// Copyright (C) 2010  Davis E. King (davis@dlib.net)
// License: Boost Software License   See LICENSE.txt for the full license.
#ifndef DLIB_IMAGE_PYRaMID_H__
#define DLIB_IMAGE_PYRaMID_H__

#include "image_pyramid_abstract.h"
#include "../pixel.h"
#include "../array2d.h"
#include "../geometry.h"
#include "spatial_filtering.h"

namespace dlib
{

// ----------------------------------------------------------------------------------------

    class pyramid_down : noncopyable
    {
    public:

        template <typename T>
        vector<double,2> point_down (
            const vector<T,2>& p
        ) const
        {
            //do return (p - vector<T,2>(2,2))/2.0;
            return p/2.0 - vector<double,2>(1,1);
        }

        template <typename T>
        vector<double,2> point_up (
            const vector<T,2>& p
        ) const
        {
            return p*2 + vector<T,2>(2,2);
        }

    // -----------------------------

        template <typename T>
        vector<double,2> point_down (
            const vector<T,2>& p,
            unsigned int levels
        ) const
        {
            vector<double,2> temp = p;
            for (unsigned int i = 0; i < levels; ++i)
                temp = point_down(temp);
            return temp;
        }

        template <typename T>
        vector<double,2> point_up (
            const vector<T,2>& p,
            unsigned int levels
        ) const
        {
            vector<double,2> temp = p;
            for (unsigned int i = 0; i < levels; ++i)
                temp = point_up(temp);
            return temp;
        }

    // -----------------------------

        rectangle rect_up (
            const rectangle& rect
        ) const
        {
            return rectangle(point_up(rect.tl_corner()), point_up(rect.br_corner()));
        }

        rectangle rect_up (
            const rectangle& rect,
            unsigned int levels
        ) const
        {
            return rectangle(point_up(rect.tl_corner(),levels), point_up(rect.br_corner(),levels));
        }

    // -----------------------------

        rectangle rect_down (
            const rectangle& rect
        ) const
        {
            return rectangle(point_down(rect.tl_corner()), point_down(rect.br_corner()));
        }

        rectangle rect_down (
            const rectangle& rect,
            unsigned int levels
        ) const
        {
            return rectangle(point_down(rect.tl_corner(),levels), point_down(rect.br_corner(),levels));
        }

    // -----------------------------

    private:
        template <typename T, typename U>
        struct both_images_rgb
        {
            const static bool value = pixel_traits<typename T::type>::rgb &&
                                      pixel_traits<typename U::type>::rgb;
        };
    public:

        template <
            typename in_image_type,
            typename out_image_type
            >
        typename disable_if<both_images_rgb<in_image_type,out_image_type> >::type operator() (
            const in_image_type& original,
            out_image_type& down
        ) const
        {
            // make sure requires clause is not broken
            DLIB_ASSERT(original.nr() > 10 && original.nc() > 10 &&
                        is_same_object(original, down) == false, 
                        "\t void pyramid_down::operator()"
                        << "\n\t original.nr(): " << original.nr()
                        << "\n\t original.nc(): " << original.nc()
                        << "\n\t is_same_object(original, down): " << is_same_object(original, down) 
                        << "\n\t this:                           " << this
                        );

            COMPILE_TIME_ASSERT( pixel_traits<typename in_image_type::type>::has_alpha == false );
            COMPILE_TIME_ASSERT( pixel_traits<typename out_image_type::type>::has_alpha == false );

            typedef typename pixel_traits<typename in_image_type::type>::basic_pixel_type bp_type;
            typedef typename promote<bp_type>::type ptype;
            array2d<ptype> temp_img;
            temp_img.set_size(original.nr(), (original.nc()-3)/2);
            down.set_size((original.nr()-3)/2, (original.nc()-3)/2);


            // This function applies a 5x5 Gaussian filter to the image.  It
            // does this by separating the filter into its horizontal and vertical
            // components and then downsamples the image by dropping every other
            // row and column.  Note that we can do these things all together in
            // one step.

            // apply row filter
            for (long r = 0; r < temp_img.nr(); ++r)
            {
                long oc = 0;
                for (long c = 0; c < temp_img.nc(); ++c)
                {
                    ptype pix1;
                    ptype pix2;
                    ptype pix3;
                    ptype pix4;
                    ptype pix5;

                    assign_pixel(pix1, original[r][oc]);
                    assign_pixel(pix2, original[r][oc+1]);
                    assign_pixel(pix3, original[r][oc+2]);
                    assign_pixel(pix4, original[r][oc+3]);
                    assign_pixel(pix5, original[r][oc+4]);

                    pix2 *= 4;
                    pix3 *= 6;
                    pix4 *= 4;
                    
                    assign_pixel(temp_img[r][c], pix1 + pix2 + pix3 + pix4 + pix5);
                    oc += 2;
                }
            }


            // apply column filter
            long dr = 0;
            for (long r = 2; r < temp_img.nr()-2; r += 2)
            {
                for (long c = 0; c < temp_img.nc(); ++c)
                {
                    ptype temp = temp_img[r-2][c] + 
                                 temp_img[r-1][c]*4 +  
                                 temp_img[r  ][c]*6 +  
                                 temp_img[r-1][c]*4 +  
                                 temp_img[r-2][c];  

                    assign_pixel(down[dr][c],temp/256);
                }
                ++dr;
            }

