"readme": "# postcss-pxtorem [](http://badge.fury.io/js/postcss-pxtorem)\n\nA plugin for [PostCSS](https://github.com/ai/postcss) that generates rem units from pixel units.\n\n## Install\n\n```shell\n$ npm install postcss-pxtorem --save-dev\n```\n\n## Usage\n\nPixels are the easiest unit to use (*opinion*). The only issue with them is that they don't let browsers change the default font size of 16. This script converts every px value to a rem from the properties you choose to allow the browser to set the font size.\n\n\n### Input/Output\n\n*With the default settings, only font related properties are targeted.*\n\n```css\n// input\nh1 {\n margin: 0 0 20px;\n font-size: 32px;\n line-height: 1.2;\n letter-spacing: 1px;\n}\n\n// output\nh1 {\n margin: 0 0 20px;\n font-size: 2rem;\n line-height: 1.2;\n letter-spacing: 0.0625rem;\n}\n```\n\n### Example\n\n```js\nvar fs = require('fs');\nvar postcss = require('postcss');\nvar pxtorem = require('postcss-pxtorem');\nvar css = fs.readFileSync('main.css', 'utf8');\nvar options = {\n replace: false\n};\nvar processedCss = postcss(pxtorem(options)).process(css).css;\n\nfs.writeFile('main-rem.css', processedCss, function (err) {\n if (err) {\n throw err;\n }\n console.log('Rem file written.');\n});\n```\n\n### options\n\nType: `Object | Null` \nDefault:\n```js\n{\n rootValue: 16,\n unitPrecision: 5,\n propList: ['font', 'font-size', 'line-height', 'letter-spacing'],\n selectorBlackList: [],\n replace: true,\n mediaQuery: false,\n minPixelValue: 0,\n exclude: /node_modules/i\n}\n```\n\n- `rootValue` (Number | Function) Represents the root element font size or returns the root element font size based on the [`input`](https://api.postcss.org/Input.html) parameter\n- `unitPrecision` (Number) The decimal numbers to allow the REM units to grow to.\n- `propList` (Array) The properties that can change from px to rem.\n - Values need to be exact matches.\n - Use wildcard `*` to enable all properties. Example: `['*']`\n - Use `*` at the start or end of a word. (`['*position*']` will match `background-position-y`)\n - Use `!` to not match a property. Example: `['*', '!letter-spacing']`\n - Combine the \"not\" prefix with the other prefixes. Example: `['*', '!font*']` \n- `selectorBlackList` (Array) The selectors to ignore and leave as px.\n - If value is string, it checks to see if selector contains the string.\n - `['body']` will match `.body-class`\n - If value is regexp, it checks to see if the selector matches the regexp.\n - `[/^body$/]` will match `body` but not `.body`\n- `replace` (Boolean) Replaces rules containing rems instead of adding fallbacks.\n- `mediaQuery` (Boolean) Allow px to be converted in media queries.\n- `minPixelValue` (Number) Set the minimum pixel value to replace.\n- `exclude` (String, Regexp, Function) The file path to ignore and leave as px.\n - If value is string, it checks to see if file path contains the string.\n - `'exclude'` will match `\\project\\postcss-pxtorem\\exclude\\path`\n - If value is regexp, it checks to see if file path matches the regexp.\n - `/exclude/i` will match `\\project\\postcss-pxtorem\\exclude\\path`\n - If value is function, you can use exclude function to return a true and the file will be ignored.\n - the callback will pass the file path as a parameter, it should returns a Boolean result.\n - `function (file) { return file.indexOf('exclude') !== -1; }`\n\n### Use with gulp-postcss and autoprefixer\n\n```js\nvar gulp = require('gulp');\nvar postcss = require('gulp-postcss');\nvar autoprefixer = require('autoprefixer');\nvar pxtorem = require('postcss-pxtorem');\n\ngulp.task('css', function () {\n\n var processors = [\n autoprefixer({\n browsers: 'last 1 version'\n }),\n pxtorem({\n replace: false\n })\n ];\n\n return gulp.src(['build/css/**/*.css'])\n .pipe(postcss(processors))\n .pipe(gulp.dest('build/css'));\n});\n```\n\n### A message about ignoring properties\nCurrently, the easiest way to have a single property ignored is to use a capital in the pixel unit declaration.\n\n```css\n// `px` is converted to `rem`\n.convert {\n font-size: 16px; // converted to 1rem\n}\n\n// `Px` or `PX` is ignored by `postcss-pxtorem` but still accepted by browsers\n.ignore {\n border: 1Px solid; // ignored\n border-width: 2PX; // ignored\n}\n```\n",
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