Hello,
the original problem that I have is to add an arrow to the end of a
plotted line. I tried this
from pylab import *
x=linspace(0, 1.85, 100)
y=sin(x)
dx=x[-1] - x[-2]
dy=y[-1] - y[-2]
plot(x,y,lw=2)
arrow(x[-2], y[-2], dx, dy,
width=.02,
length_includes_head=True,
head_length=sqrt(dx**2+dy**2),
lw=0, overhang=.1)
But this is ugly. And when I zoom in the arrowsize isnt scaled with the
linewidth.
Any idea instead to switch to the pyx package?
By,
Friedrich
Hello,
I want do add an arrow *tip* to a line with the same angle.
I have tried this:
from pylab import *
from matplotlib import collections, transforms
def MyArrow(ax, x, y, ang, scale=50, over=.5, color='k'):
ar = [(0,0), (-.5,-over), (0,1), (.5,-over), (0,0)]
col = collections.PolyCollection(
[ar],
offsets=(x, y),
transOffset=ax.transData,
color=color
)
col.set_transform(transforms.Affine2D().rotate(ang).scale(scale))
ax.add_collection(col)
plot([0,1,2], '.-', lw=2)
MyArrow(gca(), .5, .5, -pi/4)
draw()
and I get an arrow tip without the same line angle 
See the attached
image.
Can you help me to get the right transformation?
Thanks,
Friedrich
It should behave like a marker: it should not resize when I zoom in.
By, Friedrich
On Tue, Jun 03, 2008 at 03:55:48PM +0200, Friedrich Hagedorn wrote:
I want do add an arrow *tip* to a line with the same angle.