Vrftjkry

Consider the following MWE:

documentclass[margin=2mm]{standalone}

usepackage{amsmath,amssymb}

usepackage{graphics}

defmyboxmin{mathop{raisebox{.15em}{scalebox{.5}{$boxminus$}}}}



begin{document}

$A myboxmin B$

end{document}

I would like to make it better in two ways

1. Define a RescaleSymbol command in such a way the above output is obtained typing RescaleSymbol[.5]{boxminus} (say, the default value for rescaling is .75)


2. Without the raisebox, the rescaled symbol is aligned to the baseline. Now, it must take as values (half of) the height of the symbol to be rescaled.

How can I do?

You can define your new macro as: newcommand{RescaleSymbol}[2][<default_optional>]{..} with #1 the optional parameter and #2 the mandatory one. The default value for the first (optional) parameter is written in the second pair of brackets. Use the new command as RescaleSymbol[<scale>]{<symbol>} or RescaleSymbol{<symbol>} with the default scale of 0.75.

documentclass[margin=2mm]{standalone}

usepackage{amsmath,amssymb}

usepackage{graphics}



newcommand{RescaleSymbol}[2][.75]{mathop{vcenter{hbox{scalebox{#1}{$#2$}}}}}



begin{document}

$A - RescaleSymbol[.5]{boxminus} B$

end{document}

You probably have mathop to vertically center the symbol with respect to the formula axis, but this only works if the argument to mathop is a single character.

The amsmath package has a built-in mechanism for deciding whether a symbol is a mathbin or a mathrel, which is used for underset and overset.

documentclass{article}

usepackage{amsmath}

usepackage{amssymb}

usepackage{graphicx}



makeatletter

newcommand{rescalesymbol}[2][0.75]{%

  binrel@{#2}% this makes binrel@@ to mean mathbin, mathrel or empty

  binrel@@{rescale@symbol{#1}{#2}}%

}

newcommand{rescale@symbol}[2]{%

  mathpaletterescale@@symbol{{#1}{#2}}%

}

newcommand{rescale@@symbol}[2]{%

  rescale@@@symbol#1#2%

}

newcommand{rescale@@@symbol}[3]{%

  % #1=math style, #2=scale factor, #3=symbol

  vcenter{hbox{scalebox{#2}{$m@th#1#3$}}}%

}

makeatother



begin{document}



$A rescalesymbol{boxminus} B$



$scriptstyle A rescalesymbol{boxminus} B$



$A rescalesymbol[0.5]{boxminus} B$



$scriptstyle A rescalesymbol[0.5]{boxminus} B$



$A rescalesymbol{pitchfork} B$



$scriptstyle A rescalesymbol{pitchfork} B$



$A rescalesymbol[0.5]{pitchfork} B$



$scriptstyle A rescalesymbol[0.5]{pitchfork} B$



end{document}

If you want to set the kind of the symbol differently from its standard status of mathbin or mathrel, or you need a totally different kind, I suggest a trailing optional argument:

documentclass{article}

usepackage{amsmath}

usepackage{amssymb}

usepackage{graphicx}

usepackage{xparse}



makeatletter

NewDocumentCommand{rescalesymbol}{O{0.75}mo}{%

  IfNoValueTF{#3}

   {%

    binrel@{#2}% this makes binrel@@ become mathbin, mathrel or empty

    binrel@@{rescale@symbol{#1}{#2}}%

   }

   {#3binrel@@{rescale@symbol{#1}{#2}}}%

}

newcommand{rescale@symbol}[2]{%

  mathpaletterescale@@symbol{{#1}{#2}}%

}

newcommand{rescale@@symbol}[2]{%

  rescale@@@symbol#1#2%

}

newcommand{rescale@@@symbol}[3]{%

  % #1=math style, #2=scale factor, #3=symbol

  vcenter{hbox{scalebox{#2}{$m@th#1#3$}}}%

}

makeatother



begin{document}



$A rescalesymbol{boxminus} B$



$scriptstyle A rescalesymbol{boxminus} B$



$A rescalesymbol[0.5]{boxminus} B$



$scriptstyle A rescalesymbol[0.5]{boxminus} B$



$A rescalesymbol{pitchfork} B$



$scriptstyle A rescalesymbol{pitchfork} B$



$A rescalesymbol[0.5]{pitchfork}[mathop] B$



$scriptstyle A rescalesymbol[0.5]{pitchfork}[mathop] B$



end{document}