        }

    private:
        struct rgbptype 
        {
            uint16 red;
            uint16 green;
            uint16 blue;
        };
    public:
    // ------------------------------------------
    //       OVERLOAD FOR RGB TO RGB IMAGES
    // ------------------------------------------
        template <
            typename in_image_type,
            typename out_image_type
            >
        typename enable_if<both_images_rgb<in_image_type,out_image_type> >::type operator() (
            const in_image_type& original,
            out_image_type& down
        ) const
        {
            // make sure requires clause is not broken
            DLIB_ASSERT(original.nr() > 10 && original.nc() > 10 &&
                        is_same_object(original, down) == false, 
                        "\t void pyramid_down::operator()"
                        << "\n\t original.nr(): " << original.nr()
                        << "\n\t original.nc(): " << original.nc()
                        << "\n\t is_same_object(original, down): " << is_same_object(original, down) 
                        << "\n\t this:                           " << this
                        );

            COMPILE_TIME_ASSERT( pixel_traits<typename in_image_type::type>::has_alpha == false );
            COMPILE_TIME_ASSERT( pixel_traits<typename out_image_type::type>::has_alpha == false );

            array2d<rgbptype> temp_img;
            temp_img.set_size(original.nr(), (original.nc()-3)/2);
            down.set_size((original.nr()-3)/2, (original.nc()-3)/2);


            // This function applies a 5x5 Gaussian filter to the image.  It
            // does this by separating the filter into its horizontal and vertical
            // components and then downsamples the image by dropping every other
            // row and column.  Note that we can do these things all together in
            // one step.

            // apply row filter
            for (long r = 0; r < temp_img.nr(); ++r)
            {
                long oc = 0;
                for (long c = 0; c < temp_img.nc(); ++c)
                {
                    rgbptype pix1;
                    rgbptype pix2;
                    rgbptype pix3;
                    rgbptype pix4;
                    rgbptype pix5;

                    pix1.red = original[r][oc].red;
                    pix2.red = original[r][oc+1].red;
                    pix3.red = original[r][oc+2].red;
                    pix4.red = original[r][oc+3].red;
                    pix5.red = original[r][oc+4].red;
                    pix1.green = original[r][oc].green;
                    pix2.green = original[r][oc+1].green;
                    pix3.green = original[r][oc+2].green;
                    pix4.green = original[r][oc+3].green;
                    pix5.green = original[r][oc+4].green;
                    pix1.blue = original[r][oc].blue;
                    pix2.blue = original[r][oc+1].blue;
                    pix3.blue = original[r][oc+2].blue;
                    pix4.blue = original[r][oc+3].blue;
                    pix5.blue = original[r][oc+4].blue;

                    pix2.red *= 4;
                    pix3.red *= 6;
                    pix4.red *= 4;

                    pix2.green *= 4;
                    pix3.green *= 6;
                    pix4.green *= 4;

                    pix2.blue *= 4;
                    pix3.blue *= 6;
                    pix4.blue *= 4;
                    
                    rgbptype temp;
                    temp.red = pix1.red + pix2.red + pix3.red + pix4.red + pix5.red;
                    temp.green = pix1.green + pix2.green + pix3.green + pix4.green + pix5.green;
                    temp.blue = pix1.blue + pix2.blue + pix3.blue + pix4.blue + pix5.blue;

                    temp_img[r][c] = temp;

                    oc += 2;
                }
            }


            // apply column filter
            long dr = 0;
            for (long r = 2; r < temp_img.nr()-2; r += 2)
            {
                for (long c = 0; c < temp_img.nc(); ++c)
                {
                    rgbptype temp;
                    temp.red = temp_img[r-2][c].red + 
                               temp_img[r-1][c].red*4 +  
                               temp_img[r  ][c].red*6 +  
                               temp_img[r-1][c].red*4 +  
                               temp_img[r-2][c].red;  
                    temp.green = temp_img[r-2][c].green + 
                                 temp_img[r-1][c].green*4 +  
                                 temp_img[r  ][c].green*6 +  
                                 temp_img[r-1][c].green*4 +  
                                 temp_img[r-2][c].green;  
                    temp.blue = temp_img[r-2][c].blue + 
                                temp_img[r-1][c].blue*4 +  
                                temp_img[r  ][c].blue*6 +  
                                temp_img[r-1][c].blue*4 +  
                                temp_img[r-2][c].blue;  

                    down[dr][c].red = temp.red/256;
                    down[dr][c].green = temp.green/256;
                    down[dr][c].blue = temp.blue/256;
                }
                ++dr;
            }

        }

    private:


    };

// ----------------------------------------------------------------------------------------
// ----------------------------------------------------------------------------------------
// ----------------------------------------------------------------------------------------

    class pyramid_down_3_2 : noncopyable
    {
    public:

        template <typename T>
        vector<double,2> point_down (
            const vector<T,2>& p
        ) const
        {
            const double ratio = 2.0/3.0;
            //do return (p - vector<T,2>(1,1))*ratio;
            return p*ratio - vector<double,2>(ratio,ratio);
        }

        template <typename T>
        vector<double,2> point_up (
            const vector<T,2>& p
        ) const
        {
            const double ratio = 3.0/2.0;
            return p*ratio + vector<T,2>(1,1);
        }

    // -----------------------------

        template <typename T>
        vector<double,2> point_down (
            const vector<T,2>& p,
            unsigned int levels
        ) const
        {
            vector<double,2> temp = p;
            for (unsigned int i = 0; i < levels; ++i)
                temp = point_down(temp);
            return temp;
        }

        template <typename T>
        vector<double,2> point_up (
            const vector<T,2>& p,
            unsigned int levels
        ) const
        {
            vector<double,2> temp = p;
            for (unsigned int i = 0; i < levels; ++i)
                temp = point_up(temp);
            return temp;
        }

    // -----------------------------

        rectangle rect_up (
            const rectangle& rect
        ) const
        {
            return rectangle(point_up(rect.tl_corner()), point_up(rect.br_corner()));
        }

        rectangle rect_up (
            const rectangle& rect,
            unsigned int levels
        ) const
        {
            return rectangle(point_up(rect.tl_corner(),levels), point_up(rect.br_corner(),levels));
        }

