convexityconvexityConvexityConvexityconvexity (Operator)


convexityconvexityConvexityConvexityconvexity — Shape factor for the convexity of a region.


convexity(Regions : : : Convexity)

Herror convexity(const Hobject Regions, double* Convexity)

Herror T_convexity(const Hobject Regions, Htuple* Convexity)

void Convexity(const HObject& Regions, HTuple* Convexity)

HTuple HRegion::Convexity() const

static void HOperatorSet.Convexity(HObject regions, out HTuple convexity)

HTuple HRegion.Convexity()

def convexity(regions: HObject) -> Sequence[float]

def convexity_s(regions: HObject) -> float


The operator convexityconvexityConvexityConvexityConvexityconvexity calculates the convexity of each input region of RegionsRegionsRegionsRegionsregionsregions.


If is the area of the convex hull and the original area of the region the shape factor C is defined as:

The shape factor C is 1 if the region is convex (e.g., rectangle, circle etc.). If there are indentations or holes C is smaller than 1.

In the documentation of this chapter (Regions / Features), you can find an image illustrating regions which vary in their convexity.

In case of an empty region the operator convexityconvexityConvexityConvexityConvexityconvexity returns the value 0 (if no other behavior was set (see set_systemset_systemSetSystemSetSystemSetSystemset_system)). If more than one region is passed the numerical values of the contour length are stored in a tuple, the position of a value in the tuple corresponding to the position of the region in the input tuple.

Execution Information


RegionsRegionsRegionsRegionsregionsregions (input_object)  region(-array) objectHRegionHObjectHRegionHobject

Region(s) to be examined.

ConvexityConvexityConvexityConvexityconvexityconvexity (output_control)  real(-array) HTupleSequence[float]HTupleHtuple (real) (double) (double) (double)

Convexity of the input region(s).

Assertion: Convexity <= 1


The operator convexityconvexityConvexityConvexityConvexityconvexity 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>)set_system("no_object_result",<Result>)SetSystem("no_object_result",<Result>)SetSystem("no_object_result",<Result>)SetSystem("no_object_result",<Result>)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>)set_system("empty_region_result",<Result>)SetSystem("empty_region_result",<Result>)SetSystem("empty_region_result",<Result>)SetSystem("empty_region_result",<Result>)set_system("empty_region_result",<Result>). If necessary an exception is raised.

Possible Predecessors

thresholdthresholdThresholdThresholdThresholdthreshold, regiongrowingregiongrowingRegiongrowingRegiongrowingRegiongrowingregiongrowing, connectionconnectionConnectionConnectionConnectionconnection

See also

select_shapeselect_shapeSelectShapeSelectShapeSelectShapeselect_shape, area_centerarea_centerAreaCenterAreaCenterAreaCenterarea_center, shape_transshape_transShapeTransShapeTransShapeTransshape_trans