downscaling server side - not just for video

[Antoine Martin]

When the client is using a desktop-scaling value lower than 1.0, we end up sending pixels that aren't all used client-side since we end up downscaling the picture to display it. (the render target is smaller than the picture the client receives)

It would be better if the client could tell the server about the scaling factor it is using then the server can:

• choose this same factor (or more) for video scaling - easy
• downscale picture data before compression: new capability flag, new client option, image down scaling pre-compression

[Antoine Martin]

Milestone renamed

[Antoine Martin]

See also #2458.

[leo60228]

I'd argue that a major reason for this feature is shadowing. Currently, there isn't any way to use a shadowed desktop of a higher resolution than the client (at least in HTML5, the only client I use).