Function image_resample

engine/dlib/src/basis/encoder/basisu_enc.cpp:603–748

	}

	bool image_resample(const image &src, image &dst, bool srgb,
		const char *pFilter, float filter_scale, 
		bool wrapping,
		uint32_t first_comp, uint32_t num_comps)
	{
		assert((first_comp + num_comps) <= 4);

		const int cMaxComps = 4;
				
		const uint32_t src_w = src.get_width(), src_h = src.get_height();
		const uint32_t dst_w = dst.get_width(), dst_h = dst.get_height();
				
		if (maximum(src_w, src_h) > BASISU_RESAMPLER_MAX_DIMENSION)
		{
			printf("Image is too large!\n");
			return false;
		}

		if (!src_w || !src_h || !dst_w || !dst_h)
			return false;
				
		if ((num_comps < 1) || (num_comps > cMaxComps))
			return false;
				
		if ((minimum(dst_w, dst_h) < 1) || (maximum(dst_w, dst_h) > BASISU_RESAMPLER_MAX_DIMENSION))
		{
			printf("Image is too large!\n");
			return false;
		}

		if ((src_w == dst_w) && (src_h == dst_h))
		{
			dst = src;
			return true;
		}

		float srgb_to_linear_table[256];
		if (srgb)
		{
			for (int i = 0; i < 256; ++i)
				srgb_to_linear_table[i] = srgb_to_linear((float)i * (1.0f/255.0f));
		}

		const int LINEAR_TO_SRGB_TABLE_SIZE = 8192;
		uint8_t linear_to_srgb_table[LINEAR_TO_SRGB_TABLE_SIZE];

		if (srgb)
		{
			for (int i = 0; i < LINEAR_TO_SRGB_TABLE_SIZE; ++i)
				linear_to_srgb_table[i] = (uint8_t)clamp<int>((int)(255.0f * linear_to_srgb((float)i * (1.0f / (LINEAR_TO_SRGB_TABLE_SIZE - 1))) + .5f), 0, 255);
		}

		std::vector<float> samples[cMaxComps];
		Resampler *resamplers[cMaxComps];
		
		resamplers[0] = new Resampler(src_w, src_h, dst_w, dst_h,
			wrapping ? Resampler::BOUNDARY_WRAP : Resampler::BOUNDARY_CLAMP, 0.0f, 1.0f,
			pFilter, nullptr, nullptr, filter_scale, filter_scale, 0, 0);