2535 lines
		
	
	
		
			72 KiB
		
	
	
	
		
			ReStructuredText
		
	
	
	
			
		
		
	
	
			2535 lines
		
	
	
		
			72 KiB
		
	
	
	
		
			ReStructuredText
		
	
	
	
| =================================
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| :mod:`turtle` --- Turtle graphics
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| =================================
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| 
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| .. module:: turtle
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|    :synopsis: An educational framework for simple graphics applications
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| 
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| .. sectionauthor:: Gregor Lingl <gregor.lingl@aon.at>
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| 
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| **Source code:** :source:`Lib/turtle.py`
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| 
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| .. testsetup:: default
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| 
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|    from turtle import *
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|    turtle = Turtle()
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| 
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| --------------
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| 
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| Introduction
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| ============
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| 
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| Turtle graphics is a popular way for introducing programming to kids.  It was
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| part of the original Logo programming language developed by Wally Feurzeig,
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| Seymour Papert and Cynthia Solomon in 1967.
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| 
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| Imagine a robotic turtle starting at (0, 0) in the x-y plane.  After an ``import turtle``, give it the
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| command ``turtle.forward(15)``, and it moves (on-screen!) 15 pixels in the
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| direction it is facing, drawing a line as it moves.  Give it the command
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| ``turtle.right(25)``, and it rotates in-place 25 degrees clockwise.
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| 
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| .. sidebar:: Turtle star
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| 
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|    Turtle can draw intricate shapes using programs that repeat simple
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|    moves.
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| 
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|    .. image:: turtle-star.*
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|       :align: center
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| 
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|    .. literalinclude:: ../includes/turtle-star.py
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| 
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| By combining together these and similar commands, intricate shapes and pictures
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| can easily be drawn.
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| 
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| The :mod:`turtle` module is an extended reimplementation of the same-named
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| module from the Python standard distribution up to version Python 2.5.
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| 
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| It tries to keep the merits of the old turtle module and to be (nearly) 100%
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| compatible with it.  This means in the first place to enable the learning
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| programmer to use all the commands, classes and methods interactively when using
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| the module from within IDLE run with the ``-n`` switch.
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| 
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| The turtle module provides turtle graphics primitives, in both object-oriented
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| and procedure-oriented ways.  Because it uses :mod:`tkinter` for the underlying
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| graphics, it needs a version of Python installed with Tk support.
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| 
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| The object-oriented interface uses essentially two+two classes:
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| 
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| 1. The :class:`TurtleScreen` class defines graphics windows as a playground for
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|    the drawing turtles.  Its constructor needs a :class:`tkinter.Canvas` or a
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|    :class:`ScrolledCanvas` as argument.  It should be used when :mod:`turtle` is
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|    used as part of some application.
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| 
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|    The function :func:`Screen` returns a singleton object of a
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|    :class:`TurtleScreen` subclass. This function should be used when
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|    :mod:`turtle` is used as a standalone tool for doing graphics.
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|    As a singleton object, inheriting from its class is not possible.
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| 
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|    All methods of TurtleScreen/Screen also exist as functions, i.e. as part of
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|    the procedure-oriented interface.
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| 
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| 2. :class:`RawTurtle` (alias: :class:`RawPen`) defines Turtle objects which draw
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|    on a :class:`TurtleScreen`.  Its constructor needs a Canvas, ScrolledCanvas
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|    or TurtleScreen as argument, so the RawTurtle objects know where to draw.
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| 
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|    Derived from RawTurtle is the subclass :class:`Turtle` (alias: :class:`Pen`),
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|    which draws on "the" :class:`Screen` instance which is automatically
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|    created, if not already present.
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| 
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|    All methods of RawTurtle/Turtle also exist as functions, i.e. part of the
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|    procedure-oriented interface.
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| 
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| The procedural interface provides functions which are derived from the methods
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| of the classes :class:`Screen` and :class:`Turtle`.  They have the same names as
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| the corresponding methods.  A screen object is automatically created whenever a
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| function derived from a Screen method is called.  An (unnamed) turtle object is
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| automatically created whenever any of the functions derived from a Turtle method
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| is called.
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| 
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| To use multiple turtles on a screen one has to use the object-oriented interface.
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| 
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| .. note::
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|    In the following documentation the argument list for functions is given.
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|    Methods, of course, have the additional first argument *self* which is
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|    omitted here.
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| 
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| 
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| Overview of available Turtle and Screen methods
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| =================================================
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| 
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| Turtle methods
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| --------------
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| 
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| Turtle motion
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|    Move and draw
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|       | :func:`forward` | :func:`fd`
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|       | :func:`backward` | :func:`bk` | :func:`back`
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|       | :func:`right` | :func:`rt`
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|       | :func:`left` | :func:`lt`
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|       | :func:`goto` | :func:`setpos` | :func:`setposition`
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|       | :func:`setx`
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|       | :func:`sety`
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|       | :func:`setheading` | :func:`seth`
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|       | :func:`home`
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|       | :func:`circle`
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|       | :func:`dot`
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|       | :func:`stamp`
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|       | :func:`clearstamp`
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|       | :func:`clearstamps`