    // -----------------------------

        rectangle rect_down (
            const rectangle& rect
        ) const
        {
            return rectangle(point_down(rect.tl_corner()), point_down(rect.br_corner()));
        }

        rectangle rect_down (
            const rectangle& rect,
            unsigned int levels
        ) const
        {
            return rectangle(point_down(rect.tl_corner(),levels), point_down(rect.br_corner(),levels));
        }

    // -----------------------------

    private:
        template <typename T, typename U>
        struct both_images_rgb
        {
            const static bool value = pixel_traits<typename T::type>::rgb &&
                                      pixel_traits<typename U::type>::rgb;
        };
    public:

        template <
            typename in_image_type,
            typename out_image_type
            >
        typename disable_if<both_images_rgb<in_image_type,out_image_type> >::type operator() (
            const in_image_type& original,
            out_image_type& down
        ) const
        {
            // make sure requires clause is not broken
            DLIB_ASSERT(original.nr() > 10 && original.nc() > 10 &&
                        is_same_object(original, down) == false, 
                        "\t void pyramid_down_3_2::operator()"
                        << "\n\t original.nr(): " << original.nr()
                        << "\n\t original.nc(): " << original.nc()
                        << "\n\t is_same_object(original, down): " << is_same_object(original, down) 
                        << "\n\t this:                           " << this
                        );

            COMPILE_TIME_ASSERT( pixel_traits<typename in_image_type::type>::has_alpha == false );
            COMPILE_TIME_ASSERT( pixel_traits<typename out_image_type::type>::has_alpha == false );

            const long size_in = 3;
            const long size_out = 2;

            typedef typename pixel_traits<typename in_image_type::type>::basic_pixel_type bp_type;
            typedef typename promote<bp_type>::type ptype;
            down.set_size(size_out*((original.nr()-2)/size_in), size_out*((original.nc()-2)/size_in));


            long rr = 1;
            for (long r = 0; r < down.nr(); r+=size_out)
            {
                long cc = 1;
                for (long c = 0; c < down.nc(); c+=size_out)
                {
                    ptype block[size_in][size_in];
                    separable_3x3_filter_block_grayscale(block, original, rr, cc, 3, 10, 3);

                    // bi-linearly interpolate block 
                    assign_pixel(down[r][c]     , (block[0][0]*9 + block[1][0]*3 + block[0][1]*3 + block[1][1])/(16*256));
                    assign_pixel(down[r][c+1]   , (block[0][2]*9 + block[1][2]*3 + block[0][1]*3 + block[1][1])/(16*256));
                    assign_pixel(down[r+1][c]   , (block[2][0]*9 + block[1][0]*3 + block[2][1]*3 + block[1][1])/(16*256));
                    assign_pixel(down[r+1][c+1] , (block[2][2]*9 + block[1][2]*3 + block[2][1]*3 + block[1][1])/(16*256));

                    cc += size_in;
                }
                rr += size_in;
            }

        }

    private:
        struct rgbptype 
        {
            uint32 red;
            uint32 green;
            uint32 blue;
        };

    public:
    // ------------------------------------------
    //       OVERLOAD FOR RGB TO RGB IMAGES
    // ------------------------------------------
        template <
            typename in_image_type,
            typename out_image_type
            >
        typename enable_if<both_images_rgb<in_image_type,out_image_type> >::type operator() (
            const in_image_type& original,
            out_image_type& down
        ) const
        {
            // make sure requires clause is not broken
            DLIB_ASSERT(original.nr() > 10 && original.nc() > 10 &&
                        is_same_object(original, down) == false, 
                        "\t void pyramid_down_3_2::operator()"
                        << "\n\t original.nr(): " << original.nr()
                        << "\n\t original.nc(): " << original.nc()
                        << "\n\t is_same_object(original, down): " << is_same_object(original, down) 
                        << "\n\t this:                           " << this
                        );

            COMPILE_TIME_ASSERT( pixel_traits<typename in_image_type::type>::has_alpha == false );
            COMPILE_TIME_ASSERT( pixel_traits<typename out_image_type::type>::has_alpha == false );

            const long size_in = 3;
            const long size_out = 2;

            down.set_size(size_out*((original.nr()-2)/size_in), size_out*((original.nc()-2)/size_in));


            long rr = 1;
            for (long r = 0; r < down.nr(); r+=size_out)
            {
                long cc = 1;
                for (long c = 0; c < down.nc(); c+=size_out)
                {
                    rgbptype block[size_in][size_in];
                    separable_3x3_filter_block_rgb(block, original, rr, cc, 3, 10, 3);

                    // bi-linearly interpolate block 
                    down[r][c].red       = (block[0][0].red*9   + block[1][0].red*3   + block[0][1].red*3   + block[1][1].red)/(16*256);
                    down[r][c].green     = (block[0][0].green*9 + block[1][0].green*3 + block[0][1].green*3 + block[1][1].green)/(16*256);
                    down[r][c].blue      = (block[0][0].blue*9  + block[1][0].blue*3  + block[0][1].blue*3  + block[1][1].blue)/(16*256);

                    down[r][c+1].red     = (block[0][2].red*9   + block[1][2].red*3   + block[0][1].red*3   + block[1][1].red)/(16*256);
                    down[r][c+1].green   = (block[0][2].green*9 + block[1][2].green*3 + block[0][1].green*3 + block[1][1].green)/(16*256);
                    down[r][c+1].blue    = (block[0][2].blue*9  + block[1][2].blue*3  + block[0][1].blue*3  + block[1][1].blue)/(16*256);

                    down[r+1][c].red     = (block[2][0].red*9   + block[1][0].red*3   + block[2][1].red*3   + block[1][1].red)/(16*256);
                    down[r+1][c].green   = (block[2][0].green*9 + block[1][0].green*3 + block[2][1].green*3 + block[1][1].green)/(16*256);
                    down[r+1][c].blue    = (block[2][0].blue*9  + block[1][0].blue*3  + block[2][1].blue*3  + block[1][1].blue)/(16*256);

                    down[r+1][c+1].red   = (block[2][2].red*9   + block[1][2].red*3   + block[2][1].red*3   + block[1][1].red)/(16*256);
                    down[r+1][c+1].green = (block[2][2].green*9 + block[1][2].green*3 + block[2][1].green*3 + block[1][1].green)/(16*256);
                    down[r+1][c+1].blue  = (block[2][2].blue*9  + block[1][2].blue*3  + block[2][1].blue*3  + block[1][1].blue)/(16*256);

                    cc += size_in;
                }
                rr += size_in;
            }
        }

    private:


