WarpAffineNearest

Performs affine transformation on an image using the nearest-neighbor interpolation algorithm.

Before calling the WarpAffineNearest function, you need to call Init for initialization and call Set to initialize the destination image. Then call the main function of the WarpAffineNearest function, and finally call Release to release the related space.

The function interface is declared as follows:

Initialization functions:
HmppResult HMPPI_WarpAffineNearestInit(HmppiSize srcSize, HmppiSize dstSize, double coeffs[2][3], double xCenter, double yCenter, double angle, HmppiWarpDirection direction, HmppiBorderType borderType, double borderValue, int smoothEdge, HmppiWarpPolicy** pSpec);

HmppResult HMPPI_Set_64f_C1R(double value, double *dst, HmppiSize dstSize);
Main function:
HmppResult HMPPI_WarpAffineNearest_64f_C1R(const double *src, int srcStep, double *dst, int dstStep, HmppiPoint dstRoiOffset, HmppiSize dstRoiSize, const HmppiWarpPolicy *pSpec);
Release function:
HmppResult HMPPI_WarpAffineNearestRelease_32f(HmppiWarpPolicy *policy);

Parameters

Parameter	Description	Value Range	Input/Output
src	Pointer to the source image ROI	The value cannot be NULL.	Input
srcStep	Distance between starts of consecutive lines in the source image, in bytes	The value must be zero or a positive integer.	Input
srcSize	Size of the source image block	Positive integer	Input
dst	Pointer to the destination image ROI	The value cannot be NULL.	Input/Output
dstStep	Distance between starts of consecutive lines in the destination image, in bytes	The value must be zero or a positive integer.	Input
dstRoiOffset	Offset of the destination image block	The value must be zero or a positive integer.	Input
dstRoiSize	Size of the destination image block	Positive integer	Input
coeffs	Affine transformation coefficient	The value cannot be NULL.	Input
xCenter	X-coordinate of the rotation center	Within the range of srcSize	Input
yCenter	Y-coordinate of the rotation center	Within the range of srcSize	Input
angle	Rotation angle	(-180, 180)	Input
direction	Transformation direction	HMPP_WARP_FORWARD: forward transformation HMPP_WARP_BACKWARD: backward transformation	Input
smoothEdge	Edge smoothing flag	0: Edge smoothing is not supported.	Input
borderType	Border handling algorithm	The following algorithms are supported: HMPPI_BORDER_REPL HMPPI_BORDER_IN_MEM HMPPI_BORDER_CONST HMPPI_BORDER_TRANSP	Input
borderValue	Border value	Border value when border is set to HMPPI_BORDER_CONST	Input
pSpec	Pointer to the special structure	The value cannot be NULL.	Input/Output

Return Value

Success: HMPP_STS_NO_ERR
Failure: An error code is returned.

Error Codes

Error Code	Description
HMPP_STS_NO_OPERATION	This is an alarm and no operation is performed. The width or height in srcSize and dstSize is 0.
HMPP_STS_NULL_PTR_ERR	A null pointer exists.
HMPP_STS_MALLOC_FAILED	Failed to allocate memory during pSpec initialization.
HMPP_STS_SIZE_ERR	The width or height in srcSize and dstSize is a negative value.

Example

void WarpAffineNearestExample()
{
    double angle = 45;
    int xCenter = 1;
    int yCenter = 1;
    HmppiSize srcSize = {4, 4};
    HmppiSize dstSize = {6, 6};
    double src[] = {808.744309, 27255.923492, 14949.586917, 64065.764086, 59420.504942, 54345.804493, 2688.871018, 29176.134957, 35684.298050, 52137.708563, 15309.428011, 31545.366991, 9154.513170, 54118.967098, 34390.819908, 57073.143379};
    int dstLen = dstSize.width * dstSize.height;
    double *dst = HMPPS_Malloc_32f(dstLen);
 
    HmppiPoint dstOffset = {0, 0};
    HmppiWarpPolicy *pSpec = (HmppiWarpPolicy *)malloc(sizeof(HmppiWarpPolicy));
    double pborder = src[0];
    int smoothEdge = 0;
    double coeffs[2][3];
    HmppiWarpDirection direction = HMPP_WARP_FORWARD;
    HmppiBorderType borderType = HMPPI_BORDER_REPL;
    HmppResult result = HMPPI_WarpAffineNearestInit(srcSize, dstSize, coeffs, xCenter, yCenter, angle, direction, borderType, pborder, smoothEdge, pSpec);
    printf("result = %d\n", result);
    if (result != HMPP_STS_NO_ERR) {
        return;
    }
    result = HMPPI_Set_64f_C1R(0., dst, dstSize);
    printf("result = %d\n", result);
 
    if (result != HMPP_STS_NO_ERR) {
        return;
    }
    result = HMPPI_WarpAffineNearest_64f_C1R(src, srcSize.width, dst, dstSize.width, dstOffset,  dstSize, pSpec);
    printf("result = %d\n", result);
    
    if (result != HMPP_STS_NO_ERR) {
        return;
    }
    for (int i = 0; i < dstLen; i++){
        printf("%f ", dst[i]);
    }
    HMPPI_ResizeLinearRelease_32f(pSpec);
}

Output:

result = 0
result = 0
result = 0
27255.923492 14949.586917 2688.871018 31545.366991 31545.366991 57073.143379 808.744309 54345.804493 15309.428011 15309.428011 57073.143379 57073.143379 59420.504942 35684.29805 52137.708563 34390.819908 34390.819908 57073.143379 35684.29805 35684.29805 9154.51317 54118.967098 34390.819908 34390.819908 35684.29805 9154.51317 9154.51317 9154.51317 54118.967098 34390.819908 9154.51317 9154.51317 9154.51317 9154.51317 9154.51317 54118.967098

Parent topic: Image Conversion