Sass and rounding down numbers. Can this be configured?

Question

Is there any way for me to modify the way that Sass will handle decimal places? I saw a few people saying that Sass will dynamically do the (target/parent)*100 calculation n

Answer 1

First set your default precision to the highest precision you're going to need in your project.

Then, use a function like the one below (which is based on this function by Takeru Suzuki) to customize the number of decimals at the level of individual properties.

Code :

@function decimal-round ($number, $digits: 0, $mode: round) {
    $n: 1;
    // $number must be a number
    @if type-of($number) != number {
        @warn '#{ $number } is not a number.';
        @return $number;
    }
    // $digits must be a unitless number
    @if type-of($digits) != number {
        @warn '#{ $digits } is not a number.';
        @return $number;
    } @else if not unitless($digits) {
        @warn '#{ $digits } has a unit.';
        @return $number;
    }
    @if $digits > 0 {
        @for $i from 1 through $digits {
            $n: $n * 10;
        }
    }
    @if $mode == round {
        @return round($number * $n) / $n;
    } @else if $mode == ceil {
        @return ceil($number * $n) / $n;
    } @else if $mode == floor {
        @return floor($number * $n) / $n;
    } @else {
        @warn '#{ $mode } is undefined keyword.';
        @return $number;
    }
}

Output :

decimal-round(0.333)    => 0
decimal-round(0.333, 1) => 0.3
decimal-round(0.333, 2) => 0.33
decimal-round(0.666)    => 1
decimal-round(0.666, 1) => 0.7
decimal-round(0.666, 2) => 0.67

Answer 2

It can also be configured using --precision in the commandline, see SASS Changelog, version 3.1.8.

Should also add that if you want to edit @precision in numbers.rb directly, you can find numbers.rb (at least on OS X), here:

/usr/lib/ruby/user-gems/1.8/gems/sass-3.1.10/lib/sass/script

1.8 and 3.1.10 should of course be replaced with your (preferably the latest) version numbers.

Answer 3

If you are using Compass, you can easily specify the precision in your project file (config.rb) without hacking the core:

Sass::Script::Number.precision = 8

For more information see Sass documentation