[Gmsh] streamlines with labels

[Cleiton Elsner da Fonseca]

Dear Colleagues,

I have used gmsh code to pos-processing my fem approximations for 
non-Newtonian fluid flows. Now, I have to determine the vortex intensity 
of some flows, So I need t know how I can put labels in the flow 
streamlines generated by Gmsh. May  someone help me, please?

Thanks in advance.
Cleiton Fonseca