Filling rectangle in TikZ with more than one color

Question

To draw a rectangle and fill it in gray in TikZ:

\draw [fill=gray,very thick] (0,0) rectangle (2,1);

Now, I want to fill it in both gray and yellow. The best way would be if I can make diagonal stripes of gray and yellow alternately. Is there a way to do that?

Answer 1

Update: using patterns.meta

patterns.meta library was developped after this question and answers were proposed. So, it's worth to write a possible solution using the library.

The new pattern Lines can be used as an alternative to north east hatch. And if we want different colors (or patterns) over the same path, preaction or postaction has to be used to define de second or third pattern.

As you can see in following code, the new library simplifies patterns definitions:

\documentclass{standalone}
\usepackage{tikz}
\usetikzlibrary{patterns.meta}
\begin{document}
\begin{tikzpicture}
\draw[opacity=0.5, 
pattern={Lines[angle=-45, distance={5pt/sqrt(2)}]}, 
pattern color=yellow,
preaction={%
    pattern={Lines[angle=-45, distance={5pt/sqrt(2)}, xshift=2.5pt]}, 
    pattern color=gray}
] (0,0) rectangle (2,1);
\end{tikzpicture}
\end{document}

Original answer:

You can fill areas with some pattern, but you cannot combine fill with color and pattern on same path. If you want to use both, use preaction to fill with color and pattern to draw your pattern after filling.

Already predefined patterns use thin lines to draw, therefore if you want to use same width stripes, you need to define your own pattern.

Next you have two examples, both use preaction to fill with gray and pattern to draw orange stripes. First rectangle uses predefined north west lines pattern and second one a new north east hatch. (Taken from using pattern inside tikz shapes with dropped shadows)

\documentclass{standalone}
\usepackage{tikz}
\usetikzlibrary{patterns}
\makeatletter
\tikzset{% customization of pattern
         % based on <m.wibrow@gm...> - 2013-03-24 07:20: 
        hatch distance/.store in=\hatchdistance,
        hatch distance=5pt,
        hatch thickness/.store in=\hatchthickness,
        hatch thickness=5pt
        }
\pgfdeclarepatternformonly[\hatchdistance,\hatchthickness]{north east hatch}% name
    {\pgfqpoint{-1pt}{-1pt}}% below left
    {\pgfqpoint{\hatchdistance}{\hatchdistance}}% above right
    {\pgfpoint{\hatchdistance-1pt}{\hatchdistance-1pt}}%
    {
        \pgfsetcolor{\tikz@pattern@color}
        \pgfsetlinewidth{\hatchthickness}
        \pgfpathmoveto{\pgfqpoint{0pt}{0pt}}
        \pgfpathlineto{\pgfqpoint{\hatchdistance}{\hatchdistance}}
        \pgfusepath{stroke}
    }
\makeatother
\begin{document}
\begin{tikzpicture}[Pattern/.style={pattern=north east hatch, pattern color=orange, hatch distance=7pt, hatch thickness=2pt}]
\draw[preaction={fill=gray}, pattern=north west lines, pattern color=orange, draw=red] (0,0) rectangle (2,2.5);
\draw[preaction={fill=gray}, Pattern, draw=red] (2.5,0) rectangle (4.5,2.5);
\end{tikzpicture}
\end{document}

Answer 2

A bit tricky solution without defining custom pattern for rectangle a=2xb.

\documentclass{article}
\usepackage{tikz}

\begin{document}

\begin{tikzpicture}
\def\a{2}%width of rectangle
\def\b{\a/2}%height of rectangle
\def\lw{0.1}
\draw[] (0,0) rectangle (\a,\b);
\foreach \x in{0,0.2,0.4,...,\a}{
\draw [gray,line width=\lw mm](\x,0)--(0,\x/2);
\draw [gray,line width=\lw mm](\a,\x/2)--(\x,\b);}

\foreach \x in{0.1,0.3,...,\a}{
\draw [yellow,line width=\lw mm](\x,0)--(0,\x/2);
\draw [yellow,line width=\lw mm](\a,\x/2)--(\x,\b);}

\end{tikzpicture}

\end{document}

Answer 3

Using the answer I linked to above, below is a solution. The package itself does not give you an easier way I'm afraid. Unless of course you draw the pattern by hand.

\documentclass{standalone}

\usepackage{tikz}
\usetikzlibrary{patterns}

% defining the new dimensions and parameters
\newlength{\hatchspread}
\newlength{\hatchthickness}
\newlength{\hatchshift}
\newcommand{\hatchcolor}{}
% declaring the keys in tikz
\tikzset{hatchspread/.code={\setlength{\hatchspread}{#1}},
         hatchthickness/.code={\setlength{\hatchthickness}{#1}},
         hatchshift/.code={\setlength{\hatchshift}{#1}},% must be >= 0
         hatchcolor/.code={\renewcommand{\hatchcolor}{#1}}}
% setting the default values
\tikzset{hatchspread=3pt,
         hatchthickness=0.4pt,
         hatchshift=0pt,% must be >= 0
         hatchcolor=black}
% declaring the pattern
\pgfdeclarepatternformonly[\hatchspread,\hatchthickness,\hatchshift,\hatchcolor]% variables
   {custom north west lines}% name
   {\pgfqpoint{\dimexpr-2\hatchthickness}{\dimexpr-2\hatchthickness}}% lower left corner
   {\pgfqpoint{\dimexpr\hatchspread+2\hatchthickness}{\dimexpr\hatchspread+2\hatchthickness}}% upper right corner
   {\pgfqpoint{\dimexpr\hatchspread}{\dimexpr\hatchspread}}% tile size
   {% shape description
    \pgfsetlinewidth{\hatchthickness}
    \pgfpathmoveto{\pgfqpoint{0pt}{\dimexpr\hatchspread+\hatchshift}}
    \pgfpathlineto{\pgfqpoint{\dimexpr\hatchspread+0.15pt+\hatchshift}{-0.15pt}}
    \ifdim \hatchshift > 0pt
      \pgfpathmoveto{\pgfqpoint{0pt}{\hatchshift}}
      \pgfpathlineto{\pgfqpoint{\dimexpr0.15pt+\hatchshift}{-0.15pt}}
    \fi
    \pgfsetstrokecolor{\hatchcolor}
%    \pgfsetdash{{1pt}{1pt}}{0pt}% dashing cannot work correctly in all situation this way
    \pgfusepath{stroke}
   }

\begin{document}
\begin{tikzpicture}% hatchshift must be >= 0
\draw[pattern=custom north west lines,hatchthickness=5.5pt,hatchspread=15pt,hatchcolor=gray] (0,0) rectangle (2,2);
\draw[pattern=custom north west lines,hatchthickness=5.5pt,hatchspread=15pt,hatchcolor=orange,hatchshift=7.5pt] (0,0) rectangle (2,2);
\end{tikzpicture}%
\end{document}