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|       | :func:`undo`
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|       | :func:`speed`
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| 
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|    Tell Turtle's state
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|       | :func:`position` | :func:`pos`
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|       | :func:`towards`
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|       | :func:`xcor`
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|       | :func:`ycor`
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|       | :func:`heading`
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|       | :func:`distance`
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| 
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|    Setting and measurement
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|       | :func:`degrees`
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|       | :func:`radians`
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| 
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| Pen control
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|    Drawing state
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|       | :func:`pendown` | :func:`pd` | :func:`down`
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|       | :func:`penup` | :func:`pu` | :func:`up`
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|       | :func:`pensize` | :func:`width`
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|       | :func:`pen`
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|       | :func:`isdown`
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| 
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|    Color control
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|       | :func:`color`
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|       | :func:`pencolor`
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|       | :func:`fillcolor`
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| 
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|    Filling
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|       | :func:`filling`
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|       | :func:`begin_fill`
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|       | :func:`end_fill`
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| 
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|    More drawing control
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|       | :func:`reset`
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|       | :func:`clear`
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|       | :func:`write`
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| 
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| Turtle state
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|    Visibility
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|       | :func:`showturtle` | :func:`st`
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|       | :func:`hideturtle` | :func:`ht`
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|       | :func:`isvisible`
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| 
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|    Appearance
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|       | :func:`shape`
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|       | :func:`resizemode`
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|       | :func:`shapesize` | :func:`turtlesize`
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|       | :func:`shearfactor`
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|       | :func:`settiltangle`
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|       | :func:`tiltangle`
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|       | :func:`tilt`
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|       | :func:`shapetransform`
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|       | :func:`get_shapepoly`
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| 
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| Using events
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|    | :func:`onclick`
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|    | :func:`onrelease`
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|    | :func:`ondrag`
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| 
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| Special Turtle methods
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|    | :func:`begin_poly`
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|    | :func:`end_poly`
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|    | :func:`get_poly`
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|    | :func:`clone`
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|    | :func:`getturtle` | :func:`getpen`
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|    | :func:`getscreen`
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|    | :func:`setundobuffer`
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|    | :func:`undobufferentries`
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| 
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| 
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| Methods of TurtleScreen/Screen
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| ------------------------------
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| 
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| Window control
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|    | :func:`bgcolor`
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|    | :func:`bgpic`
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|    | :func:`clearscreen`
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|    | :func:`resetscreen`
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|    | :func:`screensize`
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|    | :func:`setworldcoordinates`
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| 
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| Animation control
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|    | :func:`delay`
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|    | :func:`tracer`
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|    | :func:`update`
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| 
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| Using screen events
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|    | :func:`listen`
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|    | :func:`onkey` | :func:`onkeyrelease`
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|    | :func:`onkeypress`
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|    | :func:`onclick` | :func:`onscreenclick`
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|    | :func:`ontimer`
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|    | :func:`mainloop` | :func:`done`
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| 
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| Settings and special methods
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|    | :func:`mode`
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|    | :func:`colormode`
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|    | :func:`getcanvas`
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|    | :func:`getshapes`
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|    | :func:`register_shape` | :func:`addshape`
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|    | :func:`turtles`
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|    | :func:`window_height`
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|    | :func:`window_width`
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| 
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| Input methods
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|    | :func:`textinput`
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|    | :func:`numinput`
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| 
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| Methods specific to Screen
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|    | :func:`bye`
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|    | :func:`exitonclick`
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|    | :func:`setup`
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|    | :func:`title`
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| 
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| 
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| Methods of RawTurtle/Turtle and corresponding functions
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| =======================================================
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| 
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| Most of the examples in this section refer to a Turtle instance called
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| ``turtle``.
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| 
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| Turtle motion
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| -------------
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| 
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| .. function:: forward(distance)
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|               fd(distance)
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| 
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|    :param distance: a number (integer or float)
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| 
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|    Move the turtle forward by the specified *distance*, in the direction the
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|    turtle is headed.
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| 
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|    .. doctest::
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|       :skipif: _tkinter is None
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| 
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|       >>> turtle.position()
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|       (0.00,0.00)
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|       >>> turtle.forward(25)
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|       >>> turtle.position()
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|       (25.00,0.00)
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|       >>> turtle.forward(-75)
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|       >>> turtle.position()
