======================================== :mod:`turtle` --- Turtle graphics for Tk ======================================== .. module:: turtle :synopsis: Turtle graphics for Tk .. sectionauthor:: Gregor Lingl Introduction ============ Turtle graphics is a popular way for introducing programming to kids. It was part of the original Logo programming language developed by Wally Feurzig and Seymour Papert in 1966. Imagine a robotic turtle starting at (0, 0) in the x-y plane. Give it the command ``turtle.forward(15)``, and it moves (on-screen!) 15 pixels in the direction it is facing, drawing a line as it moves. Give it the command ``turtle.left(25)``, and it rotates in-place 25 degrees clockwise. By combining together these and similar commands, intricate shapes and pictures can easily be drawn. The :mod:`turtle` module is an extended reimplementation of the same-named module from the Python standard distribution up to version Python 2.5. It tries to keep the merits of the old turtle module and to be (nearly) 100% compatible with it. This means in the first place to enable the learning programmer to use all the commands, classes and methods interactively when using the module from within IDLE run with the ``-n`` switch. The turtle module provides turtle graphics primitives, in both object-oriented and procedure-oriented ways. Because it uses :mod:`Tkinter` for the underlying graphics, it needs a version of python installed with Tk support. The object-oriented interface uses essentially two+two classes: 1. The :class:`TurtleScreen` class defines graphics windows as a playground for the drawing turtles. Its constructor needs a :class:`Tkinter.Canvas` or a :class:`ScrolledCanvas` as argument. It should be used when :mod:`turtle` is used as part of some application. Derived from :class:`TurtleScreen` is the subclass :class:`Screen`. Screen is implemented as sort of singleton, so there can exist only one instance of Screen at a time. It should be used when :mod:`turtle` is used as a standalone tool for doing graphics. All methods of TurtleScreen/Screen also exist as functions, i.e. as part of the procedure-oriented interface. 2. :class:`RawTurtle` (alias: :class:`RawPen`) defines Turtle objects which draw on a :class:`TurtleScreen`. Its constructor needs a Canvas, ScrolledCanvas or TurtleScreen as argument, so the RawTurtle objects know where to draw. Derived from RawTurtle is the subclass :class:`Turtle` (alias: :class:`Pen`), which draws on "the" :class:`Screen` - instance which is automatically created, if not already present. All methods of RawTurtle/Turtle also exist as functions, i.e. part of the procedure-oriented interface. The procedural interface provides functions which are derived from the methods of the classes :class:`Screen` and :class:`Turtle`. They have the same names as the corresponding methods. A screen object is automativally created whenever a function derived from a Screen method is called. An (unnamed) turtle object is automatically created whenever any of the functions derived from a Turtle method is called. To use multiple turtles an a screen one has to use the object-oriented interface. .. note:: In the following documentation the argument list for functions is given. Methods, of course, have the additional first argument *self* which is omitted here. Overview over available Turtle and Screen methods ================================================= Turtle methods -------------- Turtle motion Move and draw | :func:`forward` | :func:`fd` | :func:`backward` | :func:`bk` | :func:`back` | :func:`right` | :func:`rt` | :func:`left` | :func:`lt` | :func:`goto` | :func:`setpos` | :func:`setposition` | :func:`setx` | :func:`sety` | :func:`setheading` | :func:`seth` | :func:`home` | :func:`circle` | :func:`dot` | :func:`stamp` | :func:`clearstamp` | :func:`clearstamps` | :func:`undo` | :func:`speed` Tell Turtle's state | :func:`position` | :func:`pos` | :func:`towards` | :func:`xcor` | :func:`ycor` | :func:`heading` | :func:`distance` Setting and measurement | :func:`degrees` | :func:`radians` Pen control Drawing state | :func:`pendown` | :func:`pd` | :func:`down` | :func:`penup` | :func:`pu` | :func:`up` | :func:`pensize` | :func:`width` | :func:`pen` | :func:`isdown` Color control | :func:`color` | :func:`pencolor` | :func:`fillcolor` Filling | :func:`filling` | :func:`begin_fill` | :func:`end_fill` More drawing control | :func:`reset` | :func:`clear` | :func:`write` Turtle state Visibility | :func:`showturtle` | :func:`st` | :func:`hideturtle` | :func:`ht` | :func:`isvisible` Appearance | :func:`shape` | :func:`resizemode` | :func:`shapesize` | :func:`turtlesize` | :func:`settiltangle` | :func:`tiltangle` | :func:`tilt` Using events | :func:`onclick` | :func:`onrelease` | :func:`ondrag` Special Turtle methods | :func:`begin_poly` | :func:`end_poly` | :func:`get_poly` | :func:`clone` | :func:`getturtle` | :func:`getpen` | :func:`getscreen` | :func:`setundobuffer` | :func:`undobufferentries` Methods of TurtleScreen/Screen ------------------------------ Window control | :func:`bgcolor` | :func:`bgpic` | :func:`clear` | :func:`clearscreen` | :func:`reset` | :func:`resetscreen` | :func:`screensize` | :func:`setworldcoordinates` Animation control | :func:`delay` | :func:`tracer` | :func:`update` Using screen events | :func:`listen` | :func:`onkey` | :func:`onclick` | :func:`onscreenclick` | :func:`ontimer` Settings and special methods | :func:`mode` | :func:`colormode` | :func:`getcanvas` | :func:`getshapes` | :func:`register_shape` | :func:`addshape` | :func:`turtles` | :func:`window_height` | :func:`window_width` Methods specific to Screen | :func:`bye` | :func:`exitonclick` | :func:`setup` | :func:`title` Methods of RawTurtle/Turtle and corresponding functions ======================================================= Most of the examples in this section refer to a Turtle instance called ``turtle``. Turtle motion ------------- .. function:: forward(distance) fd(distance) :param distance: a number (integer or float) Move the turtle forward by the specified *distance*, in the direction the turtle is headed. >>> turtle.position() (0.00, 0.00) >>> turtle.forward(25) >>> turtle.position() (25.00,0.00) >>> turtle.forward(-75) >>> turtle.position() (-50.00,0.00) .. function:: back(distance) bk(distance) backward(distance) :param distance: a number Move the turtle backward by *distance*, opposite to the direction the turtle is headed. Do not change the turtle's heading. >>> turtle.position() (0.00, 0.00) >>> turtle.backward(30) >>> turtle.position() (-30.00, 0.00) .. function:: right(angle) rt(angle) :param angle: a number (integer or float) Turn turtle right by *angle* units. (Units are by default degrees, but can be set via the :func:`degrees` and :func:`radians` functions.) Angle orientation depends on the turtle mode, see :func:`mode`. >>> turtle.heading() 22.0 >>> turtle.right(45) >>> turtle.heading() 337.0 .. function:: left(angle) lt(angle) :param angle: a number (integer or float) Turn turtle left by *angle* units. (Units are by default degrees, but can be set via the :func:`degrees` and :func:`radians` functions.) Angle orientation depends on the turtle mode, see :func:`mode`. >>> turtle.heading() 22.0 >>> turtle.left(45) >>> turtle.heading() 67.0 .. function:: goto(x, y=None) setpos(x, y=None) setposition(x, y=None) :param x: a number or a pair/vector of numbers :param y: a number or ``None`` If *y* is ``None``, *x* must be a pair of coordinates or a :class:`Vec2D` (e.g. as returned by :func:`pos`). Move turtle to an absolute position. If the pen is down, draw line. Do not change the turtle's orientation. >>> tp = turtle.pos() >>> tp (0.00, 0.00) >>> turtle.setpos(60,30) >>> turtle.pos() (60.00,30.00) >>> turtle.setpos((20,80)) >>> turtle.pos() (20.00,80.00) >>> turtle.setpos(tp) >>> turtle.pos() (0.00,0.00) .. function:: setx(x) :param x: a number (integer or float) Set the turtle's first coordinate to *x*, leave second coordinate unchanged. >>> turtle.position() (0.00, 240.00) >>> turtle.setx(10) >>> turtle.position() (10.00, 240.00) .. function:: sety(y) :param y: a number (integer or float) Set the turtle's first coordinate to *y*, leave second coordinate unchanged. >>> turtle.position() (0.00, 40.00) >>> turtle.sety(-10) >>> turtle.position() (0.00, -10.00) .. function:: setheading(to_angle) seth(to_angle) :param to_angle: a number (integer or float) Set the orientation of the turtle to *to_angle*. Here are some common directions in degrees: =================== ==================== standard mode logo mode =================== ==================== 0 - east 0 - north 90 - north 90 - east 180 - west 180 - south 270 - south 270 - west =================== ==================== >>> turtle.setheading(90) >>> turtle.heading() 90 .. function:: home() Move turtle to the origin -- coordinates (0,0) -- and set its heading to its start-orientation (which depends on the mode, see :func:`mode`). .. function:: circle(radius, extent=None, steps=None) :param radius: a number :param extent: a number (or ``None``) :param steps: an integer (or ``None``) Draw a circle with given *radius*. The center is *radius* units left of 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 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. >>> turtle.circle(50) >>> turtle.circle(120, 180) # draw a semicircle .. 