Re: Review Comments: Light Events

From: Doug Turner 
Sent: Wednesday, August 01, 2012 3:01 AM
To: nv.balaji@samsung.com 
Cc: Robin Berjon ; public-device-apis@w3.org public-device-apis@w3.org 
Subject: Re: Review Comments: Light Events


>>>Thanks for the feedback! 


On Sun, Jul 29, 2012 at 10:32 PM, BALAJI NERELLA VENKATARAMANA <nv.balaji@samsung.com> wrote:

  Please find my comments:



  1. I would suggest to change the title to "Ambient Light Events"


>>>Happy to change the title of the spec.  The event names will remain the same.


Understandable as it is already in Firefox. It's fine by me. 


  2. Section 5.2:

           - Computing "lighting condition" (such as warm day, pitch dark etc...) from light value is non-trivial. Ligting condition corresponds to logarithm of Luminance. Therefore, it is better "lighting condition" parameter is added to the Light event. 

          - If it is not acceptable (as this information is redundant),  as an alternate, a note could be appended at the end explaining how the lighting condition could be arrived from the light value


>>>What language would you use as a note to describe how the lighting condition can be derived?
How does the following sound:

"The amount of ambient light (also known as illuminance) is measured typically with the unit "lux" (lx) or "lumens per square metre". The "lux" values are different from the human perception of the light. Human perception of light, such as "dark", "normal indoors", "bright indoors", "bright sunlight", are not linearly related to the "lux" values. Human perception of light, even though a complex phenomenon, can be modelled in a simple way for practical purposes. It can be modelled to be proportional to the logarithm of illuminance"


 
  3. Section 5.2.1

           - the unit of the value should be specified


>>>Fixed. 

Thanks




  4.  Section 5.2.2

             - For all practical purposes, I beleive, the developer would be interested in events only when the lighting condition changes. Therefore, light event should be fired only when "lighting condition" changes. I have not tested the latest Firefox implementation on mobile. Could someone please let me know how often does it fire the event?


>>>>We fire when there is a change.  The UA determines when there is a significant change.

Did you get a chance to observe how often the underlying drivers fire? Do they fire only when the "lighting condition" (human perception of light) change or when the lux values change? Anyway, this is a question out of curiosity and would not have any bearing on the spec.