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RE: [css-round-display] Method for setting the viewport into the non-rectangle display

From: Jihye Hong <jh.hong@lge.com>
Date: Wed, 27 Apr 2016 15:48:16 +0900
To: "'Brad Kemper'" <brad.kemper@gmail.com>, "'Florian Rivoal'" <florian@rivoal.net>
Cc: "'www-style list'" <www-style@w3.org>
Message-ID: <004f01d1a050$c74068d0$55c13a70$@lge.com>
> On Apr 21, 2016, at 2:59 AM, Brad Kemper < brad.kemper@gmail.com > wrote:
> 
> On Apr 20, 2016, at 12:10 AM, Jihye Hong <jh.hong@lge.com> wrote:
> > 'viewport-fit' can set the size of the bounding box which is used for
> > applying the actual viewport (visual viewport).
> > What would be the appropriate terminology for 'the bounding box'?
> 
> I was kind of wondering that too. Is it just a situation of the initial
> viewport being bigger than the visual viewport, not including content
> overflow off the bottom? Or is it that the initial viewport is smaller
> than the physical area  of the display? Do we need a new term for one of
> these, and define specifics for it?

The bounding box of the viewport means the viewing area through which you
can see the actual viewport.

For the rectangular device, the actual viewport is seen through the physical
screen of the device. So the circumscribed rectangle of the physical screen
is always the same as the bounding box for the viewport and screen.width and
screen.height can give the size of the bounding box.

The bounding box can be set to the inscribed rectangle of the physical
screen with 'viewport-fit' having the value as 'contain' when the shape of
the device is round.
But in this case, the size of the bounding box is not the same as the size
get from screen.width and screen.height.

Therefore we need a new term, "bounding box for the viewport".

The size of the initial viewport doesn't change even if we change the size
of the bounding box.

> >>  auto: Same as 'contain', except the UA may also use a slightly larger
> >>        rectangle, as long as this would not cause a significant part of
> >>        the viewport to be off screen. In any case, the rectangle must
> not
> >>        be larger than the one implied by contain. For example, on
> >>        a screen with only slightly rounded corners, the rectangle used
> >>        could be the same as with 'cover'
> > How can we know that the shape of the display is the rounded rectangle?
> 
> Media query?

Yes. So far it's hard to know the exact shape of the physical screen with
media query.
But when UA may know the shape, I think 'auto' would works as 'contain' when
the shape of the display is rectangle or round. And if the shape of the
display is the other shapes such as rounded rectangle or star-shape, it
would be the same as 'cover'.

> > When setting the size of the bounding box for the viewport on
> > non-rectangular display, we have to consider:
> >  - Clipped area which is caused because the area of the viewport
> > bounding box is larger than the area of the display.
> 
> When does this happen? Do you mean when content overflows or is zoomed? I
> might be getting confused by interpretation of the terminology. Is
> bounding box here the same as actual viewport or initial viewport or
> something else?
> 
> Or are you just referring to some of the area being clipped by the display
> shape?
It means the area being clipped by the display shape.

On the rectangular device, the bounding box of the viewport is always the
same as the physical screen of the device.
But when the device has the other shapes of screen, some parts of the
bounding box would be clipped by the screen.


Thanks,
Jihye
Received on Wednesday, 27 April 2016 06:48:51 UTC

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