An Introduction to HTML 5 Web Workers

cggallant.blogspot.com

67 points·Mamady··6 comments

i'm currently a little pissed at webwokers (yeah, i take it personally) that i can't hand them a canvaspixelarray. so basically to use workers for canvasimagemanipulation you have to copy the canvaspixelarray into an uint8array, pass it to the work, get back a uint8array and copy that one back into the imagedata.data canvaspixelarray. oh yeah, the copy actions are of course all in the main thread - so this basically defeats the reason to have webworkers in the first place.

the newest chrome has support for transferable objects that can be sent directly to a worker without being copied. this works with ArrayBuffer now, not sure if ImageData is transferable yet, but it should be eventually.

demo: http://html5-demos.appspot.com/static/workers/transferables/...

nope, the canvaspixelarray is no arraybuffer, doesn't work yet. i check for changes in that regard with every google chrome canary release.

I hope there are simple ways to disable these on browsers.

Can't imagine every tab having a load of workers in the background, ending well.

One of the pleasant things about javascript is that there are no threads. It's a shame some people have pushed for this API.

After all, it's not rocket science for a competent developer to split a long running task into chunks which are periodically run via a timeout, keeping the UI responsive.

While I agree most things could be split into chunks with a timeout, there's definitely a place for web workers, for example in canvas image processing.

I wholeheartedly agree. I had some code that had to parse several different .ply files and creat the respective 3D models, and without web workers, the process was unbearably long.

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