////
/// Functions used mostly for typography.
///
/// @group wc-sass-mixins
/// @author https://github.com/cnduk/
////

/// Takes a pixel value and returns a lovely responsive em value instead.
///
/// @param {pixel value} $px - The pixel value (including `px`)
/// @param {pixel value} $base [16px] - The base font size to use for em conversion.
///
/// @example scss - em function
///   em(10px)
///   // 0.625em
///   em(10px, 20px)
///   // 0.5em
///
@function em($px, $base: 16px){
    @return ($px / $base) * 1em;
}

/// Takes a pixel value and returns an even more lovely responsive rem value instead.
///
/// @param {pixel value} $px - The pixel value (including `px`)
///
/// @example scss - rem function
///   rem(10px)
///   // 0.625rem
///   rem(16px)
///   // 1rem
@function rem($size) {
    $remSize: $size / 16px;
    @return $remSize * 1rem;
}

/// InDesign (and the rest) measure tracking in thousandths of an em. Use this
/// function to quickly turn the values from Adobe software into usable letter-spacing
/// values we can use in css.
///
/// @param {tracking value} $value - Tracking value straight out of Adobe software.
///
/// @link http://stackoverflow.com/questions/2760784/how-to-calculate-css-letter-spacing-v-s-tracking-in-typography#answer-36612356
///
/// @example scss - tracking function
///   tracking(50)
///   // 0.05em
///   tracking(1000)
///   // 1em
@function tracking($value) {
    @return ($value / 1000) * 1em;
}


/// Return the font-group map so we can get font defaults more easily
///
/// @param {string} $group - Font group map key value
///
/// @link https://github.com/cnduk/wc-sass-fonts Require $FONT_GROUPS and $FONT_GROUP_DEFAULT from https://github.com/cnduk/wc-sass-fonts
@function font-group($group) {
    @if (map-has-key($FONT_GROUPS, $group)) {
        @return map-get($FONT_GROUPS, $group);
    }
    @else {
        @warn 'No such font group: `#{$group}`. Falling back to default.';
        @return $FONT_GROUP_DEFAULT;
    }
}