Re: What is the use case for two levels of background colors?

On Mon, May 12, 2014 at 6:12 PM, Philip Jägenstedt <philipj@opera.com> wrote:
> Using the cue box as the background box was what I did in
> http://people.opera.com/philipj/2014/03/vttscroll/background.html

There's a difference: you're putting a background on the individual
cues while the background on the region is putting a background on the
group of cues in one go. There is no chance of a gap appearing between
the cues because of this.

> However, I've realized that this creates a bit of a tension between
> two goals: in order to "look nice" the background should not be much
> bigger than the cue text, but to give the cue size to grow when the
> font size changes, it should be as big as possible.
>
> This would likely cause authors to create boxes that are too small,
> causing unnecessary line wrapping when the font size increases. Note
> that using a font-relative unit like em doesn't eliminate the problem,
> as illustrated here:
> http://jsfiddle.net/zLB3N/
>
> If the use case was to provide a common background for a number of
> lines (possibly from different cues) simply taking the bounding box of
> those lines and adding some padding would be enough.

That's what the region is for.

> However, if the background needs to be unchanging over time

What do you mean by "unchanging"?

Silvia.

> the
> algorithm would have to be much more complicated, and I don't know how
> to solve it. Letting the author set a fixed size will result in text
> becoming unreadable in some cases, even if font-relative units are
> used.
>
> Philip
>
> On Sat, May 10, 2014 at 11:20 PM, Christian Vogler
> <christian.vogler@gallaudet.edu> wrote:
>> Maybe I am off-track here, but to me it seems that the cue box (especially
>> with an auto width and height) is the logical place for having this visually
>> stable background. This should work just fine for pop-on captions, but
>> breaks down with roll-up, because in roll-up, each new line/addition is a
>> separate cue.
>>
>> I'm not sure why this decision was made, to have a separate cue of its own
>> for each new roll-up line, other than the desire to employ WebVTT's overlap
>> avoidance algorithms. Hypothetically speaking, couldn't the same use cases
>> be solved with overflow properties on cue boxes? If so, I don't see any need
>> for regions anymore. What am I missing?
>>
>> Christian
>>
>>
>> On Sat, May 10, 2014 at 5:10 PM, Philip Jägenstedt <philipj@opera.com>
>> wrote:
>>>
>>> Thanks David!
>>>
>>> If "visual stability" can be important to the end user, what should be
>>> done in the case where regions aren't used by the caption author? In
>>> 708, is it possible to have captions outside of windows?
>>>
>>> (Note that a VTTRegion background grows and shrinks with the cues
>>> within it, but it sounds like you had something slightly different in
>>> mind.)
>>>
>>> Philip
>>>
>>> On Fri, May 9, 2014 at 10:09 PM, David Singer <singer@apple.com> wrote:
>>> > I am not sure that they are useful together, but don’t they have
>>> > different visual effects?
>>> >
>>> > The background for a region causes a stable rectangular area to be
>>> > painted in that color, no mater what text (if any) is inside it.
>>> >
>>> > the background for text is only drawn around the actual characters.
>>> >
>>> > the first has the advantage of visual stability, while the second
>>> > minimizes the amount of the scene obscured.
>>> >
>>> > On May 9, 2014, at 7:07 , Philip Jägenstedt <philipj@opera.com> wrote:
>>> >
>>> >> Hi all,
>>> >>
>>> >> Does anyone know the use case for having two levels of background
>>> >> colors, specifically one background color on the individual lines of
>>> >> text and another on the region/window?
>>> >>
>>> >> The only thing I can think of is that it could make the text more
>>> >> readable for some people. However, if that is the real use case I
>>> >> think relying on regions for it is unacceptable, because the author
>>> >> may not have used regions at all. A robust solution would require the
>>> >> user agent always add that extra layer behind all cues.
>>> >>
>>> >> Thoughts?
>>> >>
>>> >> Philip
>>> >>
>>> >
>>> > David Singer
>>> > Manager, Software Standards, Apple Inc.
>>> >
>>>
>>
>>
>>
>> --
>> Christian Vogler, PhD
>> Director, Technology Access Program
>> Department of Communication Studies
>> SLCC 1116
>> Gallaudet University
>> http://tap.gallaudet.edu/
>> VP: 202-250-2795
>

Received on Monday, 12 May 2014 08:25:16 UTC