geom_hex no longer recognizes ..count..

[Ax3man]

Strongly related to #1608.

This used to work:

DF <- data.frame(x=rnorm(1000), y=rnorm(1000))
ggplot(DF) + geom_hex(aes(x=x, y=y, alpha=..count..))

But now returns the error: object 'count' not found. #1608 reported the same behavior for ..density.. but this has been resolved since. There is a perfectly viable workaround using ..value.. instead, but ..count.. seems more consistent with other stats and geoms, and old code may no longer work.

Also see on SO.

[thomasp85]

@hadley - is there a reason for renaming count to value? Looking into StatBin and StatBin2D they still use count so I think we need to be consistent...

[hadley]

No, just an oversight

[thomasp85]

@hadley Should this be fixed in hexBinSummarise() - it also touches StatSummaryHex and I'm unsure whether value rather than count is expected there..?

[thomasp85]

The default aes in StatSummaryHex uses value, but this might just be to fit the output rather than the correct behaviour...

[hadley]

Ah this is going to be awkward to fix because it's natural for stat_hex to use count, but for stat_summary_hex to use value, and they're both implemented with the same underlying stat.

Might just be better to leave the behaviour as is, and better document.

[thomasp85]

It's not too big of an issue as it can be intercepted in StatBinHex after the call to hexBinSummarise() - just needed to know where the fix should be implemented

[hadley]

But how would you know when to make the transformation? It seems like a decent amount of work for little gain.

[thomasp85]

See PR #1765