Hi all,
I've fadded doc-strings to the RawPen methods in turtlenew.py.
However, I have not yet added these doc-strings to the module-level
functions, mainly to avoid the hassles of maintaining duplicate doc
strings; I think any duplicate doc-strings should be added as a last
step. Or better yet: does anyone know how to automatically copy the
doc-strings from the RawPen methods and add them to their module-level
equivalents?
I tried as much as possible to copy from the standard Python
documentation. I also added runnable examples for each of the methods.
I am not certain if these examples would be appreciated by young
children, as I am thinking mainly of what the students in my
first-year university class would benefit from.
I made two other major changes:
- I don't think the speed (and delay) functions should return a
value when speed is None. That's effectively making them both setters
and getters, which is not good style. It forces the programmer to
remember this non-standard convention, and turtle.py already has some
odd conventions (e.g. the fill(1)/fill(0)). Thus I changed them both
to be simply setters. If getters are wanted, then lets add those as
separate functions.
- I added helper functions begin_fill() and end_fill(), which can
be used in place of fill(1) and fill(0). I can never remember if it is
fill(1) or fill(0) that should be called first.
Toby
--
Dr. Toby Donaldson
School of Computing Science
Simon Fraser University (Surrey)
----------------------------------------------------------------------------------------------------
# LogoMation-like turtle graphics
"""
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.
"""
from math import * # Also for export
import Tkinter
speeds = ['fastest', 'fast', 'normal', 'slow', 'slowest']
class Error(Exception):
pass
class RawPen:
def __init__(self, canvas):
self._canvas = canvas
self._items = []
self._tracing = 1
self._arrow = 0
self._delay = 10 # default delay for drawing
self.degrees()
self.reset()
def degrees(self, fullcircle=360.0):
""" Set angle measurement units to degrees.
Example:
>>> turtle.degrees()
"""
self._fullcircle = fullcircle
self._invradian = pi / (fullcircle * 0.5)
def radians(self):
""" Set the angle measurement units to radians.
Example:
>>> turtle.radians()
"""
self.degrees(2.0*pi)
def reset(self):
"""Clear the screen, re-center the pen, and set variables to
the default values.
Example:
>>> turtle.position()
[0.0, -22.0]
>>> turtle.heading()
100.0
>>> turtle.reset()
>>> turtle.position()
[0.0, 0.0]
>>> turtle.heading()
0.0
"""
canvas = self._canvas
self._canvas.update()
width = canvas.winfo_width()
height = canvas.winfo_height()
if width <= 1:
width = canvas['width']
if height <= 1:
height = canvas['height']
self._origin = float(width)/2.0, float(height)/2.0
self._position = self._origin
self._angle = 0.0
self._drawing = 1
self._width = 1
self._color = "black"
self._filling = 0
self._path = []
self._tofill = []
self.clear()
canvas._root().tkraise()
def clear(self):
""" Clear the screen. The turtle does not move.
Example:
>>> turtle.position()
[10.0, -20.0]
>>> turtle.heading()
270.0
>>> turtle.clear()
>>> turtle.position()
[10.0, -20.0]
>>> turtle.heading()
270.0
"""
self.fill(0)
canvas = self._canvas
items = self._items
self._items = []
for item in items:
canvas.delete(item)
self._delete_turtle()
self._draw_turtle()
def tracer(self, flag):
"""Set tracing on if flag is True, and off if it is False.
Tracing means line are drawn more slowly, with an
animation of an arrow along the line.
Example:
>>> turtle.tracer(False) # turns off Tracer
"""
self._tracing = flag
if not self._tracing:
self._delete_turtle()
self._draw_turtle()
def forward(self, distance):
""" Go forward distance steps.
Example:
>>> turtle.position()
[0.0, 0.0]
>>> turtle.heading()
0.0
>>> turtle.forward(25)
>>> turtle.position()
[25.0, 0.0]
>>> turtle.heading()
0.0
>>> turtle.forward(-75)
>>> turtle.position()
[-50.0, 0.0]
>>> turtle.heading()
0.0
"""
x0, y0 = start = self._position
x1 = x0 + distance * cos(self._angle*self._invradian)
y1 = y0 - distance * sin(self._angle*self._invradian)
self._goto(x1, y1)
def backward(self, distance):
""" Go backwards distance steps.
