GetRotateQuad

Computes vertex coordinates of the quadrangle, to which the source ROI is mapped by the ippiRotate function.

Syntax

IppStatus ippiGetRotateQuad(IppiRect srcRoi, double quad[4][2], double angle, double xShift, double yShift);

Parameters

srcRoi	Source image ROI.
quad	Output array. Contains vertex coordinates of the quadrangle, to which the source ROI is mapped by ippiRotate function.
angle	The angle of rotation in degrees.
xShift, yShift	The shifts along horizontal and vertical axes to perform after the rotation.

Description

The function ippiGetRotateQuad 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 ippiRotate. It computes vertex coordinates of the quadrangle, to which the source rectangular ROI is mapped by the ippiRotate function that rotates an image by angle degrees and shifts it by xShift, yShift.

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.

Example “Using Intel IPP Functions for Image Rotation” shows how to use the function ippiGetRotateQuad.

Return Values

ippStsNoErr	Indicates no error. Any other value indicates an error.
ippStsSizeErr	Indicates an error condition if srcRoi has a size field with zero or negative value.