Re: Constraints 2014

On 3/23/14 5:52 PM, Jim Barnett wrote:
> Assuming that Capabilities and Settings are not controversial, the 
> main requirements on Constraints that I recall have been the following 
> (if I've missed any, I'm sure someone will correct me):

Thanks Jim for this summary!

> 1. Clear distinction between mandatory and optional constraints, 
> namely all mandatory constraints must be satisfied or the error 
> callback is called.  Optional constraints may or may not be satisfied.
>
> 2.  Unknown/unsupported mandatory constraints must fail.  (Success 
> callback means that all constraints are known to be satisfied.)
>
> 3.  It must be possible to implement back-off using optional constraints.
>
> 4.  It should be possible to couple constraints, to say, for example: 
> I prefer an aspectRatio of 15/6 and width of 500.  If I can't have 
> both of those then give me aspectRatio of 4/3 and width of 400, etc.  
> (This is an example of both back off and of coupling optional 
> constraints.)  Mandatory constraints are always coupled because they 
> all must be satisfied or the api call fails. (I'm putting this as a 
> 'should', not a 'must' because there wasn't as much discussion/demand 
> for it, but several people wanted it and no one didn't want it.)

Can you express #4 using constraints please?

.: Jan-Ivar :.

> 5. The application must be notified if changing circumstances result 
> in previously satisfied mandatory constraints becoming unsatisfied.
>
> The lengthiest dispute/discussion was over whether the application 
> should be notified which mandatory constraints failed.  Some people 
> felt this made fingerprinting too easy, others felt that information 
> was important for intelligent applications.   The latter group has 
> prevailed.
>
>
> On 3/23/14 9:06 AM, Jim Barnett wrote:
>> +1. The current constraints proposal satisfies a number of 
>> requirements that we have elaborated in repeated and extensive 
>> discussions.
>
> Would it be useful to re-summarize those exact requirements at this
> juncture?
>
> .: Jan-Ivar :.
>

Received on Monday, 24 March 2014 14:07:19 UTC