Re: [PATCH v2 1/2] v4l: Add new alpha component control

[Sylwester Nawrocki <s.nawrocki@samsung.com>]

Hi Laurent,

On 12/08/2011 11:30 AM, Laurent Pinchart wrote:
>> Another use case for control range update would be with an auto-exposure
>> metering spot location controls. An available range for x and y coordinates
>> would depend on selected pixel resolution. If we would have created two
>> controls for (x, y) their range would depend on pixel (width, height)
>> respectively. So when a new format is set such controls would need to get
>> their range updated.
> 
> To be honest I'm not sure whether points, and especially rectangles, should be 
> handled as controls. We have no structure-like control type at the moment, 
> adding points might be possible, but rectangles would require either 2 point-
> liek controls or 4 controls (left, top, width, height). I don't really like 
> that. A new API (possibly based on the selection API ?) might be better.

Indeed, I don't like having 4 controls for specifying a rectangle as well, it
doesn't just sound right. I was concerned about specifying a point using
the selection API. But it could be just (left=x, top=y, width=1, height=1).


--
Regards,
Sylwester