darrow(x, y, phi=None, along=None, l=8, w=5, dist=0, dimple=0)
darrow(x, y) draws an arrow head pointing to (x,y).
Optional arguments are:
phi - Arrow points in the given direction specified in radians in paper space (0: pointing right, pi/2: pointing down, etc)
along - Arrow points in the given direction specified as a (dx,dy) vector in data space
l - Length of the arrow in points (default: 8 pt)
w - Full width of the arrow head in points (default: 5 pt)
dist - Arrow is to be retracted a given distance from the point (x, y).
dimple - The back of the arrow head is indented by dimple points.
import qplot as qp
import numpy as np
qp.figure('darrow', 3, 3)
tt = np.linspace(0, 4*np.pi, 100)
xx = np.sin(tt/2)
yy = np.sin(tt)
qp.pen('666')
qp.plot(xx, yy)
qp.brush('k')
qp.pen('k')
for n in range(5, len(xx), 10):
qp.darrow(xx[n], yy[n], along=[xx[n]-xx[n-1], yy[n]-yy[n-1]])