extpfeil

.. _tex-extpfeil:

######## extpfeil ########

The extpfeil extension adds macros for producing extensible arrows, including \xtwoheadrightarrow, \xtwoheadleftarrow, \xmapsto, \xlongequal, \xtofrom, and a non-standard \Newextarrow for creating your own extensible arrows. The latter has the form

.. describe:: \Newextarrow{\cs}{lspace,rspace}{unicode-char}

where ``\cs`` is the new control sequence name to be defined,
``lspace`` and ``rspace`` are integers representing the amount of
space (in suitably small units) to use at the left and right of
text that is placed above or below the arrow, and ``unicode-char``
is a number representing a unicode character position in either
decimal or hexadecimal notation.

For example

.. code-block:: latex

\Newextarrow{\xrightharpoonup}{5,10}{0x21C0}

defines an extensible right harpoon with barb up. Note that MathJax knows how to stretch only a limited number of characters, so you may not actually get a stretchy character this way. The characters that can be stretched may also depend on the font you have selected.

This extension is loaded automatically when the :ref:tex-autoload extension is used. To load the extpfeil extension explicitly, add '[tex]/extpfeil' to the :data:load array of the :data:loader block of your MathJax configuration, and add 'extpfeil' to the :data:packages array of the :data:tex block.

.. code-block:: javascript

window.MathJax = { loader: {load: ['[tex]/extpfeil']}, tex: {packages: {'[+]': ['extpfeil']}} };

Alternatively, use \require{extpfeil} in a TeX expression to load it dynamically from within the math on the page, if the :ref:tex-require extension is loaded.

.. _tex-extpfeil-commands:

extpfeil Commands

The extpfeil extension implements the following macros: \Newextarrow, \xlongequal, \xmapsto, \xtofrom, \xtwoheadleftarrow, \xtwoheadrightarrow

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