%% TDS3000 MATLAB ICT Get Screen 1
% Get a copy of the screen in PNG format.

%% variables
serial_port = 'com1';
buffer = 2 * 1024;
target_path = 'c:\';
target_name = 'tds_screen.png';
lf = 10; % ASCII linefeed, used to terminate commands

%% instrument communication
tds = serial(serial_port, 'InputBufferSize', buffer, ...
    'OutputBufferSize', buffer);
fopen(tds);

% Because no handshaking takes place (?), RequestToSend must be set 
% manually after opening.  The instrument will not reply otherwise.
set(tds, 'RequestToSend', 'on'); 

% configure instrument for screen capture
fwrite(tds, [':hardc:form png;inks 0;port rs232;' lf]);

% initialize data variable
binary = uint8(''); 

% begin data transfer
fwrite(tds, [':hardc star;' lf]);
pause(1);

% read loop
while get(tds, 'BytesAvailable') > 0,
    a = get(tds, 'BytesAvailable');
    binary = [binary; fread(tds, a)];
    pause(1);
end

% close connection with instrument
fclose(tds);
delete(tds);
clear tds;

%% save image data to file
% create (or overwrite) file
my_file = fopen([target_path target_name], 'w');
% write to file
fwrite(my_file, binary);
% close file
fclose(my_file);

%% notes
%{
% Variable "binary" is of dynamic size because the image data transfer 
% begins without any metadata of the size.  MATLAB complains about dynamic 
% variables but there isn't really much you can do about it.  It's small 
% enough that I do not notice any performance degradation.  Variable 
% "buffer" can also be increased to accommodate image data within one read 
% as well.
%
%}