[PATCH 2/2] protocol: Support scaled outputs and surfaces

[Bill Spitzak]

alexl at redhat.com wrote:

> Coordinates
> in other parts of the protocol, like input events, relative window
> positioning and output positioning are still in the compositor space
> rather than the scaled space. However, input has subpixel precision
> so you can still get input at full resolution.

If I understand this correctly, this means that a client that is aware 
of the high-dpi is still unable to make a surface with a size that is 
not a multiple of the scale, or to move the x/y by an amount that is not 
a multiple of the scale, or position subsurfaces at this level of accuracy.

The only way I can see to make it work is that all protocol must be in 
buffer space (or perhaps in buffer space after the rotation/reflection 
defined by buffer_transform). This also has the advantage (imho) of 
getting rid of one of the coordinate spaces a client has to think about.