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get_region_chainGetRegionChainGetRegionChainget_region_chainT_get_region_chain🔗

Short description🔗

get_region_chainGetRegionChainGetRegionChainget_region_chainT_get_region_chain — Contour of an object as chain code.

Warning🔗

get_region_chainGetRegionChain is obsolete and is only provided for reasons of backward compatibility.

Signature🔗

get_region_chain( region Region, out chain.begin.y Row, out chain.begin.x Column, out chain.code Chain )void GetRegionChain( const HObject& Region, HTuple* Row, HTuple* Column, HTuple* Chain )static void HOperatorSet.GetRegionChain( HObject region, out HTuple row, out HTuple column, out HTuple chain )def get_region_chain( region: HObject ) -> Tuple[int, int, Sequence[int]]

Herror T_get_region_chain( const Hobject Region, Htuple* Row, Htuple* Column, Htuple* Chain )

void HRegion::GetRegionChain( Hlong* Row, Hlong* Column, HTuple* Chain ) const

void HRegion.GetRegionChain( out int row, out int column, out HTuple chain )

Description🔗

The operator get_region_chainGetRegionChain returns the contour of a region. A contour is a series of pixels describing the outline of the region. The contour “lies on” the region. It starts at the smallest line number; in that line at the pixel with the largest column index. The rotation occurs clockwise. Holes of the region are ignored. The direction code (chain code) is defined as follows:

                          3       2       1
                          4       *       0
                          5       6       7

The operator get_region_chainGetRegionChain returns the code in the form of a tuple. In case of an empty region the parameters Rowrowrow and Columncolumncolumn are zero and Chainchainchain is the empty tuple.

Attention🔗

Holes of the region are ignored. Only one region may be passed, and it must have exactly one connection component.

Execution information🔗

Execution information

  • Multithreading type: reentrant (runs in parallel with non-exclusive operators).

  • Multithreading scope: global (may be called from any thread).

  • Processed without parallelization.

Parameters🔗

Regionregionregion (input_object) region → objectHObjectHRegionHObjectHobject

Region to be transformed.

Rowrowrow (output_control) chain.begin.y → (integer)HTuple (Hlong)HTuple (int / long)intHtuple (Hlong)

Line of starting point.

Columncolumncolumn (output_control) chain.begin.x → (integer)HTuple (Hlong)HTuple (int / long)intHtuple (Hlong)

Column of starting point.

Chainchainchain (output_control) chain.code-array → (integer)HTuple (Hlong)HTuple (int / long)Sequence[int]Htuple (Hlong)

Direction code of the contour (from starting point).

Value range: 0 ≤ Chain ≤ 7

Result🔗

The operator get_region_chainGetRegionChain normally returns the value 2 (H_MSG_TRUE). If more than one connection component is passed an exception is raised. 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 the operator set_system('empty_region_result',<Result>). If necessary an exception is raised.

Combinations with other operators🔗

Combinations

Possible predecessors

sobel_ampSobelAmp, thresholdThreshold, skeletonSkeleton, edges_imageEdgesImage, gen_rectangle1GenRectangle1, gen_circleGenCircle

Possible successors

approx_chainApproxChain, approx_chain_simpleApproxChainSimple

See also

copy_objCopyObj, get_region_contourGetRegionContour, get_region_polygonGetRegionPolygon

Module🔗

Foundation