geom_hex fails when filled with a continuous variable

[richierocks]

To reproduce, try:

d <- ggplot(diamonds, aes(carat, price))
d + geom_hex(aes(fill = depth))
## Error in unit(tic_pos.c, "mm") : 'x' and 'units' must have length > 0

Here's the stack trace using options(error = recover):

1: print(list(data = list(carat = c(0.23, 0.21, 0.23, 0.29, 0.31, 0.24, 0.24, 
2: print.ggplot(list(data = list(carat = c(0.23, 0.21, 0.23, 0.29, 0.31, 0.24,
3: plot-render.r#185: ggplot_gtable(data)
4: plot-render.r#82: build_guides(plot$scales, plot$layers, plot$mapping, posi
5: guides-.r#129: guides_gengrob(gdefs, theme)
6: guides-.r#220: lapply(gdefs, guide_gengrob, theme)
7: FUN(X[[1]], ...)
8: guides-.r#291: guide_gengrob.colorbar(X[[1]], ...)
9: guide-colorbar.r#265: unit(tic_pos.c, "mm")

[hadley]

This no longer fails - it probably doesn't do what you want, but makes sense as a consequence of the default grouping rules, and the inability to stack/dodge hexagons.

ggplot(mpg, aes(class, fill = hwy)) + 
  geom_bar()
ggplot(mpg, aes(class, fill = hwy, group = hwy)) + 
  geom_bar()

[mplourde]

richierocks example still fails, but an alternative method is presented here

[hadley]

@mplourde example works for me. You probably need the dev version.