euler_number — Calculate the Euler number.
The operator euler_number calculates the Euler number, i.e., the difference between the number of connection components and the number of holes.
In the documentation of this chapter (Regions / Features), you can find an image illustrating regions which vary in their Euler number.
If more than one region is passed the results are stored in tuples, the index of a value in the tuple corresponding to the index of a region in the input.
Region(s) to be examined.
Calculated Euler number.
The operator euler_number returns the value 2 (H_MSG_TRUE) if the input is not empty. The behavior in case of empty input (no input regions available) is set via the operator set_system('no_object_result',<Result>). The behavior in case of empty region (the region is the empty set) is set via set_system('empty_region_result',<Result>). If necessary an exception is raised.
threshold, regiongrowing, connection