opensource/manim
1
0
Fork 0
mirror of https://github.com/3b1b/manim.git synced 2025-08-02 02:35:22 +08:00
Code Issues Packages Projects Releases Wiki Activity

curved arcs can now handle negative angles

Browse Source
This commit is contained in:
Ben Hambrecht
2018-02-23 19:27:59 +01:00
parent 72efc2cad9
commit 497961082e
1 changed files with 17 additions and 7 deletions
Download Patch File Download Diff File Expand all files Collapse all files

24
topics/geometry.py
View File

@ -102,19 +102,22 @@ class ArcBetweenPoints(Arc):
def __init__(self, start_point, end_point, angle = TAU/4, **kwargs):
if angle == 0:
raise Exception("Arc with zero curve angle. Use Line instead.")
raise Exception("Arc with zero curve angle: use Line instead.")
midpoint = 0.5 * (start_point + end_point)
distance_vector = end_point - start_point
normal_vector = np.array([-distance_vector[1], distance_vector[0],0])
distance = np.linalg.norm(normal_vector)
normal_vector /= distance
radius = distance/2 / np.sin(0.5 * angle)
l = distance/2 / np.tan(0.5 * angle)
if angle < 0:
normal_vector *= -1
radius = distance/2 / np.sin(0.5 * np.abs(angle))
l = distance/2 / np.tan(0.5 * np.abs(angle))
arc_center = midpoint + l * normal_vector
w = start_point - arc_center
if w[0] != 0:
start_angle = np.arctan(w[1]/w[0])
start_angle = np.arctan2(w[1],w[0])
else:
start_angle = np.pi/2
@ -122,18 +125,25 @@ class ArcBetweenPoints(Arc):
radius = radius,
start_angle = start_angle,
**kwargs)
self.move_arc_center_to(arc_center)
class CurvedArrow(ArcBetweenPoints):
def __init__(self, start_point, end_point, angle = TAU/4, **kwargs):
ArcBetweenPoints.__init__(self, start_point, end_point, angle = TAU/4, **kwargs)
self.add_tip()
# I know this is in reverse, but it works
if angle >= 0:
ArcBetweenPoints.__init__(self, start_point, end_point, angle = angle, **kwargs)
self.add_tip(at_start = True, at_end = False)
else:
ArcBetweenPoints.__init__(self, end_point, start_point, angle = -angle, **kwargs)
self.add_tip(at_start = False, at_end = True)
class CurvedDoubleArrow(ArcBetweenPoints):
def __init__(self, start_point, end_point, angle = TAU/4, **kwargs):
ArcBetweenPoints.__init__(self, start_point, end_point, angle = TAU/4, **kwargs)
ArcBetweenPoints.__init__(self, start_point, end_point, angle = angle, **kwargs)
self.add_tip(at_start = True, at_end = True)