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. >>> turtle.dot() >>> turtle.fd(50); turtle.dot(20, "blue"); turtle.fd(50) .. 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)``. >>> turtle.color("blue") >>> turtle.stamp() 13 >>> turtle.fd(50) .. function:: clearstamp(stampid) :param stampid: an integer, must be return value of previous :func:`stamp` call Delete stamp with given *stampid*. >>> turtle.color("blue") >>> astamp = turtle.stamp() >>> turtle.fd(50) >>> turtle.clearstamp(astamp) .. 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. >>> for i in range(8): ... turtle.stamp(); turtle.fd(30) >>> 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. >>> 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. >>> turtle.speed(3) Tell Turtle's state ------------------- .. function:: position() pos() Return the turtle's current location (x,y) (as a :class:`Vec2D` vector). >>> turtle.pos() (0.00, 240.00) .. 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"). >>> turtle.pos() (10.00, 10.00) >>> turtle.towards(0,0) 225.0 .. function:: xcor() Return the turtle's x coordinate. >>> reset() >>> turtle.left(60) >>> turtle.forward(100) >>> print turtle.xcor() 50.0 .. function:: ycor() Return the turtle's y coordinate. >>> reset() >>> turtle.left(60) >>> turtle.forward(100) >>> print turtle.ycor() 86.6025403784 .. function:: heading() Return the turtle's current heading (value depends on the turtle mode, see :func:`mode`). >>> 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. >>> turtle.pos() (0.00, 0.00) >>> 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. >>> turtle.left(90) >>> turtle.heading() 90 >>> turtle.degrees(400.0) # angle measurement in gon >>> turtle.heading() 100 .. function:: radians() Set the angle measurement units to radians. Equivalent to ``degrees(2*math.pi)``. >>> turtle.heading() 90 >>> turtle.radians() >>> turtle.heading() 1.5707963267948966 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. >>> 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 dicionary 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. >>> turtle.pen(fillcolor="black", pencolor="red", pensize=10) >>> turtle.pen() {'pensize': 10, 'shown': True, 'resizemode': 'auto', 'outline': 1, 'pencolor': 'red', 'pendown': True, 'fillcolor': 'black', 'stretchfactor': (1,1), 'speed': 3} >>> penstate=turtle.pen() >>> turtle.color("yellow","") >>> turtle.penup() >>> turtle.pen() {'pensize': 10, 'shown': True, 'resizemode': 'auto', 'outline': 1, 'pencolor': 'yellow', 'pendown': False, 'fillcolor': '', 'stretchfactor': (1,1), 'speed': 3} >>> p.pen(penstate, fillcolor="green") >>> p.pen() {'pensize': 10, 'shown': True, 'resizemode': 'auto', 'outline': 1, 'pencolor': 'red', 'pendown': True, 'fillcolor': 'green', 'stretchfactor': (1,1), 'speed': 3} .. function:: isdown() Return ``True`` if pen is down, ``False`` if it's up. >>> 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, possibly in hex-number format (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. >>> turtle.pencolor("brown") >>> tup = (0.2, 0.8, 0.55) >>> turtle.pencolor(tup) >>> turtle.pencolor() "#33cc8c" .. function:: fillcolor(*args) Return or set the fillcolor. Four input formats are allowed: ``fillcolor()`` Return the current fillcolor as color specification string, possibly in hex-number 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. >>> turtle.fillcolor("violet") >>> col = turtle.pencolor() >>> turtle.fillcolor(col) >>> turtle.fillcolor(0, .5, 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 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. >>> turtle.color("red", "green") >>> turtle.color() ("red", "green") >>> colormode(255) >>> color((40, 80, 120), (160, 200, 240)) >>> color() ("#285078", "#a0c8f0") See also: Screen method :func:`colormode`. Filling ~~~~~~~ .. function:: filling() Return fillstate (``True`` if filling, ``False`` else). >>> 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. >>> turtle.color("black", "red") >>> turtle.begin_fill() >>> turtle.circle(60) >>> turtle.end_fill() .. function:: end_fill() Fill the shape drawn after the last call to :func:`begin_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. >>> 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:: showturtle() st() Make the turtle visible. >>> turtle.hideturtle() >>> turtle.showturtle() .. 