Important for creating annotation.
A "molten" data.frame as produced by (eg) reshape2::melt
A function which can return colors to be used in the sidebar plot
Title of the color scale. Not currently used.
Horizontal or vertical plot? Valid values are "column" and "row"
the angle of the text of the rows/columns.
Use if the values in df are valid colours and should not be mapped to a color scheme, and instead should be plotted directly.
Font size (currently unused)
Name for the mouseover label, usually "row" or "column"
A ggplot geom_tile object