Re: Pixel, Points and Spatial Measures

On 13/01/2017 09:20, Patrick H. Lauke wrote:

> Don't want to start yet another epic thread, but once more: there is no
> way to require a particular spatial measure from developers, since they
> have no way of controlling how their content is actually rendered, at
> what size. That depends on the physical size of their screen and the
> resolution it's running at, and the actual physical size is something
> that authors have no way of knowing nor detecting.
>
> Once more: as an author I have absolutely no control over the actual
> spatial size, in real-world physical units, of my content.
>
> It's not possible to provide a conversion table, as there are variables
> (the physical size of the screen, the resolution that screen is running)
> - there's no simple "X pixels equals Y centimeters/inches".

I'll add to this that you can certainly give one particular pixel size 
as a measure, and then explain that that particular value was chosen 
because on average, on a screen of physical size X, at Y resolution (in 
CSS pixels), this generally results in content that is rendered at 
physical size Z...but you simply cannot write an SC requirement for 
authors to guarantee a particular physical size outright.

As discussed previously on this list, this would also become untestable 
- testers would need to load the content on all possible / available 
screen sizes, running at all possible / common resolutions, and hold a 
ruler against the screen to measure the actual rendered size of content. 
Otherwise, their pass/fail would only be valid for just the limited 
number of screen sizes/resolutions that they DID test.

P
-- 
Patrick H. Lauke

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Received on Friday, 13 January 2017 09:26:41 UTC