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Simple Espruino Graphics webGraphics over websocket
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| function wrapInstance(g, args) { | |
| var width = g.getWidth(); | |
| var height = g.getHeight(); | |
| var page = `<script> | |
| var ws; | |
| setTimeout(function(){ | |
| ws = new WebSocket("ws://" + location.host + "/webGraphics", "protocolOne"); | |
| ws.onmessage = function (event) { | |
| if (event.data.length > 40) { | |
| // base64 -> Uint8Array | |
| // from https://stackoverflow.com/questions/12710001/how-to-convert-uint8-array-to-base64-encoded-string | |
| var buffer = new Uint8Array(atob(event.data).split("").map(c => c.charCodeAt(0))); | |
| // console.log("MSG:"+buffer.length); | |
| var cg = document.getElementById("g"); | |
| var ctx = cg.getContext("2d"); | |
| ctx.imageSmoothingEnabled = false; | |
| var myImageData = ctx.createImageData(${width}, ${height}); | |
| // make RGBA | |
| var data = []; | |
| buffer.forEach(b => data.push(b === 0 ? [255,255,255,255] : b === 5 ? [0,0,255,255] : [0,0,0,255])); | |
| myImageData.data.set([].concat.apply([], data), 0); | |
| ctx.scale(5, 5); | |
| ctx.putImageData(myImageData, 0, 0); | |
| } | |
| }; | |
| ws.onopen = function() { | |
| console.log("OPEN"); | |
| setTimeout(function() { | |
| ws.send("Hello to Espruino!"); | |
| }, 1000); | |
| }; | |
| },100); | |
| </script><canvas id="g" width="${width}px" height="${height}px" style="border: 1px solid lightgrey;" />`; | |
| function onPageRequest(req, res) { | |
| res.writeHead(200, {'Content-Type': 'text/html'}); | |
| res.end(page); | |
| } | |
| function startServer(onRequest, cb) { | |
| var server = require('ws').createServer(onRequest); | |
| server.listen(8000); | |
| server.on("websocket", function(ws) { | |
| ws.on('message',function(msg) { print("[WS] "+ msg); }); | |
| cb(ws); | |
| }); | |
| } | |
| startServer(onPageRequest, (ws) => { | |
| g.ws = ws; | |
| g.flip = function() { | |
| // Espruino ws doesn't support binary (yet), so convert to base64 | |
| ws.send(btoa(g.buffer)); | |
| }; | |
| ws.send(JSON.stringify(args)); | |
| }); | |
| } | |
| function add(G) { | |
| const GcreateArrayBuffer = G.createArrayBuffer; | |
| G.createArrayBuffer = function(width, height, bpp, opts) { | |
| // override bpp and options to capture <canvas> rendering below | |
| const g = GcreateArrayBuffer(width, height, 8, {}); | |
| wrapInstance(g, arguments); | |
| return g; | |
| }; | |
| } | |
| exports.add = add; |
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