2d.transformation.transform.skewed.html

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

<!DOCTYPE html>

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

<title>OffscreenCanvas test: 2d.transformation.transform.skewed</title>

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

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

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

<h1>2d.transformation.transform.skewed</h1>

<p class="desc">transform() with skewy matrix transforms correctly</p>

<script>

var t = async_test("transform() with skewy matrix transforms correctly");

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

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

    throw reason;

});

t.step(function() {

  var canvas = new OffscreenCanvas(100, 50);

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

  // Create green with a red square ring inside it

  ctx.fillStyle = '#0f0';

  ctx.fillRect(0, 0, 100, 50);

  ctx.fillStyle = '#f00';

  ctx.fillRect(20, 10, 60, 30);

  ctx.fillStyle = '#0f0';

  ctx.fillRect(40, 20, 20, 10);

  // Draw a skewed shape to fill that gap, to make sure it is aligned correctly

  ctx.transform(1,4, 2,3, 5,6);

  // Post-transform coordinates:

  //   [[20,10],[80,10],[80,40],[20,40],[20,10],[40,20],[40,30],[60,30],[60,20],[40,20],[20,10]];

  // Hence pre-transform coordinates:

  var pts=[[-7.4,11.2],[-43.4,59.2],[-31.4,53.2],[4.6,5.2],[-7.4,11.2],

           [-15.4,25.2],[-11.4,23.2],[-23.4,39.2],[-27.4,41.2],[-15.4,25.2],

           [-7.4,11.2]];

  ctx.beginPath();

  ctx.moveTo(pts[0][0], pts[0][1]);

  for (var i = 0; i < pts.length; ++i)

      ctx.lineTo(pts[i][0], pts[i][1]);

  ctx.fill();

  _assertPixel(canvas, 21,11, 0,255,0,255);

  _assertPixel(canvas, 79,11, 0,255,0,255);

  _assertPixel(canvas, 21,39, 0,255,0,255);

  _assertPixel(canvas, 79,39, 0,255,0,255);

  _assertPixel(canvas, 39,19, 0,255,0,255);

  _assertPixel(canvas, 61,19, 0,255,0,255);

  _assertPixel(canvas, 39,31, 0,255,0,255);

  _assertPixel(canvas, 61,31, 0,255,0,255);

  t.done();

});

</script>