PostCSS pxtransform-scale

PostCSS 单位转换插件，目前已支持小程序端（px 转rpx），H5 端（px 转 rem）及 RN 端。

基于 postcss-pxtorem。

Fork from postcss-pxtransform-scale，增加了scale配置，支持px缩放，如scale=0.5，32px转16px。

Install

$ npm install postcss-pxtransform-scale --save-dev

Usage

小程序

options = {
    platform: 'weapp',
    designWidth: 750,
}

H5

options = {
    platform: 'h5',
    designWidth: 750,
}

RN

options = {
    platform: 'rn',
    designWidth: 750,
}

动态计算designWidth

基础组件库一般是375，如果业务系统UI设计是750，可以如下配置后1:1切图，小程序、H5、RN时有效

options = {
    platform: 'h5',
    designWidth (input) {
      if (input.file.replace(/\\+/g, '/').indexOf('@nutui/nutui-taro') > -1) {
        return 375
      }
      return 750
    },
}

输入/输出

默认配置下，所有的 px 都会被转换。

/* input */
h1 {
    margin: 0 0 20px;
    font-size: 32px;
    line-height: 1.2;
    letter-spacing: 1px;
}

/* weapp output */
h1 {
    margin: 0 0 20rpx;
    font-size: 32rpx;
    line-height: 1.2;
    letter-spacing: 1rpx;
}

/* h5 output */
h1 {
    margin: 0 0 0.5rem;
    font-size: 1rem;
    line-height: 1.2;
    letter-spacing: 0.025rem;
}

/* rn output */
h1 {
    margin: 0 0 10px;
    font-size: 16px;
    line-height: 1.2;
    letter-spacing: 0.5px;
}

example

var fs = require('fs');
var postcss = require('postcss');
var pxtorem = require('postcss-pxtransform-scale');
var css = fs.readFileSync('main.css', 'utf8');
var options = {
    replace: false
};
var processedCss = postcss(pxtorem(options)).process(css).css;

fs.writeFile('main-rem.css', processedCss, function (err) {
  if (err) {
    throw err;
  }
  console.log('Rem file written.');
});

配置 options

参数默认值如下：

{
    unitPrecision: 5,
    propList: ['*'],
    selectorBlackList: [],
    replace: true,
    mediaQuery: false,
    minPixelValue: 0
}

Type: Object | Null

platform （String）（必填）

weapp 或 h5 或 rn

designWidth（Number|Function）（必填）

640 或 750 或 828

unitPrecision (Number)

The decimal numbers to allow the REM units to grow to.

propList (Array)

The properties that can change from px to rem.

• Values need to be exact matches.
• Use wildcard * to enable all properties. Example: ['*']
• Use * at the start or end of a word. (['*position*'] will match background-position-y)
• Use ! to not match a property. Example: ['*', '!letter-spacing']
• Combine the "not" prefix with the other prefixes. Example: ['*', '!font*']

selectorBlackList

(Array) The selectors to ignore and leave as px.

• If value is string, it checks to see if selector contains the string.
  • ['body'] will match .body-class
• If value is regexp, it checks to see if the selector matches the regexp.
  • [/^body$/] will match body but not .body

replace (Boolean)

replaces rules containing rems instead of adding fallbacks.

mediaQuery (Boolean)

Allow px to be converted in media queries.

minPixelValue (Number)

Set the minimum pixel value to replace.

scale (Number)

Set the scale value to transform px. For example, when scale set to 0.5, 32px will be transformed to 16px.

忽略

属性

当前忽略单个属性的最简单的方法，就是 px 单位使用大写字母。

 /*`px` is converted to `rem`*/
.convert {
    font-size: 16px; // converted to 1rem
}

 /* `Px` or `PX` is ignored by `postcss-pxtorem` but still accepted by browsers*/
.ignore {
    border: 1Px solid; // ignored
    border-width: 2PX; // ignored
}

文件

对于头部包含注释/*postcss-pxtransform-scale disable*/ 的文件，插件不予处理。

剔除

/*postcss-pxtransform-scale rn eject enable*/ 与 /*postcss-pxtransform-scale rn eject disable*/ 中间的代码， 在编译成 RN 端的样式的时候，会被删除。建议将 RN 不支持的但 H5 端又必不可少的样式放到这里面。如：样式重制相关的代码。

/*postcss-pxtransform-scale rn eject enable*/

.test {
  color: black;
}

/*postcss-pxtransform-scale rn eject disable*/