function compress_image()
    %Read Image
    A = imread('test1.jpg');

    %Get Each Channel
    redChannel = A(:,:,1);
    greenChannel=A(:,:,2);
    blueChannel=A(:,:,3);
    heightImage=size(A,1)
    widthImage=size(A,2)

    %Loop through the image
    for i=1:size(A,1)
        for j=1:size(A,2)
            %get the pixel 3 values
            red = double(redChannel(i,j));
            green = double(greenChannel(i,j));
            blue = double(blueChannel(i,j));

            %|------|--------|
            %| A    |  C     |
            %| B    |  X     |
            %|---------------|
            %we want to get predicative value for x ,if we r in the first row we will use the equation that x=A
            %if we are in the first column ,we use the equation that x=B
            %else we use the equation that x=(A+b)/2;

            %check if we r in the first pixel,we will use X=X
            if (i==1)&&(j==1)
                red= redChannel(i,j);
                green = greenChannel(i,j);
                blue = blueChannel(i,j);
            %check if we r in the first row,we will use X=A
            elseif i==1
                red= redChannel(i,j-1);
                green = greenChannel(i,j-1);
                blue = blueChannel(i,j-1);
            %check if we r in the first row,we will use X=B
            elseif j==1
                red= redChannel(i-1,j);
                green = greenChannel(i-1,j);
                blue = blueChannel(i-1,j);
            %Else we will use the equation ,we will use X=(A+B)/2;
            else
                red1= redChannel(i,j-1);
                red2= redChannel(i-1,j);
                green1= greenChannel(i,j-1);
                green2= greenChannel(i-1,j);
                blue1= blueChannel(i,j-1);
                blue2= blueChannel(i-1,j);
                red =(red1+red2)/2;
                green =(green1+green2)/2;
                blue =(blue1+blue2)/2;
            end
            redChannel(i,j)= red;
            blueChannel(i,j)= blue;
            greenChannel(i,j)= green;
        end
    end

    %Now we need to get the difference between the original image and predicative image
    redChannel2 = A(:,:,1);
    greenChannel2 = A(:,:,2);
    blueChannel2 = A(:,:,3);
    for i=1:size(A,1)
        for j=1:size(A,2)
            %get difference between each pixel
            diff1= redChannel2(i,j)- redChannel(i,j);
            diff2= greenChannel2(i,j)- greenChannel(i,j);
            diff3= blueChannel2(i,j)- blueChannel(i,j);
            %Edit the channels with the difference.
            redChannel2(i,j)= diff1;
            greenChannel2(i,j)= diff2;
            blueChannel2(i,j)= diff3;
        end
    end
    %Edit the original image with difference values to work on HUFFMAN on it.
    A(:,:,1) = redChannel2;
    A(:,:,2) = greenChannel2;
    A(:,:,3) = blueChannel2;
    %imwrite(A,'test1.jpg');

    %-----------------------------------------------------------------------------------------
    %read image
    %imhuff=imread('test1.jpg');
    %imhuff=double(imhuff);
    imhuff = A;

    frequency=zeros(1,256);
    %frequency=zeros(1,511);
    for i=1:size(imhuff,1)
        for j=1:size(imhuff,2)
            frequency(imhuff(i,j)+1)=(frequency(imhuff(i,j)+1))+1;
            %frequency(imhuff(i,j)+256)=(frequency(imhuff(i,j)+256))+1;
        end
    end
    %get probabilities
    probabilities = frequency./sum(frequency);
    symbols = 0:255;
    %symbols = -255:255;
    set(0,'RecursionLimit',520);

%-----------------------------------------------------------------------------------------
    % Create Huffman tree
    for l=1:length(symbols)       % create a vector of nodes (leaves), one for each letter
        leaves(l).val = symbols(l);
        leaves(l).zero= '';
        leaves(l).one='';
        leaves(l).prob = probabilities(l);
    end

    % combine the two nodes with lowest probability to a new node with the summed prob.
    % repeat until only one node is left
    while length(leaves)>1
        [~,I]=sort(probabilities);
        probabilities = [probabilities(I(1))+probabilities(I(2)) probabilities(I(3:end))];
        node.zero = leaves(I(1));
        node.one  = leaves(I(2));
        node.prob = probabilities(1);
        node.val = '';
        leaves = [node leaves(I(3:end))];
    end

    % pass through the tree,
    % remove unnecessary information
    % and create table recursively (depth first)
    table.val={}; table.code={};
    [tree,table] = descend(leaves(1),table,'');

%-----------------------------------------------------------------------------------------
    %Compress (Encode) RGB Channels:
    input_R = redChannel2(:);
    input_G = greenChannel2(:);
    input_B = blueChannel2(:);
    compressed_R = '';
    for l=1:length(input_R),
        compressed_R = strcat(compressed_R,table.code(ismember(cell2mat(table.val),input_R(l))));
    end
    compressed_R = char(compressed_R);

    compressed_G = '';
    for l=1:length(input_G),
        compressed_G = strcat(compressed_G,table.code(ismember(cell2mat(table.val),input_G(l))));
    end
    compressed_G = char(compressed_G);

    compressed_B = '';
    for l=1:length(input_B),
        compressed_B = strcat(compressed_B,table.code(ismember(cell2mat(table.val),input_B(l))));
    end
    compressed_B = char(compressed_B);

%-----------------------------------------------------------------------------------------
    %Calculate Compression Ratio
     % Red Channel:
     [hb,wb] = size(dec2bin(redChannel2));
     before = hb*wb;
     [ha,wa] = size(compressed_R);
     after = ha*wa;
     CR_Red = before/after;
     % Green Channel:
     [hb,wb] = size(dec2bin(greenChannel2));
     before = hb*wb;
     [ha,wa] = size(compressed_G);
     after = ha*wa;
     CR_Green = before/after;
     % Blue Channel:
     [hb,wb] = size(dec2bin(blueChannel2));
     before = hb*wb;
     [ha,wa] = size(compressed_B);
     after = ha*wa;
     CR_Blue = before/after;

     %Display
     disp(['The Huffman coding rate (Red):                ',num2str(CR_Red)]);
     disp(['The Huffman coding rate (Green):                ',num2str(CR_Green)]);
     disp(['The Huffman coding rate (Blue):                ',num2str(CR_Blue)]);

decoded_img={};
[decoded_img] = decode_tree(tree,compressed_R);
size(decoded_img)
B = reshape(decoded_img,[heightImage,widthImage]);
%K = mat2gray(B);
%imshow(K)
end


 %-----------------------------------------------------------------------------------------
function [tree, table] = descend(oldtree, oldtable, code)
    table = oldtable;
    if(~isempty(oldtree.val))
        tree.val = oldtree.val;
        table.val{end+1}  = oldtree.val;
        table.code{end+1} = code;
    else
        [tree0, table] = descend(oldtree.zero, table, strcat(code,'0'));
        [tree1, table] = descend(oldtree.one,  table, strcat(code,'1'));
        tree.zero=tree0;
        tree.one= tree1;
    end
end


function [decoded_img]=decode_tree(tree,compressed_R)
        tempTree=tree;
        n=1;

        for i=1:length(compressed_R)
                if(~isempty(tempTree))
                        decoded_img(n)=tempTree;
                        n=n+1;
                        tempTree=tree;
                end

                if(compressed_R(i)==0)
                        tempTree=tempTree.zero;
                else
                        tempTree=tempTree.one;
                end
        end