[PATCH 0/5] Scanning out buffers with transformed outputs

[Bill Spitzak]

Pekka Paalanen wrote:

>> I think there will be clients that can draw their own thumbnail images 
>> much better than the scaled full-size image, especially due to correct 
>> subpixel antialiasing, which is the reason you are communicating the 
>> rotation to the clients now.
> 
> No, that is not the main reason. The reason is to be able to directly
> scan out client surfaces, as full-screen or in an overlay plane.
> 
> Limiting to that main purpose, your other points do not seem
> applicable. I'm not aware of any hardware that can scan out "arbitrary"
> transformations without compositing first.

What I was thinking is that it would scan out when the mulitplication of 
the transform the compositor is using and the inverse of this one is the 
identity. The purpose is so clients can correctly do subpixel a-a on 
thumbnail or otherwise transformed surfaces.

Anyway it is probably not a big deal. It is a feature that as far as I 
can tell does not exist on OSX or Windows, though it is unclear how much 
of a selling point "better quality thumbnails" is.