Re: [csswg-drafts] [mediaqueries] Media Feature: "reduce transparency" user setting

(this comment is equally valid for this issue and for #442)

This seems very reasonable and useful to me.

1) I am a little worried about adding this in isolation though. I 
believe this is an OS X / iOS specific preference. If we list all (or 
even just many) such settings from all (or even just many) OSes one by
 one, I worry that we will end up with a very long list, from which 
each UA vendor will only pick a few, and authors will themselves also 
only respond to the few they know/care about. The intersection of both
 meaning that for end users, the odds of this actually working might 
be pretty low. Maybe we can spec anything we run into, wait a few 
years to see what sticks, and deprecate the rest, but I am not sure 
this is a great approach.

I think It would be very useful to see a broad survey of all such 
accessibility/preference settings across major OSes to determine:
 - If we want to expose these one by one, or if that's too fine 
grained and we need to find some higher level grouping
 - If several OSes deal with the same concern in somewhat different 
ways, to see whether and how we can design the MQ to have useful 
cross-OS semantics

2) I believe this is one of the topics, together for example with 
color inversion and contrast boosting or reduction where OS/UA vendors
 may either decide to request the content to adapt itself to the 
preference or to forcibly do the adjustment and (possibly) let the 
content know the adjustment has been done so that it can avoid doing 
things that conflict with this adjustment.

reduced-transparency: none | preferred | forced;
reduced-motion: none | preferred | forced;
color-invert: none | preferred | forced;
save-ink: none | preferred | forced;

Not all OSes will use all modes, but it would be helpful to authors to
 know what's happening to them.

How do handle the `preferred` variant should be fairly obvious, but 
for the rest:
- in forced color invert, authors should double invert the photographs
 and get rid of shadows (assuming it is done at the pixel level as on 
OS X, if there is "smart" forced color invert, we probably need a 
value to distinguish).
- in forced save-ink, authors should know not to rely on backgrounds 
to keep things readable, as they may not be displayed.
- in forced reduced animation, authors should expect that the UA may 
not run animations or transitions, and should make sure the page is 
readable/usable without them
- in forced reduced transparency, authors should expect that the UA 
may always set the alpha channel to 1, and should not rely on 
transparency actually happening to keep the page readable/usable

I think this design is likely to be sound, but I would like second 
opinions, and to evaluate it against a few more media queries and a 
few more OSes to see if it holds up.

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Received on Tuesday, 6 September 2016 03:41:41 UTC