# drawing.py
# ----------
# By Patrick Wick
#
# This program will (hopefully) draw a dog

from turtle import *
import math

# for the dog's ears
def ear(rad,color):
    pendown()
    fillcolor(color)
    begin_fill()
    # draw an ellipse, rad is the "radius" of the ellipse 
    for i in range(2):
        # two arcs, each one half of the ellipse
        circle(rad,90) # long side
        circle(rad//25,90) # short side
    end_fill()
    penup()

# main part of the dog's face
def face(rad,color):
    pendown()
    fillcolor(color)
    begin_fill()
    # draw an ellipse, rad is the "radius" of the ellipse 
    for i in range(2):
        # two arcs, each one half of the ellipse
        circle(rad,90) # long side
        circle(rad//2,90) # short side
    end_fill()
    penup()

def nose(rad):
    # circles are drawn CCW so if the turtle is facing right, the nose is upside down
    setheading(180)
    pendown()
    color = 'black'
    fillcolor(color)
    begin_fill()

    # initial position will need to be shifted +X by rad/2 to be centered
    for i in range(3):
        forward(rad)
        circle(rad,120)

    end_fill()
    penup()

    # reset position and do the dogs septum/upper lip
    forward(rad/2)
    left(90)
    forward(2*rad)
    x = xcor()
    y = ycor()
    pendown()
    # swoop right
    forward(2*rad)
    circle(rad,150)
    penup()
    goto(x,y)
    setheading(270)
    pendown()
    # swoop left
    forward(2*rad)
    circle(-rad,150)
    penup()

def eye(rad,color):
    pendown()
    fillcolor(color)
    begin_fill()
    circle(rad)
    end_fill()
    penup()

speed(0)
penup()
pencolor('black')
pensize(4)
hideturtle()

faceLength = 200

# these shifts are based on the short and long chord-lengths of the original face ellipse
halfShift = 2*(faceLength/2)*math.sin(math.pi/4)
fullShift = 2*(faceLength)*math.sin(math.pi/4)

right(20)
goto(halfShift*0.5,0)
ear(-faceLength,'sienna')
goto(-halfShift*0.5,0)
right(140)
ear(faceLength,'sienna')

goto(-halfShift*0.5,0)
setheading(-135)
face(faceLength,'white')

goto(-halfShift,-fullShift*1.25)
setheading(-45)
face(faceLength,'sienna')

setheading(0)
goto(-halfShift*0.4,-faceLength/2)
eye(faceLength/12,'black')
goto(halfShift*0.4,-faceLength/2)
eye(faceLength/12,'black')

goto(faceLength/12,-halfShift*1.25)
nose(faceLength/6)

done()