UISelect

UISelect - Interactively select polygon zone in an existing plot.

  USAGE

    [X,Y,p] = UISelect

    X,Y            polygon coordinates
    p              handle for polygon object in figure

  SEE

    See also UIInPolygon

0001 function [X,Y,polygon] = UISelect
0002 
0003 %UISelect - Interactively select polygon zone in an existing plot.
0004 %
0005 %  USAGE
0006 %
0007 %    [X,Y,p] = UISelect
0008 %
0009 %    X,Y            polygon coordinates
0010 %    p              handle for polygon object in figure
0011 %
0012 %  SEE
0013 %
0014 %    See also UIInPolygon
0015 %
0016 
0017 % Copyright (C) 2009-2011 by Michaël Zugaro
0018 %
0019 % This program is free software; you can redistribute it and/or modify
0020 % it under the terms of the GNU General Public License as published by
0021 % the Free Software Foundation; either version 3 of the License, or
0022 % (at your option) any later version.
0023 
0024 hold on;
0025 X = [];
0026 Y = [];
0027 polygon = [];
0028 last = false;
0029 
0030 while ~last,
0031     % Get next mouse click
0032     [x,y,button] = ginput(1);
0033     switch button,
0034         case 1,
0035             % Left button adds this point
0036             X(end+1,1) = x;
0037             Y(end+1,1) = y;
0038         case 2,
0039             % Middle button closes the selection
0040             last = true;
0041             if ~isempty(X),
0042                 X(end+1,1) = X(1);
0043                 Y(end+1,1) = Y(1);
0044             end
0045         case 3,
0046             % Right button cancels last point
0047             if ~isempty(X),
0048                 X(end) = [];
0049                 Y(end) = [];
0050             end
0051     end
0052     % Update existing polygon
0053     if isempty(polygon),
0054         polygon = plot(X,Y);
0055     else
0056         warning('off','MATLAB:hg:line:XDataAndYDataLengthsMustBeEqual');
0057         set(polygon,'XData',X);
0058         set(polygon,'YData',Y);
0059         warning('on','MATLAB:hg:line:XDataAndYDataLengthsMustBeEqual');
0060     end
0061 end
0062 
0063 hold off;