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|       (-50.00,0.00)
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| 
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| 
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| .. function:: back(distance)
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|               bk(distance)
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|               backward(distance)
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| 
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|    :param distance: a number
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| 
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|    Move the turtle backward by *distance*, opposite to the direction the
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|    turtle is headed.  Do not change the turtle's heading.
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| 
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|    .. doctest::
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|       :hide:
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| 
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|       >>> turtle.goto(0, 0)
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| 
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|    .. doctest::
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|       :skipif: _tkinter is None
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| 
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|       >>> turtle.position()
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|       (0.00,0.00)
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|       >>> turtle.backward(30)
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|       >>> turtle.position()
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|       (-30.00,0.00)
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| 
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| 
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| .. function:: right(angle)
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|               rt(angle)
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| 
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|    :param angle: a number (integer or float)
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| 
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|    Turn turtle right by *angle* units.  (Units are by default degrees, but
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|    can be set via the :func:`degrees` and :func:`radians` functions.)  Angle
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|    orientation depends on the turtle mode, see :func:`mode`.
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| 
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|    .. doctest::
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|       :skipif: _tkinter is None
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|       :hide:
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| 
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|       >>> turtle.setheading(22)
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| 
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|    .. doctest::
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|       :skipif: _tkinter is None
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| 
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|       >>> turtle.heading()
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|       22.0
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|       >>> turtle.right(45)
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|       >>> turtle.heading()
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|       337.0
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| 
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| 
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| .. function:: left(angle)
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|               lt(angle)
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| 
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|    :param angle: a number (integer or float)
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| 
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|    Turn turtle left by *angle* units.  (Units are by default degrees, but
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|    can be set via the :func:`degrees` and :func:`radians` functions.)  Angle
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|    orientation depends on the turtle mode, see :func:`mode`.
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| 
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|    .. doctest::
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|       :skipif: _tkinter is None
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|       :hide:
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| 
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|       >>> turtle.setheading(22)
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| 
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|    .. doctest::
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|       :skipif: _tkinter is None
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| 
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|       >>> turtle.heading()
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|       22.0
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|       >>> turtle.left(45)
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|       >>> turtle.heading()
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|       67.0
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| 
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| 
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| .. function:: goto(x, y=None)
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|               setpos(x, y=None)
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|               setposition(x, y=None)
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| 
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|    :param x: a number or a pair/vector of numbers
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|    :param y: a number or ``None``
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| 
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|    If *y* is ``None``, *x* must be a pair of coordinates or a :class:`Vec2D`
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|    (e.g. as returned by :func:`pos`).
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| 
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|    Move turtle to an absolute position.  If the pen is down, draw line.  Do
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|    not change the turtle's orientation.
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| 
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|    .. doctest::
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|       :skipif: _tkinter is None
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|       :hide:
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| 
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|       >>> turtle.goto(0, 0)
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| 
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|    .. doctest::
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|       :skipif: _tkinter is None
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| 
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|        >>> tp = turtle.pos()
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|        >>> tp
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|        (0.00,0.00)
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|        >>> turtle.setpos(60,30)
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|        >>> turtle.pos()
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|        (60.00,30.00)
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|        >>> turtle.setpos((20,80))
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|        >>> turtle.pos()
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|        (20.00,80.00)
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|        >>> turtle.setpos(tp)
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|        >>> turtle.pos()
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|        (0.00,0.00)
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| 
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| 
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| .. function:: setx(x)
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| 
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|    :param x: a number (integer or float)
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| 
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|    Set the turtle's first coordinate to *x*, leave second coordinate
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|    unchanged.
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| 
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|    .. doctest::
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|       :skipif: _tkinter is None
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|       :hide:
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| 
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|       >>> turtle.goto(0, 240)
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| 
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|    .. doctest::
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|       :skipif: _tkinter is None
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| 
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|       >>> turtle.position()
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|       (0.00,240.00)
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|       >>> turtle.setx(10)
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|       >>> turtle.position()
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|       (10.00,240.00)
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| 
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| 
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| .. function:: sety(y)
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| 
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|    :param y: a number (integer or float)
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| 
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|    Set the turtle's second coordinate to *y*, leave first coordinate unchanged.
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| 
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|    .. doctest::
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|       :skipif: _tkinter is None
