math for scss

ft_math.scss

/*
**  File:			ft_math
**  Description:	This is the math library you need in css.
**  Connect:		hochan222 - https://github.com/hochan222
**
**	List: factorial, sin, cos, tan
*/

/*
**		factorial
**	
**		Detail: This is a function that implements a factorial operation.
**		Precautions: px or other units were not processed.
**			Handle:: -
**			Cause :: -
**
**		@param	number				$end			Factorial end	value
**		@param	number				$start			Factorial start	value
**		@param	number				$currentVal		Value to be accumulated
**		@return	number				Success: Positive integer / Failure: -1
*/
@function factorial($end, $start: 1, $currentVal: 1) {
	@if type-of($end) != number {
		@return -1;
	} @else if $end < 0 {
		@return -1;
	} @else if $end == 0 {
		@return 1;
	}

	$accVal: $currentVal;  
	@for $i from $start to $end + 1 {
		$accVal: $i * $accVal;
	}
	@return $accVal;
}


/*
**		sin, cos, tan
**	
**		Detail: These are a function that created using the Taylor series principle.
**		- sin (x) = cos (x-90º)
**		- tan (x) = sin (x) / cos (x)
**
**
**		Precautions: -
**			Handle:: -
**			Cause :: -
**
**		@param	number				$rad						Radian
**		@param	number				$TAYLOR_SERIES_ITER			Number of Taylor series to repeat
**		@return	number				
*/
$PI: 3.14159265358979323846;

@function sin($rad, $TAYLOR_SERIES_ITER: 10) {
	// Normalize radian, 0 to 2π
	@if $rad < 0 {
		@return sin((-1) * $rad + $PI, $TAYLOR_SERIES_ITER);
	}
	@while ($rad >= 2 * $PI) {
		$rad: $rad - 2 * $PI;
	}
	
	$curTerm: $rad;
	$estimated: $curTerm;

	// Taylor series
	@for $i from 1 to $TAYLOR_SERIES_ITER + 1 {
		// Multiply the previous term by -x^2 / (2n * (2n-1))
		$curTerm: $curTerm * ((-1) * $rad * $rad) / (2 * $i * (2 * $i + 1));
		$estimated: $estimated + $curTerm;
	}
	@return $estimated;
}

@function cos($rad, $TAYLOR_SERIES_ITER: 10) {
	@return sin($rad + $PI / 2, $TAYLOR_SERIES_ITER);
}

@function tan($rad, $TAYLOR_SERIES_ITER: 10) {
	@return sin($rad, $TAYLOR_SERIES_ITER) / cos($rad, $TAYLOR_SERIES_ITER);
}