chromium/third_party/blink/web_tests/animations/svg-attribute-interpolation/svg-startOffset-interpolation-002.html

<!DOCTYPE html>
<html>
<head>
<script src="../../resources/ahem.js"></script>
<style>
:root {
  font: 50px Ahem;
}
</style>
</head>
<body>
<svg>
  <defs>
    <path id="path1" d="m 0 0 h 250 v 250 h -250 z"/>
  </defs>
</svg>
<template id="target-template">
<svg width="7px" height="17px" viewBox="0 0 140 340">
  <text text-anchor="middle">
    <textPath xlink:href="#path1" startOffset="50%" class="target">
      Text on a path
    </textPath>
  </text>
</svg>
</template>
<script src="resources/interpolation-test.js"></script>
<script>
'use strict';
assertAttributeInterpolation({
  property: 'startOffset',
  from: '1',
  to: '6'
}, [
  {at: -0.4, is: -1},
  {at: 0, is: 1},
  {at: 0.2, is: 2},
  {at: 0.6, is: 4},
  {at: 1, is: 6},
  {at: 1.4, is: 8}
]);
assertAttributeInterpolation({
  property: 'startOffset',
  from: '25%', // 25% of 1000px path length is 250px.
  to: '25em' // 25 times 50px font size is 1250px.
}, [
  {at: -0.4, is: -150},
  {at: 0, is: 250},
  {at: 0.2, is: 450},
  {at: 0.6, is: 850},
  {at: 1, is: 1250},
  {at: 1.4, is: 1650}
]);
</script>
</body>
</html>