% Florian Sihler, 2024
% Licensed under GNU General Public License version 3
% https://opensource.org/licenses/gpl-3.0.html
\def\filename{fancyqr}
\ProvidesPackage{\filename}[2024/10/05 version v2.1 Fancy QR-Codes]
\RequirePackage{pict2e, xfp, qrcode}

% element
% x: {\the\j}; y: {\the\i} | \@max@x \@max@y
\def\@@fancyqr@color@gradient#1{\edef\angle{\fpeval{%
   % approximate mod
   \fancyqr@gradient@angle+225 - floor((\fancyqr@gradient@angle+225)/360)*360
}}% rotate to align 0 to the right
\edef\gradient{\fpeval{%
   % we do rotate the x and y points before color drawing by
   % Mod(\fancyqr@gradient@angle,360) with the shifted origin
   % Old: #3/2 #4/2
   ((\the\j-\@half@max@x)*cos(\angle) - (\the\i-\@half@max@y)*sin(\angle) + \@half@max@x)/\@max@x * 50% rel x [0,1]
   + ((\the\j-\@half@max@x)*sin(\angle) + (\the\i-\@half@max@y)*cos(\angle) + \@half@max@y)/\@max@y * 50% rel y [0,1]
   }}\@declaredcolor{qr@fancy@gradient@br!\gradient!qr@fancy@gradient@tl}{#1}}
\def\@@fancyqr@color@default#1{\@declaredcolor{qr@fancy@gradient@tl}{#1}}
\def\@@fancyqr@color@random#1{\pgfmathrandomitem{\@fancyqr@random@c@l@r}{@@fancyqr@@randomcol}\@declaredcolor{\@fancyqr@random@c@l@r}{#1}}
\let\FancyQrColor\@@fancyqr@color@default

\def\fancyqr@rounding@factor{.5}
\edef\fancyqr@rounding@other{\fpeval{1-\fancyqr@rounding@factor}}

% O 1 O
% 2 X 3
% O 4 O
% uses \@up\@left\@right\@down
\def\GetPattern{%
\ifcsname qcc\@up\@left\@right\@down\endcsname
   \csname qcc\@up\@left\@right\@down\endcsname
\fi}

% backwards compatibility
\def\fancyqr@clap#1{\hb@xt@\z@{\hss#1\hss}}
\newdimen\fancyqr@edge@compensate \fancyqr@edge@compensate=.15\p@

% is larger to be compensated by overlaps
\def\qrm{\dimexpr\qr@modulesize+\fancyqr@edge@compensate\relax}
\long\def\qr@newpattern#1#2#3#4#5{%
\expandafter\def\csname qcc#1#2#3#4\endcsname{% scaling happens implicitly by the unitlength
   \put(\the\j,\the\numexpr\@max@y-\the\i){%
      \advance\unitlength by\fancyqr@edge@compensate\relax
      #5%
   }}%
}

% [#3][#2]
% [#4][#1]
\def\fancyqr@rounded@rect#1#2#3#4{%
   \ifnum#4=\@ne\relax \moveto(\fancyqr@rounding@factor,\z@)\else\moveto(\z@,\z@)\fi
   \ifnum#1=\@ne
      \lineto(\fancyqr@rounding@other,\z@)%
      \circlearc\fancyqr@rounding@other\fancyqr@rounding@factor\fancyqr@rounding@factor{270}{360}
   \else\lineto(\@ne,\z@)\fi
   \ifnum#2=\@ne
      \lineto(\@ne,\fancyqr@rounding@other)%
      \circlearc\fancyqr@rounding@other\fancyqr@rounding@other\fancyqr@rounding@factor{0}{90}
   \else\lineto(\@ne,\@ne)\fi
   \ifnum#3=\@ne
      \lineto(\fancyqr@rounding@factor,\@ne)%
      \circlearc\fancyqr@rounding@factor\fancyqr@rounding@other\fancyqr@rounding@factor{90}{180}
   \else\lineto(\z@,\@ne)\fi
   \ifnum#4=\@ne
      \lineto(\z@,\fancyqr@rounding@factor)%
      \circlearc\fancyqr@rounding@factor\fancyqr@rounding@factor\fancyqr@rounding@factor{180}{270}
   \else\lineto(\z@,\z@)\fi
   \fancyqr@rounded@rect@close
}
\def\fancyqr@rounded@rect@close{\fillpath}

