function datalabel(state,marker_color);
%datalabel Interactive labeling of data points on a plot
% datalabel with no arguments toggles the data tip state
% datalabel ON turns data tips on for the current figure
% datalabel OFF turns data tips off for the current figure
% datalabel('ON',S), where S is a character string specifying
% a marker and/or color will add the specified marker to
% the data tip.
%
% Click on a line to label the nearest data point.
% Click and drag on a data tip to move it.
% Right-Click on a data tip to delete it.
%
% Example:
% t = 0:pi/50:2.5*pi;
% y = sin(t);
% plot(t,y); %Try plot(y,t), too
% datalabel on
% %Click on lines to label values.
% %Click and drag to move.
% %Right click to delete.
% datalabel off
% %Existing data tips are locked in place; can't add more
% datalabel('on','.b'); %Add blue dots with next data tips
%
% smh: 5/02: Click on text to re-position text relative to data point
% Click on data point to move to a different value
%
% This function is provided as an example only. It has not been
% tested, and therefore, it is not officially supported by The
% MathWorks, Inc.
% Written by Scott Hirsch
% shirsch@mathworks.com
% Copyright 2002 - 2003 The MathWorks, Inc
%
if nargin == 0 | strcmp(state,'on') % Set the WindowButtonDownFcn
if nargin <2 ,
marker='n'; %none
color = 'r';
else
%Parse marker string
colors = 'bgrcmyk';
markers = '+o*.xsdv^><ph';
for ii=1:length(marker_color)
col_ind = strfind(colors,marker_color(ii));
if ~isempty(col_ind) %It's a color
color = marker_color(ii);
else %Try a marker instead
mark_ind = strfind(markers,marker_color(ii));
if ~isempty(mark_ind)
marker = marker_color(ii);
end;
end;
end;
end;
if ~exist('color','var'), color = 'r'; end; %set default
if ~exist('marker','var'), marker = '.'; end; %set default
%If the user specifies a color, but no marker, I use a dot.
set(gcf,'WindowButtonDownFcn','datalabel down')
setappdata(gcf,'Marker',marker);
setappdata(gcf,'Color',color);
set(gcf,'DoubleBuffer','on'); %eliminate flicker
elseif strcmp(state,'down') % Execute the WindowButtonDownFcn
htype = get(gco,'Type');
tag = get(gco,'Tag');
marker = getappdata(gcf,'Marker');
color = getappdata(gcf,'Color');
if strcmp(htype,'line') & ~strcmp(tag,'Dot') %Line - Add text object
%This is sloppy, but it works. The marker is a line named 'Dot'
%Look up nearest value on line.
%User-selected point
cp = get(gca,'CurrentPoint');
x = cp(1,1); %first xy values
y = cp(1,2); %first xy values
%Line data
xl = get(gco,'XData');
yl = get(gco,'YData');
[xv,yv] = local_nearest(x,xl,y,yl);
%For R13 or higher (MATLAB 6.5), use a background color on the text string
th = text(xv,yv,[' (' num2str(xv) ',' num2str(yv) ')']);
v=ver('MATLAB');
v=str2num(v.Version);
if v>=6.5
set(th,'BackgroundColor','y');
end;
ph = line(xv,yv, ...
'Color',color, ...
'Marker',marker, ...
'Tag','Dot', ...
'UserData',[gco th], ...
'LineStyle','none');
mh = uicontextmenu('Tag','DeleteObject', ...
'Callback','ud = get(gco,''UserData'');delete([gco ud(2)]);');
set([th ph],'UIContextMenu',mh);
set(th,'UserData',[gco ph]); %Store handle to line
elseif strcmp(htype,'text') | strcmp(tag,'Dot')
set(gco,'EraseMode','xor')
set(gcf,'WindowButtonMotionFcn','datalabel move', ...
'WindowButtonUpFcn','datalabel up');
end
elseif strcmp(state,'move') % Execute the WindowButtonMotionFcn
htype = get(gco,'Type');
tag = get(gco,'Tag');
if ~isempty(gco)
%Is this the dot or the text
if strcmp(htype,'text') %The text
th = gco;
handles = get(gco,'UserData');
ph = handles(2);
slide = 0; %Don't slide along line; just reposition text
else %The marker
ph = gco;
handles = get(gco,'UserData');
th = handles(2);
slide = 1; %Slide along line to next data point
end;
cp = get(gca,'CurrentPoint');
pt = cp(1,[1 2]);
%Constrain to Line
lh = handles(1); %Line
x = cp(1,1); %first xy values
y = cp(1,2); %first xy values
if slide %Move to new data value
xl = get(lh,'XData');
yl = get(lh,'YData');
ax = axis;
%Get nearest value
[xv,yv]=local_nearest(x,xl,y,yl);
set(th,'Position', [xv yv 0],'String',[' (' num2str(xv) ',' num2str(yv) ')'])
set(ph,'XData',xv,'YData',yv);
else %Just move text around.
set(th,'Position', [x y 0])
end;
drawnow
end;
elseif strcmp(state,'up') % Execute the WindowButtonUpFcn
htype = get(gco,'Type');
tag = get(gco,'Tag');
if strcmp(htype,'text') | strcmp(tag,'Dot')
set(gco,'EraseMode','Normal')
set(gcf,'WindowButtonMotionFcn','')
end;
elseif strcmp(state,'off') % Unset the WindowButton...Fcns
set(gcf,'WindowButtonDownFcn','','WindowButtonUpFcn','')
end
function [xv,yv]=local_nearest(x,xl,y,yl)
%Inputs:
% x Selected x value
% xl Line Data (x)
% y Selected y value
% yl Line Data (y)
%Find nearest value of [xl,yl] to (x,y)
%Special Case: Line has a single non-singleton value
if sum(isfinite(xl))==1
fin = find(isfinite(xl));
xv = xl(fin);
yv = yl(fin);
else
%Normalize axes
xlmin = min(xl);
xlmax = max(xl);
ylmin = min(yl);
ylmax = max(yl);
% xln = xl;
% xn = x;
%
% yln = yl;
% yn = y;
xln = (xl - xlmin)./(xlmax - xlmin);
xn = (x - xlmin)./(xlmax - xlmin);
yln = (yl - ylmin)./(ylmax - ylmin);
yn = (y - ylmin)./(ylmax - ylmin);
%Find nearest point using our friend Ptyhagoras
a = xln - xn; %Distance between x and the line
b = yln - yn; %Distance between y and the line
c = (a.^2 + b.^2); %Distance between point and line
%Don't need sqrt, since we get same answer anyway
[junk,ind] = min(c);
%Nearest value on the line
xv = xl(ind);
yv = yl(ind);
end;
