It is difficult to answer in your question contents.
Please describe what you want to do and what you are going to do concretely.
For example, I guessed what you want to do as follows.
- Acquire images in real time from the camera connected to the PC and keep displaying it in the window of the PC screen.
- Hold the barcode in the reading area of the camera, human confirms that it was displayed cleanly in the window, and performs barcode recognition by software trigger via POS application.
- When the program can recognize the bar code, notify it to the POS application.
There are no such functions or APIs in the existing POS framework (UnifiedPOS (OPOS / POS for .NET / JavaPOS), Windows.Devices.PointOfService).
As an alternative, the closest one is to implement UnifiedPOS ImageScanner and Scanner (Bar Code Reader) as a Hydra device on one camera.
The software trigger function is implemented as a vendor specific extension function by the DirectIO method.