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|       :hide:
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| 
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|       >>> turtle.goto(0, 40)
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| 
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|    .. doctest::
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|       :skipif: _tkinter is None
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| 
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|       >>> turtle.position()
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|       (0.00,40.00)
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|       >>> turtle.sety(-10)
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|       >>> turtle.position()
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|       (0.00,-10.00)
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| 
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| 
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| .. function:: setheading(to_angle)
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|               seth(to_angle)
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| 
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|    :param to_angle: a number (integer or float)
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| 
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|    Set the orientation of the turtle to *to_angle*.  Here are some common
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|    directions in degrees:
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| 
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|    =================== ====================
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|     standard mode           logo mode
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|    =================== ====================
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|       0 - east                0 - north
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|      90 - north              90 - east
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|     180 - west              180 - south
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|     270 - south             270 - west
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|    =================== ====================
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| 
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|    .. doctest::
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|       :skipif: _tkinter is None
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| 
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|       >>> turtle.setheading(90)
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|       >>> turtle.heading()
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|       90.0
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| 
 | |
| 
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| .. function:: home()
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| 
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|    Move turtle to the origin -- coordinates (0,0) -- and set its heading to
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|    its start-orientation (which depends on the mode, see :func:`mode`).
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| 
 | |
|    .. doctest::
 | |
|       :skipif: _tkinter is None
 | |
|       :hide:
 | |
| 
 | |
|       >>> turtle.setheading(90)
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|       >>> turtle.goto(0, -10)
 | |
| 
 | |
|    .. doctest::
 | |
|       :skipif: _tkinter is None
 | |
| 
 | |
|       >>> turtle.heading()
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|       90.0
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|       >>> turtle.position()
 | |
|       (0.00,-10.00)
 | |
|       >>> turtle.home()
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|       >>> turtle.position()
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|       (0.00,0.00)
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|       >>> turtle.heading()
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|       0.0
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| 
 | |
| 
 | |
| .. function:: circle(radius, extent=None, steps=None)
 | |
| 
 | |
|    :param radius: a number
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|    :param extent: a number (or ``None``)
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|    :param steps: an integer (or ``None``)
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| 
 | |
|    Draw a circle with given *radius*.  The center is *radius* units left of
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|    the turtle; *extent* -- an angle -- determines which part of the circle
 | |
|    is drawn.  If *extent* is not given, draw the entire circle.  If *extent*
 | |
|    is not a full circle, one endpoint of the arc is the current pen
 | |
|    position.  Draw the arc in counterclockwise direction if *radius* is
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|    positive, otherwise in clockwise direction.  Finally the direction of the
 | |
|    turtle is changed by the amount of *extent*.
 | |
| 
 | |
|    As the circle is approximated by an inscribed regular polygon, *steps*
 | |
|    determines the number of steps to use.  If not given, it will be
 | |
|    calculated automatically.  May be used to draw regular polygons.
 | |
| 
 | |
|    .. doctest::
 | |
|       :skipif: _tkinter is None
 | |
| 
 | |
|       >>> 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
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|       >>> turtle.position()
 | |
|       (0.00,240.00)
 | |
|       >>> turtle.heading()
 | |
|       180.0
 | |
| 
 | |
| 
 | |
| .. function:: dot(size=None, *color)
 | |
| 
 | |
|    :param size: an integer >= 1 (if given)
 | |
|    :param color: a colorstring or a numeric color tuple
 | |
| 
 | |
|    Draw a circular dot with diameter *size*, using *color*.  If *size* is
 | |
|    not given, the maximum of pensize+4 and 2*pensize is used.
 | |
| 
 | |
| 
 | |
|    .. doctest::
 | |
|       :skipif: _tkinter is None
 | |
| 
 | |
|       >>> turtle.home()
 | |
|       >>> turtle.dot()
 | |
|       >>> turtle.fd(50); turtle.dot(20, "blue"); turtle.fd(50)
 | |
|       >>> turtle.position()
 | |
|       (100.00,-0.00)
 | |
|       >>> turtle.heading()
 | |
|       0.0
 | |
| 
 | |
| 
 | |
| .. function:: stamp()
 | |
| 
 | |
|    Stamp a copy of the turtle shape onto the canvas at the current turtle
 | |
|    position.  Return a stamp_id for that stamp, which can be used to delete
 | |
|    it by calling ``clearstamp(stamp_id)``.
 | |
| 
 | |
|    .. doctest::
 | |
|       :skipif: _tkinter is None
 | |
| 
 | |
|       >>> turtle.color("blue")
 | |
|       >>> turtle.stamp()
 | |
|       11
 | |
|       >>> turtle.fd(50)
 | |
| 
 | |
| 
 | |
| .. function:: clearstamp(stampid)
 | |
| 
 | |
|    :param stampid: an integer, must be return value of previous
 | |
|                    :func:`stamp` call
 | |
| 
 | |
|    Delete stamp with given *stampid*.
 | |
| 
 | |
|    .. doctest::
 | |
|       :skipif: _tkinter is None
 | |
| 
 | |
|       >>> 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)
 | |
| 
 | |
| 
 | |
| .. function:: clearstamps(n=None)
 | |
| 
 | |
|    :param n: an integer (or ``None``)
 | |
| 
 | |
|    Delete all or first/last *n* of turtle's stamps.  If *n* is ``None``, delete
 | |
|    all stamps, if *n* > 0 delete first *n* stamps, else if *n* < 0 delete
 | |
|    last *n* stamps.
 | |
| 
 | |
|    .. doctest::
 | |
| 
 | |
|       >>> 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()
 | |
| 
 | |
| 
 | |
| .. function:: undo()
 | |
| 
 | |
|    Undo (repeatedly) the last turtle action(s).  Number of available
 | |
|    undo actions is determined by the size of the undobuffer.
 | |
| 
 | |
|    .. doctest::
 | |
|       :skipif: _tkinter is None
 | |
| 
 | |
|       >>> for i in range(4):
 | |
|       ...     turtle.fd(50); turtle.lt(80)
 | |
|       ...
 | |
|       >>> for i in range(8):
 | |
|       ...     turtle.undo()
 | |
| 
 | |
| 
 | |
| .. function:: speed(speed=None)
 | |
| 
 | |
|    :param speed: an integer in the range 0..10 or a speedstring (see below)
 | |
| 
 | |
|    Set the turtle's speed to an integer value in the range 0..10.  If no
 | |
|    argument is given, return current speed.
 | |
| 
 | |
|    If input is a number greater than 10 or smaller than 0.5, speed is set
 | |
|    to 0.  Speedstrings are mapped to speedvalues as follows:
 | |
| 
 | |
|    * "fastest":  0
 | |
|    * "fast":  10
 | |
|    * "normal":  6
 | |
|    * "slow":  3
 | |
|    * "slowest":  1
 | |
| 
 | |
|    Speeds from 1 to 10 enforce increasingly faster animation of line drawing
 | |
|    and turtle turning.
 | |
| 
 | |
|    Attention: *speed* = 0 means that *no* animation takes
 | |
|    place. forward/back makes turtle jump and likewise left/right make the
 | |
|    turtle turn instantly.
 | |
| 
 | |
|    .. doctest::
 | |
|       :skipif: _tkinter is None
 | |
| 
 | |
|       >>> turtle.speed()
 | |
|       3
 | |
|       >>> turtle.speed('normal')
 | |
|       >>> turtle.speed()
 | |
|       6
 | |
|       >>> turtle.speed(9)
 | |
|       >>> turtle.speed()
 | |
|       9
 | |
| 
 | |
| 
 | |
| Tell Turtle's state
 | |
| -------------------
 | |
| 
 | |
| .. function:: position()
 | |
|               pos()
 | |
| 
 | |
|    Return the turtle's current location (x,y) (as a :class:`Vec2D` vector).
 | |
| 
 | |
|    .. doctest::
 | |
|       :skipif: _tkinter is None
 | |
| 
 | |
|       >>> turtle.pos()
 | |
|       (440.00,-0.00)
 | |
| 
 | |
| 
 | |
| .. function:: towards(x, y=None)
 | |
| 
 | |
|    :param x: a number or a pair/vector of numbers or a turtle instance
 | |
|    :param y: a number if *x* is a number, else ``None``
 | |
| 
 | |
|    Return the angle between the line from turtle position to position specified
 | |
|    by (x,y), the vector or the other turtle.  This depends on the turtle's start
 | |
|    orientation which depends on the mode - "standard"/"world" or "logo".
 | |
| 
 | |
|    .. doctest::
 | |
|       :skipif: _tkinter is None
 | |
| 
 | |
|       >>> turtle.goto(10, 10)
 | |
|       >>> turtle.towards(0,0)
 | |
|       225.0
 | |
| 
 | |
| 
 | |
| .. function:: xcor()
 | |
| 
 | |
|    Return the turtle's x coordinate.
 | |
| 
 | |
|    .. doctest::
 | |
|       :skipif: _tkinter is None
 | |
| 
 | |
|       >>> turtle.home()
 | |
|       >>> turtle.left(50)
 | |
|       >>> turtle.forward(100)
 | |
|       >>> turtle.pos()
 | |
|       (64.28,76.60)
 | |
|       >>> print(round(turtle.xcor(), 5))
 | |
|       64.27876
 | |
| 
 | |
| 
 | |
| .. function:: ycor()
 | |
| 
 | |
|    Return the turtle's y coordinate.
 | |
| 
 | |
|    .. doctest::
 | |
|       :skipif: _tkinter is None
 | |
| 
 | |
