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[whatwg] [canvas] request for {create, get, put}ImageDataHD and ctx.backingStorePixelRatio

From: Boris Zbarsky <bzbarsky@MIT.EDU>
Date: Tue, 20 Mar 2012 21:08:21 -0400
Message-ID: <4F692A05.9030107@mit.edu>
On 3/20/12 7:04 PM, Glenn Maynard wrote:
> If you have previous drawing commands buffered, and you want to avoid extra
> copies, then putImageData has to block until the buffered drawing commands
> complete.

Yes, but if you're drawing to a GPU directly you want to make the copy 
up front, imo; otherwise you have to wait for the full GPU latency 
before you can return even if there are no other drawing commands in the 
pipeline, which is painful....

> The question is whether you'd need to make a copy *synchronously*, before
> putImageData returns.

If you want to do the image data put async in any way (and that includes 
any sort of direct-to-GPU setup, I'm told) then you need either sync 
copy or copy-on-write as far as I can tell.

-Boris
Received on Tuesday, 20 March 2012 18:08:21 UTC

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