CSS | stroke-opacity Property

Last Updated : 22 Nov, 2019

The stroke-opacity property is used to set the opacity of the color or pattern that is applied to the stroke of a shape. A decimal or percentage value could be used to make the stroke visible, invisible or semi-transparent. Syntax:

stroke-opacity: [0-1] | <percentage>

Parameters: This property accepts two types of parameters as mentioned above and described below:

[0-1]: It is used to set the opacity in a decimal value from 0 to 1. A value of 0 would mean that the stroke is completely transparent and invisible. A value of 1 means that the stroke is fully opaque and visible. A decimal value between these values two would give a semi-transparent stroke.
percentage: This is used to set the opacity in a percentage values. A value of 0% would mean that the stroke is completely transparent and invisible. A value of 100% means that the stroke is fully opaque and visible. A percentage value between these two values would give a semi-transparent stroke.

Below examples will illustrates the stroke-opacity property in CSS: Example 1: This example uses a value 0 to 1 to set the stroke opacity.

html

<!DOCTYPE html>
<html>

<head>
    <title>
        CSS | stroke-opacity property
    </title>

    <style>
        .stroke1 {
            
            /* completely visible stroke */
            stroke-opacity: 1.0;
            stroke: green;
            stroke-width: 20px;
        }
            
        .stroke2 {
            
            /* 50-50 visible transparent */
            stroke-opacity: 0.5;
            stroke: green;
            stroke-width: 20px;
        }
        
        .stroke3 {
            
            /* 25-75 visible transparent */
            stroke-opacity: 0.25;
            stroke: green;
            stroke-width: 20px;
        }
        
        .stroke4 {
            
            /* completely transparent stroke */
            stroke-opacity: 0;
            stroke: green;
            stroke-width: 20px;
        }
    </style>
</head>

<body style="text-align:center;">
    
    <h1 style="color: green">
        GeeksforGeeks
    </h1>
    
    <b>
        CSS | stroke-opacity
    </b>
    
    <div class="container">

        <!-- Strokes lines-->
        <svg width="400px">
            <line class="stroke1" x1="50"
                    x2="350" y1="20" y2="20" />
            
            <line class="stroke2" x1="50"
                    x2="350" y1="70" y2="70" />
            
            <line class="stroke3" x1="50"
                    x2="350" y1="120" y2="120" />
            
            <line class="stroke4" x1="50"
                    x2="350" y1="170" y2="170" />
        </svg>
    </div>
</body>

</html>

Output: decimal-val

Example 2: This example uses percentage value to set the stroke opacity.

html

<!DOCTYPE html>
<html>

<head>
    <title>
        CSS | stroke-opacity property
    </title>
    
    <style>
        .stroke1 {
            
            /* completely visible stroke */
            stroke-opacity: 100%;
            stroke: green;
            stroke-width: 20px;
        }
        
        .stroke2 {
            
            /* 50-50 visible transparent */
            stroke-opacity: 50%;
            stroke: green;
            stroke-width: 20px;
        }
        
        .stroke3 {
            
            /* 25-75 visible transparent */
            stroke-opacity: 25%;
            stroke: green;
            stroke-width: 20px;
        }
        
        .stroke4 {
            
            /* completely transparent stroke */
            stroke-opacity: 0%;
            stroke: green;
            stroke-width: 20px;
        }
    </style>
</head>

<body style="text-align:center;">
    
    <h1 style="color: green">
        GeeksforGeeks
    </h1>
    
    <b>
        CSS | stroke-opacity
    </b>
    
    <div class="container">

        <!-- Strokes lines-->
        <svg width="400px">
            <line class="stroke1" x1="50"
                    x2="350" y1="20" y2="20" />
            
            <line class="stroke2" x1="50"
                    x2="350" y1="70" y2="70" />
            
            <line class="stroke3" x1="50"
                    x2="350" y1="120" y2="120" />
            
            <line class="stroke4" x1="50"
                    x2="350" y1="170" y2="170" />
        </svg>
    </div>
</body>

</html>