"""
The arc_calculator module
=========================
It creates small segments from an arc given with G-codes parameters : origin,
end, path to center and sense of rotation.
:Example:
>>> from arc_calculator import arc_to_segments
>>> a = arc_to_segments((0,0),(5,0),(10,0))
>>> for x,y in a:
... print((x,y))
...
(0.0, 6.12323e-16)
(0.09966, -0.993334)
(0.39469, -1.94708)
(0.87331, -2.8232)
(1.51646, -3.58677)
(2.29848, -4.20735)
(3.1882, -4.66019)
(4.15015, -4.92725)
(5.14598, -4.99787)
(6.136, -4.86924)
(7.08072, -4.54649)
(7.94249, -4.04249)
(8.68696, -3.37733)
(9.28444, -2.57752)
(9.71111, -1.67495)
(10, 0)
"""
from math import atan2, cos, sin, sqrt, pi
from decimal import *
from sivicncdriver.settings import logger
getcontext().prec = 6
[docs]def arc_to_segments(start, vect_to_center, end, clockwise=False, length=1,):
"""
Creates small segments from an arc.
Uses Decimal for better precision. It yields the vertices.
:param start: The starting position
:param vect_to_center: A vector to go to the center of the arc from the
starting position
:param end: The ending position
:param clockwise: Should it go clockwise ?
:param length: length of the segments
:type start: A float tuple
:type vect_to_center: A float tuple
:type end: A float tuple
:type clockwise: bool
:type length: float
:return: None, it yields vertices.
"""
v = Decimal(vect_to_center[0]), Decimal(vect_to_center[1])
e = Decimal(end[0]), Decimal(end[1])
s = Decimal(start[0]), Decimal(start[1])
radius = (v[0]**2 + v[1]**2).sqrt()
start_angle = Decimal(atan2(-v[1], -v[0])) % Decimal(2*pi)
center = (s[0]+v[0], s[1]+v[1])
end_angle = Decimal(atan2(e[1]-center[1], e[0]-center[0]))
if clockwise:
arc_length = -Decimal(2*pi) + (end_angle - start_angle)
else:
arc_length = (end_angle - start_angle)
arc_length = arc_length % Decimal(2*pi)
if arc_length < 0 and not clockwise:
arc_length += Decimal(2*pi)
elif arc_length > 0 and clockwise:
arc_length -= Decimal(2*pi)
nb_step = int(abs(arc_length*radius/Decimal(length)))
if abs(arc_length * radius) < length:
yield start
yield end
else:
d_angle = arc_length / nb_step
angle = start_angle
for _ in range(nb_step):
yield (
float(center[0] + radius*Decimal(cos(angle))),
float(center[1] + radius*Decimal(sin(angle)))
)
angle += d_angle
yield end