vector legend depends on aspect ratio of canvas/png

[doutriaux1]

import vcs
import cdms2

vcs.download_sample_data_files()

f = cdms2.open(vcs.sample_data+"/clt.nc")
u = f("u")
v = f("v")
gm = vcs.createvector()
for height in [600,700,800]:
    x=vcs.init(geometry=(1200,height), bg=True)
    x.plot(u,v,gm)
    x.png("bug_{:d}".format(height))

gives: