Mrthfx

This code

documentclass{article}

usepackage{bytefield}



begin{document}

begin{bytefield}[leftcurly=.,leftcurlyspace=0pt]{32}

  begin{leftwordgroup}{0}

    wordbox{1}{theheight}

  end{leftwordgroup} \

  begin{leftwordgroup}{raisebox{totalheight}4}

    wordbox{2}{theheight}

  end{leftwordgroup} \

  begin{leftwordgroup}{raisebox{6ex}{12}}

    wordbox{2}{theheight}

  end{leftwordgroup}

end{bytefield}

end{document}

results in

I'd like to get the 0 and the 4 left word groups to be vertically aligned with the top of their corresponding wordboxes. However, the only way I've found to do that is to trial and error it with raisebox{6ex}. height and totalheight seem to refer to the height of the text in the group. leftwordgroup doesn't make height available the same way wordbox and bitbox does.

Is there a more precise way to specify the vertical alignment of the left wordgroup?

Update

Thanks for taking the time to help me out with this.

When this was applied to a more sophisticated use of bytefield, it's a bit off.

documentclass{standalone}

usepackage{bytefield}

usepackage{stackengine}

newcommandtopwg[2]{%

  makebox[3ex][l]{makebox[2ex][r]{tiny{#1}}}belowbaseline[-.3htstrutbox]{#2}

}



begin{document}

begin{bytefield}[leftcurly=.,leftcurlyspace=0pt]{32}

  bitheader{0,8,16,24} \

  topwg{0}{begin{leftwordgroup}{}

      begin{rightwordgroup}{Standard Header}

        wordbox{1}{theheight}

      end{rightwordgroup}

  end{leftwordgroup}} \

  topwg{4}{begin{leftwordgroup}{}

    wordbox{2}{theheight}

  end{leftwordgroup}} \

  topwg{12}{begin{leftwordgroup}{}

    wordbox{2}{theheight}

  end{leftwordgroup}}

end{bytefield}

end{document}

Again, thanks a lot for your help.

Here, I introduce topwg macro that takes two arguments. The first is the label that would otherwise go as the first argument to leftwordgroup, and the second is the leftwordgroup environment with a blank first argument.

What this does is vertically shift the word group so that, instead of having its baseline aligned with the central text, it instead places the top of the wordgroup box at the height of a strutbox.

EDITED to address some deficiencies noted by the OP. I believe the inter-box gap was caused by some glue introduced by boxes that were located at fractional baseline height. Thus, I restored the htstrutbox shift of belowbaseline and tuned the left-label relative to that with a raisebox. This also corrected the problem with the vertical position of the right-hand label. Additionally, I added a small negative vspace at the end of topwg to avoid a double-thick rule between boxes.

documentclass{article}

usepackage{bytefield}

usepackage{stackengine}

newcommandtopwg[2]{%

  raisebox{.7htstrutbox}{makebox[3ex][l]{makebox[2ex][r]{%

  tiny{#1}}}}belowbaseline[-htstrutbox]{#2}vspace{-.65pt}%

}

%renewcommandtopwg[2]{#2}

begin{document}

begin{bytefield}[leftcurly=.,leftcurlyspace=0pt]{32}

  bitheader{0,8,16,24} \

  topwg{0}{begin{leftwordgroup}{}

      begin{rightwordgroup}{Standard Header}

        wordbox{1}{theheight}

      end{rightwordgroup}

  end{leftwordgroup}} \

  topwg{4}{begin{leftwordgroup}{}

    wordbox{2}{theheight}

  end{leftwordgroup}} \

  topwg{12}{begin{leftwordgroup}{}

    wordbox{2}{theheight}

  end{leftwordgroup}}

end{bytefield}

end{document}

If you plan on having more than two digits in the label to the left of the box, you can expand the width of the two makeboxes defined in topwg. The first number (3ex) determines the width of the labels on the left while the second number (2ex) specifies the left padding for those labels.

To change the height of the left-label, change the amount of the raisebox at the beginning of topwg.

I also changed the documentclass to article rather than standalone to prevent the bottom rule from being clipped (I'm not sure why).