    };

// ----------------------------------------------------------------------------------------
// ----------------------------------------------------------------------------------------
// ----------------------------------------------------------------------------------------

    class pyramid_down_4_3 : noncopyable
    {
    public:

        template <typename T>
        vector<double,2> point_down (
            const vector<T,2>& p
        ) const
        {
            const double ratio = 3.0/4.0;
            //do return (p - vector<T,2>(1,1))*ratio;
            return p*ratio - vector<double,2>(ratio,ratio);
        }

        template <typename T>
        vector<double,2> point_up (
            const vector<T,2>& p
        ) const
        {
            const double ratio = 4.0/3.0;
            return p*ratio + vector<T,2>(1,1);
        }

    // -----------------------------

        template <typename T>
        vector<double,2> point_down (
            const vector<T,2>& p,
            unsigned int levels
        ) const
        {
            vector<double,2> temp = p;
            for (unsigned int i = 0; i < levels; ++i)
                temp = point_down(temp);
            return temp;
        }

        template <typename T>
        vector<double,2> point_up (
            const vector<T,2>& p,
            unsigned int levels
        ) const
        {
            vector<double,2> temp = p;
            for (unsigned int i = 0; i < levels; ++i)
                temp = point_up(temp);
            return temp;
        }

    // -----------------------------

        rectangle rect_up (
            const rectangle& rect
        ) const
        {
            return rectangle(point_up(rect.tl_corner()), point_up(rect.br_corner()));
        }

        rectangle rect_up (
            const rectangle& rect,
            unsigned int levels
        ) const
        {
            return rectangle(point_up(rect.tl_corner(),levels), point_up(rect.br_corner(),levels));
        }

    // -----------------------------

        rectangle rect_down (
            const rectangle& rect
        ) const
        {
            return rectangle(point_down(rect.tl_corner()), point_down(rect.br_corner()));
        }

        rectangle rect_down (
            const rectangle& rect,
            unsigned int levels
        ) const
        {
            return rectangle(point_down(rect.tl_corner(),levels), point_down(rect.br_corner(),levels));
        }

    // -----------------------------

    private:
        template <typename T, typename U>
        struct both_images_rgb
        {
            const static bool value = pixel_traits<typename T::type>::rgb &&
                                      pixel_traits<typename U::type>::rgb;
        };
    public:

        template <
            typename in_image_type,
            typename out_image_type
            >
        typename disable_if<both_images_rgb<in_image_type,out_image_type> >::type operator() (
            const in_image_type& original,
            out_image_type& down
        ) const
        {
            // make sure requires clause is not broken
            DLIB_ASSERT(original.nr() > 10 && original.nc() > 10 &&
                        is_same_object(original, down) == false, 
                        "\t void pyramid_down_4_3::operator()"
                        << "\n\t original.nr(): " << original.nr()
                        << "\n\t original.nc(): " << original.nc()
                        << "\n\t is_same_object(original, down): " << is_same_object(original, down) 
                        << "\n\t this:                           " << this
                        );

            COMPILE_TIME_ASSERT( pixel_traits<typename in_image_type::type>::has_alpha == false );
            COMPILE_TIME_ASSERT( pixel_traits<typename out_image_type::type>::has_alpha == false );

            const long size_in = 4;
            const long size_out = 3;

            typedef typename pixel_traits<typename in_image_type::type>::basic_pixel_type bp_type;
            typedef typename promote<bp_type>::type ptype;
            down.set_size(size_out*((original.nr()-2)/size_in), size_out*((original.nc()-2)/size_in));


            long rr = 1;
            for (long r = 0; r < down.nr(); r+=size_out)
            {
                long cc = 1;
                for (long c = 0; c < down.nc(); c+=size_out)
                {
                    ptype block[size_in][size_in];
                    separable_3x3_filter_block_grayscale(block, original, rr, cc, 3, 10, 3);

                    // bi-linearly interpolate block 
                    assign_pixel(down[r][c]     , (block[0][0]*25 + block[1][0]*5 + block[0][1]*5 + block[1][1])/(36*256));
                    assign_pixel(down[r][c+1]   , (block[0][1]*5  + block[0][2]*5 + block[1][1]   + block[1][2])/(12*256));
                    assign_pixel(down[r][c+2]   , (block[0][3]*25 + block[1][3]*5 + block[0][2]*5 + block[1][2])/(36*256));

                    assign_pixel(down[r+1][c]   , (block[1][0]*5  + block[2][0]*5 + block[1][1]   + block[2][1])/(12*256));
                    assign_pixel(down[r+1][c+1] , (block[1][1]    + block[1][2]   + block[2][1]   + block[2][2])/(4*256));
                    assign_pixel(down[r+1][c+2] , (block[1][3]*5  + block[2][3]*5 + block[1][2]   + block[2][2])/(12*256));

                    assign_pixel(down[r+2][c]   , (block[3][0]*25 + block[2][0]*5 + block[3][1]*5 + block[2][1])/(36*256));
                    assign_pixel(down[r+2][c+1] , (block[3][1]*5  + block[3][2]*5 + block[2][1]   + block[2][2])/(12*256));
                    assign_pixel(down[r+2][c+2] , (block[3][3]*25 + block[2][3]*5 + block[3][2]*5 + block[2][2])/(36*256));
                    cc += size_in;
                }
                rr += size_in;
            }

