function legTrackerEthogram(trans)
%legTrackerEthogram constructs ethograms given a transition matrix, as in
%figure 3d of Kain et al.
%Usage:
%legTrackerEthogram(trans)
%trans = 12x12 transition matrix generated from a sequence of behavioral
%      labels.

%make a list of nice positions for each behavioral node
nodePos=[];
nodePos=[nodePos;-0.5  1.0]; %nothing
nodePos=[nodePos; 0.0  1.0]; %adjustments
nodePos=[nodePos;-1.3  2.0]; %fwd
nodePos=[nodePos;-0.6  2.5]; %turn in place
nodePos=[nodePos; 0.1  2.5]; %crabwalk
nodePos=[nodePos; 0.8  2.0]; %complex motion
nodePos=[nodePos;-1.3  0.0]; %L1 groom
nodePos=[nodePos;-0.6 -0.5]; %head groom
nodePos=[nodePos; 0.0 -1.4]; %L2-3 groom
nodePos=[nodePos; 0.1 -0.5]; %abd groom
nodePos=[nodePos; 0.8  0.0]; %L3 groom
nodePos=[nodePos;-0.5 -1.4]; %other

%how far apart to make the ndoes
scaling=1.5;
nodePos=nodePos*scaling;

%start figure
figure;
hold on;

%put nodes into figure
plot(nodePos(:,1),nodePos(:,2),'ro', 'MarkerSize', 10);

%visualization parameters
edgeCutoff=0.00;
minEdge=0.5;
maxEdge=4;
arrowSpace=0.4;
gapMag=0.12;

%for all pairs of behavioral labels
for i=1:12
    for j=1:12
        
        %add an edge if the transition is frequent enough
        if trans(i,j)>edgeCutoff
           
            % determine start and end points of the transition edge
            startPos=nodePos(i,:);
            endPos=nodePos(j,:);
            dX=nodePos(j,1)-nodePos(i,1);
            dY=nodePos(j,2)-nodePos(i,2);
            
            %with a gap for the arrowhead
            offSet=gapMag*[-dY dX]/sqrt(dX^2+dY^2);
            lineLength=sqrt(sum((startPos-endPos).^2));
            perc=(lineLength-arrowSpace)/lineLength;
       
            %arrowhead size changes with line thickness
            colInten=1-trans(i,j);
            xVec=[startPos(1) startPos(1)+dX*perc]+offSet(1)*(1-colInten);
            yVec=[startPos(2) startPos(2)+dY*perc]+offSet(2)*(1-colInten);
           
            %draw the line
            line(xVec,yVec,'lineWidth', trans(i,j)*(maxEdge-minEdge)+minEdge, 'Color', [colInten colInten colInten]);
        end
    end
end

%frame figure
xlim([-2 3]*scaling);
ylim([-2 3]*scaling);
axis square
hold off;