plot_scale.m

% plot_scale : plot scale to figure
%
% Call:
%    plot_scale(ax,len,pos,FontSize)
%
%    ax: axis (gca)
%    len [1,2]: length of scale length in each direction
%    pos [1],[2],[3] or [4]: Position of scale plot.
%        [NW],[SW],[NE],[SE]
%
%
% Example
%        imagesc(peaks);
%        hold on;
%        plot_scale(gca,[15 15],3);
%        hold off;
%        axis image
%
%

function plot_scale(ax,len,pos,FS)

    if nargin==1
    end

    if nargin<4
        FS=6;
    end
    
    if nargin<3
        pos=3;
    end
    
    
    
    dc=0.05;
    
    if nargin==0
        ax=gca;
    end
    
    Xlim = get(ax,'Xlim');
    Ylim = get(ax,'Ylim');
    Zlim = get(ax,'Zlim');
    
    
    dx=abs(diff(Xlim));
    dy=abs(diff(Ylim));
    dz=abs(diff(Zlim));
    
    
    
    if nargin<2
        lx=0.1;
        ly=0.1;
        lz=0.1;
        lenx=lx*dx;
        leny=ly*dy;
        lenz=lz*dz;
    else
        if length(len)==1, len(2)=len(1); end
        lenx=len(1);
        leny=len(2);
        % lenz=len(3);
        lx=lenx/dx;
        ly=leny/dy;
    end
    
    
    if pos==1
        xc=dc;
        yc=dc;
        zc=dc;
    elseif pos==2
        xc=dc;
        yc=1-dc-ly;
        zc=dc;
    elseif pos==3
        xc=1-dc-lx;
        yc=dc;
        zc=dc;
    else 
        xc=1-dc-lx;
        yc=1-dc-ly;
        zc=dc;
    end
    
    
    
    % X-scale
    plot([Xlim(1)+xc*dx Xlim(1)+(xc+lx)*dx],[1 1].*(Ylim(1)+yc*dy),'k-')
    tx=text([Xlim(1)+xc*dx]+dx*lx/2,(Ylim(1)+yc*dy),num2str(lenx));
    set(tx,'HorizontalAlignment','Center')
    set(tx,'VerticalAlignment','Top')
    set(tx,'FontSize',FS,'FontName','Arial')
    
    % Y-scale
    plot([1 1].*(Xlim(1)+xc*dx),[Ylim(1)+yc*dy Ylim(1)+(yc+ly)*dy],'k-')
    ty=text([Xlim(1)+xc*dx],(Ylim(1)+yc*dy)+dy*ly/2,num2str(leny));
    set(ty,'HorizontalAlignment','Center')
    set(ty,'VerticalAlignment','Bottom')
    set(ty,'FontSize',FS,'FontName','Arial')
    set(ty,'Rotation',90)