CSS Property: mask-mode

The mask-mode property specifies whether the mask reference defined by a mask image is treated as a luminance mask (mask-mode: luminance;) or an alpha mask (mask-mode: alpha;).

EXAMPLE

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>mask-mode</title>
    <meta name="viewport" content="width=device-width, initial-scale=1, maximum-scale=1">

    <style>
        * {
            box-sizing: border-box;
        }
        div {
            width: 300px;
            height: 300px;
            border: 2px solid yellow;
            margin-bottom: 30px;
            text-align: center;
            line-height: 18em;
        }
        .a {
            width: 100%;
            height: 100%;
            background: red;
            color: #333333;
            mask-image: url("/demo/circle.png");
            mask-size: 100% 100%;
            mask-clip: border-box;
            mask-mode: alpha;
        }
        .b {
            width: 100%;
            height: 100%;
            background: orange;
            color: #333333;
            mask-image: url("/demo/circle.png");
            mask-size: 100% 100%;
            mask-clip: border-box;
            mask-mode: luminance;
        }
        .c {
            width: 100%;
            height: 100%;
            background: greenyellow;
            color: #333333;
            mask-image: url("/demo/circle.png");
            mask-size: 100% 100%;
            mask-clip: border-box;
            mask-mode: auto;
        }
    </style>
</head>
<body>
<div>
    <div class="a">mask-mode: alpha;</div>
</div>

<div>
    <div class="b">mask-mode: luminance;</div>
</div>

<div>
    <div class="c">mask-mode: auto;</div>
</div>
</body>
</html>

RESULT