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# RegionElongation

 Header: AVL.h avl

Computes the elongation factor of a region ( perfect circle has minimal elongation equal 1.0 ).

### Syntax

C++
C#

void avl::RegionElongation
(
const avl::Region& inRegion,
float& outElongation
)


### Parameters

Name Type Default Description
inRegion const Region& Input region
outElongation float&

### Description

Elongation is a measure of how long the shape is in relation to its width. The perfect circle has the minimal elongation equal to 1.0, while the upper bound doesn't exist. The operation internally approximates the region with an ellipse, and then computes the result as: Where L denotes the longer axis of the approximating ellipse, and S denotes the shorter one.

### Hints

• If the input region is not guaranteed to be non-empty, precede this filter with SkipEmptyRegion.

### Examples

 Elongation of the sample region equals to 1.702. Elongation of the sample region equals to 3.168.

### Errors

List of possible exceptions:

Error type Description
DomainError Empty region on input in RegionElongation.

### See Also

• RegionCircularity – Computes the area of a region divided by the area of a circular region having the same feature.
• ShapeElongation – Computes the elongation factor of a shape (perfect circle has minimal elongation equal 1.0).