2d.transformation.getTransform.html

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This WPT test may be referenced by the following Test IDs:
- /html/canvas/offscreen/manual/transformations/2d.transformation.getTransform.html - WPT Dashboard Interop Dashboard

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

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

<body>

<script>

// Ensure that context2d.getTransform works

const epsilon = 1e-5;

const canvas = new OffscreenCanvas(300, 150);

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

test(function(t) {

  assert_array_equals(ctx.getTransform().toFloat32Array(),

    [1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1],

    "Assert that an untransformed matrix is identity");

  ctx.scale(2, 3);

  transform = ctx.getTransform();

  assert_array_equals(ctx.getTransform().toFloat32Array(),

    [2, 0, 0, 0, 0, 3, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1],

    "Assert that context2d scaling works");

  ctx.rotate(Math.PI/2);

  transform = ctx.getTransform();

  assert_array_approx_equals(ctx.getTransform().toFloat32Array(),

    [0, 3, 0, 0, -2, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1], epsilon,

    "Assert that context2d rotate works");

  ctx.translate(1, -1);

  transform = ctx.getTransform();

  assert_array_approx_equals(ctx.getTransform().toFloat32Array(),

    [0, 3, 0, 0, -2, 0, 0, 0, 0, 0, 1, 0, 2, 3, 0, 1], epsilon,

    "Assert context2d translate works.");

  ctx.resetTransform();

  assert_array_equals(ctx.getTransform().toFloat32Array(),

    [1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1],

    "Assert that a reset matrix is identity");

}, 'This test ensures that getTransform works correctly.');

</script>

</body>