\def\FancyQrLoadDefault{%
% .
\qr@newpattern0000{\fancyqr@rounded@rect1111}%
% | | - -
\qr@newpattern1000{\fancyqr@rounded@rect1001}%
\qr@newpattern0001{\fancyqr@rounded@rect0110}%
\qr@newpattern0100{\fancyqr@rounded@rect1100}%
\qr@newpattern0010{\fancyqr@rounded@rect0011}%
% corners
\qr@newpattern1100{\fancyqr@rounded@rect1000}% bottom right
\qr@newpattern1010{\fancyqr@rounded@rect0001}% bottom left
\qr@newpattern0101{\fancyqr@rounded@rect0100}% top right
\qr@newpattern0011{\fancyqr@rounded@rect0010}% top left
% straights | --
\qr@newpattern1001{\fancyqr@rounded@rect0000}%
\qr@newpattern0110{\fancyqr@rounded@rect0000}%
% enclosed
\qr@newpattern1111{\fancyqr@rounded@rect0000}%
% t's
\qr@newpattern0111{\fancyqr@rounded@rect0000}%
\qr@newpattern1011{\fancyqr@rounded@rect0000}%
\qr@newpattern1101{\fancyqr@rounded@rect0000}%
\qr@newpattern1110{\fancyqr@rounded@rect0000}%
}
\FancyQrLoadDefault % allows to reset the style after other loads
\def\@fancy@qr@default@name{default}

\def\FancyQrLoad#1{%
\protected@edef\fancyqr@loaded@style{#1}%
\def\fancyqr@rounded@rect@close{\fillpath}%
\let\@tmp\newpattern\let\newpattern\qr@newpattern\@bsphack\def\@@tmp{#1}%
\ifx\@@tmp\@fancy@qr@default@name\FancyQrLoadDefault\else
\expandafter\edef\csname pingu@lib@#1@atcode\endcsname{\the\catcode`\@}%
\catcode`\@=11\relax
\input{fancyqr-style-#1.code}%
\catcode`\@=\csname pingu@lib@#1@atcode\endcsname
\fi\@esphack\let\newpattern\@tmp\let\@tmp\relax}


% modify the getter so everything that is not defined is white:
\def\fancy@qr@matrixentry#1#2#3{%
   \ifcsname #1@#2@#3\endcsname
   % #1 = matrix name
   % #2 = row number
   % #3 = column number
   \csname #1@#2@#3\endcsname
   \else\qr@white@format\fi
}%

\def\FancyQrDoNotPrintSquare#1#2{\def\fancy@qr@donotprint@center@x{#1}\def\fancy@qr@donotprint@center@y{#2}}
\FancyQrDoNotPrintSquare00

\newif\iffancy@qr@do@print@
\def\qr@fancy@updateif#1#2{\fancy@qr@do@print@true
\ifnum#1>\@do@y@min\relax \ifnum#1<\@do@y@max\relax \ifnum#2>\@do@x@min\relax \ifnum#2<\@do@x@max\relax \fancy@qr@do@print@false \fi\fi\fi\fi}

\newif\iffancy@qr@roundcut@
\fancy@qr@roundcut@true
\let\FancyQrHardCut\fancy@qr@roundcut@false
\let\FancyQrRoundCut\fancy@qr@roundcut@true

