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2d.state.saverestore.imageSmoothingEnabled.html 
<!DOCTYPE html>
<meta charset="utf-8">
<title>CanvasRenderingContext2D imageSmoothingEnabled save/restore test</title>
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<link rel="help" href="https://html.spec.whatwg.org/multipage/scripting.html#image-smoothing">
<script>
function createTestImage() {
  var image = document.createElement('canvas');
  var imgctx = image.getContext('2d');
  imgctx.fillStyle = "#F00";
  imgctx.fillRect(0, 0, 2, 2);
  imgctx.fillStyle = "#0F0";
  imgctx.fillRect(0, 0, 1, 1);
  return image;
}

test(function() {
  var ctx = document.createElement('canvas').getContext('2d');
  ctx.save();
  ctx.imageSmoothingEnabled = false;
  ctx.restore();
  assert_equals(ctx.imageSmoothingEnabled, true);
}, "Test that restore() undoes any modifications to imageSmoothingEnabled.");

test(function() {
  var ctx = document.createElement('canvas').getContext('2d');
  ctx.imageSmoothingEnabled = false;
  var old = ctx.imageSmoothingEnabled;
  ctx.save();
  assert_equals(ctx.imageSmoothingEnabled, old);
  ctx.restore();
}, "Test that save() doesn't modify the values of imageSmoothingEnabled.");

test(function() {
  var ctx = document.createElement('canvas').getContext('2d');
  ctx.imageSmoothingEnabled = false;
  ctx.save();
  ctx.imageSmoothingEnabled = true;
  ctx.restore();
  var image = createTestImage();
  ctx.scale(10, 10);
  ctx.drawImage(image, 0, 0);
  var pixels = ctx.getImageData(0, 0, 1, 1).data;
  assert_array_equals(pixels, [0, 255, 0, 255]);
}, "Test that restoring actually changes smoothing and not just the attribute value.");
</script>
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