DIPlib Documentation - ©1995-2013 Quantitative Imaging Group, Delft University of Technology.

# ChainCodeNew

Chain code object allocation

## SYNOPSIS

`#include "dip_chaincode.h"`

dip_Error dip_ChainCodeNew ( chaincode, resources )

## FUNCTION

Allocates an object of type `dip_ChainCode`. However, since its fields are private and currently there exist only read access functions, it is of little use creating such an object.

A `dip_ChainCode` object stores the following data:

Data type | Name | Description
`dip_int` | `startX` | Start coordinates for chain, `ChainCodeGetStart`
`dip_int` | `startY` | Start coordinates for chain, `ChainCodeGetStart`
`dip_int` | `label` | Label ID of object, `ChainCodeGetLabel`
`dip_int` | `connectivity` | Connectivity of chain, `ChainCodeGetConnectivity`
`dip_int` | `number` | Number of elements in chain, `ChainCodeGetSize`
`dip_Chain *` | `chain` | Pointer to first element in chain, `ChainCodeGetChains`

The `dip_Chain` structure has the following elements:

Data type | Name | Description
`dip_uint8` | `code` | Direction of step taken from previous to this pixel (Freeman code)
`dip_Boolean` | `border` | Pixel is on the border
`dip_Chain *` | `next` | Pointer to the next element in the chain

The `chain` parameter points to the first `dip_Chain` object in the chain, which points to the next through its `next` value. The last element in the chain has a `NULL` pointer.

Each chain element contains the `code` value (between 0 and 3 or between 0 and 7, depending on the `connectivity`) as well as a `border` value, which indicates whether the pixel is on the edge of the image or not. The `border` value is important because it indicates that the object is cut by the imaging window and needs to be treated differently.

The chain code for an object always has as many elements as the object has border pixels.

## ARGUMENTS

Data type | Name | Description
`dip_ChainCode *` | `chaincode` | Receives pointer to allocated structure
`dip_Resources` | `resources` | Resources tracking structure. See `ResourcesNew`

## SEE ALSO

`ImageChainCode`, `ChainCodeFree`, `ChainCodeArrayNew`, `ChainCodeArrayFree`, `ChainCodeGetSize`, `ChainCodeGetChains`, `ChainCodeGetStart`, `ChainCodeGetLabel`, `ChainCodeGetConnectivity`, `ChainCodeGetLength`, `ChainCodeGetLongestRun`, `ChainCodeGetFeret`