Intel® Integrated Performance Primitives Developer Guide and Reference

ID 790148
Date 11/07/2023
Public

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Document Table of Contents

WarpQuadLinearInit

Initializes the specification structure for warping an arbitrary quadrangle in the source image to the quadrangle in the destination image with the linear interpolation method.

Syntax

IppStatus ippiWarpQuadLinearInit(IppiSize srcSize, const double srcQuad[4][2], IppiSize dstSize, const double dstQuad[4][2], IppiWarpTransformType transform, IppDataType dataType, int numChannels, IppiBorderType borderType, const Ipp64f* pBorderValue, int smoothEdge, IppiWarpSpec* pSpec);

Include Files

ippi.h

Domain Dependencies

Headers: ippcore.h, ippvm.h, ipps.h

Libraries: ippcore.lib, ippvm.lib, ipps.lib

Parameters

srcSize

Size of the source image, in pixels.

srcQuad

Quadrangle in the source image.

dstSize

Size of the destination image, in pixels.

dstQuad

Quadrangle in the destination image.

transform

Type of the warp tranform. Supported values:

ippWarpAffine

Affine warping

ippWarpPerspective

Perspective warping

dataType

Data type of the source and destination images. Supported values: ipp8u, ipp16u, ipp16s, and ipp32f.

numChannels

Number of channels in the image. Supported values: 1, 3, or 4.

borderType

Type of border. Supported values:

ippBorderTransp

Outer pixels are not processed.

ippBorderInMem

Border is obtained from the source image pixels in memory.

pBorderValue

Pointer to the constant value to assign to pixels of the constant border. This parameter is applicable only to the ippBorderConst border type.

smoothEdge

Flag for edge smoothing. Supported values:
  • 0 - transformation without edge smoothing.

  • 1 - transformation with edge smoothing.

pSpec

Pointer to the specification structure.

Description

This function initializes the IppiWarpSpec structure for warping an arbitrary quadrangle in the source image to quadrangle in the destination image with the linear interpolation method. To compute the size of the specification structure, use the WarpQuadGetSize function.

Transformation coefficients are computed internally, based on the mapping of the source quadrangle to the specified destination quadrangle dstQuad and transform type transform. In case of affine transform, the function computes the coordinates of the fourth vertex of the destination quadrangle that uniquely depends on the three other vertices. If the computed coordinates are not equal to the corresponding values specified in dstQuad, the function returns the warning message and continues initialization with the computed values.

The first dimension [4] of the array specifying the quadrangle srcQuad[4][2] or dstQuad[4][2] is equal to the number of vertices, and the second dimension [2] contains the x and y coordinates of the vertex.

For an example on how to use this function, refer to the example provided with the WarpQuadNearestInit function description.

You can apply the edge smoothing feature only if the source quadrangle entirely lies in the source image.

Return Values

ippStsNoErr

Indicates no error.

ippStsNullPtrErr

Indicates an error when:
  • One of the specified pointers is NULL, excepting pBorderValue

  • The value of pBorderValue is NULL when the border type is set to ippBorderConst

ippStsSizeErr

Indicates an error when width or height of the source or destination image is less than, or equal to one.

ippStsDataTypeErr

Indicates an error when dataType has an illegal value.

ippStsWarpTransformErr

Indicates an error when transform has an illegal value.

ippStsQuadErr

Indicates an error when any of the given quadrangles is non-convex or degenerates into a triangle, line, or point.

ippStsWrongIntersectQuad

Indicates a warning that no operation is performed if the transformed source image extended with borders has no intersection with the destination image.

ippStsAffineQuadChanged

Indicates a warning when coordinates of the fourth vertex of dstQuad are changed by the function, if transform is set to ippWarpAffine.

ippStsBorderErr

Indicates an error when borderType has an illegal value.

ippStsNumChannelsErr

Indicates an error when numChannels has an illegal value.

See Also