Harriss Spiral

[vsquared]

Py5 conversion of Processing code; uses modified Turtle Graphics:

# https://gist.githubusercontent.com/nataliefreed/8483050/raw/9e3f1d0f44bcb0c872762e4b984358d375e7b5fa/turtle.pde
# https://wiki.secretgeek.net/harriss-spiral

loc = Py5Vector(0.0,0.0)
start = Py5Vector(0.0,0.0)
end = Py5Vector(0.0,0.0)
rotation = radians(90)
heading = " "

def harriss(len, limit):
  
  if (len > limit) :
    fwd(len)
    rt(radians(90))
    harriss(len/2.325, limit)
    lt(radians(180))
    harriss(len/1.325, limit)
    rt(radians(90))
    back(len)
  
def setup():
  global loc
  
  size(800, 800)
  window_title("Harriss Spiral")
  loc = Py5Vector(width/2 - 20, height - 300)
  no_fill()
  no_loop()

def draw():
  scale(1.3)
  harriss(300, 5)

#  === UTILITY FUNCTIONS === 

def fwd(len):
  global loc
  
  start = loc
  end = loc + polar(len,rotation)
  
# seg 6  
  if (int(end.y) < int(start.y)):
    heading = "SN"
# seg 5    
  if (int(end.x) < int(start.x)):
    heading = "EW"
# seg 4    
  if (int(end.y) > int(start.y)):
    heading = "NS"
# seg 3    
  if (int(end.x) > int(start.x)):
    heading = "WE" 

  if (heading == "SN") :
    stroke(255, 255, 0)
    stroke_weight(len/15)
    arc(loc.x - len/2, loc.y - len/2, len*1.414, len*1.414, radians(-45), radians(45))
  
  if (heading == "EW"):
    stroke(255, 0, 0)
    stroke_weight(len/15)
    arc(loc.x - len/2, loc.y + len/2, len*1.414, len*1.414, radians(-135), radians(-45))
  
  if (heading == "NS"):
    stroke(0, 0, 255)
    stroke_weight(len/12)
    arc(loc.x + len/2, loc.y + len/2, len*1.414, len*1.414, radians(135), radians(225))
  
  if (heading == "WE"):
    stroke(0)
    stroke_weight(len/12)
    arc(loc.x + len/2, loc.y - len/2, len*1.414, len*1.414, radians(45), radians(135))
  
  loc = end

def back(len):
  global loc
  end = loc - polar(len,rotation)
  loc = end

def lt(theta):
  global rotation
  rotation += theta

def rt(theta):
  global rotation
  rotation -= theta

def jumpTo(x,y):
  loc = Py5Vector(x, y)

# converts an angle and radius into a vector
def polar(r, theta):
  return Py5Vector(r*cos(theta), r*sin(-theta))

Output:

[villares]

That's a great one!

Another strategy for emulating turtle graphics on Processing and py5 is to use translate() and rotate()... that's what I usually do on my L-System sketches. But using a Py5Vector is a great way too.

[hx2A]

@vsquared , this looks great! bold color choices and nice curves.

[wissme]

Cool. Just a question : is it possible to use the Python turtle module from inside Py5 ?
Thanks.

[villares]

Hi @wissme !

I'd say py5 runs in Python and the turtle module also runs in Python, but both use different drawing infrastructures and different "surfaces" to draw, so they are not compatible.

If you want to do "turtle like" drawings, use a "turtle interface" with py5, I might be able to help.
https://github.com/villares/material-aulas/blob/main/Processing-Python-py5/caneta_automatica/turtle_pen.py

from turtle_pen import *

def setup():
    size(400, 400)
    start_pen()
    my_square(100) 

def my_square(side):
    for i in range(4):  # 4 times
        forward(side)   # walk with line
        turn(90)        # 90 degrees