%--------------------------------------------
%
% Package pgfplots
%
% Provides a user-friendly interface to create function plots (normal
% plots, semi-logplots and double-logplots).
% 
% It is based on Till Tantau's PGF package.
%
% Copyright 2007-2021 by Christian Feuersänger.
%
% This program is free software: you can redistribute it and/or modify
% it under the terms of the GNU General Public License as published by
% the Free Software Foundation, either version 3 of the License, or
% (at your option) any later version.
% 
% This program is distributed in the hope that it will be useful,
% but WITHOUT ANY WARRANTY; without even the implied warranty of
% MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
% GNU General Public License for more details.
% 
% You should have received a copy of the GNU General Public License
% along with this program.  If not, see <http://www.gnu.org/licenses/>.


\ifpgfplots@LUA@supported
	\pgfplotsutil@directlua{require("prepcontour");}
	\pgfplotsset{
		contour lua/.style={
			contour external={%
				% we decided to NOT precompute contour/levels:
				% @before cmd=\pgfplotscontourpopulateallkeys,
				scanline marks=required,
				script type=lua,
				%
				% this library consumes FOUR coordinates...
				script input format=x y z meta,
				% ... and it also generates FOUR. Always read the last one
				% as it is never subject to rounding issues within the
				% same contour line:
				output point meta=explicit,
				%
				script={
					copylines = 0;
					nblocks   = \if 0\ordering \pgfkeysvalueof{/pgfplots/mesh/rows}\else \pgfkeysvalueof{/pgfplots/mesh/cols}\fi;
					nlines    = \if 0\ordering \pgfkeysvalueof{/pgfplots/mesh/cols}\else \pgfkeysvalueof{/pgfplots/mesh/rows}\fi;
					if copylines == nil or nblocks == nil or nlines == nil then
						io.stderr:write("failed to parse arguments");
						os.exit(2);
					end;
					yvaries = \if 0\ordering 'x'\else 'y'\fi;
					yvaries = (yvaries == 'y');
					infile = io.open(\"\infile\", \"r\");
					outfile = io.open(\"\outfile\", \"w\");
					mesh = PrepcMesh.new(yvaries, nblocks, nlines, copylines, infile, outfile);
					\ifpgfplotsplothandlercontour@corners
					corners = true;
					\else
					corners = false;
					\fi
					\ifx\thecontourlevels\pgfutil@empty
					mesh:autocontour(\thecontournumber, \pgfplotsmetamin, \pgfplotsmetamax, corners);
					\else
					levels = {\thecontourlevels};
					for n = 1, \#levels do
						level = tonumber(levels[n]);
						if level then
							mesh:contour(level, corners);
						end;
					end;
					\fi
					io.close(infile);
					mesh:printcontours();
					io.close(outfile);
				},%
				#1,%
			},
		}
	}
\else
	% do not throw the exception at load time ... this library is
	% included as default
	\pgfplotsset{
		contour lua/.code={
			\pgfplots@error{Library 'contour lua' requires you to run in LUA mode (i.e. lualatex instead of pdflatex)}%
		}
	}
\fi