Advice on extending CanvasRenderingContext2D to support Depth Streams

[+public-canvas-api, -public-html-comments]

Hi Canvas 2D Editors,

We’re looking for your feedback with regard to extensions to the CanvasRenderingContext2D, see [1].

In addition, couple of clarifying meta questions:

* The bleeding edge and maintained W3C Editor’s Draft of the Canvas 2D spec is at [2], correct? There are quite a few W3C Editor’s Drafts with different URLs [3]. Please confirm whether [2] is the canonical URL to be referenced in other specs.

* What is the preferred mailing list for feedback and discussion related to [2]? All the W3C’s Canvas 2D Context specs ask to "e-mail feedback to public-html-comments@w3.org” yet it appears public-canvas-api (this list) would be a more appropriate. Correct?

Thanks,

-Anssi

[1] http://w3c.github.io/mediacapture-depth/#canvasrenderingcontext2d-interface
[2] http://www.w3.org/html/wg/drafts/2dcontext/master/
[3] http://damowmow.com/temp/canvas-specs


> Begin forwarded message:
> 
> Date: 9 Oct 2014 00:04:32 EEST
> From: Rob Manson <roBman@buildAR.com>
> To: <ian@hixie.ch>, <public-html-comments@w3.org>
> Cc: "public-media-capture@w3.org" <public-media-capture@w3.org>, "Kostiainen, Anssi" <anssi.kostiainen@intel.com>, "Hu, Ningxin" <ningxin.hu@intel.com>
> Subject: [mediacapture-depth] Advice on extending CanvasRenderingContext2D to support Depth Streams
> 
> Hi Ian, Rik, Jatinder, Jay and Tom,
> 
> we're working on the W3C Media Capture Depth Stream Extension[1] that adds support for depth cameras[2] to the getUserMedia() API. As part of that we've been exploring the different media processing pipelines for the Web Platform that will let us extract and post process the data from these media streams.
> 
> The difference with the depth streams is that they are Uint16Array based instead of the normal Uint8ClampedArray viewed as an RGBA ArrayBufferView. To help treat Depth Streams like other Media Streams we have taken an approach that packs 16 bits losslessly into existing codes[3].
> 
> For WebGL we are proposing a minimal extension to texImage2D and texSubImage2D where they are passed an HTMLVideoElement that includes a Depth Stream based track.
> 
> For the 2D canvas based pipeline we have proposed[4] a parallel model to ImageData called DepthData. It is very similar to ImageData except the .data is a Uint16Array and it adds some new CanvasRenderingContext2D methods like .getDepthData() that will return a DepthData object.
> 
> We're currently drafting this specification in it's own extension spec[1], the FPWD was published 7 October 2014. Now we'd ask for your feedback on the design to make sure we integrate cleanly with the CanvasRenderingContext2D to allow the extension to be integrated at a later stage if so desired.
> 
> Thanks.
> 
> roBman
> 
> [1] http://w3c.github.io/mediacapture-depth/
> [2] https://www.w3.org/wiki/Media_Capture_Depth_Stream_Extension
> [3] http://web4.cs.ucl.ac.uk/staff/j.kautz/publications/depth-streaming.pdf
> [4] http://w3c.github.io/mediacapture-depth/#canvasrenderingcontext2d-interface
> 
>

Received on Thursday, 23 October 2014 13:44:34 UTC