How to calc square root in stylus

问题

Is there a way to get Stylus calculate the square root of x?
You know, like JavaScript's Math.sqrt(x) does.

I am creating a diamond that should be centered on it's origin. the following code am i using at the moment:

vendor(prop, args...)
    -webkit-{prop} args
    -moz-{prop} args
    -o-{prop} args
    -ms-{prop} args


rotate(r)
    vendor('transform', unquote('rotate('+r+')'))
    rotate r


.diamond
    display block

    width 7ex
    height @width
    line-height @height
    rotate(-45deg)

    /* calc offset of a rotated square
     * @width * @width = $offsetX * $offsetX + $offsetY * $offsetY
     * @width * @width = ( $offset * $offset ) * 2 // for a square: $offsetX= $offsetY
     * ( @width * @width ) / 2 = ( $offset * $offset )
     * sqrt(( @width * @width ) / 2) = $offset
     * @width * sqrt(2) = $offset
     */
    $offset = @width / 1.41421356237 // =sqrt( 2 )
    margin (- $offset) 0em 0ex (- $offset ) // center the diamond on its origin

    padding 0ex 0em

    background-color red

as you can see, i managed to work it out without actually calculating the square root, but using a constant value instead. But when I looked at the Built-in Functions of Stylus, I was unable to find any method to calculate the square root.

Is there any way to get stylus calculate the square root of x?
_{Of cause the best would be to have some nice functions like LESS has built in.}

回答1:

As answered there you can use the built-in math function for this, so the custom sqrt could look better:

sqrt(x)
  return math(x, 'sqrt')

回答2:

you can use this code:

sqrt(x)
  if x == 0
    result = 0
  else
    result = 4
    for i in (0..10)
      result = ((result + (x / result)) / 2)

Demo on codepen: http://cdpn.io/jcnLF

来源：https://stackoverflow.com/questions/21033346/how-to-calc-square-root-in-stylus

标签

stylus