Drawing stars/similar with Tikz

Question

I'm writing a review for a book at the moment, and I thought I'd be clever and show off what LaTeX is capable of by adding a x-out-of-y stars graphic. Tikz can do many things so I would have thought that a trick like this would be fairly trivial, however it seems that I cannot figure out a macro to draw the shapes at the right size, let alone fancy tricks such as half-filled stars or something similar. I think the code I have so far might be headed in the right direction:

\usepackage{tikz}
\usetikzlibrary{shapes.geometric}
\usetikzlibrary{calc,shadows}

\newcommand*\starfill{%
  \tikz[baseline=(key.base),scale=-3]
  \node[star, star points=5, star point ratio=2.25, fill=black, draw](key) {S};  
}

I've tried to start by drawing a single star shape, but ideally I'd like to define like \starsranking{number}{total} that will output the appropriate shaded number of stars out of total. Is this doable? It doesn't sound particularly difficult.

Answer 1

Here's the code for fully filled stars, now slightly improved thanks to Andrew Stacey's answer to the checkerboard question:

\documentclass{minimal}
\usepackage{tikz}
\usetikzlibrary{shapes.geometric}

\newcommand\score[2]{%
  \pgfmathsetmacro\pgfxa{#1 + 1}%
  \tikzstyle{scorestars}=[star, star points=5, star point ratio=2.25, draw, inner sep=1.3pt, anchor=outer point 3]%
  \begin{tikzpicture}[baseline]
    \foreach \i in {1, ..., #2} {
      \pgfmathparse{\i<=#1 ? "yellow" : "gray"}
      \edef\starcolor{\pgfmathresult}
      \draw (\i*1.75ex, 0) node[name=star\i, scorestars, fill=\starcolor]  {};
   }
  \end{tikzpicture}%
}

\begin{document}
\score{0}{5} A meagre result.

\score{4}{5} Much better

\score{5}{5} Perfect score!

\end{document}

---

And here's the much more elaborate, much more pointless, floating point scoring star macro (I'll leave the simple one in as well, it's a lot more usable):

\documentclass{article}
\usepackage{tikz}
\usetikzlibrary{shapes.geometric, calc}

\newcommand\score[2]{%
  \pgfmathsetmacro\pgfxa{#1 + 1}%
  \tikzstyle{scorestars}=[star, star points=5, star point ratio=2.25, draw, inner sep=0.15em, anchor=outer point 3]%
  \begin{tikzpicture}[baseline]
    \foreach \i in {1, ..., #2} {
      \pgfmathparse{\i<=#1 ? "yellow" : "gray"}
      \edef\starcolor{\pgfmathresult}
      \draw (\i*1em, 0) node[name=star\i, scorestars, fill=\starcolor]  {};
    }
    \pgfmathparse{#1>int(#1) ? int(#1+1) : 0}
    \let\partstar=\pgfmathresult
    \ifnum\partstar>0
      \pgfmathsetmacro\starpart{#1-(int(#1)}
      \path [clip] ($(star\partstar.outer point 3)!(star\partstar.outer point 2)!(star\partstar.outer point 4)$) rectangle 
      ($(star\partstar.outer point 2 |- star\partstar.outer point 1)!\starpart!(star\partstar.outer point 1 -| star\partstar.outer point 5)$);
      \fill (\partstar*1em, 0) node[scorestars, fill=yellow]  {};
    \fi
  \end{tikzpicture}%
}

\begin{document}
\score{0}{5} That's appalling!

\small\score{2}{5} A meagre result.