The turtle's heading does not change.
Example:
>>> turtle.position()
[0.0, 0.0]
>>> turtle.heading()
0.0
>>> turtle.backward(30)
>>> turtle.position()
[-30.0, 0.0]
>>> turtle.heading()
0.0
"""
self.forward(-distance)
def left(self, angle):
""" Turn left angle units.
Units are by default degrees, but can be set via the degrees()
and radians() functions.
When viewed from above, the turning happens in-place around
its center point.
Example:
>>> turtle.position()
[-10.0, 135.0]
>>> turtle.heading()
22
>>> turtle.left(45)
>>> turtle.position()
[-10.0, 135.0]
>>> turtle.heading()
67.0
"""
self._angle = (self._angle + angle) % self._fullcircle
self._draw_turtle()
def right(self, angle):
""" Turn right angle units.
Units are by default degrees, but can be set via the degrees()
and radians() functions.
When viewed from above, the turning happens in-place around
its center point.
Example:
>>> turtle.position()
[-10.0, 135.0]
>>> turtle.heading()
22
>>> turtle.right(45)
>>> turtle.position()
[-10.0, 135.0]
>>> turtle.heading()
337.0
"""
self.left(-angle)
def up(self):
"""Pull the pen up -- no drawing when moving.
Example:
>>> turtle.up()
"""
self._drawing = 0
def down(self):
"""Put the pen down -- draw when moving.
Example:
>>> turtle.down()
"""
self._drawing = 1
def width(self, width):
""" Set the line to thickness to width.
Example:
>>> turtle.width(10)
"""
self._width = float(width)
def color(self, *args):
""" Set the pen color.
Three input formats are allowed:
color(s)
s is a Tk specification string, such as "red" or "yellow"
color((r, g, b))
r, g, and b represent an RGB color, and each of r, g, and b
are in the range [0..1]
color(r, g, b)
r, g, and b represent an RGB color, and each of r, g, and b
are in the range [0..1]
Example:
>>> turtle.color('brown')
>>> tup = (0.2, 0.8, 0.55)
>>> turtle.color(tup)
>>> turtle.color(0, .5, 0)
"""
if not args:
raise Error, "no color arguments"
if len(args) == 1:
color = args[0]
if type(color) == type(""):
# Test the color first
try:
id = self._canvas.create_line(0, 0, 0, 0, fill=color)
except Tkinter.TclError:
raise Error, "bad color string: %r" % (color,)
self._set_color(color)
return
try:
r, g, b = color
except:
raise Error, "bad color sequence: %r" % (color,)
else:
try:
r, g, b = args
except:
raise Error, "bad color arguments: %r" % (args,)
assert 0 <= r <= 1
assert 0 <= g <= 1
assert 0 <= b <= 1
x = 255.0
y = 0.5
self._set_color("#%02x%02x%02x" % (int(r*x+y), int(g*x+y), int(b*x+y)))
def _set_color(self,color):
self._color = color
self._draw_turtle()
def write(self, text, move=0):
""" Write text at the current pen position.
If move is true, the pen is moved to the bottom-right corner
of the text. By default, move is False.
Example:
>>> turtle.write('The race is on!')
>>> turtle.write('Home = (0, 0)', True)
"""
x, y = self._position
x = x-1 # correction -- calibrated for Windows
item = self._canvas.create_text(x, y,
text=str(text), anchor="sw",
fill=self._color)
self._items.append(item)
if move:
x0, y0, x1, y1 = self._canvas.bbox(item)
self._goto(x1, y1)
self._draw_turtle()
def fill(self, flag):
""" Call fill(1) before drawing the shape you want to fill, and
fill(0) when done.
Example:
>>> turtle.fill(1)
>>> turtle.forward(100)
>>> turtle.left(90)
>>> turtle.forward(100)
>>> turtle.left(90)
>>> turtle.forward(100)
>>> turtle.left(90)
>>> turtle.forward(100)
>>> turtle.fill(0)
"""
if self._filling:
path = tuple(self._path)
smooth = self._filling < 0
if len(path) > 2:
item = self._canvas._create('polygon', path,
{'fill': self._color,
'smooth': smooth})
self._items.append(item)
if self._tofill:
for item in self._tofill:
self._canvas.itemconfigure(item, fill=self._color)
self._items.append(item)
self._path = []
self._tofill = []
self._filling = flag
if flag:
self._path.append(self._position)
self.forward(0)
def begin_fill(self):
""" Called just before drawing a shape to be filled.
