Support for the TeX \cancel command

[sangwinc]

MathJax now has support for the TeX \cancel command, using https://cdn.jsdelivr.net/npm/mathjax@3/es5/tex-chtml.js and

MathJax.Hub.Config({
    config: ["Accessible.js", "Safe.js"],
    errorSettings: { message: ["!"] },
    skipStartupTypeset: true,
    messageStyle: "none",
    tex: {autoload: expandable({
         action: ['toggle', 'mathtip', 'texttip'],
         amscd: [[], ['CD']],
         bbox: ['bbox'],
         boldsymbol: ['boldsymbol'],
         braket: ['bra', 'ket', 'braket', 'set', 'Bra', 'Ket', 'Braket', 'Set', 'ketbra','Ketbra'],
         cancel: ['cancel', 'bcancel', 'xcancel', 'cancelto'],
         color: ['color', 'definecolor', 'textcolor', 'colorbox', 'fcolorbox'],
         enclose: ['enclose'],
         extpfeil: ['xtwoheadrightarrow', 'xtwoheadleftarrow', 'xmapsto', 'xlongequal', 'xtofrom', 'Newextarrow'],
         html: ['href', 'class', 'style', 'cssId'],
         mhchem: ['ce', 'pu'],
         newcommand: ['newcommand', 'renewcommand', 'newenvironment', 'renewenvironment', 'def', 'let'],
         unicode: ['unicode'],
         verb: ['verb']
    })}
});

Test cases are

\( {\color{red}\cancel{\color{black}x+1}}+a \)
\( \frac{x^2{\color{red}\cancel{\color{black}(x+1)}}}{\color{red}\cancel{\color{black}(x+1)}}\)

We could also add in a Maxima function cancel which typesets its argument, and another cancelwith which cancels its first argument, and indicates a replacement with the second. E.g. cancelwith(x+1,1) in maxima might typeset as

\( \stackrel{\color{red}1}{{\color{red}\cancel{\color{black}x+1}}} \)

Is this a useful addition? Comments welcome!
Chris

[sangwinc]

This should probably be disp_cancel to be consistent with disp_select in
Selecting, and highlighting part of an expression

[sangwinc]

Here is a screen shot of the above two examples.

[sangwinc]

This proved problematic with the new version of MathJax so we'll shelve it for now.