent "exitonclick()"
  to enter the mainloop.

There can be a "turtle.cfg" file in the directory where "turtle" is
stored and an additional one in the current working directory.  The
latter will override the settings of the first one.

The "Lib/turtledemo" directory contains a "turtle.cfg" file.  You can
study it as an example and see its effects when running the demos
(preferably not from within the demo-viewer).


"turtledemo" --- Scripts de Demonstração
========================================

The "turtledemo" package includes a set of demo scripts.  These
scripts can be run and viewed using the supplied demo viewer as
follows:

   python -m turtledemo

Alternatively, you can run the demo scripts individually.  For
example,

   python -m turtledemo.bytedesign

The "turtledemo" package directory contains:

* A demo viewer "__main__.py" which can be used to view the sourcecode
  of the scripts and run them at the same time.

* Multiple scripts demonstrating different features of the "turtle"
  module.  Examples can be accessed via the Examples menu.  They can
  also be run standalone.

* A "turtle.cfg" file which serves as an example of how to write and
  use such files.

Os scripts de demonstração são:

+------------------+--------------------------------+-------------------------+
| Nome             | Descrição                      | Recursos                |
|==================|================================|=========================|
| bytedesign       | Padrão de gráficos de          | "tracer()", delay,      |
|                  | tartaruga clássico complexo    | "update()"              |
+------------------+--------------------------------+-------------------------+
| chaos            | graphs Verhulst dynamics,      | coordenadas mundiais    |
|                  | shows that computer's          |                         |
|                  | computations can generate      |                         |
|                  | results sometimes against the  |                         |
|                  | common sense expectations      |                         |
+------------------+--------------------------------+-------------------------+
| relógio          | Relógio analógico que mostra o | tartarugas como as mãos |
|                  | horário do seu computador      | do relógio, ontimer     |
+------------------+--------------------------------+-------------------------+
| colormixer       | experimento com r, g, b        | "ondrag()"              |
+------------------+--------------------------------+-------------------------+
| forest           | 3 breadth-first trees          | randomization           |
+------------------+--------------------------------+-------------------------+
| fractalcurves    | Curvas de Hilbert & Koch       | recursão                |
+------------------+--------------------------------+-------------------------+
| lindenmayer      | ethnomathematics (indian       | L-System                |
|                  | kolams)                        |                         |
+------------------+--------------------------------+-------------------------+
| minimal_hanoi    | Torres de Hanoi                | Tartarugas retângulos   |
|                  |                                | como discos de Hanói    |
|                  |                                | (shape, shapesize)      |
+------------------+--------------------------------+-------------------------+
| nim              | play the classical nim game    | turtles as nimsticks,   |
|                  | with three heaps of sticks     | event driven (mouse,    |
|                  | against the computer.          | keyboard)               |
+------------------+--------------------------------+-------------------------+
| paint            | programa de desenho super      | "onclick()"             |
|                  | minimalista                    |                         |
+------------------+--------------------------------+-------------------------+
| peça             | elementar                      | tartaruga: aparência e  |
|                  |                                | animação                |
+------------------+--------------------------------+-------------------------+
| penrose          | aperiodic tiling with kites    | "stamp()"               |
|                  | and darts                      |                         |
+------------------+--------------------------------+-------------------------+
| planet_and_moon  | simulação do sistema           | formas compostas,       |
|                  | gravitacional                  | "Vec2D"                 |
+------------------+--------------------------------+-------------------------+
| round_dance      | dancing turtles rotating       | compound shapes, clone  |
|                  | pairwise in opposite direction | shapesize, tilt,        |
|                  |                                | get_shapepoly, update   |
+------------------+--------------------------------+-------------------------+
| sorting_animate  | visual demonstration of        | simple alignment,       |
|                  | different sorting methods      | randomization           |
+------------------+--------------------------------+-------------------------+
| tree             | a (graphical) breadth first    | "clone()"               |
|                  | tree (using generators)        |                         |
+------------------+--------------------------------+-------------------------+
| two_canvases     | desenho simples                | tartarugas em duas      |
|                  |                                | telas                   |
+------------------+--------------------------------+-------------------------+
| wikipedia        | um padrão do artigo Wikipédia  | "clone()", "undo()"     |
|                  | sobre gráficos de tartaruga    |                         |
+------------------+--------------------------------+-------------------------+
| yinyang          | outro exemplo elementar        | "circle()"              |
+------------------+--------------------------------+-------------------------+

Diverta-se!


Modificações desde a versão do Python 2.6
=========================================

* The methods "Turtle.tracer()", "Turtle.window_width()" and
  "Turtle.window_height()" have been eliminated. Methods with these
  names and functionality are now available only as methods of
  "Screen". The functions derived from these remain available. (In
  fact already in Python 2.6 these methods were merely duplications of
  the corresponding "TurtleScreen"/"Screen"-methods.)

* The method "Turtle.fill()" has been eliminated. The behaviour of
  "begin_fill()" and "end_fill()" have changed slightly: now  every
  filling-process must be completed with an "end_fill()" call.

* A method "Turtle.filling()" has been added. It returns a boolean
  value: "True" if a filling process is under way, "False" otherwise.
  This behaviour corresponds to a "fill()" call without arguments in
  Python 2.6.


Modificações desde a versão do Python 3.0
=========================================

* The methods "Turtle.shearfactor()", "Turtle.shapetransform()" and
  "Turtle.get_shapepoly()" have been added. Thus the full range of
  regular linear transforms is now available for transforming turtle
  shapes. "Turtle.tiltangle()" has been enhanced in functionality: it
  now can be used to get or set the tiltangle. "Turtle.settiltangle()"
  has been deprecated.

* The method "Screen.onkeypress()" has been added as a complement to
  "Screen.onkey()" which in fact binds actions to the keyrelease
  event. Accordingly the latter has got an alias:
  "Screen.onkeyrelease()".

* The method  "Screen.mainloop()" has been added. So when working only
  with Screen and Turtle objects one must not additionally import
  "mainloop()" anymore.

* Two input methods has been added "Screen.textinput()" and
  "Screen.numinput()". These popup input dialogs and return strings
  and numbers respectively.

* Two example scripts "tdemo_nim.py" and "tdemo_round_dance.py" have
  been added to the "Lib/turtledemo" directory.