% clear plus if not to be printed
\def\qr@fancy@clear@surround#1#2#3{%
   \qr@fancy@updateif{\the\numexpr#2-1}{#3}%
   \iffancy@qr@do@print@\else \expandafter\let\csname #1@\the\numexpr#2-1 @#3\endcsname\@undefined \fi
   \qr@fancy@updateif{\the\numexpr#2+1}{#3}%
   \iffancy@qr@do@print@\else \expandafter\let\csname #1@\the\numexpr#2+1 @#3\endcsname\@undefined \fi
   \qr@fancy@updateif{#2}{\the\numexpr#3-1}%
   \iffancy@qr@do@print@\else \expandafter\let\csname #1@#2@\the\numexpr#3-1\endcsname\@undefined \fi
   \qr@fancy@updateif{#2}{\the\numexpr#3+1}%
   \iffancy@qr@do@print@\else \expandafter\let\csname #1@#2@\the\numexpr#3+1\endcsname\@undefined \fi
}

\newif\if@fancyqr@image@

\def\fancy@qr@printmatrix#1{%
   \def\qr@white{0}\def\qr@black{1}%
   \protected@edef\fancyqr@currprint{#1}%
   \let\qr@black@fixed\qr@black \let\qr@white@fixed\qr@white
   \let\qr@black@format\qr@black \let\qr@white@format\qr@white
  %Set module size
  \qr@modulesize=\qr@desiredheight\relax
  \divide\qr@modulesize by \qr@size\relax
  \unitlength=\dimexpr\qr@modulesize\relax % will be re-set in placement
  \if@fancyqr@image@% image is in \fancyqr@imgbox
   \edef\@x{\fpeval{ceil((.5\wd\fancyqr@imgbox)/\qr@modulesize)+\fancyqr@img@padding@x}}%
   \edef\@y{\fpeval{ceil((.5\ht\fancyqr@imgbox+.5\dp\fancyqr@imgbox)/\qr@modulesize)+\fancyqr@img@padding@y}}%
   \FancyQrDoNotPrintSquare\@x\@y
  \fi
  \qr@minipagewidth=\qr@desiredheight
  \ifqr@tight\else \advance\qr@minipagewidth by 8\qr@modulesize\relax \fi
  \begingroup
      \edef\@max@x{\qr@numberofrowsinmatrix\fancyqr@currprint}\edef\@half@max@x{\the\numexpr\@max@x/2}%
      \edef\@max@y{\qr@numberofcolsinmatrix\fancyqr@currprint}\edef\@half@max@y{\the\numexpr\@max@y/2}%
      % redefine the border to be white!
      \qr@for \i=\@ne to \@max@y by \@ne{%
      % redefine the limits to be white!
      \qr@storetomatrix\fancyqr@currprint{\the\numexpr\z@}{\the\i}{\qr@white}%
      \qr@storetomatrix\fancyqr@currprint{\the\numexpr\@max@x+\@ne}{\the\i}{\qr@white}%
      }%
      \qr@for \i=\@ne to \@max@x by \@ne{%
         \qr@storetomatrix\fancyqr@currprint{\the\i}{\the\numexpr\z@}{\qr@white}%
         \qr@storetomatrix\fancyqr@currprint{\the\i}{\the\numexpr\@max@y+\@ne}{\qr@white}%
      }%
      \edef\@do@x@min{\the\numexpr\@half@max@x-\fancy@qr@donotprint@center@x-\@ne}%
      \edef\@do@x@max{\the\numexpr\@half@max@x+\fancy@qr@donotprint@center@x+\@ne}%
      \edef\@do@y@min{\the\numexpr\@half@max@y-\fancy@qr@donotprint@center@y-\@ne}%
      \edef\@do@y@max{\the\numexpr\@half@max@y+\fancy@qr@donotprint@center@y+\@ne}%
      \edef\@tmp@tight{\ifqr@tight\z@\else-4\fi}%
      \picture(\qr@minipagewidth,\qr@minipagewidth)(\the\numexpr\@ne+\@tmp@tight,\@tmp@tight)
      \qr@for \i=\@ne to \@max@y by \@ne{\qr@for \j=\@ne to \@max@x by \@ne{%
         \qr@fancy@updateif\i\j
         \iffancy@qr@do@print@
            \edef\@mid{\qr@matrixentry\fancyqr@currprint{\the\i}{\the\j}}%
            \ifnum\@mid=\qr@black\relax
               \iffancy@qr@roundcut@\qr@fancy@clear@surround\fancyqr@currprint{\the\i}{\the\j}\fi
               \edef\@up{\qr@matrixentry\fancyqr@currprint{\the\numexpr\the\i-\@ne}{\the\j}}%
               \edef\@left{\qr@matrixentry\fancyqr@currprint{\the\i}{\the\numexpr\the\j-\@ne}}%
               \edef\@right{\qr@matrixentry\fancyqr@currprint{\the\i}{\the\numexpr\the\j+\@ne}}%
               \edef\@down{\qr@matrixentry\fancyqr@currprint{\the\numexpr\the\i+\@ne}{\the\j}}%
               \FancyQrColor{\GetPattern}%
         \fi\fi
      }}%
      \if@fancyqr@image@
         % floating point mid
         \put(\fpeval{.5*\@max@x+.5},\fpeval{.5*\@max@y}){%
            \edef\@halfcheck{\fpeval{round(\fancy@qr@donotprint@center@x/2)}}%
            \raisebox{-.5\height}{\clap{% TODO: remove this offset
               \ifodd\@halfcheck \else\kern\qr@modulesize\fi
               \usebox\fancyqr@imgbox
            }}%
         }%
      \fi
      \endpicture
   \endgroup
}%

