function [mat2]=halftone_color (type,mat,thresh,nois,serp,BNM_size,sharp)
switch type
case 1
    mat2=(mat>thresh);
case 2
    white=round(255*rand(size(mat,1),size(mat,2),3));
    h=fspecial('lagrangian');
    m = conv2(mat(:,:,1),h);
    m=m(2:size(m)-1,2:size(m)-1);
    mat(:,:,1)=mat(:,:,1)-sharp*m;
    mat(:,:,1)=max(0,min(255,mat(:,:,1)));
    m = conv2(mat(:,:,2),h);
    m=m(2:size(m)-1,2:size(m)-1);
    mat(:,:,2)=mat(:,:,2)-sharp*m;
    mat(:,:,2)=max(0,min(255,mat(:,:,2)));
    m = conv2(mat(:,:,3),h);
    m=m(2:size(m)-1,2:size(m)-1);
    mat(:,:,3)=mat(:,:,3)-sharp*m;
    mat(:,:,3)=max(0,min(255,mat(:,:,3)));
    mat2=(mat>white);
case 3
    template=[[13 11 12 15];[4 3 2 9];[5 0 1 10];[8 6 7 14]];
    template=[template (31-template)];
    template=[template;(31-template)];
    mat2(:,:,1)=temp(template,mat(:,:,1));
    mat2(:,:,2)=temp(template,mat(:,:,2));
    mat2(:,:,3)=temp(template,mat(:,:,3));
case 4
    template=[[0 14 3 13];[8 4 11 7];[2 12 1 15];[10 6 9 5]];
    mat2(:,:,1)=temp(template,mat(:,:,1));
    mat2(:,:,2)=temp(template,mat(:,:,2));
    mat2(:,:,3)=temp(template,mat(:,:,3));
case 5
    mat2(:,:,1)=err_diff(mat(:,:,1),thresh,nois,serp);
    mat2(:,:,2)=err_diff(mat(:,:,2),thresh,nois,serp);
    mat2(:,:,3)=err_diff(mat(:,:,3),thresh,nois,serp);
case 6
    Jarvis = [0 0 0 7 5;3 5 7 5 3;1 3 5 3 1];
    Jarvis = Jarvis/sum(sum(Jarvis));
    mat2(:,:,1)=FloydSteinberg(Jarvis,thresh,mat(:,:,1)/255,nois);
    mat2(:,:,2)=FloydSteinberg(Jarvis,thresh,mat(:,:,2)/255,nois);
    mat2(:,:,3)=FloydSteinberg(Jarvis,thresh,mat(:,:,3)/255,nois);
case 7
    mat2=halftone_color(4,mat,thresh,nois,serp);
    mat2(:,:,1)=lsmb(mat2(:,:,1),mat(:,:,1));
    mat2(:,:,2)=lsmb(mat2(:,:,1),mat(:,:,2));
    mat2(:,:,3)=lsmb(mat2(:,:,1),mat(:,:,3));
case 8
    mat2=halftone_color_visual(1,mat,thresh,nois,serp,BNM_size,sharp);
case 9
    mat2 = halftone_color_visual(5,mat,thresh,nois,serp,BNM_size,sharp);
case 10
    vc=process(BNM_size);
    h=fspecial('lagrangian');
    m = conv2(mat(:,:,1),h);
    m=m(2:size(m)-1,2:size(m)-1);
    mat(:,:,1)=mat(:,:,1)-sharp*m;
    mat(:,:,1)=max(0,min(255,mat(:,:,1)));
    mat2(:,:,1)=temp(vc,mat(:,:,1));
    vc=process(BNM_size);
    m = conv2(mat(:,:,2),h);
    m=m(2:size(m)-1,2:size(m)-1);
    mat(:,:,2)=mat(:,:,2)-sharp*m;
    mat(:,:,2)=max(0,min(255,mat(:,:,2)));
    mat2(:,:,2)=temp(vc,mat(:,:,2));
    vc=process(BNM_size);
    m = conv2(mat(:,:,3),h);
    m=m(2:size(m)-1,2:size(m)-1);
    mat(:,:,3)=mat(:,:,3)-sharp*m;
    mat(:,:,3)=max(0,min(255,mat(:,:,3)));
    mat2(:,:,3)=temp(vc,mat(:,:,3));
case 11
    mat2=halftone_color_visual(3,mat,thresh,nois,serp,BNM_size,sharp);
otherwise
    mat2=mat;
end

function [mat2]=temp (template,mat)

% nice tricks played so that one can provide template and images with any sizes
% and it will still works its way out
[b1 b2]=size(template);
[l1 l2]=size(mat);
mat0=mat;
mat=zeros(b1*ceil(l1/b1),b2*ceil(l2/b2));
mat(1:l1,1:l2)=mat0;
x=max(max(template));
for i=1:ceil(l1/b1)
    for j=1:ceil(l2/b2)
        mat2(((i-1)*b1+1):(i*b1),((j-1)*b2+1):(j*b2))=(mat(((i-1)*b1+1):(i*b1),((j-1)*b2+1):(j*b2))>((template+1/2/255*(x<1)+1/2*(x>=1))*255/x));
    end
end
mat2=mat2(1:l1,1:l2);


function [mat2]=err_diff(mat,thresh,nois,serp)
[l1,l2]=size(mat);
%serpentine order
mat0=zeros(l1+2,l2+2);
mat0(2:(l1+1),2:(l2+1))=mat;
err=mat0;
mat2=mat0;
if nois
    noise=rand(l1,l2)-1/2;
else
    noise=zeros(l1,l2);
end
a=7/16*(1+noise);
b=1/16*(1+fliplr(noise));
c=5/16*(1+flipud(noise));
d=3/16*(1+fliplr(flipud(noise)));

for i=2:(l1+1)
    if (2*floor(i/2)==i)|(~serp)
        for j=2:(l2+1)
            mat0(i,j)=mat0(i,j)+a(i-1,j-1)*err(i,j-1)+b(i-1,j-1)*err(i-1,j-1)+c(i-1,j-1)*err(i-1,j)+d(i-1,j-1)*err(i-1,j+1);
            mat2(i-1,j-1)=mat0(i,j)>thresh;
            err(i,j)=mat0(i,j)-mat2(i-1,j-1)*255;
        end
    else
        for j=(l2+1):-1:2
            mat0(i,j)=mat0(i,j)+a(i-1,j-1)*err(i,j+1)+b(i-1,j-1)*err(i-1,j+1)+c(i-1,j-1)*err(i-1,j)+d(i-1,j-1)*err(i-1,j-1);
            mat2(i-1,j-1)=mat0(i,j)>thresh;
            err(i,j)=mat0(i,j)-mat2(i-1,j-1)*255;
        end
    end
end
mat2=mat2(1:l1,1:l2);