A constant line is a straight line that can be used to display, for example, an asymptote of a graph. To display constant lines on a chart, assign an array of objects specifying the properties of each constant line to the constantLines field. It is necessary to set the value property within these objects. The other properties can be set if required.
You can customize the appearance of all the value axis constant lines at once. For this purpose, use the valueAxis.constantLineStyle configuration object. Note that the properties that are set within the valueAxis.constantLine object override the corresponding properties that are set within the valueAxis.constantLineStyle object.
The following dash styles are available:
The border is a solid, continuous line.
The border is displayed using long dashes.
The border is displayed using dashes.
The border is displayed using dots.
Any combination of 'longDash', 'dash' and 'dot'
The border is displayed by repeating the specified combination. For instance, 'dashdotdash'.
A constant line label shows information on the constant line. You can configure label appearance using the label object. Within this object, you can set font properties, a position and text using corresponding fields. In addition, you can specify the horizontal and vertical alignments for the label.
You can set the label properties for all the value axis constant lines together. For this purpose, use the valueAxis.constantLineStyle.label object. Note that the properties that are set within the valueAxis.constantLine.label object override the corresponding properties that are set within the valueAxis.constantLineStyle.label object.