        }

    private:
        struct rgbptype 
        {
            uint32 red;
            uint32 green;
            uint32 blue;
        };

    public:
    // ------------------------------------------
    //       OVERLOAD FOR RGB TO RGB IMAGES
    // ------------------------------------------
        template <
            typename in_image_type,
            typename out_image_type
            >
        typename enable_if<both_images_rgb<in_image_type,out_image_type> >::type operator() (
            const in_image_type& original,
            out_image_type& down
        ) const
        {
            // make sure requires clause is not broken
            DLIB_ASSERT(original.nr() > 10 && original.nc() > 10 &&
                        is_same_object(original, down) == false, 
                        "\t void pyramid_down_4_3::operator()"
                        << "\n\t original.nr(): " << original.nr()
                        << "\n\t original.nc(): " << original.nc()
                        << "\n\t is_same_object(original, down): " << is_same_object(original, down) 
                        << "\n\t this:                           " << this
                        );

            COMPILE_TIME_ASSERT( pixel_traits<typename in_image_type::type>::has_alpha == false );
            COMPILE_TIME_ASSERT( pixel_traits<typename out_image_type::type>::has_alpha == false );

            const long size_in = 4;
            const long size_out = 3;

            down.set_size(size_out*((original.nr()-2)/size_in), size_out*((original.nc()-2)/size_in));


            long rr = 1;
            for (long r = 0; r < down.nr(); r+=size_out)
            {
                long cc = 1;
                for (long c = 0; c < down.nc(); c+=size_out)
                {
                    rgbptype block[size_in][size_in];
                    separable_3x3_filter_block_rgb(block, original, rr, cc, 3, 10, 3);

                    // bi-linearly interpolate block 
                    down[r][c].red       = (block[0][0].red*25   + block[1][0].red*5   + block[0][1].red*5   + block[1][1].red  )/(36*256);
                    down[r][c].green     = (block[0][0].green*25 + block[1][0].green*5 + block[0][1].green*5 + block[1][1].green)/(36*256);
                    down[r][c].blue      = (block[0][0].blue*25  + block[1][0].blue*5  + block[0][1].blue*5  + block[1][1].blue )/(36*256);
 
                    down[r][c+1].red     = (block[0][1].red*5    + block[0][2].red*5   + block[1][1].red     + block[1][2].red  )/(12*256);
                    down[r][c+1].green   = (block[0][1].green*5  + block[0][2].green*5 + block[1][1].green   + block[1][2].green)/(12*256);
                    down[r][c+1].blue    = (block[0][1].blue*5   + block[0][2].blue*5  + block[1][1].blue    + block[1][2].blue )/(12*256);

                    down[r][c+2].red     = (block[0][3].red*25   + block[1][3].red*5   + block[0][2].red*5   + block[1][2].red  )/(36*256);
                    down[r][c+2].green   = (block[0][3].green*25 + block[1][3].green*5 + block[0][2].green*5 + block[1][2].green)/(36*256);
                    down[r][c+2].blue    = (block[0][3].blue*25  + block[1][3].blue*5  + block[0][2].blue*5  + block[1][2].blue )/(36*256);

                    down[r+1][c].red     = (block[1][0].red*5    + block[2][0].red*5   + block[1][1].red     + block[2][1].red  )/(12*256);
                    down[r+1][c].green   = (block[1][0].green*5  + block[2][0].green*5 + block[1][1].green   + block[2][1].green)/(12*256);
                    down[r+1][c].blue    = (block[1][0].blue*5   + block[2][0].blue*5  + block[1][1].blue    + block[2][1].blue )/(12*256);
 
                    down[r+1][c+1].red   = (block[1][1].red      + block[1][2].red     + block[2][1].red     + block[2][2].red  )/(4*256);
                    down[r+1][c+1].green = (block[1][1].green    + block[1][2].green   + block[2][1].green   + block[2][2].green)/(4*256);
                    down[r+1][c+1].blue  = (block[1][1].blue     + block[1][2].blue    + block[2][1].blue    + block[2][2].blue )/(4*256);
 
                    down[r+1][c+2].red   = (block[1][3].red*5    + block[2][3].red*5   + block[1][2].red     + block[2][2].red  )/(12*256);
                    down[r+1][c+2].green = (block[1][3].green*5  + block[2][3].green*5 + block[1][2].green   + block[2][2].green)/(12*256);
                    down[r+1][c+2].blue  = (block[1][3].blue*5   + block[2][3].blue*5  + block[1][2].blue    + block[2][2].blue )/(12*256);
 
                    down[r+2][c].red     = (block[3][0].red*25   + block[2][0].red*5   + block[3][1].red*5   + block[2][1].red  )/(36*256);
                    down[r+2][c].green   = (block[3][0].green*25 + block[2][0].green*5 + block[3][1].green*5 + block[2][1].green)/(36*256);
                    down[r+2][c].blue    = (block[3][0].blue*25  + block[2][0].blue*5  + block[3][1].blue*5  + block[2][1].blue )/(36*256);
 
                    down[r+2][c+1].red   = (block[3][1].red*5    + block[3][2].red*5   + block[2][1].red     + block[2][2].red  )/(12*256);
                    down[r+2][c+1].green = (block[3][1].green*5  + block[3][2].green*5 + block[2][1].green   + block[2][2].green)/(12*256);
                    down[r+2][c+1].blue  = (block[3][1].blue*5   + block[3][2].blue*5  + block[2][1].blue    + block[2][2].blue )/(12*256);
 
                    down[r+2][c+2].red   = (block[3][3].red*25   + block[2][3].red*5   + block[3][2].red*5   + block[2][2].red  )/(36*256);
                    down[r+2][c+2].green = (block[3][3].green*25 + block[2][3].green*5 + block[3][2].green*5 + block[2][2].green)/(36*256);
                    down[r+2][c+2].blue  = (block[3][3].blue*25  + block[2][3].blue*5  + block[3][2].blue*5  + block[2][2].blue )/(36*256);
 
                    cc += size_in;
                }
                rr += size_in;
            }
        }

    private:


