"""
 turtle art toolkit is a list of additional functions
 that you can use to make artwork using the turtle.
 These functions are written in Python version 3 and
 use commands from the turtle library

 Author J Catchpole
 Date 26-11-2013
"""

# import the turtle commands for a full list see
# http://docs.python.org/3.0/library/turtle.html

from turtle import *

def polygon(line_length, sides, stroke_color, fill_color, stroke_thickness):
    color(stroke_color, fill_color)
    pensize(stroke_thickness)
    begin_fill()
    for i in range(0,sides):
        forward(line_length)
        left(360/sides)
    end_fill()

def star(line_length, angle, stroke_color, fill_color, stroke_thickness):
    color(stroke_color, fill_color)
    pensize(stroke_thickness)
    start_point = pos()
    begin_fill()
    while True:
        forward(line_length)
        left(angle)
        if (abs(pos()-start_point) < 1):
            break
    end_fill()

def curve(line_step, angle_step, total_angle, stroke_color, stroke_thickness):
    color(stroke_color)
    pensize(stroke_thickness)
    for i in range(0,total_angle,angle_step):
        forward(line_step)
        left(angle_step)

# spiral: openness needs to be a number close to one
# line_step and angle_step are probably best set to one
def spiral(line_step, angle_step, openness, total_angle, stroke_color, stroke_thickness):
    color(stroke_color)
    pensize(stroke_thickness)
    for i in range(0,total_angle,angle_step):
        forward(int(line_step*openness**i))
        left(angle_step)

""""
These are some sensible ways to call the functions to make shapes & patterns
explore the possibilies by changing the parameters
"""
spiral(1, 1, 1.02, 90, "purple", 3)
polygon(50, 10, "blue", "green", 4)
curve(2,3,90,"black", 3)
star(100, 160, "yellow", "red", 2)