Rotate

Rotates an image around the origin (0,0) and then shifts it.

Syntax

Case 1: Operation on pixel-order data

IppStatus ippiRotate_<mod>(const Ipp<datatype>* pSrc, IppiSize srcSize, int srcStep, IppiRect srcRoi, Ipp<datatype>* pDst, int dstStep, IppiRect dstRoi, double angle, double xShift, double yShift, int interpolation);

Supported values for mod:

8u_C1R	16u_C1R	32f_C1R	64f_C1R
8u_C3R	16u_C3R	32f_C3R	64f_C3R
8u_C4R	16u_C4R	32f_C4R	64f_C4R
8u_AC4R	16u_AC4R	32f_AC4R	64f_AC4R

Case 2: Operation on planar-order data

IppStatus ippiRotate_<mod>(const Ipp<datatype>* const pSrc[3], IppiSize srcSize, int srcStep, IppiRect srcRoi, Ipp<datatype>* const pDst[3], int dstStep, IppiRect dstRoi, double angle, double xShift, double yShift, int interpolation);

Supported values for mod:

8u_P3R

16u_P3R

32f_P3R

64f_P3R

IppStatus ippiRotate_<mod>(const Ipp<datatype>* const pSrc[4], IppiSize srcSize, int srcStep, IppiRect srcRoi, Ipp<datatype>* const pDst[4], int dstStep, IppiRect dstRoi, double angle, double xShift, double yShift, int interpolation);

Supported values for mod:

8u_P4R

16u_P4R

32f_P4R

64f_P4R

Parameters

pSrc	Pointer to the source image origin. An array of separate pointers to each plane for data in planar format.
srcSize	Size in pixels of the source image.
srcStep	Distance in bytes between starts of consecutive lines in the source image buffer.
srcRoi	Region of interest in the source image (of the IppiRect type).
pDst	Pointer to the destination image origin. An array of separate pointers to each plane for data in planar format.
dstStep	Distance in bytes between starts of consecutive lines in the destination image buffer.
dstRoi	Region of interest in the destination image (of the IppiRect type).
angle	The angle of rotation in degrees. The source image is rotated counterclockwise around the origin (0,0).
xShift, yShift	The shifts along horizontal and vertical axes to perform after the rotation.
interpolation	Specifies the interpolation mode. Possible values are:
	IPPI_INTER_NN - nearest neighbor interpolation
	IPPI_INTER_LINEAR - linear interpolation
	IPPI_INTER_CUBIC - cubic interpolation
	IPPI_INTER_CUBIC2P_CATMULLROM - Catmull-Rom spline
	the following flag is used additionally to the above modes:
	IPPI_SMOOTH_EDGE - edge smoothing

Description

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

This function rotates the ROI of the source image by angle degrees (counterclockwise for positive angle values) around the origin (0,0) that is implied to be in the top left corner, and shifts it by xShift and yShift values along the x- and y- axes, respectively. The result is resampled using the interpolation mode specified by the interpolation parameter, and written to the destination image ROI.

If you need to rotate an image about an arbitrary center (xCenter, yCenter), use the function ippiGetRotateShift to compute the appropriate xShift, yShift values, and then call ippiRotate with these values as input parameters.

Alternatively, you can use the ippiRotateCenter function instead.

Figure “Rotation of an Image” shows the result of rotating the sample image by 10 degrees.

Rotation of an Image

The figures below illustrate how the SMOOTH_EDGE option affects the resulting destination image appearance. Both images are computed as a result of rotating the same source image by 9 degrees using the same interpolation method, with the SMOOTH_EDGE option turned off and on, respectively. The use of this option has an antialiasing effect seen on the right border of image b) in Figure “The Effect of Edge Smoothing in the Destination Image”.

The Effect of Edge Smoothing in the Destination Image

Example “Using Intel IPP Functions for Image Rotation” shows how to use the function ippiRotate_8u_C1R.

Return Values

ippStsNoErr	Indicates no error. Any other value indicates an error or a warning.
ippStsNullPtrErr	Indicates an error condition if one of the specified pointers is NULL.
ippStsSizeErr	Indicates an error condition if any image dimension has zero or negative value.
ippStsInterpolationErr	Indicates an error condition if interpolation has an illegal value.
ippStsRectErr	Indicates an error condition if width or height of the intersection of the srcRoi and source image is less than or equal to 1.
ippStsWrongIntersectROIErr	Indicates an error condition if srcRoi has no intersection with the source image.
ippStsWrongIntersectQuad	Indicates a warning that no operation is performed if the transformed source ROI has no intersection with the destination ROI.