Output scaling should be merged with the existing "buffer_transform"
(the 8-value enumeration describing 90 degree rotations/reflections).
I think in the end Wayland is going to have to have arbitrary affine
transforms in the api, and it might make sense to decide a standard for
these now, so that they are not split up amoung several apis like what
is happening now. Apparently there is worry about using floating point
in the api, but I think the following proposal that only uses integers
or fixed point works:
Translation are given as 2 24.8 fixed-point numbers.
Scale is 4 unsigned numbers: w,h,W,H. You can think of these as the size
of the source and destination, or w/W and h/H are the scaling factors.
Rotation and skew are 4 integers: x0,y0,x1,y1. The X and Y axis are
rotated to point at these positions. To avoid skew use x1==-y0 and
y1==x0. Flipping the signs can be used to make reflections.
This setup allows some useful numbers with somewhat intuitive results,
and avoids trying to specify irrational numbers using integers.
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