The colors in the IntPic package The idea in what concerns the colors is the following: the reader is free to choose his colors (taking into account that the latex xcolor package is used), but we try to make users life reasonably easy. He is allowed to choose tones. The default colors used by &IntPic; are not many, although (from our experience) sufficient for most examples.
Colors by tones The colors are divided by tones.

    gap> IP_ColorsRedTones; #red
    [ "red", "red!50", "red!20", "red!80!green!50", "red!80!blue!60" ]

\begin{center} \includegraphics[scale=1.2]{../images/red_tones.pdf} \end{center} <br><center><img src="../images/red_tones.jpg"></center><br>

    gap> IP_ColorsGreenTones; #green
    [ "green", "green!50", "green!20", "green!80!red!50", "green!80!blue!60" ]

\begin{center} \includegraphics[scale=1.2]{../images/green_tones.pdf} \end{center} <br><center><img src="../images/green_tones.jpg"></center><br>

    gap> IP_ColorsBlueTones; #blue
    [ "blue", "blue!50", "blue!20", "blue!80!red!50", "blue!80!green!60" ]

\begin{center} \includegraphics[scale=1.2]{../images/blue_tones.pdf} \end{center} <br><center><img src="../images/blue_tones.jpg"></center><br>

    gap> IP_ColorsCompRedTones; # cyan (complement of red)
    [ "-red", "-red!50", "-red!20", "-red!80!green!50", "-red!80!blue!60" ]

\begin{center} \includegraphics[scale=1.2]{../images/comp_red_tones.pdf} \end{center} <br><center><img src="../images/comp_red_tones.jpg"></center><br>

    gap> IP_ColorsCompGreenTones; # magenta (complement of green)
    [ "-green", "-green!50", "-green!20", "-green!80!red!50", "-green!80!blue!60"
     ]

\begin{center} \includegraphics[scale=1.2]{../images/comp_green_tones.pdf} \end{center} <br><center><img src="../images/comp_green_tones.jpg"></center><br>

    gap> IP_ColorsCompBlueTones; # yellow (complement of blue)
    [ "-blue", "-blue!50", "-blue!20", "-blue!80!red!50", "-blue!80!green!60" ]

\begin{center} \includegraphics[scale=1.2]{../images/comp_blue_tones.pdf} \end{center} <br><center><img src="../images/comp_blue_tones.jpg"></center><br>

    gap> IP_ColorsDGrayTones; # dark gray
    [ "black!80", "black!70", "black!60", "black!50", "black!40" ]

\begin{center} \includegraphics[scale=1.2]{../images/dark_gray_tones.pdf} \end{center} <br><center><img src="../images/dark_gray_tones.jpg"></center><br>

    gap> IP_ColorsLGrayTones; # light gray
    [ "black!30", "black!25", "black!20", "black!15", "black!10" ]

\begin{center} \includegraphics[scale=1.2]{../images/light_gray_tones.pdf} \end{center} <br><center><img src="../images/light_gray_tones.jpg"></center><br>
Lists of colors

    gap> ListsOfIP_Colors;
    [ [ "red", "red!50", "red!20", "red!80!green!50", "red!80!blue!60" ],
      [ "green", "green!50", "green!20", "green!80!red!50", "green!80!blue!60" ],
      [ "blue", "blue!50", "blue!20", "blue!80!red!50", "blue!80!green!60" ],
      [ "-red", "-red!50", "-red!20", "-red!80!green!50", "-red!80!blue!60" ],
      [ "-green", "-green!50", "-green!20", "-green!80!red!50",
          "-green!80!blue!60" ],
      [ "-blue", "-blue!50", "-blue!20", "-blue!80!red!50", "-blue!80!green!60" ],
      [ "black!80", "black!70", "black!60", "black!50", "black!40" ],
      [ "black!30", "black!25", "black!20", "black!15", "black!10" ] ]

    gap> IP_Colors;
    [ "red", "red!50", "red!20", "red!80!green!50", "red!80!blue!60", "green",
      "green!50", "green!20", "green!80!red!50", "green!80!blue!60", "blue",
      "blue!50", "blue!20", "blue!80!red!50", "blue!80!green!60", "-red",
      "-red!50", "-red!20", "-red!80!green!50", "-red!80!blue!60", "-green",
      "-green!50", "-green!20", "-green!80!red!50", "-green!80!blue!60", "-blue",
      "-blue!50", "-blue!20", "-blue!80!red!50", "-blue!80!green!60", "black!80",
      "black!70", "black!60", "black!50", "black!40", "black!30", "black!25",
      "black!20", "black!15", "black!10" ]

The IntPic default list of colors The colors are shuffled by concatenating the transposed of the matrix ListsOfIP_Colors. The list obtained is taken as the default list of colors.

    gap> ShuffledIP_colors;
    [ "red", "green", "blue", "-red", "-green", "-blue", "black!80", "black!30",
      "red!50", "green!50", "blue!50", "-red!50", "-green!50", "-blue!50",
      "black!70", "black!25", "red!20", "green!20", "blue!20", "-red!20",
      "-green!20", "-blue!20", "black!60", "black!20", "red!80!green!50",
      "green!80!red!50", "blue!80!red!50", "-red!80!green!50", "-green!80!red!50",
      "-blue!80!red!50", "black!50", "black!15", "red!80!blue!60",
      "green!80!blue!60", "blue!80!green!60", "-red!80!blue!60",
      "-green!80!blue!60", "-blue!80!green!60", "black!40", "black!10" ]

\begin{center} \includegraphics[width=0.8\textwidth]{../images/intpic_default_colors.pdf} \end{center} <br><center><img src="../images/intpic_default_colors.jpg"></center><br> These are the &IntPic; default colors. Although the user is free to use other colors, we warn that there is a need of compatibility with the colors used in other packages (the &LaTeX; xcolor, for instance). To emphasize the integers of some sets by using some of the colors in some list of colors (for instance the default colors) one may use empty lists to force the non usage of the colors whose order in the list of colors is the order of these empty lists in the array of integers to be emphasized.
gap> m3 := Filtered([1..40],i->i mod 3=0); [ 3, 6, 9, 12, 15, 18, 21, 24, 27, 30, 33, 36, 39 ] gap> m5 := Filtered([1..40],i->i mod 5=0); [ 5, 10, 15, 20, 25, 30, 35, 40 ] gap> m7 := Filtered([1..40],i->i mod 7=0); [ 7, 14, 21, 28, 35 ] gap> gap> arr := [[],[],m3,[],m5,[],m7];; gap> tkz:=IP_TikzArrayOfIntegers([1..40],10,rec(highlights:=arr));;
\begin{center} \includegraphics[width=0.8\textwidth]{../images/mults_3_5_7} \end{center} <br><center><img src="../images/mults_3_5_7.jpg"></center><br>
Functions to deal with colors For the moment we only provide one function, which shuffles colors from lists of colors. Shuffle colors from lists of colors The argument mat is a list of lists of colors of the same length. The output is obtained by concatenating the transposed of mat.
gap> ShuffleIP_Colors([IP_ColorsRedTones,IP_ColorsCompBlueTones]); [ "red", "-blue", "red!50", "-blue!50", "red!20", "-blue!20", "red!80!green!50", "-blue!80!red!50", "red!80!blue!60", "-blue!80!green!60" ]
\begin{center} \includegraphics[scale=1.2]{../images/shuffle_red_comp_blue.pdf} \end{center} <br><center><img src="../images/shuffle_red_comp_blue.jpg"></center><br>