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KaTeX/docs/options.md
Erik Demaine 2202aa774f Comments without terminating newlines, \href fixes, \url support (#1529)
* Comments without terminating newlines in nonstrict mode

Fix #1506 by allowing single-line comments (`%` without terminating newline)
in nonstrict mode.  `Lexer` and `MacroExpander` now store the `Settings`
object, so the `Lexer` can complain about missing newline according to the
`strict` setting.  I filtered this out from the snapshot tests with a slightly
different `replacer`.

* Reimplement \href like \verb, add \url

Major restructuring to lex URL arguments differently, e.g. to support
`\href%{hello}` and `\href{http://foo.com/#test%}{hello}`.  The new URL
parsing code is simpler, but involves a special case in `parseSymbol`
like `\verb`.

Also add support for `\url` while we're here.

* Cleanup

* Fix flow errors and improve error messages

* Add \url to documentation

* Improve doc formatting
2018-07-31 14:13:30 -04:00

40 lines
4.1 KiB
Markdown

---
id: options
title: Options
---
You can provide an object of options as the last argument to [`katex.render` and `katex.renderToString`](api.md). Available options are:
- `displayMode`: `boolean`. If `true` the math will be rendered in display mode, which will put the math in display style (so `\int` and `\sum` are large, for example), and will center the math on the page on its own line. If `false` the math will be rendered in inline mode. (default: `false`)
- `throwOnError`: `boolean`. If `true` (the default), KaTeX will throw a `ParseError` when it encounters an unsupported command or invalid LaTeX. If `false`, KaTeX will render unsupported commands as text, and render invalid LaTeX as its source code with hover text giving the error, in the color given by `errorColor`.
- `errorColor`: `string`. A color string given in the format `"#XXX"` or `"#XXXXXX"`. This option determines the color that unsupported commands and invalid LaTeX are rendered in when `throwOnError` is set to `false`. (default: `#cc0000`)
- `macros`: `object`. A collection of custom macros. Each macro is a property with a name like `\name` (written `"\\name"` in JavaScript) which maps to a string that describes the expansion of the macro. Single-character keys can also be included in which case the character will be redefined as the given macro (similar to TeX active characters). *This object will be modified* if the LaTeX code defines its own macros via `\gdef`, which enables consecutive calls to KaTeX to share state.
- `colorIsTextColor`: `boolean`. If `true`, `\color` will work like LaTeX's `\textcolor`, and take two arguments (e.g., `\color{blue}{hello}`), which restores the old behavior of KaTeX (pre-0.8.0). If `false` (the default), `\color` will work like LaTeX's `\color`, and take one argument (e.g., `\color{blue}hello`). In both cases, `\textcolor` works as in LaTeX (e.g., `\textcolor{blue}{hello}`).
- `maxSize`: `number`. All user-specified sizes, e.g. in `\rule{500em}{500em}`, will be capped to `maxSize` ems. If set to `Infinity` (the default), users can make elements and spaces arbitrarily large.
- `maxExpand`: `number`. Limit the number of macro expansions to the specified number, to prevent e.g. infinite macro loops. If set to `Infinity`, the macro expander will try to fully expand as in LaTeX. (default: 1000)
- `allowedProtocols`: `string[]`. Allowed protocols in `\href`. Use `_relative` to allow relative urls, and `*` to allow all protocols. (default: `["http", "https", "mailto", "_relative"]`)
- `strict`: `boolean` or `string` or `function` (default: `"warn"`). If `false` or `"ignore`", allow features that make writing LaTeX convenient but are not actually supported by (Xe)LaTeX (similar to MathJax). If `true` or `"error"` (LaTeX faithfulness mode), throw an error for any such transgressions. If `"warn"` (the default), warn about such behavior via `console.warn`. Provide a custom function `handler(errorCode, errorMsg, token)` to customize behavior depending on the type of transgression (summarized by the string code `errorCode` and detailed in `errorMsg`); this function can also return `"ignore"`, `"error"`, or `"warn"` to use a built-in behavior. A list of such features and their `errorCode`s:
- `"unknownSymbol"`: Use of unknown Unicode symbol, which will likely also
lead to warnings about missing character metrics, and layouts may be
incorrect (especially in terms of vertical heights).
- `"unicodeTextInMathMode"`: Use of Unicode text characters in math mode.
- `"mathVsTextUnits"`: Mismatch of math vs. text commands and units/mode.
- `"commentAtEnd"`: Use of `%` comment without a terminating newline.
LaTeX would thereby comment out the end of math mode (e.g. `$`),
causing an error.
A second category of `errorCode`s never throw errors, but their strictness
affects the behavior of KaTeX:
- `"newLineInDisplayMode"`: Use of `\\` or `\newline` in display mode
(outside an array/tabular environment). In strict mode, no line break
results, as in LaTeX.
For example:
```js
katex.render("c = \\pm\\sqrt{a^2 + b^2}\\in\\RR", element, {
displayMode: true,
macros: {
"\\RR": "\\mathbb{R}"
}
});
```