<script src = "../../resources/js-test.js"></script> <script src = "./script-tests/canvas-toBlob-toDataURL-race.js"></script> <script type = 'text/javascript'> description("Verifies if JPEG image encoding on main thread (toDataURL) conflicts with image encoding on async thread (toBlob)"); //Fire a bunch of toBlob operations of canvas to keep the async thread busy var j = 0; // due to async nature of toBlob we need a separate counter for (var i = 0; i < numToBlobCalls; i++) { canvas.toBlob(function(blob) { url = URL.createObjectURL(blob); testImages[j++].src = url; }, "image/jpeg", 1.0); } //Then file a bunch of toDataURL operation on main thread, so both threads now compete for image encoding for (var i = numToBlobCalls; i < (numToDataURLCalls + numToBlobCalls); i++) { testImages[i].src = canvas.toDataURL("image/jpeg", 1.0); } </script>