UPDD is much more than a conventional pointer device driver. Obviously, as a pointer device driver, it is responsible for moving the system pointer and emulating mouse clicks, but the driver also caters for external applications to interface with every aspect of the driver functionality, allowing for applications to directly interface with the pointer device rather than be driven via mouse emulation.
This type of interface is commonly known as an Application Programming Interface (API). The API can be used to receive touch data, stylus information, pressure data, performed gestures etc and to directly update driver settings and parameters. The UPDD API was implemented in the earliest versions of the driver, however, these notes are specific to UPDD version 6 and above.
The vast majority of applications are unaware of the pointer device in use and have been written to be driven by the system pointer interface as implemented by mice, pen, tablet, touch pads and touch screens. However, certain specific or specialist applications may be much more suited to direct interaction with the pointer device and in these cases the application will need to interface via some form of API.
It may also be the case that some applications need to change driver characteristics or settings, and the API can be used for this purpose.
UPDD implements a comprehensive API interface that is available under all operating systems. To utilize the API you will need to know the files involved, how to integrate, the API function calls and the driver’s settings that may be affected by the API, topics that are covered in this section.