|       >>> turtle.home()
 | |
|       >>> turtle.left(60)
 | |
|       >>> turtle.forward(100)
 | |
|       >>> print(turtle.pos())
 | |
|       (50.00,86.60)
 | |
|       >>> print(round(turtle.ycor(), 5))
 | |
|       86.60254
 | |
| 
 | |
| 
 | |
| .. function:: heading()
 | |
| 
 | |
|    Return the turtle's current heading (value depends on the turtle mode, see
 | |
|    :func:`mode`).
 | |
| 
 | |
|    .. doctest::
 | |
|       :skipif: _tkinter is None
 | |
| 
 | |
|       >>> turtle.home()
 | |
|       >>> turtle.left(67)
 | |
|       >>> turtle.heading()
 | |
|       67.0
 | |
| 
 | |
| 
 | |
| .. function:: distance(x, y=None)
 | |
| 
 | |
|    :param x: a number or a pair/vector of numbers or a turtle instance
 | |
|    :param y: a number if *x* is a number, else ``None``
 | |
| 
 | |
|    Return the distance from the turtle to (x,y), the given vector, or the given
 | |
|    other turtle, in turtle step units.
 | |
| 
 | |
|    .. doctest::
 | |
|       :skipif: _tkinter is None
 | |
| 
 | |
|       >>> turtle.home()
 | |
|       >>> turtle.distance(30,40)
 | |
|       50.0
 | |
|       >>> turtle.distance((30,40))
 | |
|       50.0
 | |
|       >>> joe = Turtle()
 | |
|       >>> joe.forward(77)
 | |
|       >>> turtle.distance(joe)
 | |
|       77.0
 | |
| 
 | |
| 
 | |
| Settings for measurement
 | |
| ------------------------
 | |
| 
 | |
| .. function:: degrees(fullcircle=360.0)
 | |
| 
 | |
|    :param fullcircle: a number
 | |
| 
 | |
|    Set angle measurement units, i.e. set number of "degrees" for a full circle.
 | |
|    Default value is 360 degrees.
 | |
| 
 | |
|    .. doctest::
 | |
|       :skipif: _tkinter is None
 | |
| 
 | |
|       >>> 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
 | |
| 
 | |
| 
 | |
| .. function:: radians()
 | |
| 
 | |
|    Set the angle measurement units to radians.  Equivalent to
 | |
|    ``degrees(2*math.pi)``.
 | |
| 
 | |
|    .. doctest::
 | |
|       :skipif: _tkinter is None
 | |
| 
 | |
|       >>> turtle.home()
 | |
|       >>> turtle.left(90)
 | |
|       >>> turtle.heading()
 | |
|       90.0
 | |
|       >>> turtle.radians()
 | |
|       >>> turtle.heading()
 | |
|       1.5707963267948966
 | |
| 
 | |
|    .. doctest::
 | |
|       :skipif: _tkinter is None
 | |
|       :hide:
 | |
| 
 | |
|       >>> turtle.degrees(360)
 | |
| 
 | |
| 
 | |
| Pen control
 | |
| -----------
 | |
| 
 | |
| Drawing state
 | |
| ~~~~~~~~~~~~~
 | |
| 
 | |
| .. function:: pendown()
 | |
|               pd()
 | |
|               down()
 | |
| 
 | |
|    Pull the pen down -- drawing when moving.
 | |
| 
 | |
| 
 | |
| .. function:: penup()
 | |
|               pu()
 | |
|               up()
 | |
| 
 | |
|    Pull the pen up -- no drawing when moving.
 | |
| 
 | |
| 
 | |
| .. function:: pensize(width=None)
 | |
|               width(width=None)
 | |
| 
 | |
|    :param width: a positive number
 | |
| 
 | |
|    Set the line thickness to *width* or return it.  If resizemode is set to
 | |
|    "auto" and turtleshape is a polygon, that polygon is drawn with the same line
 | |
|    thickness.  If no argument is given, the current pensize is returned.
 | |
| 
 | |
|    .. doctest::
 | |
|       :skipif: _tkinter is None
 | |
| 
 | |
|       >>> turtle.pensize()
 | |
|       1
 | |
|       >>> turtle.pensize(10)   # from here on lines of width 10 are drawn
 | |
| 
 | |
| 
 | |
| .. function:: pen(pen=None, **pendict)
 | |
| 
 | |
|    :param pen: a dictionary with some or all of the below listed keys
 | |
|    :param pendict: one or more keyword-arguments with the below listed keys as keywords
 | |
| 
 | |
|    Return or set the pen's attributes in a "pen-dictionary" with the following
 | |
|    key/value pairs:
 | |
| 
 | |
|    * "shown": True/False
 | |
|    * "pendown": True/False
 | |
|    * "pencolor": color-string or color-tuple
 | |
|    * "fillcolor": color-string or color-tuple
 | |
|    * "pensize": positive number
 | |
|    * "speed": number in range 0..10
 | |
|    * "resizemode": "auto" or "user" or "noresize"
 | |
|    * "stretchfactor": (positive number, positive number)
 | |
|    * "outline": positive number
 | |
|    * "tilt": number
 | |
| 
 | |
|    This dictionary can be used as argument for a subsequent call to :func:`pen`
 | |
|    to restore the former pen-state.  Moreover one or more of these attributes
 | |
|    can be provided as keyword-arguments.  This can be used to set several pen
 | |
|    attributes in one statement.
 | |
| 
 | |
|    .. doctest::
 | |
|       :skipif: _tkinter is None
 | |
|       :options: +NORMALIZE_WHITESPACE
 | |
| 
 | |
|       >>> 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')]
 | |
| 
 | |
| .. function:: isdown()
 | |
| 
 | |
|    Return ``True`` if pen is down, ``False`` if it's up.
 | |
| 
 | |
|    .. doctest::
 | |
|       :skipif: _tkinter is None
 | |
| 
 | |
|       >>> turtle.penup()
 | |
|       >>> turtle.isdown()
 | |
|       False
 | |
|       >>> turtle.pendown()
 | |
|       >>> turtle.isdown()
 | |
|       True
 | |
| 
 | |
| 
 | |
| Color control
 | |
| ~~~~~~~~~~~~~
 | |
| 
 | |
| .. function:: pencolor(*args)
 | |
| 
 | |
|    Return or set the pencolor.
 | |
| 
 | |
|    Four input formats are allowed:
 | |
| 
 | |
|    ``pencolor()``
 | |
|       Return the current pencolor as color specification string or
 | |
|       as a tuple (see example).  May be used as input to another
 | |
|       color/pencolor/fillcolor call.
 | |
| 
 | |
|    ``pencolor(colorstring)``
 | |
|       Set pencolor to *colorstring*, which is a Tk color specification string,
 | |
|       such as ``"red"``, ``"yellow"``, or ``"#33cc8c"``.
 | |
| 
 | |
|    ``pencolor((r, g, b))``
 | |
|       Set pencolor 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 :func:`colormode`).
 | |
| 
 | |
|    ``pencolor(r, g, b)``
 | |
|       Set pencolor 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 outline of that polygon is drawn with the
 | |
|    newly set pencolor.
 | |
| 
 | |
|    .. doctest::
 | |
|       :skipif: _tkinter is None
 | |
| 
 | |
|        >>> 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)
 | |
| 
 | |
| 
 | |
| .. function:: fillcolor(*args)
 | |
| 
 | |
|    Return or set the fillcolor.
 | |
| 
 | |
|    Four input formats are allowed:
 | |
| 
 | |
|    ``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 :func:`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.
 | |
| 
 | |
|    .. doctest::
 | |
|       :skipif: _tkinter is None
 | |
| 
 | |
|        >>> 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)
 | |
| 
 | |
| 
 | |
| .. function:: 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 :func:`pencolor` and
 | |
|       :func:`fillcolor`.
 | |
| 
 | |
|    ``color(colorstring)``, ``color((r,g,b))``, ``color(r,g,b)``
 | |
|       Inputs as in :func:`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.
 | |
| 
 | |
|    .. doctest::
 | |
|       :skipif: _tkinter is None
 | |
| 
 | |
|        >>> turtle.color("red", "green")
 | |
|        >>> turtle.color()
 | |
|        ('red', 'green')
 | |
|        >>> color("#285078", "#a0c8f0")
 | |
|        >>> color()
 | |
|        ((40.0, 80.0, 120.0), (160.0, 200.0, 240.0))
 | |
| 
 | |
| 
 | |
| See also: Screen method :func:`colormode`.
 | |
| 
 | |
| 
 | |
| Filling
 | |
| ~~~~~~~
 | |
| 
 | |
| .. doctest::
 | |
|    :skipif: _tkinter is None
 | |
|    :hide:
 | |
| 
 | |
|    >>> turtle.home()
 | |
| 
 | |
| .. function:: filling()
 | |
| 
 | |
|    Return fillstate (``True`` if filling, ``False`` else).
 | |
| 
 | |
|    .. doctest::
 | |
|       :skipif: _tkinter is None
 | |
| 
 | |
|        >>> turtle.begin_fill()
 | |
|        >>> if turtle.filling():
 | |
|        ...    turtle.pensize(5)
 | |
|        ... else:
 | |
|        ...    turtle.pensize(3)
 | |
| 
 | |
| 
 | |
| 
 | |
| .. function:: begin_fill()
 | |
| 
 | |
|    To be called just before drawing a shape to be filled.
 | |
| 
 | |
| 
 | |
| .. function:: end_fill()
 | |
| 
 | |
|    Fill the shape drawn after the last call to :func:`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.
 | |
| 
 | |
|    .. doctest::
 | |
|       :skipif: _tkinter is None
 | |
| 
 | |
|       >>> turtle.color("black", "red")
 | |
|       >>> turtle.begin_fill()
 | |
|       >>> turtle.circle(80)
 | |
|       >>> turtle.end_fill()
 | |
| 
 | |
| 
 | |
| More drawing control
 | |
| ~~~~~~~~~~~~~~~~~~~~
 | |
| 
 | |
| .. function:: reset()
 | |
| 
 | |
|    Delete the turtle's drawings from the screen, re-center the turtle and set
 | |
|    variables to the default values.
 | |
| 
 | |
|    .. doctest::
 | |
|       :skipif: _tkinter is None
 | |
| 
 | |
|       >>> 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
 | |
| 
 | |
| 
 | |
| .. function:: 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.
 | |
| 
 | |
| 
 | |
| .. function:: write(arg, move=False, align="left", font=("Arial", 8, "normal"))
 | |
| 
 | |
|    :param arg: object to be written to the TurtleScreen
 | |
|    :param move: True/False
 | |
|    :param align: one of the strings "left", "center" or right"
 | |
|    :param 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)
 | |
| 
 | |
| 
 | |
| Turtle state
 | |
| ------------
 | |
| 
 | |
| Visibility
 | |
| ~~~~~~~~~~
 | |
| 
 | |
| .. function:: hideturtle()
 | |
|               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.
 | |
| 
 | |
|    .. doctest::
 | |
|       :skipif: _tkinter is None
 | |
| 
 | |
|       >>> turtle.hideturtle()
 | |
| 
 | |
| 
 | |
| .. function:: showturtle()
 | |
|               st()
 | |
| 
 | |
|    Make the turtle visible.
 | |
| 
 | |
|    .. doctest::
 | |
|       :skipif: _tkinter is None
 | |
| 
 | |
|       >>> turtle.showturtle()
 | |
| 
 | |
| 
 | |
| .. function:: isvisible()
 | |
| 
 | |
|    Return ``True`` if the Turtle is shown, ``False`` if it's hidden.
 | |
| 
 | |
|    >>> turtle.hideturtle()
 | |
|    >>> turtle.isvisible()
 | |
|    False
 | |
|    >>> turtle.showturtle()
 | |
|    >>> turtle.isvisible()
 | |
|    True
 | |
| 
 | |
| 
 | |
| Appearance
 | |
| ~~~~~~~~~~
 | |
| 
 | |
| .. function:: shape(name=None)
 | |
| 
 | |
|    :param 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 :func:`register_shape`.
 | |
| 
 | |
|    .. doctest::
 | |
|       :skipif: _tkinter is None
 | |
| 
 | |
|       >>> turtle.shape()
 | |
|       'classic'
 | |
|       >>> turtle.shape("turtle")
 | |
|       >>> turtle.shape()
 | |
|       'turtle'
 | |
| 
 | |
| 
 | |
| .. function:: resizemode(rmode=None)
 | |
| 
 | |
|    :param rmode: one of the 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": adapts the appearance of the turtle corresponding to the value of pensize.
 | |
|    - "user": adapts the appearance of the turtle according to the values of
 | |
|      stretchfactor and outlinewidth (outline), which are set by
 | |
|      :func:`shapesize`.
 | |
|    - "noresize": no adaption of the turtle's appearance takes place.
 | |
| 
 | |
