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

[Jae-Joon L. <lee...@gm...>]

On Wed, Jan 30, 2013 at 7:11 AM, 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?
>

Can you elaborate why you cannot just use shrinkA and shrinkB?

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

What the problem of doing above?

Note that the unit of shrinkA and shrinkB is points, and they are
independent of mutation_scale, which only affects the size of the arrow.

Regards,

-JJ