Rule mark displays each data item as a line segment. Rules can span the whole width or height of the view. Alternatively, they may have specific endpoints.
It's actually a rectangle!
Currently, rule mark is just a specialization of Rect mark. This imposes some shortcomings, such as missing support for slanted lines and variable stroke widths.
TODO, but in principle, the same as in Rect mark.
TODO, but in principle, the same as in Rect mark plus the following:
The stroke width of the lines in pixels.
The minimum length of the rule. The property translates to
minWidthof Rect mark.