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. >>> turtle.hideturtle() .. function:: isvisible() Return True if the Turtle is shown, False if it's hidden. >>> turtle.hideturtle() >>> print turtle.isvisible(): False 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`. >>> turtle.shape() "arrow" >>> 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. >>> turtle.resizemode("noresize") >>> turtle.resizemode() "noresize" .. function:: shapesize(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. >>> turtle.resizemode("user") >>> turtle.shapesize(5, 5, 12) >>> turtle.shapesize(outline=8) .. 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). >>> 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). >>> turtle.shape("circle") >>> turtle.shapesize(5,2) >>> turtle.settiltangle(45) >>> stamp() >>> turtle.fd(50) >>> turtle.settiltangle(-45) >>> stamp() >>> turtle.fd(50) .. function:: tiltangle() Return the current tilt-angle, i.e. the angle between the orientation of the turtleshape and the heading of the turtle (its direction of movement). >>> turtle.shape("circle") >>> turtle.shapesize(5,2) >>> turtle.tilt(45) >>> turtle.tiltangle() 45 Using events ------------ .. function:: onclick(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 num: 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: >>> 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 num: 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. >>> 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 num: 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. >>> 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. >>> p = turtle.get_poly() >>> turtle.register_shape("myFavouriteShape", p) .. function:: clone() Create and return a clone of the turtle with same position, heading and turtle properties. >>> mick = Turtle() >>> joe = mick.clone() .. function:: getturtle() Return the Turtle object itself. Only reasonable use: as a function to return the "anonymous turtle": >>> pet = getturtle() >>> pet.fd(50) >>> pet >>> turtles() [] .. function:: getscreen() Return the :class:`TurtleScreen` object the turtle is drawing on. TurtleScreen methods can then be called for that object. >>> ts = turtle.getscreen() >>> ts >>> 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. >>> turtle.setundobuffer(42) .. function:: undobufferentries() Return number of entries in the undobuffer. >>> while undobufferentries(): ... undo() .. _compoundshapes: Excursus about the use of 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: >>> s = Shape("compound") >>> poly1 = ((0,0),(10,-5),(0,10),(-10,-5)) >>> s.addcomponent(poly1, "red", "blue") >>> poly2 = ((0,0),(10,-5),(-10,-5)) >>> s.addcomponent(poly2, "blue", "red") 3. Now add the Shape to the Screen's shapelist and use it: >>> register_shape("myshape", s) >>> shape("myshape") .. 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``. 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. >>> screen.bgcolor("orange") >>> screen.bgcolor() "orange" >>> screen.bgcolor(0.5,0,0.5) >>> screen.bgcolor() "#800080" .. 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() 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. .. note:: This TurtleScreen method is available as a global function only under the name ``clearscreen``. The global function ``clear`` is another one derived from the Turtle method ``clear``. .. function:: reset() resetscreen() Reset all Turtles on the Screen to their initial state. .. 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:: 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-tupel, 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. >>> turtle.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. >>> 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 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: >>> screen.delay(15) >>> screen.delay() 15 .. 