Question: Add annotation color bar to ggplot or ggvis barplot

[Jason]

Does anyone know how to add an annotation color bar to a `ggplot` or `ggvis/plotly/... barplot`?

An example would be like "Heatmap 1" below, with a color bar (blue and red) representing sample information as type a or type b:


[Kieron Scully]

I think this is what you want and then some: https://bioconductor.org/packages/3.7/bioc/vignettes/ComplexHeatmap/inst/doc/s4.heatmap_annotation.html

It goes into a fair amount of detail about only drawing the metadata of the heatmap.