Example:
>>> turtle.begin_fill()
>>> turtle.forward(100)
>>> turtle.left(90)
>>> turtle.forward(100)
>>> turtle.left(90)
>>> turtle.forward(100)
>>> turtle.left(90)
>>> turtle.forward(100)
>>> turtle.end_fill()
"""
self.fill(1)
def end_fill(self):
""" Called after drawing a shape to be filled.
Example:
>>> turtle.begin_fill()
>>> turtle.forward(100)
>>> turtle.left(90)
>>> turtle.forward(100)
>>> turtle.left(90)
>>> turtle.forward(100)
>>> turtle.left(90)
>>> turtle.forward(100)
>>> turtle.end_fill()
"""
self.fill(0)
def circle(self, radius, extent=None):
""" Draw a circle with given radius.
The center is radius units left of the turtle; extent
determines which part of the circle is drawn. If not given,
the entire circle is drawn.
If extent is not a full circle, one endpoint of the arc is the
current pen position. The arc is drawn in a counter clockwise
direction if radius is positive, otherwise in a clockwise
direction. In the process, the direction of the turtle is
changed by the amount of the extent.
>>> turtle.circle(50)
>>> turtle.circle(120, 180) # half a circle
"""
if extent is None:
extent = self._fullcircle
x0, y0 = self._position
xc = x0 - radius * sin(self._angle * self._invradian)
yc = y0 - radius * cos(self._angle * self._invradian)
if radius >= 0.0:
start = self._angle - 90.0
else:
start = self._angle + 90.0
extent = -extent
if self._filling:
if abs(extent) >= self._fullcircle:
item = self._canvas.create_oval(xc-radius, yc-radius,
xc+radius, yc+radius,
width=self._width,
outline="")
self._tofill.append(item)
item = self._canvas.create_arc(xc-radius, yc-radius,
xc+radius, yc+radius,
style="chord",
start=start,
extent=extent,
width=self._width,
outline="")
self._tofill.append(item)
if self._drawing:
if abs(extent) >= self._fullcircle:
item = self._canvas.create_oval(xc-radius, yc-radius,
xc+radius, yc+radius,
width=self._width,
outline=self._color)
self._items.append(item)
item = self._canvas.create_arc(xc-radius, yc-radius,
xc+radius, yc+radius,
style="arc",
start=start,
extent=extent,
width=self._width,
outline=self._color)
self._items.append(item)
angle = start + extent
x1 = xc + abs(radius) * cos(angle * self._invradian)
y1 = yc - abs(radius) * sin(angle * self._invradian)
self._angle = (self._angle + extent) % self._fullcircle
self._position = x1, y1
if self._filling:
self._path.append(self._position)
self._draw_turtle()
def heading(self):
""" Returns the turtle's current heading.
Example:
>>> turtle.heading()
67.0
"""
return self._angle
def setheading(self, angle):
""" Set the turtle facing the given angle.
Here are some common directions in degrees:
0 - east
90 - north
180 - west
270 - south
Example:
>>> turtle.setheading(90)
>>> turtle.heading()
90
>>> turtle.setheading(128)
>>> turtle.heading()
128
"""
self._angle = angle
self._draw_turtle()
def window_width(self):
""" Returns the width of the turtle window.
Example:
>>> turtle.window_width()
640
"""
width = self._canvas.winfo_width()
if width <= 1: # the window isn't managed by a geometry manager
width = self._canvas['width']
return width
def window_height(self):
""" Returns the height of the turtle window.
Example:
>>> turtle.window_height()
768
"""
height = self._canvas.winfo_height()
if height <= 1: # the window isn't managed by a geometry manager
height = self._canvas['height']
return height
def position(self):
""" Returns the current (x, y) location of the turtle.
Example:
>>> turtle.position()
[0.0, 240.0]
>>> x, y = turtle.position()
>>> x
0.0
>>> y
240.0
"""
x0, y0 = self._origin
x1, y1 = self._position
return [x1-x0, -y1+y0]
def setx(self, xpos):
""" Sets the turtle's x coordinate to be xpos.
