freehanddraw.m

function [lineobj,xs,ys] = freehanddraw(varargin)
% [LINEOBJ,XS,YS] = FREEHANDDRAW(ax_handle,line_options)
%
% Draw a smooth freehand line object on the current axis (default),
% or on the axis specified by handle in the first input argument.
% Left-click to begin drawing, right-click to terminate, or double-click
% to close contour and terminate.
% 
%
% INPUT ARGUMENTS:  First:      axis handle (optional)
%                  Additional: valid line property/value pairs
%
% OUTPUT ARGUMENTS: 1) Handle to line object
%                  2) x-data
%                  3) y-data
% (Note that output args 2 and 3 can also be extracted from the first output
% argument.)
%
% Ex: [myobj,xs,ys] = freehanddraw(gca,'color','r','linewidth',3);
%     freehanddraw('linestyle','--');
%
% Written by Brett Shoelson, PhD
% shoelson@helix.nih.gov
% 3/29/05
% Modified:
% 10/05/05: Now allows double-click closing of contour

axdef = 0;
if nargin ~= 0 && ishandle(varargin{1})
	try
		axes(varargin{1});
		axdef = 1;
	catch
		error('If the initial input argument is a handle, it must be to a valid axis.');
	end
end
	
	
%Get current figure and axis parameters
oldvals = get(gcf);
oldhold = ishold(gca);

hold on;

set(gcf,'Pointer','crosshair','doublebuffer','on');

%Get the initial point
[xs,ys,zs] = ginput(1);

%Create and store line object
if axdef
	lineobj = line(xs,ys,'tag','tmpregsel',varargin{2:end});
else
	lineobj = line(xs,ys,'tag','tmpregsel',varargin{:});
end
setappdata(gcf,'lineobj',lineobj);

%Modify wbmf of current figure to update lineobject on mouse motion
set(gcf,'windowbuttonmotionfcn',@wbmfcn);
set(gcf,'windowbuttondownfcn',@wbdfcn);
%Wait for right-click or double-click
while ~strcmp(get(gcf,'SelectionType'),'alt') & ~strcmp(get(gcf,'SelectionType'),'open')
	drawnow;
end

%Extract xyz data from line object for return in output variables
%(Also retrievable from first output argument)
if nargout > 1
	xs = get(getappdata(gcf,'lineobj'),'xdata')';
end
if nargout > 2
	ys = get(getappdata(gcf,'lineobj'),'ydata')';
end

%Clear temporary variables from base workspace
evalin('caller','clear tmpx tmpy tmpz done gca lineobj');

%Reset figure parameters
set(gcf,'Pointer',oldvals.Pointer,...
	'windowbuttonmotionfcn',oldvals.WindowButtonMotionFcn,...
    'windowbuttondownfcn',oldvals.WindowButtonDownFcn);

if isfield(oldvals, 'DoubleBuffer')
set(gcf,'doublebuffer',oldvals.DoubleBuffer);
end 

%Reset hold value of the axis
if ~oldhold, hold off; end 

function wbmfcn(varargin)
lineobj = getappdata(gcf,'lineobj');
if strcmp(get(gcf,'selectiontype'),'normal');
    tmpx = get(lineobj,'xdata');
    tmpy = get(lineobj,'ydata');
    a=get(gca,'currentpoint');
    set(lineobj,'xdata',[tmpx,a(1,1)],'ydata',[tmpy,a(1,2)]);
    drawnow;
else
    setappdata(gcf,'lineobj',lineobj);
end

function wbdfcn(varargin)
lineobj = getappdata(gcf,'lineobj');
if strcmp(get(gcf,'selectiontype'),'open')
    tmpx = get(lineobj,'xdata');
    tmpy = get(lineobj,'ydata');
    a=get(gca,'currentpoint');
    set(lineobj,'xdata',[tmpx,tmpx(1)],'ydata',[tmpy,tmpy(1)]);
    setappdata(gcf,'lineobj',lineobj);
    drawnow;
end
return