|    ``resizemode("user")`` is called by :func:`shapesize` when used with arguments.
 | |
| 
 | |
|    .. doctest::
 | |
|       :skipif: _tkinter is None
 | |
| 
 | |
|       >>> turtle.resizemode()
 | |
|       'noresize'
 | |
|       >>> turtle.resizemode("auto")
 | |
|       >>> turtle.resizemode()
 | |
|       'auto'
 | |
| 
 | |
| 
 | |
| .. function:: shapesize(stretch_wid=None, stretch_len=None, outline=None)
 | |
|               turtlesize(stretch_wid=None, stretch_len=None, outline=None)
 | |
| 
 | |
|    :param stretch_wid: positive number
 | |
|    :param stretch_len: positive number
 | |
|    :param outline: positive number
 | |
| 
 | |
|    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.
 | |
| 
 | |
|    .. doctest::
 | |
|       :skipif: _tkinter is None
 | |
| 
 | |
|       >>> 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)
 | |
| 
 | |
| 
 | |
| .. function:: shearfactor(shear=None)
 | |
| 
 | |
|    :param shear: number (optional)
 | |
| 
 | |
|    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.
 | |
| 
 | |
|    .. doctest::
 | |
|       :skipif: _tkinter is None
 | |
| 
 | |
|        >>> turtle.shape("circle")
 | |
|        >>> turtle.shapesize(5,2)
 | |
|        >>> turtle.shearfactor(0.5)
 | |
|        >>> turtle.shearfactor()
 | |
|        0.5
 | |
| 
 | |
| 
 | |
| .. function:: tilt(angle)
 | |
| 
 | |
|    :param angle: a number
 | |
| 
 | |
|    Rotate the turtleshape by *angle* from its current tilt-angle, but do *not*
 | |
|    change the turtle's heading (direction of movement).
 | |
| 
 | |
|    .. doctest::
 | |
|       :skipif: _tkinter is None
 | |
| 
 | |
|       >>> turtle.reset()
 | |
|       >>> turtle.shape("circle")
 | |
|       >>> turtle.shapesize(5,2)
 | |
|       >>> turtle.tilt(30)
 | |
|       >>> turtle.fd(50)
 | |
|       >>> turtle.tilt(30)
 | |
|       >>> turtle.fd(50)
 | |
| 
 | |
| 
 | |
| .. function:: settiltangle(angle)
 | |
| 
 | |
|    :param angle: a number
 | |
| 
 | |
|    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).
 | |
| 
 | |
|    .. doctest::
 | |
|       :skipif: _tkinter is None
 | |
| 
 | |
|       >>> turtle.reset()
 | |
|       >>> turtle.shape("circle")
 | |
|       >>> turtle.shapesize(5,2)
 | |
|       >>> turtle.settiltangle(45)
 | |
|       >>> turtle.fd(50)
 | |
|       >>> turtle.settiltangle(-45)
 | |
|       >>> turtle.fd(50)
 | |
| 
 | |
|    .. deprecated:: 3.1
 | |
| 
 | |
| 
 | |
| .. function:: tiltangle(angle=None)
 | |
| 
 | |
|    :param angle: a number (optional)
 | |
| 
 | |
|    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).
 | |
| 
 | |
|    .. doctest::
 | |
|       :skipif: _tkinter is None
 | |
| 
 | |
|       >>> turtle.reset()
 | |
|       >>> turtle.shape("circle")
 | |
|       >>> turtle.shapesize(5,2)
 | |
|       >>> turtle.tilt(45)
 | |
|       >>> turtle.tiltangle()
 | |
|       45.0
 | |
| 
 | |
| 
 | |
| .. function:: shapetransform(t11=None, t12=None, t21=None, t22=None)
 | |
| 
 | |
|    :param t11: a number (optional)
 | |
|    :param t12: a number (optional)
 | |
|    :param t21: a number (optional)
 | |
|    :param t12: a number (optional)
 | |
| 
 | |
|    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.
 | |
| 
 | |
|    .. doctest::
 | |
|       :skipif: _tkinter is None
 | |
| 
 | |
|       >>> turtle = Turtle()
 | |
|       >>> turtle.shape("square")
 | |
|       >>> turtle.shapesize(4,2)
 | |
|       >>> turtle.shearfactor(-0.5)
 | |
|       >>> turtle.shapetransform()
 | |
|       (4.0, -1.0, -0.0, 2.0)
 | |
| 
 | |
| 
 | |
| .. function:: 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.
 | |
| 
 | |
|    .. doctest::
 | |
|       :skipif: _tkinter is None
 | |
| 
 | |
|       >>> turtle.shape("square")
 | |
|       >>> turtle.shapetransform(4, -1, 0, 2)
 | |
|       >>> turtle.get_shapepoly()
 | |
|       ((50, -20), (30, 20), (-50, 20), (-30, -20))
 | |
| 
 | |
| 
 | |
| Using events
 | |
| ------------
 | |
| 
 | |
| .. function:: onclick(fun, btn=1, add=None)
 | |
|    :noindex:
 | |
| 
 | |
|    :param fun: a function with two arguments which will be called with the
 | |
|                coordinates of the clicked point on the canvas
 | |
|    :param btn: number of the mouse-button, defaults to 1 (left mouse button)
 | |
|    :param 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:
 | |
| 
 | |
|    .. doctest::
 | |
|       :skipif: _tkinter is None
 | |
| 
 | |
|       >>> def turn(x, y):
 | |
|       ...     left(180)
 | |
|       ...
 | |
|       >>> onclick(turn)  # Now clicking into the turtle will turn it.
 | |
|       >>> onclick(None)  # event-binding will be removed
 | |
| 
 | |
| 
 | |
| .. function:: onrelease(fun, btn=1, add=None)
 | |
| 
 | |
|    :param fun: a function with two arguments which will be called with the
 | |
|                coordinates of the clicked point on the canvas
 | |
|    :param btn: number of the mouse-button, defaults to 1 (left mouse button)
 | |
|    :param 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.
 | |
| 
 | |
|    .. doctest::
 | |
|       :skipif: _tkinter is None
 | |
| 
 | |
|       >>> 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.
 | |
| 
 | |
| 
 | |
| .. function:: ondrag(fun, btn=1, add=None)
 | |
| 
 | |
|    :param fun: a function with two arguments which will be called with the
 | |
|                coordinates of the clicked point on the canvas
 | |
|    :param btn: number of the mouse-button, defaults to 1 (left mouse button)
 | |
|    :param 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.
 | |
| 
 | |
|    .. doctest::
 | |
|       :skipif: _tkinter is None
 | |
| 
 | |
|       >>> turtle.ondrag(turtle.goto)
 | |
| 
 | |
|    Subsequently, clicking and dragging the Turtle will move it across
 | |
|    the screen thereby producing handdrawings (if pen is down).
 | |
| 
 | |
| 
 | |
| Special Turtle methods
 | |
| ----------------------
 | |
| 
 | |
| .. function:: begin_poly()
 | |
| 
 | |
|    Start recording the vertices of a polygon.  Current turtle position is first
 | |
|    vertex of polygon.
 | |
| 
 | |
| 
 | |
| .. function:: 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.
 | |
| 
 | |
| 
 | |
| .. function:: get_poly()
 | |
| 
 | |
|    Return the last recorded polygon.
 | |
| 
 | |
|    .. doctest::
 | |
|       :skipif: _tkinter is None
 | |
| 
 | |
|       >>> 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)
 | |
| 
 | |
| 
 | |
| .. function:: clone()
 | |
| 
 | |
|    Create and return a clone of the turtle with same position, heading and
 | |
|    turtle properties.
 | |
| 
 | |
|    .. doctest::
 | |
|       :skipif: _tkinter is None
 | |
| 
 | |
|       >>> mick = Turtle()
 | |
|       >>> joe = mick.clone()
 | |
| 
 | |
| 
 | |
| .. function:: getturtle()
 | |
|               getpen()
 | |
| 
 | |
|    Return the Turtle object itself.  Only reasonable use: as a function to
 | |
|    return the "anonymous turtle":
 | |
| 
 | |
|    .. doctest::
 | |
|       :skipif: _tkinter is None
 | |
| 
 | |
|       >>> pet = getturtle()
 | |
|       >>> pet.fd(50)
 | |
|       >>> pet
 | |
|       <turtle.Turtle object at 0x...>
 | |
| 
 | |
| 
 | |
| .. function:: getscreen()
 | |
| 
 | |
|    Return the :class:`TurtleScreen` object the turtle is drawing on.
 | |
|    TurtleScreen methods can then be called for that object.
 | |
| 
 | |
|    .. doctest::
 | |
|       :skipif: _tkinter is None
 | |
| 
 | |
|       >>> ts = turtle.getscreen()
 | |
|       >>> ts
 | |
|       <turtle._Screen object at 0x...>
 | |
|       >>> ts.bgcolor("pink")
 | |
| 
 | |
| 
 | |
| .. function:: setundobuffer(size)
 | |
| 
 | |
|    :param size: an integer or ``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 :func:`undo` method/function.  If *size* is
 | |
|    ``None``, the undobuffer is disabled.
 | |
| 
 | |
|    .. doctest::
 | |
|       :skipif: _tkinter is None
 | |
| 
 | |
|       >>> turtle.setundobuffer(42)
 | |
| 
 | |
| 
 | |
| .. function:: undobufferentries()
 | |
| 
 | |
|    Return number of entries in the undobuffer.
 | |
| 
 | |
|    .. doctest::
 | |
|       :skipif: _tkinter is None
 | |
| 
 | |
|       >>> while undobufferentries():
 | |
|       ...     undo()
 | |
| 
 | |
| 
 | |
| 
 | |
| .. _compoundshapes:
 | |
| 
 | |
| Compound shapes
 | |
| ---------------
 | |
| 
 | |
| To use compound turtle shapes, which consist of several polygons of different
 | |
| color, you must use the helper class :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
 | |
|    :meth:`addcomponent` method.
 | |
| 
 | |
|    For example:
 | |
| 
 | |
|    .. doctest::
 | |
|       :skipif: _tkinter is None
 | |
| 
 | |
|       >>> 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:
 | |
| 
 | |
|    .. doctest::
 | |
|       :skipif: _tkinter is None
 | |
| 
 | |
|       >>> register_shape("myshape", s)
 | |
|       >>> shape("myshape")
 | |
| 
 | |
| 
 | |
| .. note::
 | |
| 
 | |
|    The :class:`Shape` class is used internally by the :func:`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``.
 | |
| 
 | |
| .. doctest::
 | |
|    :skipif: _tkinter is None
 | |
|    :hide:
 | |
| 
 | |
|    >>> screen = Screen()
 | |
| 
 | |
| Window control
 | |
| --------------
 | |
| 
 | |
| .. function:: bgcolor(*args)
 | |
| 
 | |
|    :param 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.
 | |
| 
 | |
|    .. doctest::
 | |
|       :skipif: _tkinter is None
 | |
| 
 | |
|       >>> screen.bgcolor("orange")
 | |
|       >>> screen.bgcolor()
 | |
|       'orange'
 | |
|       >>> screen.bgcolor("#800080")
 | |
|       >>> screen.bgcolor()
 | |
|       (128.0, 0.0, 128.0)
 | |
| 
 | |
| 
 | |
| .. function:: bgpic(picname=None)
 | |
| 
 | |
|    :param 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"
 | |
| 
 | |
| 
 | |
| .. function:: clear()
 | |
|    :noindex:
 | |
| 
 | |
|    .. note::
 | |
|       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``.
 | |
| 
 | |
| 
 | |
| .. function:: 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.
 | |
| 
 | |
| 
 | |
| .. function:: reset()
 | |
|    :noindex:
 | |
| 
 | |
|    .. note::
 | |
|       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``.
 | |
| 
 | |
| 
 | |
| .. function:: resetscreen()
 | |
| 
 | |
|    Reset all Turtles on the Screen to their initial state.
 | |
| 
 | |
| 
 | |
| .. function:: screensize(canvwidth=None, canvheight=None, bg=None)
 | |
| 
 | |
|    :param canvwidth: positive integer, new width of canvas in pixels
 | |
|    :param canvheight: positive integer, new height of canvas in pixels
 | |
|    :param 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 ;-)
 | |
| 
 | |
| 
 | |
| .. function:: setworldcoordinates(llx, lly, urx, ury)
 | |
| 
 | |
|    :param llx: a number, x-coordinate of lower left corner of canvas
 | |
|    :param lly: a number, y-coordinate of lower left corner of canvas
 | |
|    :param urx: a number, x-coordinate of upper right corner of canvas
 | |
|    :param 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.
 | |
| 
 | |
