_pcmrFlairColorAndMapFunctions.scss

// Functions
// ===============================================================================
//
// There's some stuff that I need fine-grained control over. These
// functions give it to me in spades. 
//  
// The following are all third-party functions.


// color-contrast() and related courtesy of Lu Nelson 
// http://codepen.io/lunelson/pen/jENxwB
// LINEAR to LOGARITHMIC and vice-versa
@function lin2log($n) {
	@if $n <= 0.00313 {
		@return $n * 12.92;
	}
	@else {
		@return 1.055 * pow($n, 1 / 2.4) - 0.055;
	}
}

@function log2lin($n) {
	@if $n <= 0.04045 {
		@return $n / 12.92;
	}
	@else {
		@return pow(($n + 0.055) / 1.055, 2.4);
	}
}

// sRGB BT-709 BRIGHTNESS
@function brightness($c) {
	$rlin: log2lin(red($c) / 255);
	$glin: log2lin(green($c) / 255);
	$blin: log2lin(blue($c) / 255);
	@return lin2log(0.2126 * $rlin + 0.7152 * $glin + 0.0722 * $blin) * 100;
}

// Compares contrast of a given color to the light/dark arguments and returns 
// whichever is most "contrasty"
@function color-contrast($color, 
						 $dark: $PLACEHOLDER-BLACK, 
						 $light: $PLACEHOLDER-WHITE) {
	@if $color == null {
		@return null;
	}
	@else {
		$color-brightness: brightness($color);
		$text-light-brightness: brightness($light);
		$text-dark-brightness: brightness($dark);
		@return if(abs($color-brightness - $text-light-brightness) > 
		abs($color-brightness - $text-dark-brightness), $light, $dark);
	}
}

// Function to retrieve value in nested map without a trillion map-gets
// Takes map as first arg, arglist as the second and beyond
@function map-get-nested($map, $keys...) {
	@each $key in $keys {
		$map: map-get($map, $key);
	}
	@return $map;
}

// Function to check if nested key exists. 
// Takes map as first arg, arglist as the second and beyond
@function map-has-nested-key($map, $keys...) {
	@each $key in $keys {
		@if not map-has-key($map, $key) {
			@return false;
		}
		$map: map-get($map, $key);
	}
	@return true;
}

// Courtesy of http://hugogiraudel.com/2013/08/08/advanced-sass-list-functions/
@function remove($list, $value, $recursive: false) {
	$result: ();
	@for $i from 1 through length($list) {
		@if type-of(nth($list, $i)) == list and $recursive {
			$result: append($result, remove(nth($list, $i), $value, $recursive));
		}
		@else if nth($list, $i) != $value {
			$result: append($result, nth($list, $i));
		}
	}
	@return $result;
}

@function map-set($map, $key, $value) {
	$new: ($key: $value);
	@return map-merge($map, $new);
}