CSS Function - tan()

The CSS function tan() is a trigonometric operation that calculates the tangent of a given number and returns a value in the range -infinity to infinity.

This function performs a single calculation and interprets the input as radians, and the output can be either a <number> or an <angle>.

Possible values

The function tan(angle) accepts only a single value as a parameter.

  • angle - A calculation that yields either a <number> or an <angle>. When unitless numbers are used, they are to be understood as a measure in radians representing an <angle>.

Return Value

The tangent of an angle will always give a value between -∞ and +∞.

  • If the angle is infinity, -infinity, or NaN, the result is NaN.

  • If the angle is 0⁻, the result is 0⁻.

  • If the angle corresponds to an asymptote value (e.g. 90deg, 270deg etc.), the result is explicitly undefined. Authors should not expect tan() to provide any specific value for these inputs.

Syntax

tan( <calc-sum> )

CSS tan() - Drawing Trapezoid

  • CSS variables are used to define the dimensions and skewing angle of the trapezoids.

  • The calc() function calculates the width of the trapezoids based on the tan() function.

  • Each trapezoid is represented as a div element with the class .trapezoid.

<html>
<head>
<style>
   .trapezoid {
      --top-width: 100px; 
      --bottom-width: 200px; 
      --height: 150px; 
      --skew-angle: 30deg;
      width: calc(100px + (2 * var(--height) / tan(var(--skew-angle))));
      height: var(--height);
      background-color: skyblue; 
      transform: skewX(var(--skew-angle));
      margin-bottom: 20px; 
      margin-left: 40px;
   }
</style>
</head>
<body>
<div class="trapezoid"></div>
<div class="trapezoid"></div>
</body>
</html>
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