Objective Chart is designed to allow new chart styles to be added using a chart extension system.

You can add new styles to change the appearance of labels, axes, and data display by defining a new style ID. You need only to define a new graph style ID (in the range 00c00000 to 00ff0000) or axis style ID (in the range c0000000 to ff000000).

When the draw routines in SRGDisplayBase encounter an unknown axis type ID, they call the virtual functions DrawCustomAxis() and DrawCustomLabels(). PrepareCustom() and DrawCustomData() are called for an unknown graph type ID.

You must derive your own class from SRGraphDisplay or one of the chart-specific display classes and define the appropriate DrawCustomXXX() functions to perform your desired actions. You can probably copy and modify one of the existing draw functions.

This technique is discussed in more detail in Chapter 16, “Chart Extensions.”