1 files changed, 51 insertions, 0 deletions
diff --git a/testing/web-platform/tests/html/canvas/offscreen/layers/2d.layer.global-states.alpha.w.html b/testing/web-platform/tests/html/canvas/offscreen/layers/2d.layer.global-states.alpha.w.html
new file mode 100644
index 0000000000..694f31e208
--- /dev/null
+++ b/testing/web-platform/tests/html/canvas/offscreen/layers/2d.layer.global-states.alpha.w.html
@@ -0,0 +1,51 @@
+<!DOCTYPE html>
+<!-- DO NOT EDIT! This test has been generated by /html/canvas/tools/gentest.py. -->
+<html class="reftest-wait">
+<link rel="match" href="2d.layer.global-states.alpha-expected.html">
+<title>Canvas test: 2d.layer.global-states.alpha</title>
+<h1>2d.layer.global-states.alpha</h1>
+<p class="desc">Checks that layers correctly use global render states.</p>
+<canvas id="canvas" width="200" height="200">
+  <p class="fallback">FAIL (fallback content)</p>
+</canvas>
+<script id='myWorker' type='text/worker'>
+  self.onmessage = function(e) {
+    const canvas = new OffscreenCanvas(200, 200);
+    const ctx = canvas.getContext('2d');
+
+    ctx.fillStyle = 'rgba(0, 0, 255, 1)';
+
+    var circle = new Path2D();
+    circle.arc(90, 90, 45, 0, 2 * Math.PI);
+    ctx.fill(circle);
+
+    ctx.globalAlpha = 0.6;
+
+    ctx.beginLayer();
+
+    // Enable compositing in the layer to validate that draw calls in the layer
+    // won't individually composite with the background.
+    ctx.globalCompositeOperation = 'screen';
+
+    ctx.fillStyle = 'rgba(225, 0, 0, 1)';
+    ctx.fillRect(50, 50, 75, 50);
+    ctx.fillStyle = 'rgba(0, 255, 0, 1)';
+    ctx.fillRect(70, 70, 75, 50);
+
+    ctx.endLayer();
+
+    const bitmap = canvas.transferToImageBitmap();
+    self.postMessage(bitmap, bitmap);
+  };
+</script>
+<script>
+  const blob = new Blob([document.getElementById('myWorker').textContent]);
+  const worker = new Worker(URL.createObjectURL(blob));
+  worker.addEventListener('message', msg => {
+    const outputCtx = document.getElementById("canvas").getContext('2d');
+    outputCtx.drawImage(msg.data, 0, 0);
+    document.documentElement.classList.remove("reftest-wait");
+  });
+  worker.postMessage(null);
+</script>
+</html>