    };

// ----------------------------------------------------------------------------------------
// ----------------------------------------------------------------------------------------
// ----------------------------------------------------------------------------------------

    class pyramid_down_5_4 : noncopyable
    {
    public:

        template <typename T>
        vector<double,2> point_down (
            const vector<T,2>& p
        ) const
        {
            const double ratio = 4.0/5.0;
            //do return (p - vector<T,2>(1,1))*ratio;
            return p*ratio - vector<double,2>(ratio,ratio);
        }

        template <typename T>
        vector<double,2> point_up (
            const vector<T,2>& p
        ) const
        {
            const double ratio = 5.0/4.0;
            return p*ratio + vector<T,2>(1,1);
        }

    // -----------------------------

        template <typename T>
        vector<double,2> point_down (
            const vector<T,2>& p,
            unsigned int levels
        ) const
        {
            vector<double,2> temp = p;
            for (unsigned int i = 0; i < levels; ++i)
                temp = point_down(temp);
            return temp;
        }

        template <typename T>
        vector<double,2> point_up (
            const vector<T,2>& p,
            unsigned int levels
        ) const
        {
            vector<double,2> temp = p;
            for (unsigned int i = 0; i < levels; ++i)
                temp = point_up(temp);
            return temp;
        }

    // -----------------------------

        rectangle rect_up (
            const rectangle& rect
        ) const
        {
            return rectangle(point_up(rect.tl_corner()), point_up(rect.br_corner()));
        }

        rectangle rect_up (
            const rectangle& rect,
            unsigned int levels
        ) const
        {
            return rectangle(point_up(rect.tl_corner(),levels), point_up(rect.br_corner(),levels));
        }

    // -----------------------------

        rectangle rect_down (
            const rectangle& rect
        ) const
        {
            return rectangle(point_down(rect.tl_corner()), point_down(rect.br_corner()));
        }

        rectangle rect_down (
            const rectangle& rect,
            unsigned int levels
        ) const
        {
            return rectangle(point_down(rect.tl_corner(),levels), point_down(rect.br_corner(),levels));
        }

    // -----------------------------

    private:
        template <typename T, typename U>
        struct both_images_rgb
        {
            const static bool value = pixel_traits<typename T::type>::rgb &&
                                      pixel_traits<typename U::type>::rgb;
        };
    public:

        template <
            typename in_image_type,
            typename out_image_type
            >
        typename disable_if<both_images_rgb<in_image_type,out_image_type> >::type operator() (
            const in_image_type& original,
            out_image_type& down
        ) const
        {
            // make sure requires clause is not broken
            DLIB_ASSERT(original.nr() > 10 && original.nc() > 10 &&
                        is_same_object(original, down) == false, 
                        "\t void pyramid_down_5_4::operator()"
                        << "\n\t original.nr(): " << original.nr()
                        << "\n\t original.nc(): " << original.nc()
                        << "\n\t is_same_object(original, down): " << is_same_object(original, down) 
                        << "\n\t this:                           " << this
                        );

            COMPILE_TIME_ASSERT( pixel_traits<typename in_image_type::type>::has_alpha == false );
            COMPILE_TIME_ASSERT( pixel_traits<typename out_image_type::type>::has_alpha == false );

            const long size_in = 5;
            const long size_out = 4;

            typedef typename pixel_traits<typename in_image_type::type>::basic_pixel_type bp_type;
            typedef typename promote<bp_type>::type ptype;
            down.set_size(size_out*((original.nr()-2)/size_in), size_out*((original.nc()-2)/size_in));


            long rr = 1;
            for (long r = 0; r < down.nr(); r+=size_out)
            {
                long cc = 1;
                for (long c = 0; c < down.nc(); c+=size_out)
                {
                    ptype block[size_in][size_in];
                    separable_3x3_filter_block_grayscale(block, original, rr, cc, 3, 10, 3);

                    // bi-linearly interpolate block 
                    assign_pixel(down[r][c]     , (block[0][0]*49 + block[1][0]*7  + block[0][1]*7 + block[1][1]    )/(64*256));
                    assign_pixel(down[r][c+1]   , (block[0][1]*35 + block[0][2]*21 + block[1][1]*5 + block[1][2]*3  )/(64*256));
                    assign_pixel(down[r][c+2]   , (block[0][3]*35 + block[0][2]*21 + block[1][3]*5 + block[1][2]*3  )/(64*256));
                    assign_pixel(down[r][c+3]   , (block[0][4]*49 + block[0][3]*7  + block[1][4]*7 + block[1][3]    )/(64*256));

                    assign_pixel(down[r+1][c]   , (block[1][0]*35 + block[1][1]*5  + block[2][0]*21 + block[1][1]*3 )/(64*256));
                    assign_pixel(down[r+1][c+1] , (block[1][1]*25 + block[1][2]*15 + block[2][1]*15 + block[2][2]*9 )/(64*256));
                    assign_pixel(down[r+1][c+2] , (block[1][2]*15 + block[1][3]*25 + block[2][2]*9  + block[2][3]*15)/(64*256));
                    assign_pixel(down[r+1][c+3] , (block[1][3]*5  + block[1][4]*35 + block[2][3]*3  + block[2][4]*21)/(64*256));

