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

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

On Tue, Jan 29, 2013 at 5:11 PM, Skipper Seabold <jss...@gm...>wrote:

> 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)
>
>
>
>
>
>
I went ahead and cross-posted to stackoverflow, if anyone wants to try
answer there. Seems to get more traffic than mailing lists these day.

http://stackoverflow.com/questions/14594786/fancyarrowpatch-to-edge-of-marker-with-known-size

Skipper