%--------------------------------------------
%
% 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 2007/2008 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/>.
%
%--------------------------------------------


\def\pgfplotslibrarysurf@initstream{%
	\if\pgfplotslibrarysurf@bytespercoordinate4%
		\pgfplots@warning{************** The generated postscript file may not be compatible with all viewers. Consider using \string\pgfplotsset{surf shading/precision=postscript} for improved compatibility. Or: convert it to pdf, that will work correctly. **************}%
	\fi
	% binary doesn't work due to limitations of DVI.
	% We NEED an ASCII encoding.
	%
	\def\pgfplotslibrarysurf@filter@encode{ASCIIHexEncode}%
	\def\pgfplotslibrarysurf@filter@decode{ASCIIHexDecode}%
}%

% The lowlevel call for surface shadings. It uses a pattern type 2
% dictionary as fill color and has thus several things to do. 
%
% It appears the dvips implementation is simpler than the pdftex
% implementation - I did not need to adjust the matrix (don't know
% why).
\def\pgfplotslibrarysurfdraw{%
	\pgfpicture
	\pgfplotssys@do@surfshading@fillpaths\pgfplots@loc@TMPa%
	\global\let\pgfplots@glob@TMPa=\pgfplots@loc@TMPa
	\pgfpathrectanglecorners
		{\pgfplotslibrarysurf@corner@sw}
		{\pgfplotslibrarysurf@corner@ne}%
	\pgfplotslibrarysurfusepath
	\endpgfpicture
	\leavevmode% ??
}

% To be used inside of a pgfpicture.
%
% #1: a macro name. The contents of this macro needs to be written
% into the pdf pattern dictionary contained in the pdf resources of
% the current context. The current context is either the current page
% or an xform object.
%
%
\def\pgfplotssys@do@surfshading@fillpaths#1{%
%http://www.ghostscript.com/pipermail/gs-devel/2002-September/005763.html
%http://www.tek-tips.com/viewthread.cfm?qid=1183719&page=4
%	\pgf@process{\pgfpointdiff{\pgfplotslibrarysurf@corner@sw}{\pgfkeysvalueof{/pgfplots/surf shading/anchor}}}%
%	\pgf@sys@bp@correct\pgf@x%
%	\pgf@sys@bp@correct\pgf@y%
	\pgfsys@invoke{%
		<<	
			%/Type /Pattern
			/PatternType 2
			/Shading
			<<
				/ShadingType \pgfplotslibrarysurf@type\space
				/BitsPerCoordinate \pgfplotslibrarysurf@bitspercoordinate\space
				/BitsPerComponent \pgfplotslibrarysurf@bitspercomponent\space % Note: this here is the reason why I can't use ASCII85Decode
				\if5\pgfplotslibrarysurf@type
					/VerticesPerRow \pgfkeysvalueof{/pgfplots/surf shading/cols}
				\else
					/BitsPerFlag 8
				\fi
				/ColorSpace /Device\pgfplotslibrarysurf@colorspace
				/Decode [\pgfplotslibrarysurf@decode]
				\ifpgfplotslibrarysurf@usecolormap
					/Function \pgfkeysvalueof{/pgfplots/surf shading/colormap}
				\fi
				/DataSource	
					currentfile 
						% direct binary output not possible: DVI
						% doesn't support it (?)
						%<< /EODCount \pgfplotslibrarysurf@binarystream@len\space /EODString () >>  /SubFileDecode filter
						% not completely implemented :
						%/ASCII85Decode filter
						% works:
						/ASCIIHexDecode filter
						/ReusableStreamDecode filter
							\pgfplotslibrarysurf@binarystream
							%\csname pgfp@bin@126\endcsname% tilde ~> is end-of-input indicator for ASCII85Decode
							> % end-of-input indicator for ASCIIHexDecode
			>>
		>> [ 1 0 0 1 0 0 ] makepattern setpattern
		% I don't know why I don't need the shifts here !? But it
		% appears to work, so never mind.
%		>> [ 1 0 0 1 \pgf@sys@tonumber\pgf@x\space \pgf@sys@tonumber\pgf@y ] makepattern setpattern
		% 'setpattern' is a shortcut for changing the colorspace and
		% the color to pattern.
	}%
}

\endinput
% vi: ft=tex
