Vizlib Bar Chart supports Reference Lines for both the y-Axis and for the x-Axis.
Measure/Dimension Value defines the Measure or Dimension against which the reference line will be plotted in the chart (Figure 1). You can use the Label settings to edit your label. Position defines the position of the label, either above (left) or below (right) the reference line. The Font settings control your label font, allowing you to choose the Font Color, Font Size, Font Style and Text Opacity.
Figure 1: Value, Line, Font
You can choose a Label Position (Figure 2), and define the label's place in the reference line with Align. You can choose to enable an Outline, and define the Outline Background, Outline Border, Outline Stroke Width, and the Outline Border Radius.
Figure 2: Align, Outline
If you show a reference line, you can use the Line settings to define the Line Color, Line Width, Line Opacity, and the Line Style (Figure 3). You can also Show or Hide the reference line depending on a calculation condition.
Figure 3: Line