Unit converter

_unit.sass

/////////////////////////////
//  SIZE
/////////////////////////////

// Base size should be the em height on the html element
$base-size: 16px !default
$pi: 3.14159265 !default

// Android uses density-independent pixels. Using the same terminology here for conversions.
// Convert dips to em, rem, or px
$dip-conversion: em !default

// Context offset
$em-offset: 1 !default

// Convert dips to em or rem (px will not work because the W3C spec considers px to be density independent pixels)
$px-conversion: em !default

@function dip($number, $em-offset, $dip-conversion)
  $unitless-em-offset: $em-offset / 1em
  @if unitless($em-offset)
    $unitless-em-offset: $em-offset
  @if $dip-conversion == px
    @return $number * 1px
  @if $dip-conversion == em
    @return ($number / ($base-size / 1px)) * (1 / $unitless-em-offset) * 1em
  @if $dip-conversion == rem
    @return $number / ($base-size / 1px) * 1rem

@function dp($number, $em-offset, $dip-conversion)
  @return dip($number, $em-offset, $dip-conversion)

// Simple px => em conversion
@function em($number, $em-offset)
  @return dip($number, $em-offset, em)

// Simple px => rem conversion
@function rem($number, $em-offset)
  @return dip($number, $em-offset, rem)


/////////////////////////////
//  TIME
/////////////////////////////

@function ms($time)
  @if unit($time) == ms
    @return $time
  @if unit($time) == s
    @return ($time / 1s) * 1000ms
  @else
    @warn "#{unit($time)} is not a unit of time"

@function s($time)
  @if unit($time) == s
    @return $time
  @if unit($time) == ms
    @return ($time / 1ms) / 1000 * 1s
  @else
    @warn "#{unit($time)} is not a unit of time"


/////////////////////////////
//  FREQUENCY
/////////////////////////////

@function Hz($frequency)
  @if unit($frequency) == Hz
    @return $frequency
  @if unit($frequency) == kHz
    @return ($frequency / 1kHz) * 1000Hz
  @else
    @warn "#{unit($frequency)} is not a unit of frequency"

@function kHz($frequency)
  @if unit($frequency) == kHz
    @return $frequency
  @if unit($frequency) == Hz
    @return ($frequency / 1Hz) / 1000 * 1kHz
  @else
    @warn "#{unit($frequency)} is not a unit of frequency"


/////////////////////////////
//  SCREEN
/////////////////////////////

@function dpi($resolution)
  @if unit($resolution) == dpi
    @return $resolution
  @if unit($resolution) == dpcm
    @return ($resolution / 1dpcm) / 2.54 * 1dpi
  @else
    @warn "#{unit($resolution)} is not a unit of resolution"


@function dpcm($resolution)
  @if unit($resolution) == dpcm
    @return $resolution
  @if unit($resolution) == dpi
    @return ($resolution / 1dpi) * 2.54dpcm
  @else
    @warn "#{unit($resolution)} is not a unit of resolution"


/////////////////////////////
//  ANGLE MEASUREMENTS
/////////////////////////////


@function deg($value)
  @if unit($value) == deg
    @return $value
  @if unit($value) == rad
    @return ( $value / 1rad ) * 180 / $pi * 1deg
  @if unit($value) == grad
    @return ( $value / 1grad ) * 180 / $pi * 1deg
  @if unit($value) == turn
    @return ( $value / 1turn ) * 180 / $pi * 1deg
  @else
    @warn "#{unit($value)} is not a unit of angle"


@function rad($value)
  @if unit($value) == rad
    @return $value
  @if unit($value) == deg
    @return ( $value / 1rad ) * 180 / $pi * 1deg
  @if unit($value) == grad
    @return ( $value / 1grad ) * 180 / $pi * 1deg
  @if unit($value) == turn
    @return ( $value / 1turn ) * 180 / $pi * 1deg
  @else
    @warn "#{unit($value)} is not a unit of angle"


@function grad($value)
  @if unit($value) == grad
    @return $value
  @if unit($value) == rad
    @return ( $value / 1rad ) * 180 / $pi * 1deg
  @if unit($value) == deg
    @return ( $value / 1grad ) * 180 / $pi * 1deg
  @if unit($value) == turn
    @return ( $value / 1turn ) * 180 / $pi * 1deg
  @else
    @warn "#{unit($value)} is not a unit of angle"


@function turn($value)
  @if unit($value) == turn
    @return $value
  @if unit($value) == rad
    @return ( $value / 1rad ) * 180 / $pi * 1deg
  @if unit($value) == grad
    @return ( $value / 1grad ) * 180 / $pi * 1deg
  @if unit($value) == deg
    @return ( $value / 1turn ) * 180 / $pi * 1deg
  @else
    @warn "#{unit($value)} is not a unit of angle"



@warn (deg(1.4rad))