# tkturtle.py (TCL/Tk Version) # Walker M. White (wmw2) # August 20, 2015 """Cornell implementation of the Tk Turtle This module is preferable to the default turtle module for several reasons. First, it makes it easier to support simultaneous turtle windows. Second, it provides support for custom color models. Finally, the attributes and methods have been streamlined to make them easier to understand for beginners.""" import colormodel import turtle import os # Necessary to retrieve pen graphic _PATH = os.path.dirname(colormodel.__file__) # Private class. Not publicly available. Emulates the Screen singleton. class _Window(turtle.TurtleScreen): """Internal private class to emulate the Screen singleton""" # PRIVATE ATTRIBUTES: # _root: Reference to the turtle screen root # _canvas: Reference to the internal drawing canvas # _title: Reference to the window title bar # BUILT-IN METHODS # Copy of turtle.Screen, as non-singleton def __init__(self,x=100,y=100,width=800,height=800): """**Constructor**: creates a copy of turtle.Screen, as a non-singleton :param x: initial x coordinate (default 0) **Precondition**: int > 0 :param y: initial y coordinate (default 0) **Precondition**: int > 0 :param width: initial window width (default 800) **Precondition**: int > 0 :param height: initial window height (default 800) **Precondition**: int > 0 :param scale: initial window scale (default 0.75) **Precondition**: float > 0 All parameters are optional.""" self._title = turtle._CFG["title"] self._root = turtle._Root() self._root.title(self._title) self._root.ondestroy(self._destroy) canvwidth = turtle._CFG["canvwidth"] canvheight = turtle._CFG["canvheight"] self._root.setupcanvas(width, height, canvwidth, canvheight) self._canvas = self._root._getcanvas() turtle.TurtleScreen.__init__(self, self._canvas) self._setup(width, height, x, y) def _setup(self, width=turtle._CFG["width"], height=turtle._CFG["height"], startx=turtle._CFG["leftright"], starty=turtle._CFG["topbottom"]): """Sets the size and position of the main window. :param x: initial x coordinate (default 0) **Precondition**: int > 0 :param y: initial y coordinate (default 0) **Precondition**: int > 0 :param width: initial window width (default 800) **Precondition**: int > 0 :param height: initial window height (default 800) **Precondition**: int > 0 :param scale: initial window scale (default 0.75) **Precondition**: float > 0 All parameters are optional.""" if not hasattr(self._root, "set_geometry"): return sw = self._root.win_width() sh = self._root.win_height() if isinstance(width, float) and 0 <= width <= 1: width = sw*width if startx is None: startx = (sw - width) / 2 if isinstance(height, float) and 0 <= height <= 1: height = sh*height if starty is None: starty = (sh - height) / 2 self._root.set_geometry(width, height, startx, starty) self.update() def _destroy(self): """Destroys this window and its associated assets""" root = self._root turtle.Turtle._pen = None turtle.Turtle._screen = None self._root = None self._canvas = None turtle.TurtleScreen._RUNNING = True root.destroy() class Window(object): """Instances are GUI windows that support turtle graphics You should construct a Window object before constructing a Turtle or Pen. You will only need one Window object for the entire assignment. """ # PRIVATE ATTRIBUTES: # _frame: The backing store for this window # MUTABLE PROPERTIES @property def x(self): """The x coordinate for top left corner of window **Invariant**: x must be an int > 0""" return self._x @x.setter def x(self,value): assert (type(value) == int), "value %s is not an int" % `value` assert (value >= 0), "value %s is negative" % `value` self._x = value self._reshape() @property def y(self): """The y coordinate for top left corner of window **Invariant**: y must be an int > 0""" return self._y @y.setter def y(self,value): assert (type(value) == int), "value %s is not an int" % `value` assert (value >= 0), "value %s is negative" % `value` self._y = value self._reshape() @property def width(self): """The width of the window in pixels **Invariant**: width must be an int > 0""" return self._width @width.setter def width(self,value): assert (type(value) == int), "value %s is not an int" % `value` assert (value > 0), "value %s is negative" % `value` self._width = value self._reshape() @property def height(self): """The height of the window in pixels **Invariant**: height must be an int > 0""" return self._height @height.setter def height(self,value): assert (type(value) == int), "value %s is not an int" % `value` assert (value > 0), "value %s is negative" % `value` self._height = value self._reshape() @property def title(self): """The title displayed at top of window bar **Invariant**: title must be a string""" return self._frame._title @title.setter def title(self,value): assert (type(value) == str), "value %s is not a string" % `value` self._frame._root.title(value) self._frame._title = value @property def resizable(self): """Whether or not the Window supports user resizing **Invariant**: resizable must be a bool""" return self._frame._root.resizable() == '1 1' @resizable.setter def resizable(self,value): assert (type(value) == bool), "value %s is not a bool" % `value` self._resizable = value flag = 1 if value else 0 self._frame._root.resizable(flag, flag) # IMMUTABLE PROPERTIES @property def turtles(self): """The list of all turtles attached to this Window *This attribute may not be altered directly*""" return self._turtles[:] @property def pens(self): """The list of all pens attached to this Window *This attribute may not be altered directly*""" return self._pencils[:] @property def shapes(self): """The list containing all supported turtle shapes *This attribute may not be altered directly*""" return self._frame.getshapes() # BUILT-IN METHODS def __init__(self,x=100,y=100,width=800,height=800): """**Constructor**: creates a new Window to support turtle graphics :param x: initial x coordinate (default 100) **Precondition**: int :param y: initial y coordinate (default 100) **Precondition**: int :param width: initial window width (default 800) **Precondition**: int :param height: initial window height (default 800) **Precondition**: int All parameters are optional.""" assert (type(x) == int), "x-coordinate %s is not an int" % `x` assert (x > 0), "x-coordinate %s is negative" % `x` assert (type(y) == int), "y-coordinate %s is not an int" % `y` assert (y > 0), "y-coordinate %s is negative" % `y` assert (type(width) == int), "width %s is not an int" % `width` assert (width > 0), "width %s is negative" % `width` assert (type(height) == int), "height %s is not an int" % `height` assert (height > 0), "height %s is negative" % `height` self._frame = _Window(x,y,width,height) self._x = x self._y = y self._width = width self._height = height # Initialize the lists self._turtles = [] self._pencils = [] try: self._frame.addshape('pen.gif' if _PATH == '' else _PATH+'/pen.gif') except turtle.TurtleGraphicsError as e: print 'Attempt to use pencil graphic failed' print e def __del__(self): """Destroys this window and its associated assets""" try: self._frame._destroy() except: pass self._turtles = [] self._pencils = [] del self._frame # FRIEND METHODS def _reshape(self): """Resize this window to the current set dimensions""" self._frame._setup(width=self._width,height=self._height, startx=self._x,starty=self._y) def _addTurtle(self,turt): """Add a turtle to this window. :param turt: the graphics turtle **Precondition**: turt is not already in this Window """ assert (type(turt) == Turtle), "Parameter %s is not a valid Turtle object" % `turt` self._turtles.append(turt) def _addPen(self,pen): """Add a pen to this window. :param pen: the graphics pen **Precondition**: pen is not already in this Window """ assert (type(pen) == Pen), "Parameter %s is not a valid graphics pen" % `turt` self._pencils.append(pen) def _removeTurtle(self,turt): """Remove a turtle from this window. :param turt: the graphics turtle **Precondition**: turt is in this Window > 0 """ if turt in self._turtles: self._turtles.remove(turt) def _removePen(self,pen): """Remove a pen from this window. :param pen: the graphics pen **Precondition**: pen is in this Window > 0 """ if pen in self._pencils: self._pencils.remove(pen) # PUBLIC METHODS def clear(self): """Erase the contents of this Window All Turtles and Pens are eliminated from the Window. Any attempt to use a previously created Turtle or Pen will fail.""" self._frame.clear() self._turtles = [] self._gpens = [] def bye(self): """Closes the graphics Window, deleting all assets""" self._frame._destroy() self._turtles = [] self._gpens = [] del self._frame def beep(self): """Plays an OS specific alert sound""" self._frame._root.bell() def iconify(self): """Shrinks the window down to an icon, effectively hiding it""" self._frame._root.iconify() def deiconify(self): """Expands the window from an icon so that it is visible""" self._frame._root.deiconify() def setMaxSize(self,width,height): """Sets the maximum size for this window Any attempt to resize a dimension beyond the maximum size will fail. :param width: the maximum window width **Precondition**: width is an int > 0 :param height: the maximum height width **Precondition**: height is an int > 0 """ assert (type(width) == int), "width %s is not an int" % `width` assert (width > 0), "width %s is negative" % `width` assert (type(height) == int), "height %s is not an int" % `height` assert (height > 0), "height %s is negative" % `height` self._frame._root.maxsize(width,height) def setMinSize(self,width,height): """Sets the minimum size for this window Any attempt to resize a dimension below the minimum size will fail. :param width: the minimum window width **Precondition**: width is an int > 0 :param height: the minimum height width **Precondition**: height is an int > 0 """ assert (type(width) == int), "width %s is not an int" % `width` assert (width > 0), "width %s is negative" % `width` assert (type(height) == int), "height %s is not an int" % `height` assert (height > 0), "height %s is negative" % `height` self._frame._root.minsize(width,height) # UNSUPPORTED METHODS def flush(self): """Unsupported method for compatibility""" pass def stroke(self, path, clr): """Unsupported method for compatibility""" pass def fill(self, path, clr): """Unsupported method for compatibility""" pass def write(self, fname): """Unsupported method for compatibility""" pass # TURTLE HELPERS def _is_turtle_color(c): """**Returns**: True if c is a valid color value. Turtles accept RGB, HSV, strings (for named colors), or tuples. :param c: a potential color value """ return (type(c) == colormodel.RGB or type(c) == colormodel.HSV or type(c) == str or type(c) == tuple) def _to_turtle_color(c): """**Returns**: The given color value, converted to an internal format This method allows us to support all color formats, while using a single color format for the backend. For the PyX backend, the unified color is a Tk-supported color value :param c: the color value **Precondition**: is_turtle_color(c) must be True """ return c.tkColor() if (type(c) == colormodel.RGB or type(c) == colormodel.HSV) else c class Turtle(object): """Instances represent a graphics turtle. A graphics turtle is a pen that is controlled by direction and movement. The turtle is a cursor that that you control by moving it left, right, forward, or backward. As it moves, it draws a line of the same color as the Turtle. """ # PRIVATE ATTRIBUTES: # _screen: Reference to the Tkinter drawing canvas # _turtle: Reference to the TK turtle primitive # MUTABLE PROPERTIES @property def heading(self): """The heading of this turtle in degrees. Heading is measured counter clockwise from due east. **Invariant**: Value must be a float""" return float(self._turtle.heading()) @heading.setter def heading(self,value): assert type(value) in [int, float], "value %s is not a valid number" % `value` self._turtle.setheading(value) @property def speed(self): """The animation speed of this turtle. The speed is an integer from 0 to 10. Speed = 0 means that no animation takes place. The methods forward/back makes turtle jump and likewise left/right make the turtle turn instantly. Speeds from 1 to 10 enforce increasingly faster animation of line drawing and turtle turning. 