2d.text.measure.text-clusters-split.tentative.html

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This test has a WPT meta file that expects 1 subtest issues.
This WPT test may be referenced by the following Test IDs:
- /html/canvas/offscreen/text/2d.text.measure.text-clusters-split.tentative.html - WPT Dashboard Interop Dashboard

<!DOCTYPE html>

<!-- DO NOT EDIT! This test has been generated by /html/canvas/tools/gentest.py. -->

<meta charset="UTF-8">

<title>OffscreenCanvas test: 2d.text.measure.text-clusters-split.tentative</title>

<script src="/resources/testharness.js"></script>

<script src="/resources/testharnessreport.js"></script>

<script src="/html/canvas/resources/canvas-tests.js"></script>

<h1>2d.text.measure.text-clusters-split.tentative</h1>

<p class="desc">Test that getTextClusters() splits the input correctly into the minimal clusters, keeping emojis together.</p>

<script>

var t = async_test("Test that getTextClusters() splits the input correctly into the minimal clusters, keeping emojis together.");

var t_pass = t.done.bind(t);

var t_fail = t.step_func(function(reason) {

    throw reason;

});

t.step(function() {

  var canvas = new OffscreenCanvas(400, 200);

  var ctx = canvas.getContext('2d');

  function getClusterIndexes(text) {

    const clusters = ctx.measureText(text).getTextClusters();

    const result = [];

    for (let i = 0; i < clusters.length; i++) {

      const end = clusters[i].end;

      if (end === (i + 1 < clusters.length ? clusters[i + 1].start : text.length)) {

        result.push(clusters[i].start);

      } else {

        result.push([clusters[i].start, clusters[i].end]);

    return result;

  function assertClusterIndexes(text, expected) {

    const actual = getClusterIndexes(text);

    assert_array_equals(actual, expected);

  ctx.font = '50px serif';

  const text = 'ABC ☺️❤️';

  ctx.fillText(text, 20, 100);

  assertClusterIndexes(text, [0, 1, 2, 3, 4, 6]);

  // [UAX#29]: https://unicode.org/reports/tr29/

  // [UAX#29] GB9: × (Extend | ZWJ)

  assertClusterIndexes('X\u200DY', [0, 2]);

  // [UAX#29] GB11: \p{Extended_Pictographic} Extend* ZWJ × \p{Extended_Pictographic}

  assertClusterIndexes('\u{1FFFD}\u200D\u{1FFFD}', [0]);

  t.done();

});

</script>