• New feature**

Allow an option to display a chart so that bars are horizontal.

Benefits (why should this be implemented?):

Vertical bars limit the number of bars you can have, and in the case of a timeline, limit the elapsed time that can be shown. With vertical bars, when you expand the time period, the bars get thinner and thinner until they are squished into lines or become merged, unless you enforce averaging, which loses some detail and may hide sudden peaks. Horizontal bars allow a chart to expand down as far as required without losing bar integrity or requiring averaging or refactoring of data.

Notes

Invited to open this task by @Sannita at this discussion at WP:VPT.

Concerns were raised about the ability to view horizontal bar charts on mobile. In general, this is not a problem; see for example horziontal bar chart demo.