protocol questions

[Matthias Clasen]

On Sat, Mar 30, 2013 at 7:56 AM, Daniel Stone <daniel at fooishbar.org> wrote:

>
>
>
>> - Various input events have a time field. The spec doesn't really say
>> anything about this. What is it good for, and what units are these -
>> monotonic time ?
>>
>
> Monotonic (ideally) time in an undefined domain, i.e. they're only
> meaningful on relation to each other.
>
>

What can you do with them ? For the use case that Giulio mentioned
(double-click detection), I'd need to know at least if the difference
between two times is seconds or milliseconds or microseconds...


- Still on popups, I don't see a way for the client to dismiss the
>> popup, or is that handled by just destroying the surface ?
>>
>
> Indeed, just destroy the surface or attach a NULL buffer.
>

Good to know. I don't think the spec mentions at all that 'attach NULL
buffer' == unmap.


- Buffer transformations - fun. How do these relate to each of the
>> following ?
>>    - resize edges
>>    - transient offset
>>    - buffer attach x/y
>>    - input/opaque/damage regions
>>    - surface x/y in motion events
>>
>
> All the latter occur on surfaces rather than buffers, so are unaffected.
>  Buffer transforms are meant to support situations like where your screen
> is rotated 90°, and your client can also render rotated in order to avoid
> that extra blit.  So it doesn't affect the event pipeline at all, only the
> display pipeline.
>

That sounds right for resize edgets and motion events, certainly. For some
of the others, at least the wording of the spec is not always very clear on
this point. E.g. for buffer attach x/y, the wl_surface.attach docs say:

        The x and y arguments specify the location of the new pending
        buffer's upper left corner, relative to the current buffer's
        upper left corner.

See how it talks about the current buffer's upper left corner. Should that
say 'the surface's upper left corner, then ?
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