The following are utility classes that can be used for UI customization.

Xamarin.Android C#

pdftron.PDF.Tools.ToolManager
A class containing methods for interacting with tools.

pdftron.PDF.Tools.Tool
An abstract base class that is inherited by many tool classes.

Xamarin.iOS C#

pdftron.PDF.Tools.PTToolManager
A class responsible for forwarding events from the PDFViewCtrl to Tools, and coordinating the control and data flow between tools.

pdftron.PDF.Tools.PTTool
An abstract base class that implements the Tools.framework default and shared functionality for the PTToolSwitching protocol.