|    .. doctest::
 | |
|       :skipif: _tkinter is None
 | |
| 
 | |
|       >>> 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
 | |
| 
 | |
|    .. doctest::
 | |
|       :skipif: _tkinter is None
 | |
|       :hide:
 | |
| 
 | |
|       >>> screen.reset()
 | |
|       >>> for t in turtles():
 | |
|       ...      t.reset()
 | |
| 
 | |
| 
 | |
| Animation control
 | |
| -----------------
 | |
| 
 | |
| .. function:: delay(delay=None)
 | |
| 
 | |
|    :param 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.
 | |
| 
 | |
|    Optional argument:
 | |
| 
 | |
|    .. doctest::
 | |
|       :skipif: _tkinter is None
 | |
| 
 | |
|       >>> screen.delay()
 | |
|       10
 | |
|       >>> screen.delay(5)
 | |
|       >>> screen.delay()
 | |
|       5
 | |
| 
 | |
| 
 | |
| .. function:: tracer(n=None, delay=None)
 | |
| 
 | |
|    :param n: nonnegative integer
 | |
|    :param delay: nonnegative integer
 | |
| 
 | |
|    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
 | |
|    :func:`delay`).
 | |
| 
 | |
|    .. doctest::
 | |
|       :skipif: _tkinter is None
 | |
| 
 | |
|       >>> screen.tracer(8, 25)
 | |
|       >>> dist = 2
 | |
|       >>> for i in range(200):
 | |
|       ...     fd(dist)
 | |
|       ...     rt(90)
 | |
|       ...     dist += 2
 | |
| 
 | |
| 
 | |
| .. function:: update()
 | |
| 
 | |
|    Perform a TurtleScreen update. To be used when tracer is turned off.
 | |
| 
 | |
| See also the RawTurtle/Turtle method :func:`speed`.
 | |
| 
 | |
| 
 | |
| Using screen events
 | |
| -------------------
 | |
| 
 | |
| .. function:: 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 :func:`listen` to the onclick method.
 | |
| 
 | |
| 
 | |
| .. function:: onkey(fun, key)
 | |
|               onkeyrelease(fun, key)
 | |
| 
 | |
|    :param fun: a function with no arguments or ``None``
 | |
|    :param 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 :func:`listen`.)
 | |
| 
 | |
|    .. doctest::
 | |
|       :skipif: _tkinter is None
 | |
| 
 | |
|       >>> def f():
 | |
|       ...     fd(50)
 | |
|       ...     lt(60)
 | |
|       ...
 | |
|       >>> screen.onkey(f, "Up")
 | |
|       >>> screen.listen()
 | |
| 
 | |
| 
 | |
| .. function:: onkeypress(fun, key=None)
 | |
| 
 | |
|    :param fun: a function with no arguments or ``None``
 | |
|    :param 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 :func:`listen`.)
 | |
| 
 | |
|    .. doctest::
 | |
|       :skipif: _tkinter is None
 | |
| 
 | |
|       >>> def f():
 | |
|       ...     fd(50)
 | |
|       ...
 | |
|       >>> screen.onkey(f, "Up")
 | |
|       >>> screen.listen()
 | |
| 
 | |
| 
 | |
| .. function:: onclick(fun, btn=1, add=None)
 | |
|               onscreenclick(fun, btn=1, add=None)
 | |
| 
 | |
|    :param fun: a function with two arguments which will be called with the
 | |
|                coordinates of the clicked point on the canvas
 | |
|    :param btn: number of the mouse-button, defaults to 1 (left mouse button)
 | |
|    :param 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``:
 | |
| 
 | |
|    .. doctest::
 | |
|       :skipif: _tkinter is None
 | |
| 
 | |
|       >>> 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
 | |
| 
 | |
|    .. note::
 | |
|       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``.
 | |
| 
 | |
| 
 | |
| .. function:: ontimer(fun, t=0)
 | |
| 
 | |
|    :param fun: a function with no arguments
 | |
|    :param t: a number >= 0
 | |
| 
 | |
|    Install a timer that calls *fun* after *t* milliseconds.
 | |
| 
 | |
|    .. doctest::
 | |
|       :skipif: _tkinter is None
 | |
| 
 | |
|       >>> running = True
 | |
|       >>> def f():
 | |
|       ...     if running:
 | |
|       ...         fd(50)
 | |
|       ...         lt(60)
 | |
|       ...         screen.ontimer(f, 250)
 | |
|       >>> f()   ### makes the turtle march around
 | |
|       >>> running = False
 | |
| 
 | |
| 
 | |
| .. function:: mainloop()
 | |
|               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()
 | |
| 
 | |
| 
 | |
| Input methods
 | |
| -------------
 | |
| 
 | |
| .. function:: textinput(title, prompt)
 | |
| 
 | |
|    :param title: string
 | |
|    :param 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:")
 | |
| 
 | |
| 
 | |
| .. function:: numinput(title, prompt, default=None, minval=None, maxval=None)
 | |
| 
 | |
|    :param title: string
 | |
|    :param prompt: string
 | |
|    :param default: number (optional)
 | |
|    :param minval: number (optional)
 | |
|    :param maxval: number (optional)
 | |
| 
 | |
|    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)
 | |
| 
 | |
| 
 | |
| Settings and special methods
 | |
| ----------------------------
 | |
| 
 | |
| .. function:: mode(mode=None)
 | |
| 
 | |
|    :param 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 :mod:`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.
 | |
| 
 | |
|    ============ ========================= ===================
 | |
|        Mode      Initial turtle heading     positive angles
 | |
|    ============ ========================= ===================
 | |
|     "standard"    to the right (east)       counterclockwise
 | |
|       "logo"        upward    (north)         clockwise
 | |
|    ============ ========================= ===================
 | |
| 
 | |
|    .. doctest::
 | |
|       :skipif: _tkinter is None
 | |
| 
 | |
|       >>> mode("logo")   # resets turtle heading to north
 | |
|       >>> mode()
 | |
|       'logo'
 | |
| 
 | |
| 
 | |
| .. function:: colormode(cmode=None)
 | |
| 
 | |
|    :param cmode: one of the values 1.0 or 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*.
 | |
| 
 | |
|    .. doctest::
 | |
|       :skipif: _tkinter is None
 | |
| 
 | |
|       >>> 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)
 | |
| 
 | |
| 
 | |
| .. function:: getcanvas()
 | |
| 
 | |
|    Return the Canvas of this TurtleScreen.  Useful for insiders who know what to
 | |
|    do with a Tkinter Canvas.
 | |
| 
 | |
|    .. doctest::
 | |
|       :skipif: _tkinter is None
 | |
| 
 | |
|       >>> cv = screen.getcanvas()
 | |
|       >>> cv
 | |
|       <turtle.ScrolledCanvas object ...>
 | |
| 
 | |
| 
 | |
| .. function:: getshapes()
 | |
| 
 | |
|    Return a list of names of all currently available turtle shapes.
 | |
| 
 | |
|    .. doctest::
 | |
|       :skipif: _tkinter is None
 | |
| 
 | |
|       >>> screen.getshapes()
 | |
|       ['arrow', 'blank', 'circle', ..., 'turtle']
 | |
| 
 | |
| 
 | |
| .. function:: register_shape(name, shape=None)
 | |
|               addshape(name, shape=None)
 | |
| 
 | |
|    There are three different ways to call this function:
 | |
| 
 | |
|    (1) *name* is the name of a gif-file and *shape* is ``None``: Install the
 | |
|        corresponding image shape. ::
 | |
| 
 | |
|        >>> screen.register_shape("turtle.gif")
 | |
| 
 | |
|        .. note::
 | |
|           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.
 | |
| 
 | |
|        .. doctest::
 | |
|           :skipif: _tkinter is None
 | |
| 
 | |
|           >>> screen.register_shape("triangle", ((5,-3), (0,5), (-5,-3)))
 | |
| 
 | |
|    (3) *name* is an arbitrary string and shape is a (compound) :class:`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)``.
 | |
| 
 | |
| 
 | |
| .. function:: turtles()
 | |
| 
 | |
|    Return the list of turtles on the screen.
 | |
| 
 | |
|    .. doctest::
 | |
|       :skipif: _tkinter is None
 | |
| 
 | |
|       >>> for turtle in screen.turtles():
 | |
|       ...     turtle.color("red")
 | |
| 
 | |
| 
 | |
| .. function:: window_height()
 | |
| 
 | |
|    Return the height of the turtle window. ::
 | |
| 
 | |
|        >>> screen.window_height()
 | |
|        480
 | |
| 
 | |
| 
 | |
| .. function:: window_width()
 | |
| 
 | |
|    Return the width of the turtle window. ::
 | |
| 
 | |
|        >>> screen.window_width()
 | |
|        640
 | |
| 
 | |
| 
 | |
| .. _screenspecific:
 | |
| 
 | |
| Methods specific to Screen, not inherited from TurtleScreen
 | |
| -----------------------------------------------------------
 | |
| 
 | |
| .. function:: bye()
 | |
| 
 | |
|    Shut the turtlegraphics window.
 | |
| 
 | |
| 
 | |
| .. function:: 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
 | |
|    :file:`turtle.cfg`.  In this case IDLE's own mainloop is active also for the
 | |
|    client script.
 | |
| 
 | |
| 
 | |
| .. function:: 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
 | |
|    :file:`turtle.cfg` file.
 | |
| 
 | |
|    :param width: if an integer, a size in pixels, if a float, a fraction of the
 | |
|                  screen; default is 50% of screen
 | |
|    :param height: if an integer, the height in pixels, if a float, a fraction of
 | |
|                   the screen; default is 75% of screen
 | |
|    :param 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
 | |
|    :param 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
 | |
| 
 | |
|    .. doctest::
 | |
|       :skipif: _tkinter is None
 | |
| 
 | |
|       >>> 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
 | |
| 
 | |
| 
 | |
| .. function:: title(titlestring)
 | |
| 
 | |
|    :param titlestring: a string that is shown in the titlebar of the turtle
 | |
|                        graphics window
 | |
| 
 | |
|    Set title of turtle window to *titlestring*.
 | |
| 
 | |
|    .. doctest::
 | |
|       :skipif: _tkinter is None
 | |
| 
 | |
|       >>> screen.title("Welcome to the turtle zoo!")
 | |
| 
 | |
| 
 | |
| Public classes
 | |
| ==============
 | |
| 
 | |
| 
 | |
| .. class:: RawTurtle(canvas)
 | |
|            RawPen(canvas)
 | |
| 
 | |
|    :param canvas: a :class:`tkinter.Canvas`, a :class:`ScrolledCanvas` or a
 | |
|                   :class:`TurtleScreen`
 | |
| 
 | |
|    Create a turtle.  The turtle has all methods described above as "methods of
 | |
|    Turtle/RawTurtle".
 | |
| 
 | |
| 
 | |
| .. class:: Turtle()
 | |
| 
 | |
|    Subclass of RawTurtle, has the same interface but draws on a default
 | |
|    :class:`Screen` object created automatically when needed for the first time.
 | |
| 
 | |
| 
 | |
| .. class:: TurtleScreen(cv)
 | |
| 
 | |
|    :param cv: a :class:`tkinter.Canvas`
 | |
| 
 | |
|    Provides screen oriented methods like :func:`setbg` etc. that are described
 | |
|    above.
 | |
| 
 | |
| .. class:: Screen()
 | |
| 
 | |
|    Subclass of TurtleScreen, with :ref:`four methods added <screenspecific>`.
 | |
| 
 | |
| 
 | |
| .. class:: ScrolledCanvas(master)
 | |
| 
 | |
|    :param 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:: Shape(type_, data)
 | |
| 
 | |
|    :param 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
 | |
|                :meth:`addcomponent` method)
 | |
|    =========== ===========
 | |
| 
 | |
|    .. method:: addcomponent(poly, fill, outline=None)
 | |
| 
 | |
|       :param poly: a polygon, i.e. a tuple of pairs of numbers
 | |
|       :param fill: a color the *poly* will be filled with