                    assign_pixel(down[r+2][c]   , (block[3][0]*35 + block[3][1]*5  + block[2][0]*21 + block[1][1]*3 )/(64*256));
                    assign_pixel(down[r+2][c+1] , (block[3][1]*25 + block[3][2]*15 + block[2][1]*15 + block[2][2]*9 )/(64*256));
                    assign_pixel(down[r+2][c+2] , (block[3][2]*15 + block[3][3]*25 + block[2][2]*9  + block[2][3]*15)/(64*256));
                    assign_pixel(down[r+2][c+3] , (block[3][3]*5  + block[3][4]*35 + block[2][3]*3  + block[2][4]*21)/(64*256));

                    assign_pixel(down[r+3][c]   , (block[4][0]*49 + block[3][0]*7  + block[4][1]*7 + block[3][1]    )/(64*256));
                    assign_pixel(down[r+3][c+1] , (block[4][1]*35 + block[4][2]*21 + block[3][1]*5 + block[3][2]*3  )/(64*256));
                    assign_pixel(down[r+3][c+2] , (block[4][3]*35 + block[4][2]*21 + block[3][3]*5 + block[3][2]*3  )/(64*256));
                    assign_pixel(down[r+3][c+3] , (block[4][4]*49 + block[4][3]*7  + block[3][4]*7 + block[3][3]    )/(64*256));

                    cc += size_in;
                }
                rr += size_in;
            }

        }

    private:
        struct rgbptype 
        {
            uint32 red;
            uint32 green;
            uint32 blue;
        };

    public:
    // ------------------------------------------
    //       OVERLOAD FOR RGB TO RGB IMAGES
    // ------------------------------------------
        template <
            typename in_image_type,
            typename out_image_type
            >
        typename enable_if<both_images_rgb<in_image_type,out_image_type> >::type operator() (
            const in_image_type& original,
            out_image_type& down
        ) const
        {
            // make sure requires clause is not broken
            DLIB_ASSERT(original.nr() > 10 && original.nc() > 10 &&
                        is_same_object(original, down) == false, 
                        "\t void pyramid_down_5_4::operator()"
                        << "\n\t original.nr(): " << original.nr()
                        << "\n\t original.nc(): " << original.nc()
                        << "\n\t is_same_object(original, down): " << is_same_object(original, down) 
                        << "\n\t this:                           " << this
                        );

            COMPILE_TIME_ASSERT( pixel_traits<typename in_image_type::type>::has_alpha == false );
            COMPILE_TIME_ASSERT( pixel_traits<typename out_image_type::type>::has_alpha == false );

            const long size_in = 5;
            const long size_out = 4;

            down.set_size(size_out*((original.nr()-2)/size_in), size_out*((original.nc()-2)/size_in));


            long rr = 1;
            for (long r = 0; r < down.nr(); r+=size_out)
            {
                long cc = 1;
                for (long c = 0; c < down.nc(); c+=size_out)
                {
                    rgbptype block[size_in][size_in];
                    separable_3x3_filter_block_rgb(block, original, rr, cc, 3, 10, 3);

                    // bi-linearly interpolate block 
                    down[r][c].red       = (block[0][0].red*49   + block[1][0].red*7    + block[0][1].red*7    + block[1][1].red     )/(64*256);
                    down[r][c].green     = (block[0][0].green*49 + block[1][0].green*7  + block[0][1].green*7  + block[1][1].green   )/(64*256);
                    down[r][c].blue      = (block[0][0].blue*49  + block[1][0].blue*7   + block[0][1].blue*7   + block[1][1].blue    )/(64*256);

                    down[r][c+1].red     = (block[0][1].red*35   + block[0][2].red*21   + block[1][1].red*5    + block[1][2].red*3   )/(64*256);
                    down[r][c+1].green   = (block[0][1].green*35 + block[0][2].green*21 + block[1][1].green*5  + block[1][2].green*3 )/(64*256);
                    down[r][c+1].blue    = (block[0][1].blue*35  + block[0][2].blue*21  + block[1][1].blue*5   + block[1][2].blue*3  )/(64*256);

                    down[r][c+2].red     = (block[0][3].red*35   + block[0][2].red*21   + block[1][3].red*5    + block[1][2].red*3   )/(64*256);
                    down[r][c+2].green   = (block[0][3].green*35 + block[0][2].green*21 + block[1][3].green*5  + block[1][2].green*3 )/(64*256);
                    down[r][c+2].blue    = (block[0][3].blue*35  + block[0][2].blue*21  + block[1][3].blue*5   + block[1][2].blue*3  )/(64*256);

                    down[r][c+3].red     = (block[0][4].red*49   + block[0][3].red*7    + block[1][4].red*7    + block[1][3].red     )/(64*256);
                    down[r][c+3].green   = (block[0][4].green*49 + block[0][3].green*7  + block[1][4].green*7  + block[1][3].green   )/(64*256);
                    down[r][c+3].blue    = (block[0][4].blue*49  + block[0][3].blue*7   + block[1][4].blue*7   + block[1][3].blue    )/(64*256);

                    down[r+1][c].red     = (block[1][0].red*35   + block[1][1].red*5    + block[2][0].red*21   + block[1][1].red*3   )/(64*256);
                    down[r+1][c].green   = (block[1][0].green*35 + block[1][1].green*5  + block[2][0].green*21 + block[1][1].green*3 )/(64*256);
                    down[r+1][c].blue    = (block[1][0].blue*35  + block[1][1].blue*5   + block[2][0].blue*21  + block[1][1].blue*3  )/(64*256);