\def\fancy@qr@setup#1{%
   \qr@creatematrix{#1}%
   \expandafter\gdef\csname #1@numrows\endcsname{\qr@size}%
   \expandafter\gdef\csname #1@numcols\endcsname{\qr@size}%
   % we do not need to create blank because we store all
   \qr@placefinderpatterns{#1}%
   \qr@placetimingpatterns{#1}%
   \qr@placealignmentpatterns{#1}%
}

\newcount\c@fancy@a \newcount\c@fancy@b
% the normal data is... well...
\def\fancy@qr@writedata#1#2{%
  % #1 = name of a matrix that has been prepared with finder patterns, timing patterns, etc.
  % #2 = a string consisting of 0's and 1's to write into the matrix.
  \expandafter\c@fancy@a\the\numexpr\qr@numberofrowsinmatrix{#1}\relax
  \expandafter\c@fancy@b\the\numexpr\qr@numberofcolsinmatrix{#1}\relax
  \edef\qr@datatowrite{#2\relax}%
  \c@qr@i0\relax
  \@whilenum\c@qr@i<\c@fancy@a\do{%
      \c@qr@j0 \advance\c@qr@i\@ne
      \@whilenum\c@qr@j<\c@fancy@b\do{%
         \advance\c@qr@j\@ne
         \expandafter\fancy@qr@writebit\qr@datatowrite:{#1}%
      }%
  }%
}

\def\fancy@qr@writebit#1#2:#3{%
  % #3 = matrix name
  % (qr@i,qr@j) = position to write in (LaTeX counters)
  % #1 = bit to be written
  % #2 = remaining bits plus '\relax' as an end-of-file marker
  \edef\qr@datatowrite{#2}%
  \ifnum#1=1
    \qr@storetomatrix{#3}{\number\c@qr@i}{\number\c@qr@j}{\qr@black}%
  \else
    \qr@storetomatrix{#3}{\number\c@qr@i}{\number\c@qr@j}{\qr@white}%
  \fi
}%


\def\fancy@qr@printsavedbinarymatrix#1{%
   \def\qr@binarystring{#1\relax\relax}%
   \fancy@qr@setup{@tmp}%
   \fancy@qr@writedata{@tmp}{\qr@binarystring}%
   \fancy@qr@printmatrix{@tmp}%
}%