1 is the slowest speed while 10 is the fastest (non-instantaneous) speed. **Invariant**: Value must be an integer value in the range 0..10.""" return self._turtle.speed() @speed.setter def speed(self,value): assert (type(value) == int), "value %s is not an int" % `value` assert (value >= 0 or value <= 10), "value %s is outside the range 0..10" % `value` self._turtle.speed(value) @property def color(self): """The color of this turtle. All subsequent draw commands (forward/back) draw using this color. If the color changes, it only affects future draw commands, not past ones. **Invariant**: Value must be either a string with a color name, a 3 element tuple of floats between 0 and 1 (inclusive), or an object in an additive color model (e.g. RGB or HSV).""" return self._color @color.setter def color(self,value): assert (_is_turtle_color(value)), "value %s is not a valid color input" % `value` self._turtle.color(_to_turtle_color(value)) self._color = self._turtle.color()[0] @property def visible(self): """Indicates whether the turtle's icon is visible. Drawing commands will still work while the turtle icon is hidden. There will just be no indication of the turtle's current location on the screen. **Invariant**: Value must be a bool""" return self._turtle.isvisible() @visible.setter def visible(self,value): assert (type(value) == bool), "value %s is not a bool" % `value` if value and not self._turtle.isvisible(): self._turtle.showturtle() elif not value and self._turtle.isvisible(): self._turtle.hideturtle() @property def drawmode(self): """Indicates whether the turtle is in draw mode. All drawing calls are active if an only if this mode is True **Invariant**: Value must be a bool""" return self._turtle.isdown() @drawmode.setter def drawmode(self,value): assert (type(value) == bool), "value %s is not a bool" % `value` if value and not self._turtle.isdown(): self._turtle.pendown() elif not value and self._turtle.isdown(): self._turtle.penup() # IMMUTABLE PROPERTIES @property def x(self): """The x-coordinate of this turtle. To change the x coordinate, use one of the drawing methods. *This attribute may not be (directly) altered*""" return self._turtle.xcor() @property def y(self): """The y-coordinate of this turtle. To change the x coordinate, use one of the drawing methods. *This attribute may not be (directly) altered*""" return self._turtle.ycor() # BUILT-IN METHODS def __init__(self,screen,position=(0, 0), color='red', heading=180, speed=0): """**Constructor**: Creates a new turtle to draw on the given screen. :param screen: window object that turtle will draw on. **Precondition**: object of type Window. :param position: initial turtle position (origin is screen center) **Precondition**: 2D tuple of floats or ints. :param color: initial turtle color (default red) **Precondition**: either a string with a color name, a 3 element tuple of floats between 0 and 1 (inclusive), or an object in an additive color model (e.g. RGB or HSV). :param heading: initial turtle directions (default 180) **Precondition**: a float or int :param speed: initial turtle speed (default 0) **Precondition**: a int between 0 and 10, inclusive The argument ``screen`` is not optional.""" assert type(screen) == Window, "parameter $s is not a Window object" % `screen` assert (_is_turtle_color(color)), "paramter %s is not a valid color input" % `color` self._turtle = turtle.RawTurtle(screen._frame) self._turtle.hideturtle() self._screen = screen screen._addTurtle(self) self._turtle.shape('turtle') self._turtle.penup() self.color = color self._turtle.setposition(position) self._turtle.setheading(heading) self._turtle.speed(speed) self._turtle.pendown() self._turtle.showturtle() def __repr__(self): """**Returns**: An unambiguous string representation of this turtle. """ return str(self.__class__)+str(self) def __str__(self): """**Returns**: A readable string representation of this turtle. """ return 'Turtle[position={}, color={}, heading={}]'.format((self.x,self.y), self.color, self.heading) def __del__(self): """Deletes this turtle object. """ self.clear() self._screen._removeTurtle(self) del self._turtle # PUBLIC METHODS def forward(self,distance): """Moves the turtle forward by the given amount. :param distance: distance to move in pixels **Precondition**: a float or int This method draws a line if drawmode is True.""" assert (type(distance) in [int, float]), "parameter distance:%s is not a valid number" % `distance` self._turtle.forward(distance) def backward(self,distance): """Moves the turtle backward by the given amount. :param distance: distance to move in pixels **Precondition**: a float or int This method draws a line if drawmode is True.""" assert (type(distance) in [int, float]), "parameter distance:%s is not a valid number" % `distance` self._turtle.backward(distance) def right(self,degrees): """Turns the turtle to the right by the given amount. :param degrees: amount to turn right in degrees **Precondition**: a float or int Nothing is drawn when this method is called.""" assert (type(degrees) in [int, float]), "parameter degrees:%s is not a valid number" % `distance` self._turtle.right(degrees) def left(self,degrees): """Turns the turtle to the left by the given amount. :param degrees: amount to turn left in degrees **Precondition**: a float or int Nothing is drawn when this method is called.""" assert (type(degrees) in [int, float]), "parameter degrees:%s is not a valid number" % `distance` self._turtle.left(degrees) def move(self,x,y): """Moves the turtle to given position without drawing. :param x: new x position for turtle **Precondition**: a float or int :param y: new y position for turtle **Precondition**: a float or int This method does not draw, regardless of the drawmode.""" assert (type(x) in [int, float]), "parameter x:%s is not a valid number" % `x` assert (type(y) in [int, float]), "parameter y:%s is not a valid number" % `y` d = self._turtle.isdown() if d: self._turtle.penup() self._turtle.setposition(x,y) if d: self._turtle.pendown() def clear(self): """Deletes the turtle's drawings from the window. This method does not move the turtle or alter its attributes.""" self._turtle.clear() def reset(self): """Deletes the turtle's drawings from the window. This method re-centers the turtle and resets all attributes to their default values.""" self._turtle.clear() self._turtle.setposition((0,0)) self._turtle.shape('turtle') self.color = 'red' self.heading = 180 self.speed = 0 def flush(self): """Unsupported method for compatibility""" pass class Pen(object): """Instances represent a graphics pen. A graphics pen is like a turtle except that it does not have a heading, and there is no drawmode attribute. Instead, the pen relies on explicit drawing commands such as drawLine or drawCircle. Another difference with the pen is that it can draw solid shapes. The pen has an attribute called ``fill``. When this attribute is set to True, it will fill the insides of any polygon traced by its drawLine method. However, the fill will not be completed until fill is set to False, or the move method is invoked.""" # PRIVATE ATTRIBUTES: # _screen: Reference to the Tkinter drawing canvas # _turtle: Reference to the TK turtle primitive # MUTABLE PROPERTIES @property def speed(self): """The animation speed of this pen. The speed is an integer from 0 to 10. Speed = 0 means that no animation takes place. The drawLine and drawCircle methods happen instantly with no animation. Speeds from 1 to 10 enforce increasingly faster animation of line drawing. 1 is the slowest speed while 10 is the fastest (non-instantaneous) speed. **Invariant**: Value must be an integer value in the range 0..10.""" return self._turtle.speed() @speed.setter def speed(self,value): assert (type(value) == int), "value %s is not an int" % `value` assert (value >= 0 or value <= 10), "value %s is outside the range 0..10" % `value` self._turtle.speed(value) @property def fill(self): """The fill status of this pen. If the fill status is True, then the pen will fill the insides of any polygon or circle subsequently traced by its drawLine or drawCircle method. If the attribute changes, it only affects future draw commands, not past ones. Switching this attribute between True and False allows the pen to draw both solid and hollow shapes. **Invariant**: Value must be an bool.""" return self._turtle.fill() @fill.setter def fill(self,value): assert (type(value) == bool), "value %s is not a bool" % `value` self._turtle.fill(value) # Make the pen state relative to fill. #if value and not self._turtle.isdown(): # self._turtle.pendown() #elif not value and self._turtle.isdown(): # self._turtle.penup() @property def color(self): """Silent, unsupported property requested by a beta tester""" assert False, 'Pen does not have a color; use pencolor or fillcolor' @color.setter def color(self,value): assert False, 'Pen does not have a color; use pencolor or fillcolor' @property def