                    down[r+1][c+1].red   = (block[1][1].red*25   + block[1][2].red*15   + block[2][1].red*15   + block[2][2].red*9   )/(64*256);
                    down[r+1][c+1].green = (block[1][1].green*25 + block[1][2].green*15 + block[2][1].green*15 + block[2][2].green*9 )/(64*256);
                    down[r+1][c+1].blue  = (block[1][1].blue*25  + block[1][2].blue*15  + block[2][1].blue*15  + block[2][2].blue*9  )/(64*256);

                    down[r+1][c+2].red   = (block[1][2].red*15   + block[1][3].red*25   + block[2][2].red*9    + block[2][3].red*15  )/(64*256);
                    down[r+1][c+2].green = (block[1][2].green*15 + block[1][3].green*25 + block[2][2].green*9  + block[2][3].green*15)/(64*256);
                    down[r+1][c+2].blue  = (block[1][2].blue*15  + block[1][3].blue*25  + block[2][2].blue*9   + block[2][3].blue*15 )/(64*256);

                    down[r+1][c+3].red   = (block[1][3].red*5    + block[1][4].red*35   + block[2][3].red*3    + block[2][4].red*21  )/(64*256);
                    down[r+1][c+3].green = (block[1][3].green*5  + block[1][4].green*35 + block[2][3].green*3  + block[2][4].green*21)/(64*256);
                    down[r+1][c+3].blue  = (block[1][3].blue*5   + block[1][4].blue*35  + block[2][3].blue*3   + block[2][4].blue*21 )/(64*256);

                    down[r+2][c].red     = (block[3][0].red*35   + block[3][1].red*5    + block[2][0].red*21   + block[1][1].red*3   )/(64*256);
                    down[r+2][c].green   = (block[3][0].green*35 + block[3][1].green*5  + block[2][0].green*21 + block[1][1].green*3 )/(64*256);
                    down[r+2][c].blue    = (block[3][0].blue*35  + block[3][1].blue*5   + block[2][0].blue*21  + block[1][1].blue*3  )/(64*256);

                    down[r+2][c+1].red   = (block[3][1].red*25   + block[3][2].red*15   + block[2][1].red*15   + block[2][2].red*9   )/(64*256);
                    down[r+2][c+1].green = (block[3][1].green*25 + block[3][2].green*15 + block[2][1].green*15 + block[2][2].green*9 )/(64*256);
                    down[r+2][c+1].blue  = (block[3][1].blue*25  + block[3][2].blue*15  + block[2][1].blue*15  + block[2][2].blue*9  )/(64*256);

                    down[r+2][c+2].red   = (block[3][2].red*15   + block[3][3].red*25   + block[2][2].red*9    + block[2][3].red*15  )/(64*256);
                    down[r+2][c+2].green = (block[3][2].green*15 + block[3][3].green*25 + block[2][2].green*9  + block[2][3].green*15)/(64*256);
                    down[r+2][c+2].blue  = (block[3][2].blue*15  + block[3][3].blue*25  + block[2][2].blue*9   + block[2][3].blue*15 )/(64*256);

                    down[r+2][c+3].red   = (block[3][3].red*5    + block[3][4].red*35   + block[2][3].red*3    + block[2][4].red*21  )/(64*256);
                    down[r+2][c+3].green = (block[3][3].green*5  + block[3][4].green*35 + block[2][3].green*3  + block[2][4].green*21)/(64*256);
                    down[r+2][c+3].blue  = (block[3][3].blue*5   + block[3][4].blue*35  + block[2][3].blue*3   + block[2][4].blue*21 )/(64*256);

                    down[r+3][c].red     = (block[4][0].red*49   + block[3][0].red*7    + block[4][1].red*7   + block[3][1].red      )/(64*256);
                    down[r+3][c].green   = (block[4][0].green*49 + block[3][0].green*7  + block[4][1].green*7 + block[3][1].green    )/(64*256);
                    down[r+3][c].blue    = (block[4][0].blue*49  + block[3][0].blue*7   + block[4][1].blue*7  + block[3][1].blue     )/(64*256);

                    down[r+3][c+1].red   = (block[4][1].red*35   + block[4][2].red*21   + block[3][1].red*5   + block[3][2].red*3    )/(64*256);
                    down[r+3][c+1].green = (block[4][1].green*35 + block[4][2].green*21 + block[3][1].green*5 + block[3][2].green*3  )/(64*256);
                    down[r+3][c+1].blue  = (block[4][1].blue*35  + block[4][2].blue*21  + block[3][1].blue*5  + block[3][2].blue*3   )/(64*256);

                    down[r+3][c+2].red   = (block[4][3].red*35   + block[4][2].red*21   + block[3][3].red*5   + block[3][2].red*3    )/(64*256);
                    down[r+3][c+2].green = (block[4][3].green*35 + block[4][2].green*21 + block[3][3].green*5 + block[3][2].green*3  )/(64*256);
                    down[r+3][c+2].blue  = (block[4][3].blue*35  + block[4][2].blue*21  + block[3][3].blue*5  + block[3][2].blue*3   )/(64*256);

                    down[r+3][c+3].red   = (block[4][4].red*49   + block[4][3].red*7    + block[3][4].red*7   + block[3][3].red      )/(64*256);
                    down[r+3][c+3].green = (block[4][4].green*49 + block[4][3].green*7  + block[3][4].green*7 + block[3][3].green    )/(64*256);
                    down[r+3][c+3].blue  = (block[4][4].blue*49  + block[4][3].blue*7   + block[3][4].blue*7  + block[3][3].blue     )/(64*256);

 
                    cc += size_in;
                }
                rr += size_in;
            }
        }

    private:


    };

// ----------------------------------------------------------------------------------------
// ----------------------------------------------------------------------------------------
// ----------------------------------------------------------------------------------------

}

#endif // DLIB_IMAGE_PYRaMID_H__

