Re: Unifying the rendering approach

On 5 Mar 2014 18:29, "Victor Carbune" <victor.carbune@gmail.com> wrote:
>
> On Tue, Mar 4, 2014 at 10:46 PM, Silvia Pfeiffer
> <silviapfeiffer1@gmail.com> wrote:
> >
> > On 4 Mar 2014 20:58, "Victor Carbune" <victor.carbune@gmail.com> wrote:
> >>
> >> On Mon, Mar 3, 2014 at 11:55 PM, Silvia Pfeiffer
> >> <silviapfeiffer1@gmail.com> wrote:
> >> >
> >> > On Tue, Mar 4, 2014 at 12:34 AM, Victor Carbune
> >> > <victor.carbune@gmail.com> wrote:
> >> > > On Mon, Mar 3, 2014 at 12:53 PM, Silvia Pfeiffer
> >> > > <silviapfeiffer1@gmail.com> wrote:
> >> > >> On Mon, Mar 3, 2014 at 10:41 PM, Victor Carbune
> >> > >> <victor.carbune@gmail.com> wrote:
> >> > >>> On Mon, Mar 3, 2014 at 12:11 PM, Silvia Pfeiffer
> >> > >>> <silviapfeiffer1@gmail.com> wrote:
> >> > >>>>
> >> > >>>> Aha! I see. The first case is so as to keep the line counting
> >> > >>>> correct
> >> > >>>> for snap-to-lines cues, I assume? Couldn't we make these two
cases
> >> > >>>> into a single case if the line positioning both for
snap-to-lines
> >> > >>>> and
> >> > >>>> for non-snap-to-lines is done on the anonymous region that wraps
> >> > >>>> each
> >> > >>>> cue? What's the advantage of splitting these two cases?
> >> > >>>
> >> > >>> If we throw non-snap-to-lines cues within regions it means that
we
> >> > >>> need to support a rendering case for these cues within regions,
and
> >> > >>> also support named regions on them.
> >> > >>
> >> > >> I don't think so, since it will be the region that is placed, not
the
> >> > >> cue. So, the cue inside the region is still placed "snap-to-line"
> >> > >> even
> >> > >> if the line is basically just a single line (minus line wrapping
and
> >> > >> newlines).
> >> > >
> >> > > Well, it's one thing to deal with snap-to-lines, where you only
move
> >> > > one line on top of the other until they don't overlap, and another
one
> >> > > is to deal with overlap between a percentage-positioned cues
together
> >> > > with line-positioned cues; moving lines is simple and
straightforward.
> >> >
> >> > Correct. I don't see how this is relevant though. If we give all
> >> > non-region cues their own anonymous region box, then we never have to
> >> > worry about cue overlap inside regions. All we have to worry about is
> >> > region overlap.
> >> >
> >> > Was your intent to separate overlap avoidance for the percentage
> >> > positioned non-region cues from overlap avoidance of the regions?
That
> >> > would potentially cause overlap between non-region non-snap-to-line
> >> > cues and snap-to-line cues (in regions), right? Are you suggesting
not
> >> > to deal with that? Would we even do overlap avoidance for regions?
> >>
> >> I want to avoid solving overlap avoidance between non-snap-to-lines
> >> and snap-to-lines cues by:
> >> *) ensuring they never end up in the same region (thus, I don't see a
> >> need to support non-snap-to-lines cues with author-specified regions,
> >> there's no use-case for this situation)
> >> *) deferring the overlap avoidance mechanism to regions.
> >
> > Agree. That's why I wouldn't want all non-snap-to-lines cues end up in a
> > single full-viewport-sized region.
> >
> >> > >>> *) No need to think what happens if some percentage-positioned
cue
> >> > >>> overlaps a line-positioned cue (see "underspecced overlapping
> >> > >>> positioning" bug)
> >> > >>
> >> > >> We still have to deal with overlapping cues, no matter whether
they
> >> > >> are in snap-to-lines regions or in non-snap-to-lines regions.
> >> > >
> >> > > This would move to dealing with overlapping regions - which we
decided
> >> > > we don't want to support, right? Or at least differ it to a higher
> >> > > level mechanism that would deal with all the caption boxes from any
> >> > > format ending up on the screen.
> >> >
> >> > Hmm... I thought we didn't want to deal with overlap for region-cues.
> >> > But you're now also saying we don't want to deal with overlap for
> >> > non-region snap-to-line cues. I don't think that was the intention.
> >>
> >> We need unification: imagine, exaggerating here, having
> >> {snap-to-lines, non-snap-to-lines} x {region, non-region} type of
> >> cues.
> >>
> >> One solution is for all cues to end up in regions, anonymous or
> >> author-specified, for rendering purposes.
> >
> > Yes, that's the best approach IMO.
> >
> >> > I can imagine a single overlap avoidance algorithm that works on
lines
> >> > only where for percentage-positioned cues a line is deemed occupied
if
> >> > a part of a cue is in it.
> >> >
> >> >
> >> > >>> *) Better abstraction: author can already obtain exactly the same
> >> > >>> positioning using regions that they can with
percentage-positioned
> >> > >>> cues. Why integrate two different elements solving the same
problem
> >> > >>> together, if we can keep only one?
> >> > >>
> >> > >> Because it avoids another big case statement in the rendering
> >> > >> algorithm. This way we have all three cases in one branch rather
than
> >> > >> 2 different branches. Also, this is just about the rendering,
since
> >> > >> we're still keeping the two different ways of specifying
positioning
> >> > >> (cues with line cue setting and cues inside regions).
> >> > >
> >> > > Wouldn't this simply be something like: if non-snap-to-lines=true
> >> > > create on the fly an anonymous region, render the text in it
according
> >> > > to the rules in "paragraph where layout in a region is done" and
then
> >> > > resize the anonymous to perfectly match the cue and set the region
> >> > > positioning parameters accordingly?
> >> >
> >> > Hold on. Earlier you said that all non-snap-to-lines cue will be
> >> > rendered in a single anonymous region that covers the full viewport.
> >> > What you are instead describing here is the rendering approach for
> >> > snap-to-lines-cues.
> >>
> >> This was for snap-to-lines cues with no author-specified region.
> >
> > Oh! But then you can't do overlap avoidance with these cues either.
>
> Well if all the snap-to-lines cues without an author-specified region
> go into the same anonymous region of the size of the video, then you
> are just using the cue snap-to-lines positioning algorithm to do
> overlapping.

I didn't mean for cues to share a region unless they were authored with a
region.

> > I'd rather they go into  individual regions, too, and are all dealt
with by
> > a single overlap avoidance approach that works on regions.
>
> Then how do you honor line positioning for a cue that has no region,
> and has line:3 attribute? You will have to make position the region in
> line 3 of the video viewport, rather than the text lines of the cue in
> a region.

Correct. That's what I thought we are doing with all cues now.

Silvia.

> >> > If you are indeed creating an anonymous region per non-snap-to-lines
> >> > cue, too, then that agrees with what I was arguing for.
> >>
> >> Yes, I want an anonymous region for each non-snap-to-line cue.
> >>
> >> For a snap-to-line to line cue I see the two cases I mentioned:
> >> *) There's no region attribute set and then the cue belong to the
> >> default region with the full-viewport size
> >> *) There's a region attribute set and then the cue ends up in that
> >> particular region.
> >
> > Silvia.