convertSVG2txt.m

function rc = convertSVG2txt(fName) 
%   convertSVG2txt.m 
%       reads in .SVG (version 1.1) file and writes out .txt file of (x,y) nodes  
%       
%   David Healy
%   February 2017 
%   d.healy@abdn.ac.uk 

%% Copyright
% Permission is hereby granted, free of charge, to any person obtaining a
% copy of this software and associated documentation files (the
% "Software"), to deal in the Software without restriction, including
% without limitation the rights to use, copy, modify, merge, publish,
% distribute, sublicense, and/or sell copies of the Software, and to permit
% persons to whom the Software is furnished to do so, subject to the
% following conditions:
% 
% The above copyright notice and this permission notice shall be included
% in all copies or substantial portions of the Software.
% 
% THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
% OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
% MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
% NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
% DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
% OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
% USE OR OTHER DEALINGS IN THE SOFTWARE.

rc = 0 ; 

disp('Converting .svg file to .txt file...') ; 

% fName = 'ThinSection_H12Z.svg' ; 
[sRawLines, result] = readtext(fName, '>', '', '', 'textual') ; 

sRawLines = char(sRawLines) ; 
nRawLines = result.rows ; 

sPolyLines = cell(nRawLines,1) ;  
sLines = cell(nRawLines,1) ;  

fVersion = 0 ; 
iPoly = 0 ; 
iLine = 0 ; 
fPoly = 0 ; 
fLine = 0 ; 
fPath = 0 ; 

for i = 1:nRawLines 
    
    sThisLine = sRawLines(i, :) ; 
    
    %   find the SVG version, and print it 
    if ~fVersion
        iVersion = strfind(sThisLine, '<svg version') ; 
        if iVersion > 0 
            disp(sThisLine(iVersion+1:19)) ; 
            fVersion = 1 ; 
        end ; 
    end ;        
    
    %   is this a <poly or <line tag? 
    if strfind(sThisLine, '<poly')
        fPoly = 1 ; 
        fLine = 0 ; 
        iPoly = iPoly + 1 ; 
%         disp('Starting a <polyline ...') ; 
    end ; 

    if strfind(sThisLine, '<line')
        fLine = 1 ; 
        fPoly = 0 ; 
        iLine = iLine + 1 ; 
%         disp('Starting a <line ...') ; 
    end ; 
        
    if strfind(sThisLine, '<path')
        fPath = 1 ;
        fPoly = 0 ; 
        fLine = 0 ; 
%         disp('Found a <path ...') ; 
        continue ;
    end ; 
    
    %   is this the end of a line?
    if strcmp(sThisLine(end), '/')
    
        if fPath 
            fPath = 0 ; 
            continue ; 
        end ; 
        
        %   if building a polyline, finish it 
        if fPoly 
            sPolyLines(iPoly,1) = strcat(sPolyLines(iPoly,1), ',', cellstr(sThisLine)) ; 
        end ; 
        %   if building a line, finish it 
        if fLine  
            sLines(iLine,1) = strcat(sLines(iLine,1), ',', cellstr(sThisLine)) ; 
        end ; 
        
        %   else reset & jog on 
        fPoly = 0 ; 
        fLine = 0 ; 
       
    else
        
        if strfind(sThisLine, '</svg')
            continue ; 
        end ; 
        
        if strfind(sThisLine, '</g')
            continue ; 
        end ; 
        
        %   if building a polyline, add to it 
        if fPoly 
            sPolyLines(iPoly,1) = strcat(sPolyLines(iPoly,1), ',', cellstr(sThisLine)) ; 
        end ; 
        
        %   if building a line, add to it 
        if fLine  
            sLines(iLine,1) = strcat(sLines(iLine,1), ',', cellstr(sThisLine)) ; 
        end ; 
        
    end ; 
    
end ;

disp(['Read ', num2str(nRawLines), ' lines']) ;
disp(['Built ', num2str(iPoly), ' polylines']) ;
disp(['Built ', num2str(iLine), ' lines']) ;

sNewPolyLines = sPolyLines(1:iPoly,1) ; 
sNewLines = sLines(1:iLine, 1) ; 

%   loop through polylines extracting (x,y) coordinate pairs 
fNewName = [ fName(1:end-4), 'converted.txt' ] ; 
fID = fopen(fNewName, 'w') ; 
for i = 1:iPoly 
    
    if iscellstr(sNewPolyLines(i,:))
        sThisLine = char(sNewPolyLines(i,:)) ; 
    else
        continue ; 
    end ; 
    lThisLine = length(sThisLine) ; 
    
    %   find points 
    iS = strfind(sThisLine, 'points="') ; 
    iStartPoints = iS(1) + length('points="') ; 
    iEndPoints = lThisLine - 2 ; 
    sPoints = sThisLine(iStartPoints:iEndPoints) ; 

    %   strip out (x,y) pairs 
    nPolyPoints = str2num(sPoints) ;
    for j = 1:length(nPolyPoints)
        fprintf(fID, '%12.4f\t', nPolyPoints(j)) ; 
    end ; 
    fprintf(fID, '\n') ; 
    
end ; 

%   loop through lines extracting (x,y) coordinate pairs 
for i = 1:iLine 
    
    if iscellstr(sNewLines(i,:)) 
        sThisLine = char(sNewLines(i,:)) ; 
    else
        continue ; 
    end ; 
    
    lThisLine = length(sThisLine) ; 

    %   find points 
    ix1 = strfind(sThisLine, 'x1="') + 4 ; 
    iy1 = strfind(sThisLine, 'y1="') + 4 ; 
    ix2 = strfind(sThisLine, 'x2="') + 4 ; 
    iy2 = strfind(sThisLine, 'y2="') + 4 ; 
    
    x1 = str2double(sThisLine(ix1:iy1-7)) ; 
    y1 = str2double(sThisLine(iy1:ix2-7)) ; 
    x2 = str2double(sThisLine(ix2:iy2-7)) ; 
    y2 = str2double(sThisLine(iy2:lThisLine-2)) ; 
    
    fprintf(fID, '%12.4f\t%12.4f\t%12.4f\t%12.4f\n', x1, y1, x2, y2) ; 
    
end ;  
fclose(fID) ; 

if iPoly + iLine > 0 
    rc = 1 ; 
else 
    rc = 0 ; 
end ; 

end