pencolor(self): """The pen color of this pen. The pen color is used for drawing lines and circles. All subsequent draw commands draw using this color. If the color changes, it only affects future draw commands, not past ones. This color is only used for lines and the border of circles. It is not the color used for filling in solid areas (if the ``fill`` attribute is True). See the attribute ``fillcolor`` for solid shapes. **Invariant**: Value must be either a string with a color name, a 3 element tuple of floats between 0 and 1 (inclusive), or an object in an additive color model (e.g. RGB or HSV).""" return self._pencolor @pencolor.setter def pencolor(self,value): assert (_is_turtle_color(value)), "value %s is not a valid color input" % `value` self._turtle.color(_to_turtle_color(value),self._fillcolor) self._pencolor = self._turtle.color()[0] @property def fillcolor(self): """The fill color of this turtle. The fill color is used for filling in solid shapes. If the ``fill`` attribute is True, all subsequent draw commands fill their insides using this color. If the color changes, it only affects future draw commands, not past ones. This color is only used for filling in the insides of solid shapes. It is not the color used for the shape border. See the attribute ``pencolor`` for the border color. **Invariant**: Value must be either a string with a color name, a 3 element tuple of floats between 0 and 1 (inclusive), or an object in an additive color model (e.g. RGB or HSV).""" return self._fillcolor @fillcolor.setter def fillcolor(self,value): assert (_is_turtle_color(value)), "value %s is not a valid color input" % `value` self._turtle.color(self._pencolor,_to_turtle_color(value)) self._pencolor = self._turtle.color()[0] self._fillcolor = self._turtle.color()[1] @property def visible(self): """Indicates whether the pen's icon is visible. Drawing commands will still work while the pen icon is hidden. There will just be no indication of the pen's current location on the screen. **Invariant**: Value must be a bool""" return self._turtle.isvisible() @visible.setter def visible(self,value): assert (type(value) == bool), "value %s is not a bool" % `value` if value and not self._turtle.isvisible(): self._turtle.showturtle() elif not value and self._turtle.isvisible(): self._turtle.hideturtle() @property def origin(self): """Represents the pen origin in the draw window. This property is used by the Window to reset the pen. This is a "friend" property and the invariant is not enforced. **Invariant**: Value is pair of numbers""" return self._origin @origin.setter def origin(self,value): self._origin = value # IMMUTABLE PROPERTIES @property def x(self): """The x-coordinate of this pen. To change the x coordinate, use one of the drawing methods. *This attribute may not be (directly) altered*""" return self._turtle.xcor() @property def y(self): """The y-coordinate of this pen. To change the y coordinate, use one of the drawing methods. *This attribute may not be (directly) altered*""" return self._turtle.ycor() # BUILT-IN METHODS def __init__(self,screen,position=(0, 0), color='red', speed=0): """**Constructor**: Creates a new pen to draw on the given screen. :param screen: window object that pen will draw on. **Precondition**: object of type Window. :param position: initial pen position (origin is screen center) **Precondition**: 2D tuple of floats or ints. :param color: initial pen and fill color (default red) **Precondition**: either a string with a color name, a 3 element tuple of floats between 0 and 1 (inclusive), or an object in an additive color model (e.g. RGB or HSV). :param speed: initial turtle speed (default 0) **Precondition**: a int between 0 and 10, inclusive The argument ``screen`` is not optional.""" assert type(screen) == Window, "parameter $s is not a Window object" % `screen` assert (_is_turtle_color(color)), "paramter %s is not a valid color input" % `color` self._turtle = turtle.RawTurtle(screen._frame) self._turtle.hideturtle() self._screen = screen screen._addPen(self) try: self._turtle.shape('pen.gif' if _PATH == '' else _PATH+'/pen.gif') except turtle.TurtleGraphicsError as e: print 'Attempt to use pencil graphic failed' print e self._turtle.penup() self._turtle.setposition(position) self._turtle.color(color) self._turtle.speed(speed) self._turtle.pendown() self._turtle.showturtle() # Record current color # "pair" seems unused #pair = self._turtle.color() self._pencolor = self._turtle.color()[0] self._fillcolor = self._turtle.color()[0] def __repr__(self): """**Returns**: An unambiguous string representation of this pen. """ return str(self.