The DataGraph framework is Cocoa framework that allows you to use the underlying drawing engine of DataGraph inside your own application. This is not a standard plotting library, which typically expect you to master a number of functions and methods before anything shows up on the screen. The DataGraph framework allows you to use the DataGraph application to lay out the graph, and then you load the graph file in directly in your code.
If you do not have a DataGraph license, you can still try out the framework, but you get a watermark on all your graph views. If you have a license for the DataGraph application, this watermark is not displayed and exporting is enabled.