Inquiries

There are a number of inquiry routines available to investigate the properties of the current picture. AGI_INAME and AGI_ICOM inquire the name and description of the current picture. AGI_ISAMD inquires if the given picture is on the same physical device as the current picture. AGI_ISAMP inquires if the given picture identifier points to the same picture in the database as the current picture identifier. AGI_IPOBS tests if the current picture is obscured either partially or totally by a specified picture in the database. Obscuration means here that the given picture intersects the current picture and that it overlays the current picture (was created more recently). The obscuration of the current picture can be tested against all subsequent pictures in the database by specifying a negative number in place of the picture identifier in the argument list. AGI_ITOBS tests the obscuration of a number of test points. The test points are specified in the coordinate system of the current picture, and each point is tested in turn for obscuration by any picture overlying the current one.