__class__)+str(self) def __str__(self): """**Returns**: A readable string representation of this pen. """ return 'Pen(position={}, pencolor={}, fillcolor={})'.format(self._turtle.position(), self.pencolor, self.fillcolor) def __del__(self): """Deletes this pen object. """ self._screen._removePen(self) del self._turtle # DRAWING METHODS def move(self,x,y): """Moves the pen to given position without drawing. :param x: new x position for pen **Precondition**: a float or int :param y: new y position for pen **Precondition**: a float or int If the ``fill`` attribute is currently True, this method will complete the fill before moving to the new region. The space between the original position and (x,y) will not be connected.""" assert (type(x) in [int, float]), "parameter x:%s is not a valid number" % `x` assert (type(y) in [int, float]), "parameter y:%s is not a valid number" % `y` fstate = self._turtle.fill() if fstate: # only need to do this if in mid-fill self._turtle.fill(False) self._turtle.penup() self._turtle.setposition(x,y) self._turtle.pendown() if fstate: # only need to do this if in mid-fill self._turtle.fill(True) def drawLine(self, dx, dy): """Draws a line segment (dx,dy) from the current pen position :param dx: change in the x position **Precondition**: a float or int :param dy: change in the y position **Precondition**: a float or int The line segment will run from (x,y) to (x+dx,y+dy), where (x,y) is the current pen position. When done, the pen will be at position (x+dx,y+dy)""" assert (type(dx) in [int, float]), "parameter x:%s is not a valid number" % `dx` assert (type(dy) in [int, float]), "parameter y:%s is not a valid number" % `dy` x = self._turtle.xcor() y = self._turtle.ycor() self._turtle.setposition(x+dx, y+dy) def drawTo(self, x, y): """Draws a line from the current pen position to (x,y) :param x: finishing x position for line **Precondition**: a float or int :param y: finishing y position for line **Precondition**: a float or int When done, the pen will be at (x, y).""" assert (type(x) in [int, float]), "parameter x:%s is not a valid number" % `x` assert (type(y) in [int, float]), "parameter y:%s is not a valid number" % `y` self._turtle.setposition(x, y) def drawCircle(self, r): """Draw a circle of radius r centered on the pen. :param r: radius of the circle **Precondition**: a float or int The center of the circle is the current pen coordinates. When done, the position of the pen will remain unchanged""" assert (type(r) in [int, float]), "parameter r:%s is not a valid number" % `r` x = self._turtle.xcor() y = self._turtle.ycor() # Move the pen into position fstate = self._turtle.pendown() if fstate: self._turtle.penup() self._turtle.setposition(x, y-r) if fstate: self._turtle.pendown() # Draw the circle and fill if necessary self._turtle.circle(r) self.flush() # Return the pen to the position if fstate: self._turtle.penup() self._turtle.setposition(x, y) if fstate: self._turtle.pendown() # PUBLIC METHODS def clear(self): """Deletes the pen's drawings from the window. This method does not move the pen or alter its attributes.""" self._turtle.clear() def reset(self): """Deletes the pen's drawings from the window. This method re-centers the pen and resets all attributes to their default values.""" self._turtle.clear() self._turtle.setposition((0,0)) try: self._turtle.shape('pencil.gif') except: self._turtle.shape('classic') self._turtle.color('red') self.speed = 0 #pair = self._turtle.color() self._pencolor = self._turtle.color()[0] self._fillcolor = self._turtle.color()[0] def flush(self): """Fills in the current drawing, but retains state. Normally, an object is not filled until you set the state to False. Calling this method executes this fill, without setting the state to False. If fill is False, this method does nothing.""" if self.fill: self._turtle.fill(False) self._turtle.fill(True)