Calculate the difference of two regions.
difference calculates the set-theoretic difference of two regions:
(Regions in Region) - (Regions in Sub)The resulting region is defined as the input region (Region) with all points from Sub removed.
Empty regions are valid for both parameters. On output, empty regions may result. The value of the system flag 'store_empty_region' determines the behavior in this case.
|
Region (input_object) |
region(-array) -> object |
| Regions to be processed. | |
|
Sub (input_object) |
region(-array) -> object |
| The union of these regions is subtracted from Region. | |
|
RegionDifference (output_object) |
region(-array) -> object |
| Resulting region. | |
/* provides the region X without the points in Y */ difference(X,Y,RegionDifference)
Let N be the number of regions, F_1 be their average area, and F_2 be the total area of all regions in Sub. Then the runtime complexity is O(F_1 * log(F_1) + N * (sqrt(F_1) + sqrt(F_2))).
difference always returns the value 2 (H_MSG_TRUE). The behavior in case of empty input (no regions given) can be set via set_system('no_object_result',<Result>) and the behavior in case of an empty input region via set_system('empty_region_result',<Result>). If necessary, an exception handling is raised.
difference is reentrant and processed without parallelization.
threshold, connection, regiongrowing, pouring, class_ndim_norm
intersection, union1, union2, complement, symm_difference
Foundation
