text: import { Blaze } from 'meteor/blaze';
  import { Session } from 'meteor/session';
  
  Blaze.registerHelper('avatarUrlFromUsername', getAvatarUrlFromUsername);
  
  this.getAvatarAsPng = function(username, cb) {
  	const image = new Image;
  	image.src = getAvatarUrlFromUsername(username);
  	image.onload = function() {
  
  		const canvas = document.createElement('canvas');
  		canvas.width = image.width;
  		canvas.height = image.height;
  		const context = canvas.getContext('2d');
  		context.drawImage(image, 0, 0);
  		try {
  			return cb(canvas.toDataURL('image/png'));
  		} catch (e) {
  			return cb('');
  		}
  	};
  	return image.onerror = function() {
  		return cb('');
  	};
  };
  
  this.updateAvatarOfUsername = function(username) {
  
  	const key = `avatar_random_${ username }`;
  	Session.set(key, Math.round(Math.random() * 1000));
  
  	Object.keys(RoomManager.openedRooms).forEach((key) => {
  		const room = RoomManager.openedRooms[key];
  		const url = getAvatarUrlFromUsername(username);
  		$(room.dom).find(`.message[data-username='${ username }'] .avatar-image`).css('background-image', `url(${ url })`);
  	});
  	return true;
  };
  