postcss-plugin-px2viewport

A plugin for PostCSS that converts px to viewport units or/and rem.

Options

Default:

{
  viewportWidth: 750,
  remRatio: 10,
  unitPrecision: 5,
  minPixelValue: 1,
  toRem: false,
  toViewport: true,
  handleDpx: false,
  mediaQuery: false,
  exclude: ''
}

• viewportWidth (Number) The width of the viewport.
• remRatio (Number) For generates the root element font-size.
• unitPrecision (Number) The decimal numbers to allow the REM units to grow to.
• minPixelValue (Number) Set the minimum pixel value to replace.
• toRem (Boolean) Whether to convert to rem.
• toViewport (Boolean) Whether to convert to vw.
• handleDpx (Boolean) Whether to handle dpx unit, close it can improve efficiency..
• mediaQuery (Boolean) Allow px to be converted in media queries.
• exclude (String | Regex) file path that excluded.

If you set the toRem is true. You'll append some codes into your entry file.

document.documentElement.style.fontSize = document.documentElement.clientWidth / 10 + 'px'

About unit dpx

It support dpx to resolve a pixel border problems. You need add some codes into your entry file like this.

if (window.devicePixelRatio && window.devicePixelRatio >= 2) {
  var fakeBody = document.createElement('body')
  var testElement = document.createElement('div')
  testElement.style.border = '.5px solid transparent'
  fakeBody.appendChild(testElement)
  docEl.appendChild(fakeBody)
  if (testElement.offsetHeight === 1) {
    docEl.classList.add('hairlines')
  }
  docEl.removeChild(fakeBody)
}

About unit rpx

rpx will just convert to px.

handleDpx

If you set options toRem and handleDpx to true. It suggests that you add the below codes into your entry file.

(function flexible (window, document) {
  var docEl = document.documentElement
  var dpr = window.devicePixelRatio || 1

  // set 1rem = viewWidth / 10
  function setRemUnit () {
    var rem = docEl.clientWidth / 10
    docEl.style.fontSize = rem + 'px'
  }

  setRemUnit()

  // reset rem unit on page resize
  window.addEventListener('resize', setRemUnit)
  window.addEventListener('pageshow', function (e) {
    if (e.persisted) {
      setRemUnit()
    }
  })

  // detect 0.5px supports
  if (dpr >= 2) {
    var fakeBody = document.createElement('body')
    var testElement = document.createElement('div')
    testElement.style.border = '.5px solid transparent'
    fakeBody.appendChild(testElement)
    docEl.appendChild(fakeBody)
    if (testElement.offsetHeight === 1) {
      docEl.classList.add('hairlines')
    }
    docEl.removeChild(fakeBody)
  }
}(window, document))

Example

.class .line {
  margin: -10px .5vh;
  padding: 5vmin 9.5px 1px;
  border: 3px solid black;
  border-bottom-width: 1px;
  font-size: 14px;
  line-height: 20px;
  color: #fff;
}
.class2 {
  border: 1px solid black;
  margin-bottom: 1px;
  font-size: 20px;
  line-height: 30px;
}
@media (min-width: 750px) {
  .class3 {
    border: 1dpx solid 10px;
    font-size: 16px;
    line-height: 22rpx;
  }
}
.class4 {
  border-top: 1dpx solid black;
  border-bottom: 1dpx solid black;
}

// convert to

.class .line {
  margin: -0.13333rem .5vh;
  margin: -1.33333vw .5vh;
  padding: 5vmin 0.12667rem 1px;
  padding: 5vmin 1.26667vw 1px;
  border: 0.04rem solid black;
  border: 0.4vw solid black;
  border-bottom-width: 1px;
  font-size: 0.18667rem;
  font-size: 1.86667vw;
  line-height: 0.26667rem;
  line-height: 2.66667vw;
  color: #fff;
}
.class2 {
  border: 1px solid black;
  margin-bottom: 1px;
  font-size: 0.26667rem;
  font-size: 2.66667vw;
  line-height: 0.4rem;
  line-height: 4vw;
}
@media (min-width: 750px) {
  .class3 {
    border: 1px solid 0.13333rem;
    border: 1px solid 1.33333vw;
    font-size: 0.21333rem;
    font-size: 2.13333vw;
    line-height: 22px;
  }
  .hairlines .class3 {
    border: 0.5px solid 0.13333rem;
    border: 0.5px solid 1.33333vw;
  }
}
.class4 {
  border-top: 1px solid black;
  border-bottom: 1px solid black;
}
.hairlines .class4 {
  border-top: 0.5px solid black;
  border-bottom: 0.5px solid black;
}