[Matplotlib-users] FancyArrowPatch to edge of marker with known size?

[Skipper S. <jss...@gm...>]

Say I have a marker with a known size in points and I want to draw an arrow
to this point. How can I get the ends points for the arrow? As you can see
in the below, it overlaps the markers. I want to go to the edge. I can use
shrinkA and shrinkB to do what I want, but I don't see how they're related
to the points size**.5. Or should I somehow do the transformation using the
known angle between the two points and the point itself. I don't know how
to translate a point in data coordinates and the offset it in a certain
direction by size**.5 points. Can anyone help clear this up?

Skipper

import matplotlib.pyplot as plt
from matplotlib.patches import FancyArrowPatch

point1 = (138.21, 19.5)
x1, y1 = point1
point2 = (67.0, 30.19)
x2, y2 = point2
size = 700

fig, ax = plt.subplots()
ax.scatter(*zip(point1, point2), marker='o', s=size)

# if I need to get and use the angles
dx = x2 - x1
dy = y2 - y1
d = np.sqrt(dx**2 + dy**2)

arrows = FancyArrowPatch(posA=(x1, y1), posB=(x2, y2),
                            color = 'k',
                            arrowstyle="-|>",
                            mutation_scale=700**.5,
                            connectionstyle="arc3")

ax.add_patch(arrows)