Code not working. I need to move the image blocks by swapping cell's position inside the main image matrix. Help?

clc;clear;close all;warning off;
imdata = imread('check.jpg');
new_dims = size(imdata) - rem(size(imdata), 3);
imdata = imdata(1:new_dims(1),1:new_dims(2), :);
figure(1)

image(imdata)
text(100,300,'You Have40 Secs To Solve it !','FontSize',14,'Color','y');
text(150,350,'Use Arrow Keys : ','FontSize',14,'Color','y');
text(295,400,'\uparrow','FontSize',20,'Color','y','FontWeight','Bold'); 
text(225,450,'\leftarrow   \downarrow   \rightarrow','FontSize',20,'Color','y','FontWeight','Bold'); 
pause(3)
%%Arrange into 3x3 cell
block_dims = new_dims./[3 3 1];
blocks = mat2cell(imdata, block_dims(1)*ones(3,1), block_dims(2)*ones(3,1), block_dims(3));
%blacking the 9th image first
blocks(9) = {zeros(block_dims, class(imdata))};

%%Rearrange randomly
blocks(1:9) = blocks(randperm(9));
%%Set one block to zero
%
%blocks(3) = {zeros(block_dims, class(imdata))};
%%Return to image
puzzle = cell2mat(blocks);
disp(blocks)
%%Plot input and output
figure(2)
subplot(2,1,1), image(puzzle), axis equal;
%subplot(2,1,2),implay(timer_examp()), axis equal;
%truesize
k=index(cell{blocks(9)})% i am just trying to index a cell

pause(3)
%*      bold*timer_examp()
%play
tic
move = 0;k = ind(blocks(9))
while ~isequal(puzzle,[1:3;4:6;7:9])
    move= move+1;
    m=waitforbuttonpress;
     key = get(gcf,'CurrentKey');
   % only works for keyboardinput if m==0
; %if it doesn't works then try find (blocks==9)

          if strcmp(key,'uparrow')
           blocks{k}=blocks{k-1};
          elseif strcmp(key,'leftarrow')&& (k>3)
                  blocks(k) =blocks(k-3);
          elseif strcmp(key,'rightarrow')&&(k<3)
              blocks(k)= blocks(k+3);
          elseif strcmp(key,'downarrow')
              blocks(k) = blocks(k+3);
          else
              blocks(k)
          end
  end

[Walter Roberson]

What error are you encountering ?

[Zurez]

I hope that by now , you have understood that half of the code generates a scrambled image/ now I want the user to solve the image puzzle. Now whenever a user should press an arrow key/ let say suppose the uparrow , the black block of the image puzzle should move up. That can only happen if i swap the black cell with the picture block cell above it... I am just not able to do that. Also I want a timer to run , just below the image frame. timer_examp is the timer function.

Answer 1

[Walter Roberson]

other_k = k - 1;
blocks([k other_k]) = blocks([other_k k]);

[Zurez]

Thank you so much for the information. Now the code works if I give key a fixed value... say 9. but I want k to automatically get the index value of the blackened cell. Can you help me on that??

[Walter Roberson]

What is ind() ? And how could your present code not be giving error messages, considering that you already used k-1 ?

[Zurez]

clc;clear;close all;warning off; imdata = imread('check.jpg'); new_dims = size(imdata) - rem(size(imdata), 3); imdata = imdata(1:new_dims(1),1:new_dims(2), :);

%% Arrange into 3x3 cell block_dims = new_dims./[3 3 1]; blocks = mat2cell(imdata, block_dims(1)*ones(3,1), block_dims(2)*ones(3,1), block_dims(3)); %blacking the 9th image first blocks(9) = {zeros(block_dims, class(imdata))}; % this has become iirelevnet now :p a=blocks;

%% Rearrange randomly blocks(1:9) = blocks(randperm(9)); %% Set one block to zero % %blocks(3) = {zeros(block_dims, class(imdata))}; %% Return to image puzzle = cell2mat(blocks); disp(blocks) %% Plot input and output figure(2) image(puzzle);

k=9% i am just trying give a value to 9

move = 0; while ~isequal(puzzle,[1:3;4:6;7:9]) move= move+1; m=waitforbuttonpress; key = get(gcf,'CurrentKey');

        if strcmp(key,'uparrow')
            other_k = k - 1;
blocks([k other_k]) = blocks([other_k k]);
puzzle = cell2mat(blocks);
image(puzzle);

         %blocks(k)=blocks(k-1);
        elseif strcmp(key,'leftarrow')
                other_k = k - 3;
blocks([k other_k]) = blocks([other_k k]);
puzzle = cell2mat(blocks);
image(puzzle);
  disp(key)
        elseif strcmp(key,'rightarrow')
            other_k = k +3;
blocks([k other_k]) = blocks([other_k k]);
puzzle = cell2mat(blocks);
image(puzzle);
  disp(key)
          %  blocks(k)= blocks(k+3);
        elseif strcmp(key,'downarrow')
            other_k = k + 1;
blocks([k other_k]) = blocks([other_k k]);
puzzle = cell2mat(blocks);
image(puzzle);disp(key)

        else
            blocks(k)
            puzzle = cell2mat(blocks);
image(puzzle);

        end
end

[Zurez]

The above is my updated code. I have remove or commented out what I don't need. The value of the blackened block should change every time. And therefore the value of k should also change. How should I do that?