The linewidth of hatching in matplotib plots that take the hatch keyword is very thin. I found some postings from several years ago about this and a claim that a patch was made, but I still cannot figure out a way to increase the linewidth of hatches. Is there a way to do this?
Unfortunately setting the linewidth of a hatch in an Agg backend is not currently possible. The width is hardcoded in the src/_backend_agg.cpp file to be "1.0":
hatch_path_stroke.width(1.0);
The same is true for other backends such as the PDF one, but it might be easier to monkey patch for those cases.