\newsavebox\fancyqr@imgbox
\newif\if@fancyqr@randomcolor@
\define@key{fancyqr}{image x padding}{\def\fancyqr@img@padding@x{#1}}
\define@key{fancyqr}{image y padding}{\def\fancyqr@img@padding@y{#1}}
\define@key{fancyqr}{image padding}{\def\fancyqr@img@padding@x{#1}\def\fancyqr@img@padding@y{#1}}
\define@key{fancyqr}{image}{\@fancyqr@image@true\savebox\fancyqr@imgbox{#1}}
\define@key{fancyqr}{color}{\@fancyqr@randomcolor@false\@fancyqr@gradientfalse\colorlet{qr@fancy@gradient@tl}{#1}}
\define@key{fancyqr}{left color}{\@fancyqr@randomcolor@false\colorlet{qr@fancy@gradient@br}{#1}}
\define@key{fancyqr}{l color}{\@fancyqr@randomcolor@false\colorlet{qr@fancy@gradient@br}{#1}}
\define@key{fancyqr}{right color}{\@fancyqr@randomcolor@false\colorlet{qr@fancy@gradient@tl}{#1}}
\define@key{fancyqr}{r color}{\@fancyqr@randomcolor@false\colorlet{qr@fancy@gradient@tl}{#1}}
\define@key{fancyqr}{gradient angle}{\@fancyqr@randomcolor@false\def\fancyqr@gradient@angle{#1}}
\define@boolkey{fancyqr}[@fancyqr@]{gradient}[true]{}% if@fancyqr@gradient
\define@key{fancyqr}{random color}{\@fancyqr@randomcolor@true\def\@fancyqr@random@colors{#1}}
\define@key{fancyqr}{width}{\setkeys{qr}{height=#1}}
\define@key{fancyqr}{size}{\setkeys{qr}{height=#1}}
% \fancyqr@loaded@style
\def\fancyqr@flat@style{flat}
\define@boolkey{fancyqr}[@fancyqr@]{classic}[true]{} % if@fancyqr@classic
\def\fancyqr@classic{%
\ifx\fancyqr@loaded@style\fancyqr@flat@style\else\FancyQrLoad{\fancyqr@flat@style}\fi
\setkeys{fancyqr}{%
   gradient=false,color=black,l color=black,r color=black%
}%
}

\def\fancyqrset#1{\setkeys{qr,fancyqr}{#1}}
\fancyqrset{image padding=0,gradient=true,gradient angle=135,r color=teal,l color=purple}

\def\@fancyqr@init{\let\qr@printsavedbinarymatrix\fancy@qr@printsavedbinarymatrix\let\qr@matrixentry\fancy@qr@matrixentry\let\qr@printmatrix\fancy@qr@printmatrix}
\def\fancyqr{\@ifstar\s@fancyqr\ns@fancyqr}
% we rebuild some parts of qrcode to allow this macro to extend the keys while keeping the wrapper
\def\s@fancyqr{\qr@starinvokedtrue\@@fancyqr}
\def\ns@fancyqr{\qr@starinvokedfalse\@@fancyqr}
\newcommand\@@fancyqr[1][]{\begingroup\@fancyqr@init
\ifqr@starinvoked\qr@hyperlinkfalse\fi
\setkeys{qr,fancyqr}{#1}%
\if@fancyqr@classic\fancyqr@classic\fi%
\if@fancyqr@randomcolor@%
\ifcsname pgfmathdeclarerandomlist\endcsname\else
\PackageError{fancyqr}{Random colors requested but pgfmath not loaded}{Please load pgfmath if you want this}\fi
\pgfmathdeclarerandomlist{@@fancyqr@@randomcol}{\@fancyqr@random@colors}\let\FancyQrColor\@@fancyqr@color@random\else\if@fancyqr@gradient\let\FancyQrColor\@@fancyqr@color@gradient\fi\fi
\bgroup\qr@verbatimcatcodes\qr@setescapedspecials\qrcode@in}
\endinput