Example:
>>> turtle.position()
[10.0, 240.0]
>>> turtle.setx(10)
>>> turtle.position()
[10.0, 240.0]
"""
x0, y0 = self._origin
x1, y1 = self._position
self._goto(x0+xpos, y1)
def sety(self, ypos):
""" Sets the turtle's y coordinate to be ypos.
Example:
>>> turtle.position()
[0.0, 0.0]
>>> turtle.sety(-22)
>>> turtle.position()
[0.0, -22.0]
"""
x0, y0 = self._origin
x1, y1 = self._position
self._goto(x1, y0-ypos)
def towards(self, *args):
"""Returns the angle, which corresponds to the line
from turtle-position to point (x,y).
Argument can be two coordinates or one pair of coordinates
or a RawPen/Pen instance.
Example:
>>> turtle.position()
[10.0, 10.0]
>>> turtle.towards(0,0)
225.0
"""
if len(args) == 2:
x, y = args
else:
arg = args[0]
if isinstance(arg, RawPen):
x, y = arg.position()
else:
x, y = arg
x0, y0 = self.position()
dx = x - x0
dy = y - y0
return (atan2(dy,dx) / self._invradian) % self._fullcircle
def goto(self, *args):
""" Goto the given point.
If the pen is down, then a line will be drawn. The turtle's
orientation does not change.
Two input formats are accepted:
goto(x, y)
go to point (x, y)
goto((x, y))
go to point (x, y)
Example:
>>> turtle.position()
[0.0, 0.0]
>>> turtle.heading()
0.0
>>> turtle.goto(50, -45)
>>> turtle.position()
[50.0, -45.0]
>>> turtle.heading()
0.0
"""
if len(args) == 1:
try:
x, y = args[0]
except:
raise Error, "bad point argument: %r" % (args[0],)
else:
try:
x, y = args
except:
raise Error, "bad coordinates: %r" % (args[0],)
x0, y0 = self._origin
self._goto(x0+x, y0-y)
def _goto(self, x1, y1):
x0, y0 = self._position
self._position = map(float, (x1, y1))
if self._filling:
self._path.append(self._position)
if self._drawing:
if self._tracing:
dx = float(x1 - x0)
dy = float(y1 - y0)
distance = hypot(dx, dy)
nhops = int(distance)
item = self._canvas.create_line(x0, y0, x0, y0,
width=self._width,
capstyle="round",
fill=self._color)
try:
for i in range(1, 1+nhops):
x, y = x0 + dx*i/nhops, y0 + dy*i/nhops
self._canvas.coords(item, x0, y0, x, y)
self._draw_turtle((x,y))
self._canvas.update()
self._canvas.after(self._delay)
# in case nhops==0
self._canvas.coords(item, x0, y0, x1, y1)
self._canvas.itemconfigure(item, arrow="none")
except Tkinter.TclError:
# Probably the window was closed!
return
else:
item = self._canvas.create_line(x0, y0, x1, y1,
width=self._width,
capstyle="round",
fill=self._color)
self._items.append(item)
self._draw_turtle()
def speed(self, speed):
""" Set the turtle's speed.
speed must one of these five strings:
'fastest' is a 0 ms delay
'fast' is a 5 ms delay
'normal' is a 10 ms delay
'slow' is a 15 ms delay
'slowest' is a 20 ms delay
Example:
>>> turtle.speed('slow')
"""
try:
speed = speed.strip().lower()
self._delay = speeds.index(speed) * 5
except:
raise ValueError, "%r is not a valid speed. speed must be
one of %s" % (speed, speeds)
def delay(self, delay):
""" Sets the drawing delay in milliseconds.
