Sub-surface protocol

[John Kåre Alsaker]

On Tue, Dec 18, 2012 at 6:40 AM, Bill Spitzak <spitzak at gmail.com> wrote:
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> On Dec 17, 2012, at 5:01 PM, John Kåre Alsaker wrote:
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> Then a client such as gimp could draw all it's display into a single buffer.
>
> To get the different color correction of the center display, it would
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> declare a subsurface containing this and set it's color correction
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> differently using the wayland api. This would only allocate one buffer,
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> which would save memory, but more importantly it should make internal code
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> in gimp easier as you could work around a toolkit that assumes only one
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> output buffer.
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> My approach to color correct rendering in Wayland is to let the
> compositor handle it and have the clients simply specify which color
> space they are using. Only the compositor can render clients correctly
> when they are displayed on multiple monitors (unless we introduce a
> way to set a buffer per-output).
>
>
> Yes this is what I am assuming.
>
> What I am asking is if it makes sense for a client to draw two different
> color spaces into the same buffer. The larger area is color space A, and a
> rectangular subarea is color space B. It then tells wayland to make the main
> window color space A, and then makes a subwindow with the clipped subarea
> and tells wayland that it is color space B.
>
> The reason is to save buffer space, and also to work around toolkits and
> drawing api's where it is a lot more practical to draw everything into the
> same buffer.
I don't see any problem with doing that unless you want different bit-depths.

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