\rule - LaTeX layout command

\rule{2em}{3em}

Renderer support

Package	MathJax	KaTeX	XeTeX
`base`	MathJax: Full	KaTeX: Partial	XeTeX: Partial
`textmacros`	MathJax: Full	KaTeX: Partial	XeTeX: Partial

Syntax#

\ruleo:L[1em]optional dimensionm:L{1em}dimensionm:L{1em}dimension

Argspec o:L m:L m:L — one optional and two mandatory arguments. Same argspec in base and textmacros. Reading argspecs

base

\rule[1em]2em3em

textmacros

\text{\rule{1em}{2pt}}

textmacros

\text{\rule[3pt]1em 2pt}

Package	Signature	Allowed mode	Notes
`base`	`o:L m:L m:L`	math	Used to insert a solid rectangular rule with a specified width and height, optionally shifted vertically via an optional bracket argument.
`textmacros`	`o:L m:L m:L`	text	Used in text mode to draw a solid rule of specified width and thickness, optionally raised or lowered by an offset.

TeXForm parses this entry as prefix syntax; the package determines its argument specification.

`base`
Input	Case	MathJax	KaTeX	XeTeX
`\rule{1pt}{1pt}`	Positive · baseline	Pass	Pass	Pass
`\rule[1pt]{1pt}{1pt}`	Positive · vary:o[0]	Pass	Pass	Pass
`\rule 1pt{1pt}`	Positive · bare[1]	Pass	Fail	Fail
`\rule{1pt}1pt`	Positive · bare[2]	Pass	Pass	Fail
`\rule[a]{1pt}{1pt}`	Negative · neg:L[0]	Pass	Fail	Fail
`\rule{a}{1pt}`	Negative · neg:L[1]	Fail	Fail	Fail
`\rule{1pt}{a}`	Negative · neg:L[2]	Fail	Fail	Fail

`textmacros`
Input	Case	MathJax	KaTeX	XeTeX
`\rule{1pt}{1pt}`	Positive · baseline	Pass	Pass	Pass
`\rule[1pt]{1pt}{1pt}`	Positive · vary:o[0]	Pass	Pass	Pass
`\rule 1pt{1pt}`	Positive · bare[1]	Pass	Fail	Fail
`\rule{1pt}1pt`	Positive · bare[2]	Pass	Pass	Fail
`\rule[a]{1pt}{1pt}`	Negative · neg:L[0]	Pass	Fail	Fail
`\rule{a}{1pt}`	Negative · neg:L[1]	Fail	Fail	Fail
`\rule{1pt}{a}`	Negative · neg:L[2]	Fail	Fail	Fail