Example:
>>> turtle.delay(15)
"""
if int(delay) < 0:
raise ValueError, "delay must be greater than or equal to 0"
self._delay = int(delay)
def _draw_turtle(self, position=[]):
if not self._tracing:
return
if position == []:
position = self._position
x,y = position
distance = 8
dx = distance * cos(self._angle*self._invradian)
dy = distance * sin(self._angle*self._invradian)
self._delete_turtle()
self._arrow = self._canvas.create_line(x-dx,y+dy,x,y,
width=self._width,
arrow="last",
capstyle="round",
fill=self._color)
self._canvas.update()
def _delete_turtle(self):
if self._arrow != 0:
self._canvas.delete(self._arrow)
self._arrow = 0
_root = None
_canvas = None
_pen = None
_width = 0.50 # 50% of window for width
_height = 0.75 # 75% of window for height
_startx = None
_starty = None
_title = "Turtle Graphics" # default title
class Pen(RawPen):
def __init__(self):
global _root, _canvas, _width, _height
if _root is None:
_root = Tkinter.Tk()
_root.wm_protocol("WM_DELETE_WINDOW", self._destroy)
_root.title(_title)
if _canvas is None:
# XXX Should have scroll bars
_canvas = Tkinter.Canvas(_root, background="white")
_canvas.pack(expand=1, fill="both")
setup(width=_width, height= _height, startx=_startx, starty=_starty)
RawPen.__init__(self, _canvas)
def _destroy(self):
global _root, _canvas, _pen
root = self._canvas._root()
if root is _root:
_pen = None
_root = None
_canvas = None
root.destroy()
def _getpen():
global _pen
if not _pen:
_pen = Pen()
return _pen
class Turtle(Pen):
pass
def degrees(): _getpen().degrees()
def radians(): _getpen().radians()
def reset(): _getpen().reset()
def clear(): _getpen().clear()
def tracer(flag): _getpen().tracer(flag)
def forward(distance): _getpen().forward(distance)
def backward(distance): _getpen().backward(distance)
def left(angle): _getpen().left(angle)
def right(angle): _getpen().right(angle)
def up(): _getpen().up()
def down(): _getpen().down()
def width(width): _getpen().width(width)
def color(*args): _getpen().color(*args)
def write(arg, move=0): _getpen().write(arg, move)
def fill(flag): _getpen().fill(flag)
def begin_fill(): _getpen().begin_fill()
def end_fill(): _getpen.end_fill()
def circle(radius, extent=None): _getpen().circle(radius, extent)
def goto(*args): _getpen().goto(*args)
def heading(): return _getpen().heading()
def setheading(angle): _getpen().setheading(angle)
def position(): return _getpen().position()
def window_width(): return _getpen().window_width()
def window_height(): return _getpen().window_height()
def setx(xpos): _getpen().setx(xpos)
def sety(ypos): _getpen().sety(ypos)
def towards(*args): return _getpen().towards(*args)
def done(): _root.mainloop()
def delay(delay=-1): return _getpen().delay(delay)
def speed(speed=''): return _getpen().speed(speed)
def setup(**geometry):
global _root, _canvas, _width, _height, _startx, _starty
_width = geometry.get('width',_width)
_height = geometry.get('height',_height)
_startx = geometry.get('startx', _startx)
_starty = geometry.get('starty', _starty)
if _root:
if 0 < _width <= 1:
_width = _root.winfo_screenwidth() * _width
if 0 < _height <= 1:
_height = _root.winfo_screenheight() * _height
# center window on screen
if _startx is None:
_startx = (_root.winfo_screenwidth() - _width) / 2
if _starty is None:
_starty = (_root.winfo_screenheight() - _height) / 2
_root.geometry("%dx%d+%d+%d" % (_width, _height, _startx, _starty))
def title(title):
global _title
_title = title
def demo():
reset()
tracer(1)
up()
backward(100)
down()
# draw 3 squares; the last filled
width(3)
for i in range(3):
if i == 2:
fill(1)
for j in range(4):
forward(20)
left(90)
if i == 2:
color("maroon")
fill(0)
up()
forward(30)
down()
width(1)
color("black")
# move out of the way
tracer(0)
up()
right(90)
forward(100)
right(90)
forward(100)
right(180)
down()
# some text
write("startstart", 1)
write("start", 1)
color("red")
# staircase
for i in range(5):
forward(20)
left(90)
forward(20)
right(90)
# filled staircase
fill(1)
for i in range(5):
forward(20)
left(90)
forward(20)
right(90)
fill(0)
# more text
write("end")
if __name__ == '__main__':
_root.mainloop()
if __name__ == '__main__':
demo()
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