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.) Second argument sets delay value (see :func:`delay`). >>> 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) :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`.) >>> def f(): ... fd(50) ... lt(60) ... >>> 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 num: 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: >>> 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. >>> running = True >>> def f(): if running: fd(50) lt(60) screen.ontimer(f, 250) >>> f() ### makes the turtle marching around >>> running = False 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 ============ ========================= =================== >>> 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*. >>> screen.colormode() 1.0 >>> 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. >>> cv = screen.getcanvas() >>> cv .. function:: getshapes() Return a list of names of all currently available turtle shapes. >>> 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. .. 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. (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)``. >>> screen.register_shape("turtle.gif") >>> screen.register_shape("triangle", ((5,-3), (0,5), (-5,-3))) .. function:: turtles() Return the list of turtles on the screen. >>> 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 dicionary 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 startx: if positive, starting position in pixels from the top edge of the screen, if negative from the bottom edge, if None, center window vertically >>> screen.setup (width=200, height=200, startx=0, starty=0) # sets window to 200x200 pixels, in upper left of screen >>> screen.setup(width=.75, height=0.5, startx=None, starty=None) # sets window to 75% of screen by 50% of screen and centers .. 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*. >>> screen.title("Welcome to the turtle zoo!") The public classes of the module :mod:`turtle` ============================================== .. 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 `. .. class:: ScrolledCavas(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 compund 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: >>> 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:`Demo/turtle` 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). Demo scripts ============ There is a set of demo scripts in the turtledemo directory located in the :file:`Demo/turtle` directory in the source distribution. It contains: - a set of 15 demo scripts demonstrating differet features of the new module :mod:`turtle` - a demo viewer :file:`turtleDemo.py` which can be used to view the sourcecode of the scripts and run them at the same time. 14 of the examples can be accessed via the Examples menu; all of them can also be run standalone. - The example :file:`turtledemo_two_canvases.py` demonstrates the simultaneous use of two canvases with the turtle module. Therefore it only can be run standalone. - There is a :file:`turtle.cfg` file in this directory, which also serves as an example for how to write and use such files. The demoscripts are: +----------------+------------------------------+-----------------------+ | Name | Description | Features | +----------------+------------------------------+-----------------------+ | bytedesign | complex classical | :func:`tracer`, delay,| | | turtlegraphics pattern | :func:`update` | +----------------+------------------------------+-----------------------+ | chaos | graphs verhust dynamics, | world coordinates | | | proves that you must not | | | | trust computers' computations| | +----------------+------------------------------+-----------------------+ | clock | analog clock showing time | turtles as clock's | | | of your computer | hands, ontimer | +----------------+------------------------------+-----------------------+ | colormixer | experiment with r, g, b | :func:`ondrag` | +----------------+------------------------------+-----------------------+ | fractalcurves | Hilbert & Koch curves | recursion | +----------------+------------------------------+-----------------------+ | lindenmayer | ethnomathematics | L-System | | | (indian kolams) | | +----------------+------------------------------+-----------------------+ | minimal_hanoi | Towers of Hanoi | Rectangular Turtles | | | | as Hanoi discs | | | | (shape, shapesize) | +----------------+------------------------------+-----------------------+ | 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` | +----------------+------------------------------+-----------------------+ | tree | a (graphical) breadth | :func:`clone` | | | first tree (using generators)| | +----------------+------------------------------+-----------------------+ | wikipedia | a pattern from the wikipedia | :func:`clone`, | | | article on turtle graphics | :func:`undo` | +----------------+------------------------------+-----------------------+ | yingyang | 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.