plot.xts - bar chart type

[rossb34]

Although line type='h' gives a vertical line that can pass as a bar when there's enough data, sometimes you need a barplot style rectangle instead.

The closest example is PerformanceAnalytics::chart.StackedBar. It uses barplot internally, and aligns that plot with axTicksByTime.

It's not exactly clear how the behavior should work. It might need to act almost exactly like chart.StackedBar.xts if there are multiple columns passed into a single plot (and positive and negative values need to be plotted separately). If each line gets it's own panel, it's much simpler.

This might be a more generally useful comment, but Peter Carl has had good luck using pretty with barplot, specifically for the y-axis. For example, the code below gives a much better result than without it, keeping the data from being compressed to the edge of the plot area. That might be true for lines as well.

bp <- barplot(momentum, las=1, horiz=TRUE, axes=FALSE, 
    names.arg=names.arg, xlim = range(pretty(momentum)), ...=...)
axis(1, at=pretty(momentum))

https://github.com/joshuaulrich/xtsExtra/issues/4