Re: [mediacapture-screen-share] Handle source device pixel ratio

Sorry I missed the work going on in #84.

While this is going in the right direction, I have a some concerns the changes don't properly handle some scaling scenarios I originally reported.

The biggest issue is the recommendation to use `window.devicePixelRatio` as a scaling factor. There are some cases where that ratio doesn't correspond to the pixel density of the source (multi-monitor setups on Windows 10, page zoom of the current document).

I would also like to see a way to expose the source pixel ratio of the captured content. Simply reading `window.devicePixelRatio` doesn't work as explained above.
When `resizeMode == "none"`, it would allow the application to know by which factor it should scale / render the content to get back to the original "logical" size.

Here is an example:
I have a super high DPI monitor where the pixel ratio is 5.0
My application would like as high fidelity as possible so it selects `resizemode=none`.
I transmit to another device, or render locally on another monitor, where `window.devicePixelRatio == 2.0`.
My application would like to preserve scale as much as possible and creates a video element which size is `original_size * 2 / 5`.

-- 
GitHub Notification of comment by mhofman
Please view or discuss this issue at https://github.com/w3c/mediacapture-screen-share/issues/35#issuecomment-435213752 using your GitHub account

Received on Thursday, 1 November 2018 22:52:33 UTC