numix-gtk-theme/gtk-3.0/scss/_functions.scss

$modules: () !default;

@mixin exports($name) {
	@if (not index($modules, $name)) {
		$modules: append($modules, $name) !global;

		@content;
	}
}

@function alpha($color, $amount) {
	@if type-of($color) == "color" {
		@return fade-out($color, (1 - $amount));
	} @else {
		@return unquote("alpha(#{$color},#{$amount})");
	}
}

@function shade($color, $amount) {
	@if type-of($color) == "color" {
		@if ($amount > 1) {
			@return lighten($color, ($amount - 1) * lightness($color))
		} @else {
			@return darken($color, (1 - $amount) * lightness($color))
		}
	} @else {
		@return unquote("shade(#{$color},#{$amount})");
	}
}

@function mix($color1, $color2, $amount) {
	@return unquote("mix(#{$color1},#{$color2},#{$amount})");
}

@function border_normal($color) {
	@return shade($color, $contrast);
}

@function border_focus($color) {
	@return shade($color, ($contrast - .05));
}

@function border_active($color) {
	@return shade($color, ($contrast - .1));
}

@function border_insensitive($color) {
	@return shade($color, ($contrast + .05));
}

@mixin linear-gradient($color, $direction: to bottom) {
	@if $gradient == 0 {
		background-color: $color;
		background-image: none;
	} @else {
		$amount: $gradient / 2;

		background-color: $color;
		background-image: linear-gradient($direction,
			shade($color, (1 + $amount)),
			shade($color, (1 - $amount))
		);
	}
}

@mixin border($color) {
	border-color: border_normal($color);

	&:focus, &:hover { border-color: border_focus($color); }

	&:active, &:active:hover,
	&:active:focus, &:active:hover:focus,
	&:checked, &:checked:hover,
	&:checked:focus, &:checked:hover:focus { border-color: border_active($color); }

	&:insensitive { border-color: border_insensitive($color); }

	&:active:insensitive, &:checked:insensitive { border-color: border_normal($color); }
}