Summary

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From PR #25167:

Looks like warpAffine/warpPerspective are a good place to add a new smaller HAL function which would do the same processing as opt_SSE4_1::WarpAffineInvoker_Blockline_SSE41, opt_AVX2::warpAffineBlockline and other similar functions, e.g. here:

opencv/modules/imgproc/src/imgwarp.cpp

Lines 2304 to 2334 in 78ed6de

	x1 = 0;
	#if CV_TRY_SSE4_1
	if( useSSE4_1 )
	opt_SSE4_1::WarpAffineInvoker_Blockline_SSE41(adelta + x, bdelta + x, xy, X0, Y0, bw);
	else
	#endif
	{
	#if CV_SIMD128
	{
	v_int32x4 v_X0 = v_setall_s32(X0), v_Y0 = v_setall_s32(Y0);
	int span = VTraits<v_uint16x8>::vlanes();
	for( ; x1 <= bw - span; x1 += span )
	{
	v_int16x8 v_dst[2];
	#define CV_CONVERT_MAP(ptr,offset,shift) v_pack(v_shr<AB_BITS>(v_add(shift,v_load(ptr + offset))),\
	v_shr<AB_BITS>(v_add(shift,v_load(ptr + offset + 4))))
	v_dst[0] = CV_CONVERT_MAP(adelta, x+x1, v_X0);
	v_dst[1] = CV_CONVERT_MAP(bdelta, x+x1, v_Y0);
	#undef CV_CONVERT_MAP
	v_store_interleave(xy + (x1 << 1), v_dst[0], v_dst[1]);
	}
	}
	#endif
	for( ; x1 < bw; x1++ )
	{
	int X = (X0 + adelta[x+x1]) >> AB_BITS;
	int Y = (Y0 + bdelta[x+x1]) >> AB_BITS;
	xy[x1*2] = saturate_cast<short>(X);
	xy[x1*2+1] = saturate_cast<short>(Y);
	}
	}

I agree. If smaller HAL functions were added, the code could be better modified in the spirit of HAL design.

Perhaps it would be better to move this include to cpp files in order to limit public HAL interface to hal/interface.h. Is it possible?

Refactoring and some cleanup (warpAffine/warpPerspective/headers) can be postponed to the next PR.

Part 1.5: New Interfaces (Ready for PR)

• Core
• ImgProc
• Add smaller WarpAffine & WarpPerspective HAL interface
• Shrink cv::ndsrvp::warpAffine & cv::ndsrvp::warpPerspective into ...Blockline & ...BlocklineNN
• Implement cv::ndsrvp::remap via new cv_hal_remap32f interface

What's noticing is that the remap function called by warpAffine and warpPerspective does not use HAL interface cv_hal_remap32f.

Performance tests

Remap

Geometric mean (ms)

Pull Request Readiness Checklist

See details at https://github.com/opencv/opencv/wiki/How_to_contribute#making-a-good-pull-request

• I agree to contribute to the project under Apache 2 License.
• To the best of my knowledge, the proposed patch is not based on a code under GPL or another license that is incompatible with OpenCV
• The PR is proposed to the proper branch
• There is a reference to the original bug report and related work
• There is accuracy test, performance test and test data in opencv_extra repository, if applicable
  Patch to opencv_extra has the same branch name.
• The feature is well documented and sample code can be built with the project CMake