import * as sys from "@sys"; const video = document.$("video"); video.onsizechange = function() { let [w,h] = this.state.box("dimension"); document.$("form").value = { width:w, height:h }; } document.on("click","#snapshot", async function() { let frame = video.style.imageOf("foreground-image"); let arrayBuffer = frame.toBytes("png"); const path = URL.toPath(__DIR__ + "frame.png"); const file = await sys.fs.open(path, "w+", 0o666); await file.write(arrayBuffer); await file.close(); });

This demo simulates partial video frame update. See sdk/include/behaviors/behavior_video_generator.cpp source. On each frame (24 FPS) it updates portion of the frame.