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Results for tag: webworkers

HTML5 Canvas Animation Converted to Video

I was recently playing around with dat.gui and the cool FizzyText animation made me consider the concept of exporting HTML5 Canvas to video. I have previously covered canvas to video conversion but it was specific to making a photo slideshow. Today, I want to create a simple script in JavaScript that will grab any CANVAS element, on any website, retrieve the image frames, and compile them into a video file.
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Make Animated GIFs from Videos with HTML5

Make animated GIF from HTML5 video

HTML5 Animated GIF Creator

Last time, I showed how to make screenshots of videos with HTML5 and now I will take that concept further by showing how to make animated GIFs from videos. You could send video frames to the server and use something like FFmpeg or ImageMagick to create the animated GIF but since I have recently stumbled upon this port of as3gif GIFPlayer to JS, I wanted to make this work completely on the client side. I will try to improve some processing with Web Workers but this will still be very CPU intensive.
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HTML5 Web Workers for AJAX Requests

Web Workers and Ajax

Sometimes you need to load and process a ton of data on the client-side, but how do you do that without blocking the UI? The problem with JavaScript on the browser is that it runs on a single thread. In other words, two scripts or processes cannot run simultaneously. If you are processing JavaScript after page load, the end user cannot interact dynamically with the page. The JavaScript will not handle UI events while processing something else. If you process something large before page load, the end user has to wait all-together which is a horrible user experience.

Running scripts asynchronously also does not help as non-blocking does not mean concurrency. So, how do you process two JavaScript functions at the same time? As the title suggests, HTML5 has Web Workers which bring threading to JavaScript and this post is going to show how to use web workers to not only process multiple scripts at the same time, but also make AJAX requests in Web Workers.
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