Re: [Bug 26526] Fix aspect ratio constraint

On 11/09/2014 1:55 PM, Stefan Håkansson LK wrote:
> On 2014-09-11 19:48, cowwoc wrote:
>> On 11/09/2014 12:21 PM, bugzilla@jessica.w3.org wrote:
>>> https://www.w3.org/Bugs/Public/show_bug.cgi?id=26526
>>>
>>> Jan-Ivar Bruaroey [:jib] <jib@mozilla.com> changed:
>>>
>>>               What    |Removed                     |Added
>>> ----------------------------------------------------------------------------
>>>                     CC|                            |jib@mozilla.com
>>>
>>> --- Comment #3 from Jan-Ivar Bruaroey [:jib] <jib@mozilla.com> ---
>>> I think the existing epsilon covers inaccuracies in double just fine, and that
>>> arguments to change it were in the opposite direction, chasing the problem of
>>> interpreting expectations correctly of people entering decimals by hand.
>>>
>>> I believe Harald proposed 1/1000 [1], and I indicated perhaps 1/100 as being
>>> better, citing wikipedia [2] as evidence that accuracy-needs on aspect don't
>>> rise with higher resolutions.
>>>
>>> [1] http://lists.w3.org/Archives/Public/public-media-capture/2014Aug/0056.html
>>> [2] http://lists.w3.org/Archives/Public/public-media-capture/2014Aug/0084.html
>>>
>> I believe your reasoning is still flawed. You shouldn't evaluate the
>> "goodness" of an epsilon by looking at a handful of resolutions as
>> you've done. You need to evaluate the epsilon against the entire
>> resolution space from 1x1 through 16k.
>>
>> For example, what happens when a user asks for an aspect ratio of 8/12?
>> He might be aiming for 800x1200 but you'll give him 788x1200 for an
>> epsilon of 1/100. That's a huge error margin.
> I agree, and I think we could go with Cullen's proposal, i.e. the spec
> default (which currently means 1e-10. Everyone has a calculator at hand
> I believe, so getting 10 decimals should not be hard.

I just tested 1x1 through 76,800 (80k resolution) against that epsilon 
and the error margin is plus/minus 1.2 * 10^-7. Sounds good to me.

Gili

Received on Thursday, 11 September 2014 19:02:30 UTC