Axis label justification goes bananas after `switch_axis_position` for `angle = 90` about cowplot

[clauswilke]

This is on CRAN now.

[Ax3man]

Centering them on the tick marks seems impossible altogether.

[clauswilke]

Yes. I'm pretty sure this is a bug in ggplot2 or grid. Similar problems arise without switching the axis position, correct?

[Ax3man]

I don't think so. See this example:

ggplot(data = melted_cormat, aes(x=Var1, y=Var2, fill=value)) + 
  geom_tile() + theme_bw(base_size=20) +  xlab("")+ylab("")+
  theme(axis.text.x = element_text(angle = 90, hjust = 1, vjust=0.5)) +
  coord_equal(expand = 0)

Here the alignment seems fine.

I've seen before that the justification can do weird things though. Would it be worth it to try and detect the 90 degree angle and make the adjustment?

[clauswilke]

Ok, I get it now. It used to be that ggplot would simply ignore hjust and vjust when labels were rotated 90 degrees, but that seems to be fixed now. The problem is indeed the reversion of the axis. There is no generic code to invert a grid object, it's just a lot of manual fiddling.

If you look at lines 12, 13 and 28, 29 here, you can see how I'm inverting the hjust/vjust value and the x/y coordinate. To work with rotations, maybe we need to invert both hjust and vjust and x and y in all cases.

I don't like special-casing this so it works with 90 degrees. There must be a general transform that can be done. I don't think I'll have time to look into this any time soon, but if you want to investigate, those are the lines that will need to be changed.