The NOBLACK Method

This is the recommended method to build the grabbing window.

Upon setting the GrabWindow parameter to the NOBLACK value, the grabbing window adjusts itself in size and position in such a way that:

Only pixels bearing luminance information are acquired.
The possible grabber restrictions are taken into account.

The WindowX_Px and WindowY_Ln parameters are adjusted to the effective size of the grabbing window.

Thereafter, the user is allowed to readjust the grabbing window position by amending OffsetX_Px and OffsetY_Ln to non-zero values.

The grabber's sampling frequency, which can differ from the camera's pixel clock frequency when analog or master synchronization is used, remains unchanged when GrabWindow is set to NOBLACK.