function nXY = digitize()%function iXY = digitize()%                                                                            %jdc 17-Feb-00%PURPOSE   %     > Interactively digitizes data from an image file.  %     > X-Y axis scales can be any combination of linear, log.%     > Automatic compensation for angular misalignment of  %       image with respect to screen axes.%INPUT%       (All input is interactively prompted)%     > imagename - image filespec (any Matlab-compatible format)%     > three points defining coordinate axes  %     > arbitrary number of points on graph - digitized with left mouse button  %OUTPUT%     > numbered sets of iXY triplets written to screen and optionally to disc storage%     > iXY - 3 x i matrix of all points digitized from image %%TYPICAL CALL %       digitize <RETURN>%       It is necessary to switch between the MATLAB command window and the graphic display window to%       enter the prompted information.% This file is not part of MZDDE. It was downloaded from the MATLAB Central File Exchamge.% A small modification was required to get it working under Matlab 6 Release 13.% Also, a GUI file dialog is now used to select the image file.% http://www.mathworks.com/matlabcentral/fileexchange/loadFile.do?objectId=287&objectType=file% The author is J Cogdell. This is a rather useful utility.% $Header:$fmts = imformats; % Get the available image formats that will be read by imread% Cook up a string to give to uigetfileallimagefmts = '';for i = 1:length(fmts)    if length(fmts(i).ext) == 1      extensions = ['*.' char(fmts(i).ext)];    else       extensions = ['*.' char(fmts(i).ext(1)) ';*.' char(fmts(i).ext(2))];    end    uigetstring{i,1} = extensions;    uigetstring{i,2} = fmts(i).description;    allimagefmts = [allimagefmts ';' extensions];enduigetstring{end+1,1} = allimagefmts;uigetstring{end,2} = 'All Known Image File Formats';uigetstring{end+1,1} = '*.*';uigetstring{end,2} = 'All Files (*.*)';[filename, pathname] = uigetfile(uigetstring, 'Select an Image File');imagename = [pathname filename];pic = imread(imagename);imshow(pic);set(gcf,'Units','normalized','Position',[0 .15 1 .85])set(gca,'Units','normalized','Position',[0   0 1   1]);fprintf([ 'Select the plot origin with the left mouse button ...\n' 7])[Xopixels,Yopixels] = ginput(1);line(Xopixels,Yopixels,'Marker','.','Color','r')OriginXYdata = input([   '  Enter the [x y] graph values at the origin => ' 7]);if length(OriginXYdata)==1,   OriginXYdata(2) = input(['       Enter the Y graph value at the origin => ' 7]);endfprintf(['\nSelect a point on the X-axis ...\n' 7])[XAxisXpixels,XAxisYpixels] = ginput(1);line(XAxisXpixels,XAxisYpixels,'Marker','.','Color','r')XAxisXdata = input(['Enter the X-value of the point => ' 7]);logx =     input(   ' X-axis scale? [ {lin} | log ] => ','s');if findstr('log',lower(logx)),   logx = 1;   scalefactorXdata = log10(XAxisXdata/OriginXYdata(1));else   logx = 0;   scalefactorXdata = XAxisXdata - OriginXYdata(1);end th = atan((XAxisYpixels-Yopixels)/(XAxisXpixels-Xopixels));   % note image file line 1 is at top%fprintf(          '              Graph rotation angle: %+3.1f degrees +cw\n', th*180/pi)rotmat = [cos(th) sin(th); -sin(th) cos(th)];    % axis rotation matrixfprintf(['\nSelect a point on the Y-axis ...\n' 7])[YAxisXpixels,YAxisYpixels] = ginput(1);line(YAxisXpixels,YAxisYpixels,'Marker','.','Color','r')YAxisYdata = input(['Enter the Y-value of the point => ' 7]);logy =     input(   ' Y-axis scale? [ {lin} | log ] => ','s');if findstr('log',lower(logy)),   logy = 1;   scalefactorYdata = log10(YAxisYdata/OriginXYdata(2));else   logy = 0;   scalefactorYdata = YAxisYdata - OriginXYdata(2);end delxyx = rotmat*[(XAxisXpixels-Xopixels);(XAxisYpixels-Yopixels)];delxyy = rotmat*[(YAxisXpixels-Xopixels);(YAxisYpixels-Yopixels)];delXcal = delxyx(1);delYcal = delxyy(2);numberformat = '%6.2f';nXY = [];ng = 0;while 1,   fprintf(['\n Select graph points with left mouse button ...\n',...              ' To terminate capture - select a point to the left of or below the graph axes\n' 7])   n = 0;   %---------------------------------------------------------------------------------------- data acquire loop   while 1      [x,y] = ginput(1);                             line(x,y,'Marker','+','Color','g')      xy = rotmat*[(x-Xopixels);(y-Yopixels)];      delXpoint = xy(1);      delYpoint = xy(2);      if delXpoint>=0 & delYpoint<=0,               if logx,            x = OriginXYdata(1)*10^(delXpoint/delXcal*scalefactorXdata);         else            x = OriginXYdata(1) + delXpoint/delXcal*scalefactorXdata;         end         if logy,             y = OriginXYdata(2)*10^(delYpoint/delYcal*scalefactorYdata);         else              y = OriginXYdata(2) + delYpoint/delYcal*scalefactorYdata;         end         n = n+1;         xpt(n) = x;         ypt(n) = y;         fprintf(      ['%4.0f  ' numberformat '  ' numberformat '\n'],n,x,y)         ng = ng+1;         nXY(ng,:) = [n x y];      else         break      end   end   %---------------------------------------------------------------------------------------------   fname =        input([   '  Enter a filespec to save the data to (default: no save) => ' 7],'s');   if ~isempty(fname),      numberformat = input(['        Enter a format to save the data (default: %6.2f ) => ' 7],'s');      if isempty(numberformat),         numberformat = '%6.2f';      end            for i = 1:n,         fprintf(fname,['%4.0f  ' numberformat '  ' numberformat '\n'],i,xpt(i),ypt(i));      end            I = findstr('\',fname);      if ~isempty(I),         for i = length(I):-1:1,            fname = [fname(1:i) '\' fname(i+1:length(fname))];         end      end         fprintf([   sprintf(['                         %3.0f x-y data pairs saved to file => ' fname],n) '\n'])   end   yn = input([            '          Digitize more data from this graph? [ {y} | n ] => ' 7],'s');   if findstr('n',lower(yn)),      break   endend