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Add get_cap_edges()

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jan 2018-09-02 22:40:20 -07:00
parent 832e3b46fa
commit f3115baabe
1 changed files with 27 additions and 0 deletions
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masque/shapes/arc.py
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@ -312,6 +312,33 @@ class Arc(Shape):
(self.offset, scale/norm_value, rotation, self.dose), \
lambda: Arc(radii=radii*norm_value, angles=angles, width=width, layer=self.layer)
def get_cap_edges(self) -> numpy.ndarray:
'''
:returns: [[[x0, y0], [x1, y1]], array of 4 points, specifying the two cuts which
[[x2, y2], [x3, y3]]], would create this arc from its corresponding ellipse.
'''
a_ranges = self._angles_to_parameters()
mins = []
maxs = []
for a, sgn in zip(a_ranges, (-1, +1)):
wh = sgn * self.width/2
rx = self.radius_x + wh
ry = self.radius_y + wh
sin_r = numpy.sin(self.rotation)
cos_r = numpy.cos(self.rotation)
sin_a = numpy.sin(a)
cos_a = numpy.cos(a)
# arc endpoints
xn, xp = sorted(rx * cos_r * cos_a - ry * sin_r * sin_a)
yn, yp = sorted(rx * sin_r * cos_a + ry * cos_r * sin_a)
mins.append([xn, yn])
maxs.append([xp, yp])
return numpy.array([mins, maxs]) + self.offset
def _angles_to_parameters(self) -> numpy.ndarray:
'''
:return: "Eccentric anomaly" parameter ranges for the inner and outer edges, in the form