especificos-videos/front/controllers/uploadCtrl.js

app.controller('uploadCtrl', function ($scope, $http,video,notify) {
	$scope.profesor="";
	$scope.texto1="";
	$scope.texto2="";
	$scope.video = video; 
	$scope.diapos = [];
	var canvas = document.getElementById('c');
	var container = canvas.parentNode;
	var ctx = canvas.getContext('2d');
	var dpr = window.devicePixelRatio || 1;
	var img = new Image();
	var diapos = [];

	img.src="https://curso.especificosba.com.ar/diapo/EBA/1.png"; //Cargo la imagen inicial, a espera de informacion
	img.onload=function(){ //Cuando una imagen carga en mi obj imagen, quiero que se dibuje en canvas
		ctx.drawImage(img,0,0,canvas.width, canvas.height);
	}
	$scope.updateDiapos = function(d) {
		diapos = JSON.parse(d);
		parseMessage(diapos[0]);
	}
	function respondCanvas(){
		canvas.setAttribute('width', container.offsetWidth);
		canvas.setAttribute('height', container.offsetWidth/4*3);
	}
	
	respondCanvas();

	if (!String.prototype.format) {
		String.prototype.format = function() {
		var args = arguments;
		    return this.replace(/{(\d+)}/g, function(match, number) { 
		      return
				( typeof args[number] != 'undefined' ? args[number] : match );
		    });
		};
	}

	function parseMessage(msg){
		if (msg==undefined)
			return;
		switch(msg.type){
			case "draw":
				drawOnCanvas(msg.points,msg.color);
				break;
			case "clean":
				ctx.drawImage(img,0,0,canvas.width, canvas.height);
				break;
			case "diapo":
				img.src="https://curso.especificosba.com.ar/diapo/{0}/{1}.png".format(msg.PDF,msg.slide);
				break;
		}
	}
	function drawOnCanvas(points,color) {
		if(points.length==0) return;
		ctx.strokeStyle = color;
		ctx.beginPath();
		ctx.moveTo(points[0].x, points[0].y);
		 
		for(var i=1; i<points.length; i++) {
			ctx.lineTo(points[i].x, points[i].y);
		}
		ctx.stroke();
	}

	$scope.post = function() {
		var data = {
					prof: $scope.profesor,
					texto1: $scope.texto1,
					texto2: $scope.texto2,
					id: $scope.video._id,
					diapos: diapos
				};
		$http.post('/back/upload/', data)
		.success(function(data,state) {
			notify({message:data.status,classes:"alert"});
		})
		.error(function(data) {
			notify({message:data.status,classes:"alert alert-danger"});
		});
	};
});