# Arrows in plots

Dear Matplotlib-Users,

I would like to add arrows at the corners of the
blue line to illustrate the order of the
iterates. Is it possible to realize it with
matplotlib ?

Nils

Some time ago (before the arrow patch), I wrote a small function to do this. I hope that this is also useful for you.

ยทยทยท

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def arrow(p1, p2, style=None, linewidth=1):
import math
import pylab as P
linex = [p1[0], p2[0]]
liney = [p1[1], p2[1]]
theta0 = math.atan2(liney[1]-liney[0], linex[1]-linex[0])
thetaa = math.pi/12
theta1 = theta0 - thetaa
theta2 = theta0 + thetaa
L = 0.05
xh = linex[1]
yh = liney[1]
xa1 = xh - L*math.cos(theta1)
ya1 = yh - L*math.sin(theta1)
xa2 = xh - L*math.cos(theta2)
ya2 = yh - L*math.sin(theta2)
P.plot(linex, liney, style, linewidth=linewidth)
P.plot([xa1, xh, xa2], [ya1, yh, ya2], 'k-', linewidth=linewidth)
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Nils Wagner wrote:

Dear Matplotlib-Users,

I would like to add arrows at the corners of the
blue line to illustrate the order of the
iterates. Is it possible to realize it with
matplotlib ?

Nils

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