 | |
|       :param outline: a color for the poly's outline (if given)
 | |
| 
 | |
|       Example:
 | |
| 
 | |
|       .. doctest::
 | |
|          :skipif: _tkinter is None
 | |
| 
 | |
|          >>> 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 :ref:`compoundshapes`.
 | |
| 
 | |
| 
 | |
| .. class:: 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`` vector addition
 | |
|    * ``a - b`` vector subtraction
 | |
|    * ``a * b`` inner product
 | |
|    * ``k * a`` and ``a * k`` multiplication with scalar
 | |
|    * ``abs(a)`` absolute value of a
 | |
|    * ``a.rotate(angle)`` rotation
 | |
| 
 | |
| 
 | |
| Help and configuration
 | |
| ======================
 | |
| 
 | |
| How to use help
 | |
| ---------------
 | |
| 
 | |
| 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 :func:`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.
 | |
| 
 | |
| .. function:: write_docstringdict(filename="turtle_docstringdict")
 | |
| 
 | |
|    :param 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 :file:`{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 :mod:`turtle` with online help in your
 | |
| native language, you have to translate the docstrings and save the resulting
 | |
| file as e.g. :file:`turtle_docstringdict_german.py`.
 | |
| 
 | |
| If you have an appropriate entry in your :file:`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
 | |
| 
 | |
| Short explanation of selected entries:
 | |
| 
 | |
| - The first four lines correspond to the arguments of the :meth:`Screen.setup`
 | |
|   method.
 | |
| - Line 5 and 6 correspond to the arguments of the method
 | |
|   :meth:`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
 | |
|   :file:`turtle_docstringdict_italian.py` will be loaded at import time (if
 | |
|   present on the import path, e.g. in the same directory as :mod:`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 :func:`exitonclick` to enter the
 | |
|   mainloop.
 | |
| 
 | |
| There can be a :file:`turtle.cfg` file in the directory where :mod:`turtle` is
 | |
| stored and an additional one in the current working directory.  The latter will
 | |
| override the settings of the first one.
 | |
| 
 | |
| The :file:`Lib/turtledemo` directory contains a :file:`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).
 | |
| 
 | |
| 
 | |
| :mod:`turtledemo` --- Demo scripts
 | |
| ==================================
 | |
| 
 | |
| .. module:: turtledemo
 | |
|    :synopsis: A viewer for example turtle scripts
 | |
| 
 | |
| The :mod:`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 :mod:`turtledemo` package directory contains:
 | |
| 
 | |
| - A demo viewer :file:`__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 :mod:`turtle`
 | |
|   module.  Examples can be accessed via the Examples menu.  They can also
 | |
|   be run standalone.
 | |
| - A :file:`turtle.cfg` file which serves as an example of how to write
 | |
|   and use such files.
 | |
| 
 | |
| The demo scripts are:
 | |
| 
 | |
| .. tabularcolumns:: |l|L|L|
 | |
| 
 | |
| +----------------+------------------------------+-----------------------+
 | |
| | Name           | Description                  | Features              |
 | |
| +================+==============================+=======================+
 | |
| | bytedesign     | complex classical            | :func:`tracer`, delay,|
 | |
| |                | turtle graphics pattern      | :func:`update`        |
 | |
| +----------------+------------------------------+-----------------------+
 | |
| | chaos          | graphs Verhulst dynamics,    | world coordinates     |
 | |
| |                | shows that computer's        |                       |
 | |
| |                | computations can generate    |                       |
 | |
| |                | results sometimes against the|                       |
 | |
| |                | common sense expectations    |                       |
 | |
| +----------------+------------------------------+-----------------------+
 | |
| | clock          | analog clock showing time    | turtles as clock's    |
 | |
| |                | of your computer             | hands, ontimer        |
 | |
| +----------------+------------------------------+-----------------------+
 | |
| | colormixer     | experiment with r, g, b      | :func:`ondrag`        |
 | |
| +----------------+------------------------------+-----------------------+
 | |
| | forest         | 3 breadth-first trees        | randomization         |
 | |
| +----------------+------------------------------+-----------------------+
 | |
| | fractalcurves  | Hilbert & Koch curves        | recursion             |
 | |
| +----------------+------------------------------+-----------------------+
 | |
| | lindenmayer    | ethnomathematics             | L-System              |
 | |
| |                | (indian kolams)              |                       |
 | |
| +----------------+------------------------------+-----------------------+
 | |
| | minimal_hanoi  | Towers of Hanoi              | Rectangular Turtles   |
 | |
| |                |                              | as Hanoi discs        |
 | |
| |                |                              | (shape, shapesize)    |
 | |
| +----------------+------------------------------+-----------------------+
 | |
| | nim            | play the classical nim game  | turtles as nimsticks, |
 | |
| |                | with three heaps of sticks   | event driven (mouse,  |
 | |
| |                | against the computer.        | keyboard)             |
 | |
| +----------------+------------------------------+-----------------------+
 | |
| | paint          | super minimalistic           | :func:`onclick`       |
 | |
| |                | drawing program              |                       |
 | |
| +----------------+------------------------------+-----------------------+
 | |
| | peace          | elementary                   | turtle: appearance    |
 | |
| |                |                              | and animation         |
 | |
| +----------------+------------------------------+-----------------------+
 | |
| | penrose        | aperiodic tiling with        | :func:`stamp`         |
 | |
| |                | kites and darts              |                       |
 | |
| +----------------+------------------------------+-----------------------+
 | |
| | planet_and_moon| simulation of                | compound shapes,      |
 | |
| |                | gravitational system         | :class:`Vec2D`        |
 | |
| +----------------+------------------------------+-----------------------+
 | |
| | round_dance    | dancing turtles rotating     | compound shapes, clone|
 | |
| |                | pairwise in opposite         | shapesize, tilt,      |
 | |
| |                | direction                    | get_shapepoly, update |
 | |
| +----------------+------------------------------+-----------------------+
 | |
| | sorting_animate| visual demonstration of      | simple alignment,     |
 | |
| |                | different sorting methods    | randomization         |
 | |
| +----------------+------------------------------+-----------------------+
 | |
| | tree           | a (graphical) breadth        | :func:`clone`         |
 | |
| |                | first tree (using generators)|                       |
 | |
| +----------------+------------------------------+-----------------------+
 | |
| | two_canvases   | simple design                | turtles on two        |
 | |
| |                |                              | canvases              |
 | |
| +----------------+------------------------------+-----------------------+
 | |
| | wikipedia      | a pattern from the wikipedia | :func:`clone`,        |
 | |
| |                | article on turtle graphics   | :func:`undo`          |
 | |
| +----------------+------------------------------+-----------------------+
 | |
| | yinyang        | another elementary example   | :func:`circle`        |
 | |
| +----------------+------------------------------+-----------------------+
 | |
| 
 | |
| Have fun!
 | |
| 
 | |
| 
 | |
| Changes since Python 2.6
 | |
| ========================
 | |
| 
 | |
| - The methods :meth:`Turtle.tracer`, :meth:`Turtle.window_width` and
 | |
|   :meth:`Turtle.window_height` have been eliminated.
 | |
|   Methods with these names and functionality are now available only
 | |
|   as methods of :class:`Screen`. The functions derived from these remain
 | |
|   available. (In fact already in Python 2.6 these methods were merely
 | |
|   duplications of the corresponding
 | |
|   :class:`TurtleScreen`/:class:`Screen`-methods.)
 | |
| 
 | |
| - The method :meth:`Turtle.fill` has been eliminated.
 | |
|   The behaviour of :meth:`begin_fill` and :meth:`end_fill`
 | |
|   have changed slightly: now  every filling-process must be completed with an
 | |
|   ``end_fill()`` call.
 | |
| 
 | |
| - A method :meth:`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.
 | |
| 
 | |
| Changes since Python 3.0
 | |
| ========================
 | |
| 
 | |
| - The methods :meth:`Turtle.shearfactor`, :meth:`Turtle.shapetransform` and
 | |
|   :meth:`Turtle.get_shapepoly` have been added. Thus the full range of
 | |
|   regular linear transforms is now available for transforming turtle shapes.
 | |
|   :meth:`Turtle.tiltangle` has been enhanced in functionality: it now can
 | |
|   be used to get or set the tiltangle. :meth:`Turtle.settiltangle` has been
 | |
|   deprecated.
 | |
| 
 | |
| - The method :meth:`Screen.onkeypress` has been added as a complement to
 | |
|   :meth:`Screen.onkey` which in fact binds actions to the keyrelease event.
 | |
|   Accordingly the latter has got an alias: :meth:`Screen.onkeyrelease`.
 | |
| 
 | |
| - The method  :meth:`Screen.mainloop` has been added. So when working only
 | |
|   with Screen and Turtle objects one must not additionally import
 | |
|   :func:`mainloop` anymore.
 | |
| 
 | |
| - Two input methods has been added :meth:`Screen.textinput` and
 | |
|   :meth:`Screen.numinput`. These popup input dialogs and return
 | |
|   strings and numbers respectively.
 | |
| 
 | |
| - Two example scripts :file:`tdemo_nim.py` and :file:`tdemo_round_dance.py`
 | |
|   have been added to the :file:`Lib/turtledemo` directory.
 | |
| 
 | |
| 
 | |
| .. doctest::
 | |
|    :skipif: _tkinter is None
 | |
|    :hide:
 | |
| 
 | |
|    >>> for turtle in turtles():
 | |
|    ...      turtle.reset()
 | |
|    >>> turtle.penup()
 | |
|    >>> turtle.goto(-200,25)
 | |
|    >>> turtle.pendown()
 | |
|    >>> turtle.write("No one expects the Spanish Inquisition!",
 | |
|    ...      font=("Arial", 20, "normal"))
 | |
|    >>> turtle.penup()
 | |
|    >>> turtle.goto(-100,-50)
 | |
|    >>> turtle.pendown()
 | |
|    >>> turtle.write("Our two chief Turtles are...",
 | |
|    ...      font=("Arial", 16, "normal"))
 | |
|    >>> turtle.penup()
 | |
|    >>> turtle.goto(-450,-75)
 | |
|    >>> turtle.write(str(turtles()))
 |