\Huge{\score{4.4}{5} Wooo!}

\end{document}

Answer 2

Asymptote version stars.asy:

size(200);
real sc=20;

picture score(real scoreMark=0,guide star=scale(sc)*unitcircle, int maxscore=5, 
  pen linePen=nullpen, pen bgPen=darkblue, pen scorePen=orange){
  picture pic;
  guide[] g;  
  for(int i=0;i<maxscore;++i){
    g.push(shift((2sc*i,0))*star);
  }
  assert(maxscore>0 && scoreMark>=0 && scoreMark<=maxscore,"***** Wrong score.");
  fill(pic,box((-sc,-sc),(maxscore*2sc-sc,sc)),bgPen);
  fill(pic,box((-sc,-sc),(scoreMark*2sc-sc,sc)),scorePen);
  clip(pic,g);
  draw(pic,g,linePen);
  return pic;
}

guide star;
pair p;
for(int i=0;i<5;++i){
  p=rotate(72*i)*N;
  star=star--p;
  star=star--(scale(0.382)*rotate(72*i+36)*N);
}
star=scale(sc)*(star--cycle);

add(score(scoreMark=1,star,maxscore=7),(0,0));
add(score(scoreMark=2,star,maxscore=7,linePen=lightred,bgPen=lightblue),(0,-3sc));
add(score(scoreMark=3.5,star,maxscore=5,linePen=lightred,bgPen=lightblue),(0,-6sc));
add(score(scoreMark=3.75,star,maxscore=4,linePen=olive,bgPen=white,scorePen=lightgreen),(0,-9sc));

add(score(4.2,bgPen=green+opacity(0.3),scorePen=red+opacity(0.5)),(0,3sc));

To get a standalone stars.pdf run asy -f pdf stars.asy.

Answer 3

With PSTricks.

\documentclass[preview,border=12pt,varwidth]{standalone}
\usepackage{pstricks}
\usepackage{multido}
\SpecialCoor
\makeatletter
\def\LoadPSVars{\pstVerb{/ptcm {\pst@number\psunit div} bind def}}
\makeatother

\def\points{}
\def\Star{%
    \xdef\points{}% cleaning
    \multido{\iR=0+72,\ir=36+72}{5}{\xdef\points{\points (10pt;\iR)(5pt;\ir)}}
    \expandafter\pspolygon\points}

\def\Rating#1{% #1: percentage
    \psscalebox{0.35}{%
    \begin{pspicture}(11pt,-11pt)(111pt,11pt)
    \LoadPSVars
    \psclip{\pscustom{\psLoop{5}{\translate(20pt,0)\Star}}}
        \psframe*[linecolor=yellow](11pt,-11pt)(!#1 11 add ptcm 11 ptcm)
    \endpsclip
    \pscustom{\psLoop{5}{\translate(20pt,0)\Star}}
    \end{pspicture}}}

\begin{document}
\begin{enumerate}
    \item \Rating{100} PSTricks
    \item \Rating{50} Asymptote
    \item \Rating{20} Metapost
    \item \Rating{5} TikZ
\end{enumerate}
\end{document}

Warning:

• \rput will not work inside \pscustom. Use \translate instead!
• standalone discards my ptcm operator defined in the preamble, so I have to load it manually inside pspicture. It is sad!

Answer 4

I have written a package for ConTeXt that draws X out of Y graphics. It is primarily meant to draw numbers in presentations. It offers stars as one of the options:

\usemodule[visualcounter]

\definepalet
  [star-colors]
  [active=yellow,
     past=yellow,
   future=gray]

\definevisualcounter
  [stars]
  [markers]
  [mpsetups=visualcounter::markers:star, 
   width=1.5EmWidth,
   distance=0.25EmWidth,
   palette=star-colors, 
  ]

\starttext

\startTEXpage[offset=2mm]
\startitemize
  \item \usevisualcounter[n=1, last=5]{stars} That's appalling!
  \item \usevisualcounter[n=2, last=5]{stars} A meagre result.
  \item \usevisualcounter[n=4, last=5]{stars} Woo!
\stopitemize
\stopTEXpage
\stoptext

See documentation for more details.

As the primary purpose of this module is to display page numbers, it does not support fractional values.

Answer 5

Jake's answer is very good. Here's the extra half star:

\node[scorestars,fill=gray] {};
\path node[scorestars,fill=yellow] (s) {} [clip] (s.south west) rectangle (s.north);