GetAffineQuad

Computes vertex coordinates of the quadrangle, to which the source ROI rectangle is mapped by the affine transform.

Syntax

IppStatus ippiGetAffineQuad (IppiRect srcRoi , double quad [4][2], const double coeffs[2][3]);

Parameters

srcRoi

Region of interest in the source image (of the IppiRect type).

quad

Output array. Contains vertex coordinates of the quadrangle, to which the source ROI is mapped by the affine transform function.

coeffs

The given affine transform coefficients.

Description

The function ippiGetAffineQuad is declared in the ippi.h file. It operates with ROI (see ROI Processing in Geometric Transforms).

This function is used as a support function for ippiWarpAffine. It computes vertex coordinates of the quadrangle, to which the source rectangular ROI is mapped by the affine transform function ippiWarpAffine using the given coefficients coeffs.

The first dimension [4] of the array quad[4][2] is equal to the number of vertices, and the second dimension [2] means x and y coordinates of the vertex. Quadrangle vertices have the following meaning:

quad[0] corresponds to the transformed top-left corner of the source ROI,

quad[1] corresponds to the transformed top-right corner of the source ROI,

quad[2] corresponds to the transformed bottom-right corner of the source ROI,

quad[3] corresponds to the transformed bottom-left corner of the source ROI.

Return Values

ippStsNoErr

Indicates no error. Any other value indicates an error.

ippStsCoeffErr

Indicates an error condition if c00*c11 - c01*c10 = 0.

ippStsSizeErr

Indicates an error condition if srcRoi has a size field with zero or negative value.

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