Table vertical centering : what am I doing wrong?

Question

I know there are multiple questions and their answers on the topic but I can't make it work. I tried multiple codes to make a table, the one I have now works as long as I don't use images. And I would like very much to use them.

here is my MWE :

\documentclass[border=5pt]{standalone}
\usepackage[utf8]{inputenc}
\usepackage{tikz,esvect}
\usepackage{tabularray}
\usepackage{multirow}


\begin{document}

\setlength\arraycolsep{1pt}

\begin{tblr}{
  colspec = {Q[c,m]Q[c,m]Q[c,m]Q[c,m]},
  stretch = 0,
  rowsep = 6pt,
  hlines = {1.2pt},
  vlines = {1.2pt},
}

        Famille
    & 
        Nom
    & 
        Schéma 
    &
        Torseur Cinématique
 \\   
    \SetCell[r=2]{} Liaison à direction
     &
     Glissière
     & 
     \includegraphics[height=2cm]{glissiere.png}
     & 
        $VVV = \displaystyle \frac{zz}{\displaystyle \int dx}$
\\  
        
     &
        Plane
     & 
          \includegraphics[height=2cm]{plane.png}
     &
         $VVV = \displaystyle \frac{zz}{\displaystyle \int dx}$
\\   
\end{tblr}


\end{document}

Here is the result, despite Q[c,m] :

You can see that the content of the second and fourth column are lower than expected and in the third column it's higher : as if the bottom of the images were vertically aligned with the text in the other columns

If you like overleaf here is a link to a directory of my MWE : https://www.overleaf.com/read/wmbbxqyssxvd

I know that using images complicates my MWE but it is at the heart of my problem. so here they are :

Follow up question : Why are the tables in LaTeX so awful to use ?

Answer 1

You need to move images baseline to images vertical center. This can be done on several vays, but seems (to my opinion) that valign of adjustbox is the most handy. Doing this you not need option m in columns specifications:

\documentclass[border=5pt]{standalone}

\usepackage[export]{adjustbox}   % <---
\usepackage{tikz,esvect}
\usepackage{tabularray}
\UseTblrLibrary{amsmath}
\newcommand\ds{\displaystyle}    % <---


\begin{document}
    \begin{tblr}{colspec = {X[c] Q[c]Q[c] Q[c, mode=dmath]}, % <---
                 colsep  = 2pt,
                 row{1}  = {mode=text},                      % <---
                 hlines  = {1.2pt},  vlines = {1.2pt},
                }
Famille & Nom       & Schéma    & Torseur Cinématique               \\
\SetCell[r=2]{c}    Liaison à direction
        & Glissière & \includegraphics[height=2cm, valign=m]{example-image-duck}%{glissiere.png}
                                & VVV = \frac{zz}{\ds \int dx}      \\
        & Plane     & \includegraphics[height=2cm, valign=m]{example-image-duck}%{plane.png}
                                & VVV = \frac{zz}{\ds \int dx}
                \\
    \end{tblr}
\end{document}

Off-topic: In above MWE are

• for shorter code for \displaystyle is defined new command \ds
• last column in is display math style (do you really need integral in fraction as display style?)
• used is only tabularray syntax (\colsep in table preamble instead \setlength\arraycolsep{1pt} before table)

• In cases, when for images you insert tikz code, than for moving image baseline to it vertical center, add baseline=(current bounding box.center) to tikzpicture options.

Edit:

In case, that texts in some cells have few lines, that for their vertical centering you should replace X[c] with X[c, ]`:

    \begin{tblr}{colspec = {X[c,m] Q[c,m]Q[c] Q[c, mode=dmath]}, % <---
                 colsep  = 2pt,
                 row{1}  = {mode=text},                      % <---
                 hlines  = {1.2pt},  vlines = {1.2pt},
                }
Famille & Nom       & Schéma    & Torseur Cinématique               \\
\SetCell[r=2]{c}    Liaison à direction
        & Glissière & \includegraphics[height=2cm, valign=m]{example-image-duck}%{glissiere.png}
                                & VVV = \frac{zz}{\ds \int dx}      \\
        & {Plane\\ Plane\\ Plane}    
                    & \includegraphics[height=2cm, valign=m]{example-image-duck}%{plane.png}
                                & VVV = \frac{zz}{\ds \int dx}
                \\
    \end{tblr}

Answer 2

It seems to me that:

• for the vertical alignment of the images, we need h and not m;
• the text of column 2 is aligned vertically with the = of column 4, if you want to align vertically with the image, I haven't found anything other than a manual adjustment with {\\[-1ex]Plane} or use adjustbox

the code

    \documentclass[border=5pt]{standalone}
    %https://tex.stackexchange.com/questions/680131/table-vertical-centering-what-am-i-doing-wrong
    \usepackage{tabularray}
    \usepackage{graphicx}
    \usepackage{adjustbox}% <-- added
    \begin{document}
    \setlength\arraycolsep{1pt}
    \begin{tblr}{
    %colspec = {Q[c]Q[c]Q[c,h]Q[c]},
    colspec = {*{4}{Q[c]}},% with adjsutbox
    stretch = 0,
    rowsep = 6pt,
    hlines = {1.2pt},
    vlines = {1.2pt},
    }
            Famille
        & 
            Nom
        & 
            Schéma 
        &
            Torseur Cinématique
    \\   
        \SetCell[r=2]{} Liaison à direction
        &
        Glissière
        & 
        %\includegraphics[height=2cm]{example-image-a}
        \adjustbox{valign=M}{\includegraphics[height=2cm]{example-image-a}}
        & 
                $VVV = \displaystyle \frac{zz}{\displaystyle \int dx}$
    \\        
        &
        %{\\[-1ex]Plane}
        %& 
        %    \includegraphics[height=2cm]{example-image-b}
        Plane
        & 
        \adjustbox{valign=M}{\includegraphics[height=2cm]  {example-image-b}}
        &
            $VVV = \displaystyle \frac{zz}{\displaystyle \int dx}$
    \\   
    \end{tblr}
    \end{document}

Another possibility with nicematrix and adjustbox

    \documentclass[border=5pt]{standalone}
    \usepackage{nicematrix}
    \usepackage{graphicx}
    \usepackage{adjustbox}
    \begin{document}
    \begin{NiceTabular}{c c c}[hvlines,cell-space-limits=1mm]
    %\Body
    Glissière & 
    \adjustbox{valign=M}{\includegraphics[height=3cm]{example-image-b}}
    & $VVV = \displaystyle \frac{zz}{\displaystyle \int dx}$ \\
    \end{NiceTabular}
    \end{document}