Just to add a bit more info: this mostly seems to be a problem when plotting with colors='none'. A workaround of sorts is to plot with some color map and set alpha to a very low number (but not zero) to hide the colors, though this isn't really ideal.

There are then some pdf viewer-dependent issues: there is reasonable hatching when viewed in Evince, but the transparency is not shown in Chrome, and no hatches are shown in Adobe Reader.

I think @pelson introduced contourf hatching - do you have any ideas?

do you have any ideas?

Not immediately no. The contour hatching is just making use of the existing patch hatching functionality, so I'm guessing the same problem exists for PDF with that too. I seem to remember that there is a difference in behaviour when plotting hatches to Agg vs the PDF backend in that the hatch colours are defined by the colors keyword argument in one but not the other, and as a result they are not being drawn in the PDF backend. This could potentially be solved by having a 2-phase draw stage which draws the patches, and then draws the hatches independently, and ideally where the color and linewidth of the hatch could be controlled as well. This would definately take some development effort to achieve, but I think it would be well worthwhile...

I think this is the same issue: PDF viewed in chrome also isn't showing the correct hatching with fill_between (for example, See Fig.8 or Fig.11 in http://arxiv.org/pdf/1606.01900v1.pdf --- they should be light grey instead of dark black shaded regions). I can try to produce a MWE if that would be helpful.

This seems to be better, but still wrong on v2.0.0b1

http://matplotlib.org/2.0.0b1/mpl_examples/pylab_examples/contourf_hatching_01.pdf

http://matplotlib.org/2.0.0b1/examples/pylab_examples/contourf_hatching.html

attn @jkseppan

Am I missing something, or is hatching working just fine in those examples?

@QuLogic The hatches in the pdf are wrong like in #6228

Closed in #7421