London Web Performance Group - Instantly loading web apps and lossy PNGs from the FT, hosted by Twitter
Tuesday 11 November 2014, 19:45 - 20:45
20 Air Street, W1B 5AN, London, Reino Unido
Instantly loading web apps and lossy PNGs from the FT Click here to register and purchase ticket Beer & Pizzas will be provided due to the generosity of our Group Sponsors : Akamai, AppDynamics, Cedexis, Dynatrace, Dyn, The Financial Times, Google Chrome, NCC Group, Neustar, PEER1, and SciVisum. This month we have two talks from the Financial Times that give an insight into next-generation performance techniques - including powering instant-fast applications using the upcoming ServiceWorker, and a technique for getting the lossy compression of JPEG and the alpha transparency of PNG in one backwards compatible image format. Speakers Offline-first Web Apps Matt Andrews The upcoming HTML5 feature known as Service Worker is set to turn the web on its head, enabling websites to run without an internet connection and to load quickly even when the connection is bad. But with that evolutionary step, web applications need to become more complex, and to handle the fact that their source code may remain on a device for much longer than a single session. Without the safety net of starting fresh every time the user hits a link, considerations such as memory management, data consistency, encapsulation and backwards compatibility now come into play. Front-end developers are suddenly fully-fledged software engineers! The web page is our app platform, and the browser our runtime. The fastest byte is a byte not sent, so the fastest website is the website that doesn’t need to load anything. Step with me into a world of good hacks, unbeatable performance and smart, multivariate responsiveness, drawn from experience building web apps for the FT and The Economist. Lossy Compression of True-color PNG Images Kornel Lesinski PNG is currently the only image format that works across all browsers and supports alpha channel. Backwards-compatible lossy encoding is much easier to deploy on the Web than a set of vendor-specific alternative image formats, but can still significantly reduce bandwidth and page loading times. I’m going to present a lossy compression method for PNG images that is based on PNG filters. It’s compatible with the standard decoders and can generate files 20%-40% smaller than a usual lossless encoding. Unlike conversion of PNG to a palette, this technique works with true-color images. It can be applied to PNG files as they’re streamed, with relatively little computing power and memory, which makes it perfect for automatic Front-End Optimization tools and proxies. I’m going to demonstrate tools that designers and developers can use today to recompress PNGs manually or in batches. FAQs What time should I arrive? • Entry to the meetup is from 18:15 to 18:45. Please be on time as with two talks we will be starting at the advertised time. Beer and pizzas will be served up at approx. 20:30 and the meetup will end at 22:00 and all attendees must exit the building by 22:30. Why have you started charging for your meetup events? • We are charging a nominal £5 entry for our meetup events primarily to reduce the very high level 'no shows' that we have had in the past. This is very frustrating for those that really want to go but end up not being able to attend as all the spots have been taken.The 'waitlist' concept relies on 'no shows' actually releasing their space, and we find that this just doesn't happen. 'No shows' also cause difficulties for us in terms of food and drink provision and event checkin/security. All food and drink is provided due the generosity of our sponsors and the entry fees are used towards the general operation of the group. As we are a non-profit making community association, any annual surplus from both sponsorship and attendance fees will be donated to IT related charities. Do I have to bring my printed ticket to the event? • Yes - It really helps us if you can bring your Eventbrite paper or online ticket (containing the QR code) to the checkin desk at the event. What is the refund policy? • In the event of the event being cancelled by the organisers, then a full refund will be made. No other refunds will be made under any circumstances. You can transfer you ticket to someone else via Eventbrite. The name on the registration/ticket doesn't match the attendee. Is that okay? • As we are using corporate facilities to host the meetup, security will perform a name check at check-in so its much easier if for everyone if you purchase your ticket in the correct name. Are there ID requirements or an age limit to enter the event? • ID will be required if you are not the named ticket holder. Our group sponsors provide alcholic drinks during the meetup session so you have to be over 18 to benefit from those. Click here to register and purchase ticket
Publicado por: Miquel Camps