Figure 14: Rendering a line plot with the step style [src]
Step style refers to an alternate way of rendering line plots by not drawing a direct line between two adjacent points but rather draw two segments. The first segment being a horizontal line to the next X-value and then a vertical line from that point to the correct Y-value. This is perhaps easier demonstrated by an example as seen below.
You specify that you want the plot to be rendered with this style by calling the method SetStepStyle() on the lineplot.