Added an eye for the Newman projection

Question

To better understand the axis of vision in the Newman projection, I would like to add a symbolic eye (while searching, I found this code: Symbol for eye (looking for a library) ) in the middle of my figure as in the image below

After drawing my molecule with \chemfig, the addition of the eye is done at the bottom right and not in the axis as desired:

    \documentclass[border=3mm]{standalone}
\usepackage{chemmacros}
\usepackage{chemfig}
\newcommand*\lateraleye{%
       \scalebox{0.15}{
    \tikzset{every picture/.style={line width=0.75pt}} 
    \begin{tikzpicture}[x=0.75pt,y=0.75pt,yscale=-1,xscale=1]
    \draw  [line width=1.5]  (300,100.33) .. controls (326,122) and (352,135) .. (378,139.33) .. controls (352,143.67) and (326,156.67) .. (300,178.33) ;
    \draw  [fill={rgb, 255:red, 0; green, 0; blue, 0 }  ,fill opacity=1 ] (308.94,116.33) .. controls (313.87,116.33) and (317.86,125.51) .. (317.85,136.83) .. controls (317.84,148.15) and (313.84,157.33) .. (308.91,157.33) .. controls (303.99,157.32) and (300,148.14) .. (300.01,136.82) .. controls (300.02,125.5) and (304.02,116.32) .. (308.94,116.33) -- cycle ;
    \draw  [draw opacity=0][line width=1.5]  (314.84,166.6) .. controls (311.87,164.64) and (309.14,162.18) .. (306.76,159.24) .. controls (295.12,144.82) and (296.6,124.33) .. (310.07,113.45) .. controls (311.48,112.32) and (312.96,111.33) .. (314.5,110.49) -- (331.14,139.55) -- cycle ; \draw  [line width=1.5]  (314.84,166.6) .. controls (311.87,164.64) and (309.14,162.18) .. (306.76,159.24) .. controls (295.12,144.82) and (296.6,124.33) .. (310.07,113.45) .. controls (311.48,112.32) and (312.96,111.33) .. (314.5,110.49) ;
    \draw  [fill={rgb, 255:red, 255; green, 255; blue, 255 }  ,fill opacity=1 ] (304.43,124.2) .. controls (306.09,124.25) and (307.32,128.01) .. (307.18,132.6) .. controls (307.05,137.19) and (305.59,140.88) .. (303.93,140.83) .. controls (302.27,140.78) and (301.03,137.02) .. (301.17,132.43) .. controls (301.31,127.83) and (302.76,124.15) .. (304.43,124.2) -- cycle ;
    \end{tikzpicture}
    },}
\begin{document}
\chemfig{H-[:60]{\color{purple}C}(&lt;[:140,,,,green]{\color{green}H})(&lt;:[:115,,,,magenta]{\color{magenta}H})-{\color{cyan}C}(&lt;[:-75,,,,blue]{\color{blue}OH})(&lt;:[:-45,,,,brown]{\color{brown}H})-[:60,,,,red]{\color{red}H}}
\lateraleye{}
\end{document}

how can i move the eye in my \chemfig figure?

Can you use this answer to your Newman angles question in combination with this viewpoint question in writing your students guide on Newman projections? — alchemist, Feb 18 '23 at 17:36

score 5 · Answer 1 · answered Feb 09 '23 at 15:00

The trick is to re-write the code for the molecule, such that the first atom is the left C. The first atom in the code of a molecule always sits on the baseline:

\documentclass[border=3mm]{standalone}
\usepackage{chemfig}
\newcommand*\lateraleye{%
    \begin{tikzpicture}[x=0.75pt, y=0.75pt, yscale=-0.15, xscale=0.15]
    \draw[very thin]  (300,100.33) .. controls (326,122) and (352,135) .. (378,139.33) .. controls (352,143.67) and (326,156.67) .. (300,178.33) ;
    \fill (308.94,116.33) .. controls (313.87,116.33) and (317.86,125.51) .. (317.85,136.83) .. controls (317.84,148.15) and (313.84,157.33) .. (308.91,157.33) .. controls (303.99,157.32) and (300,148.14) .. (300.01,136.82) .. controls (300.02,125.5) and (304.02,116.32) .. (308.94,116.33) -- cycle ;
    \draw[very thin] (314.84,166.6) .. controls (311.87,164.64) and (309.14,162.18) .. (306.76,159.24) .. controls (295.12,144.82) and (296.6,124.33) .. (310.07,113.45) .. controls (311.48,112.32) and (312.96,111.33) .. (314.5,110.49) ; 
    \fill[white] (304.43,124.2) .. controls (306.09,124.25) and (307.32,128.01) .. (307.18,132.6) .. controls (307.05,137.19) and (305.59,140.88) .. (303.93,140.83) .. controls (302.27,140.78) and (301.03,137.02) .. (301.17,132.43) .. controls (301.31,127.83) and (302.76,124.15) .. (304.43,124.2) -- cycle ;
    \end{tikzpicture}%
}
\begin{document}
\chemfig{{\color{purple}C}(-[:240]H)(&lt;[:140,,,,green]{\color{green}H})(&lt;:[:115,,,,magenta]{\color{magenta}H})-{\color{cyan}C}(&lt;[:-75,,,,blue]{\color{blue}OH})(&lt;:[:-45,,,,brown]{\color{brown}H})-[:60,,,,red]{\color{red}H}}
\lateraleye


\end{document}

(I also simplified the code for the eye icon a bit.)

Sandy G · Accepted Answer · 2023-02-09T18:20:53.773

You can enclose the chemfig in a \vcentered \hbox:

\[\vcenter{\hbox{\chemfig{H-[:60]{\color{purple}C}(<[:140,,,,green]{\color{green}H})(<:[:115,,,,magenta]{\color{magenta}H})-{\color{cyan}C}(<[:-75,,,,blue]{\color{blue}OH})(<:[:-45,,,,brown]{\color{brown}H})-[:60,,,,red]{\color{red}H}}}}
\lateraleye{}\]

Unrelated, but the code for the eye is overly complicated. Here is a simpler version:

\documentclass{article}
\usepackage{chemfig}
\newcommand{\eyel}{40} % increase (up to 45) for shorter eyelashes
\colorlet{eyecolor}{green!60!black}
\newcommand\lateraleye{%
  \scalebox{0.4}[.5]{\tikz[line cap=round, line join=round]{
    \draw(225:1) arc (225:270:1) arc (90:135:1) (270-\eyel:1) arc (180-\eyel/2:180+\eyel/2:{sqrt(2-2cos(\eyel))}); % outline
    \draw[eyecolor, fill=eyecolor]({-sqrt(2-2cos(\eyel))},-1) arc(-180:180:.07 and .15); % iris
    \fill[white, shift={(.03,.03)}] ({-sqrt(2-2cos(\eyel))},-1)circle[x radius=.02, y radius=.05]; % accent
  }}
}
\begin{document}
[
  \vcenter{\hbox{\chemfig{H-[:60]{\color{purple}C}(<[:140,,,,green]{\color{green}H})(<:[:115,,,,magenta]{\color{magenta}H})-{\color{cyan}C}(<[:-75,,,,blue]{\color{blue}OH})(<:[:-45,,,,brown]{\color{brown}H})-[:60,,,,red]{\color{red}H}}}}
  \hspace{.5cm}\lateraleye
]
\end{document}

Added an eye for the Newman projection

2 Answers2