Function MNNSamplerI420Nearest

source/backend/cpu/compute/ImageProcessFunction.cpp:879–921

    }
}
void MNNSamplerI420Nearest(const unsigned char* source, unsigned char* dest, MNN::CV::Point* points, size_t sta,
                           size_t count, size_t capacity, size_t iw, size_t ih, size_t yStride) {
    auto srcY  = source;

    auto dstY  = dest + sta;
    auto dstUV = dest + (capacity) + (sta / 2) * 2;
    auto stride = yStride;
    if (yStride == 0) {
        stride = iw;
    }
    auto srcU = source + stride * ih;
    MNNSamplerC1Nearest(srcY, dstY, points, 0, count, capacity, iw, ih, stride);

    MNN::CV::Point uvPoints[2];
    uvPoints[0].fX = (points[0].fX - 0.01f) / 2.0f;
    uvPoints[0].fY = (points[0].fY - 0.01f) / 2.0f;
    uvPoints[1].fX = points[1].fX / 2.0f;
    uvPoints[1].fY = points[1].fY / 2.0f;
    if (yStride == 0) {
        stride =  ((iw + 1) / 2);
    }
    auto srcV = srcU + stride * ((ih + 1) / 2);
    auto uvCount = (count + 1) / 2;
    {
        MNN::CV::Point curPoints;
        curPoints.fX = uvPoints[0].fX;
        curPoints.fY = uvPoints[0].fY;
        float dy     = uvPoints[1].fY;
        float dx     = uvPoints[1].fX;
        float xMax   = ((iw + 1) / 2) - 1;
        float yMax   = ((ih + 1) / 2) - 1;

        for (int i = 0; i < uvCount; ++i) {
            int y = (int)roundf(__clamp(curPoints.fY, 0, yMax));
            int x = (int)roundf(__clamp(curPoints.fX, 0, xMax));
            curPoints.fY += dy;
            curPoints.fX += dx;
            auto offset = y * stride + x;
            dstUV[2 * i + 0] = srcV[offset];
            dstUV[2 * i + 1] = srcU[offset];
        }
    }
}

void MNNSamplerNV21Copy(const unsigned char* source, unsigned char* dest, MNN::CV::Point* points, size_t sta,
                        size_t count, size_t capacity, size_t iw, size_t ih, size_t yStride) {