sequencestart(titlestr)

function sequencestart(titlestr)
% SEQUENCESTART(TITLE) - Create a sequence diagram figure window.
%
% Any sequence diagram routine must start with this function.
%
% See Also: SEQUENCEADDLINK, SEQUENCERETURNLINK, SEQUENCEDTORNODE
    
% Author: Eric Ludlam
% Copyright (c) 2006 The MathWorks Inc.

    SD.fig = figure;
    SD.ax = axes;
    
    if nargin == 0
        title('Sequence Diagram')
    else
        title(titlestr);
    end
    
    ylabel('<--- Time');
    xlabel('Location');
    
    set(SD.ax,'ydir','reverse');
    
    % SEQUENCE DATA STRUCTURE SETUP
    
    SD.nodes = [];
    SD.links = [];
    
    % SAVE DATA
    
    setappdata(SD.fig,'SD',SD);