<!DOCTYPE html>
<html>
  <head>
    <meta charset="utf-8">
    <title>backdrop-filter interpolation</title>
    <link rel="help" href="https://drafts.fxtf.org/filter-effects-2/#BackdropFilterProperty">
    <meta name="assert" content="Partially matching lists interpolate.">
    <script src="/resources/testharness.js"></script>
    <script src="/resources/testharnessreport.js"></script>
    <script src="/css/support/interpolation-testcommon.js"></script>
    <style>
      body {
        color: blue;
      }
    </style>
  </head>
  <body>
    <script>
      'use strict';

      test_interpolation({
        property: 'backdrop-filter',
        from: 'none',
        to: 'opacity(0.5) hue-rotate(180deg)',
      }, [
        {at: -0.5, expect: 'opacity(1) hue-rotate(-90deg)'},
        {at: 0.25, expect: 'opacity(0.875) hue-rotate(45deg)'},
        {at: 0.5, expect: 'opacity(0.75) hue-rotate(90deg)'},
        {at: 1, expect: 'opacity(0.5) hue-rotate(180deg)'},
        {at: 1.5, expect: 'opacity(0.25) hue-rotate(270deg)'},
      ]);

      test_interpolation({
        property: 'backdrop-filter',
        from: 'blur(6px)',
        to: 'blur(10px) hue-rotate(180deg)'
      }, [
        {at: -0.5, expect: 'blur(4px) hue-rotate(-90deg)'},
        {at: 0.25, expect: 'blur(7px) hue-rotate(45deg)'},
        {at: 0.5, expect: 'blur(8px) hue-rotate(90deg)'},
        {at: 1, expect: 'blur(10px) hue-rotate(180deg)'},
        {at: 1.5, expect: 'blur(12px) hue-rotate(270deg)'},
      ]);

      // Mismatched lists:
      test_no_interpolation({
        property: 'backdrop-filter',
        from: 'grayscale(0) blur(0px)',
        to: 'blur(10px)'
      });
    </script>
  </body>
</html>
