Reputation: 2956
Is there any way to create a 'wavy' arrow in matplotlib / python please?
Ideally, I'd like to recreate something like the following:
Upvotes: 3
Views: 7142
Reputation: 468
I made a general version (function that returns a Patch
for any given start and end coordinates) from the previous post snippet.
def curly_arrow(start, end, arr_size = 1, n = 5, col='gray', linew=1., width = 0.1):
xmin, ymin = start
xmax, ymax = end
dist = np.sqrt((xmin - xmax)**2 + (ymin - ymax)**2)
n0 = dist / (2 * np.pi)
x = np.linspace(0, dist, 151) + xmin
y = width * np.sin(n * x / n0) + ymin
line = plt.Line2D(x,y, color=col, lw=linew)
del_x = xmax - xmin
del_y = ymax - ymin
ang = np.arctan2(del_y, del_x)
line.set_transform(mpl.transforms.Affine2D().rotate_around(xmin, ymin, ang) + ax.transData)
ax.add_line(line)
verts = np.array([[0,1],[0,-1],[2,0],[0,1]]).astype(float) * arr_size
verts[:,1] += ymax
verts[:,0] += xmax
path = mpath.Path(verts)
patch = mpatches.PathPatch(path, fc=col, ec=col)
patch.set_transform(mpl.transforms.Affine2D().rotate_around(xmax, ymax, ang) + ax.transData)
return patch
arr_size
- size of the arrow, linew
- linewidth of the arrow, n
- number of wiggles, width
- "vertical" (latitudinal) size of the wiggles.
Example of usage:
fig, ax = plt.subplots()
ax.add_patch(curly_arrow((20, 20), (2, 10), n=10, arr_size=2))
ax.set_xlim(0,30)
ax.set_ylim(0,30)
PS. You'll also need to import:
import numpy as np
import matplotlib.pyplot as plt
import matplotlib.path as mpath
import matplotlib.patches as mpatches
import matplotlib as mpl
Upvotes: 4
Reputation: 339580
To reproduce the wavy arrow from the question, you may use a line plot and a triangle
import numpy as np
import matplotlib.pyplot as plt
import matplotlib.path as mpath
import matplotlib.patches as mpatches
fig, ax = plt.subplots()
x = np.linspace(0,9*np.pi,151)
y = np.sin(x)
ax.plot(x,y, color="gray", lw="3")
verts = np.array([[0,1],[0,-1],[2,0],[0,1]]).astype(float)*1.3
verts[:,0] += 9*np.pi
path = mpath.Path(verts)
patch = mpatches.PathPatch(path, fc='gray', ec="gray")
ax.add_patch(patch)
ax.axis("off")
ax.set_aspect("equal",'datalim')
ax.relim()
ax.autoscale_view()
plt.show()
Upvotes: 6