W3C home > Mailing lists > Public > public-html@w3.org > July 2016

Gallery element

From: Hans Schmucker <i@hansschmucker.de>
Date: Thu, 7 Jul 2016 15:44:10 +0200 (CEST)
To: public-html@w3c.org
Message-ID: <324017056.24501.5ea3ddc5-55ea-43b0-9a1b-22ebb1dcafd2.open-xchange@email.1und1.de>
Hello everybody

Right now this is little more than a description of a problem with a rough
outline how a solution could work, so there are obviously a lot of issues not
discussed in this proposal. What I'd like to discuss is whether this has any
place in the HTML specification at all. My personal opinion is that it would
lend meaning to something that today is mostly tag-soup, but your opinion may
differ and that's what I'm most interested in hearing about.

IF there is consensus that this IS worth investigating, then I'd gladly help
write up a few proposals and sample implementations.

Maybe I’m overlooking something, but I’m currently writing another JS gallery
(there are some special requirements, but that’s beside the point) and there’s
one thing that bothers me: There really is no way to write a perfect gallery for
all platforms, for the simple reason that the conventions for displaying a list
of images are very different for practically every platform.

Desktop users are used to menu-less thumbnail overviews with lightboxes for
full-size images, because zooming is not a huge priority. Mobile users prefer
full-screen images without any controls, but with appropriate gestures in place.
The specifics (like how annotations are presented, which options are present and
which animations are expected) even differ between OS versions.

All that combined with the simple fact that there simply is no way to mark up a
gallery correctly at this time, while the web is exploding with graphics, makes
me think that we should consider adding gallery element.

A gallery should be a _a series of related pictures which have a combined topic,
as well as an individual message._

Its content (one figure per item) should be shown to the user in a way which is
_appropriate for the platform_, allowing him to _navigate among the figures_
(giving an overview first and allowing him to drill down) as well as showing the
content in a way which allows him to _inspect all its aspects_ (i.e. zooming).

A full-screen gallery would be best from a user’s perspective, but webpages
would have big reservations about their gallery being displayed outside the
context of their page. So the gallery element should NOT function as a link to a
full-screen application, but like a normal block element, displaying the gallery
overview in the specified area (along with appropriate controls).

The user agent may choose an appropriate size for the individual pictures,
without any limitations. A _content attribute_ may be given to allow for
appropriate presentation. Values may (for example) include photo, icon, art..

Each picture may have a title, which the user agent must show along with each
image. The description on the other hand should be shown only when an image is
inspected individually. The user agent may hide the caption after a brief
period, but it must initially be visible.

Example:
<h2>My photos</h2>
<gallery content="photo" protected="true">
    <figure>
        <picture><img title="Test photo 1" alt="The first test, showing Mannheim
at night" srcset="test1s.png"/></picture>
        <figcaption>A beautiful night</figcaption>
    </figure>
    <figure>
        <picture><img title="Test photo 2" alt="The first test, showing a street
at night" srcset="test1s.png"/></picture>
        <figcaption>OK, so it’s slightly blurry</figcaption>
    </figure>
</gallery>

 
A user agent may also provide appropriate actions for each image, for example
download, share, print and so on. A gallery may indicate that its content is
protected by specifying protected="true", in which case the user agent should
restrict the use to pure viewing (however, actual protection is not required,
the presence of protected="true" merely indicates the intended use).

Galleries may also be nested. If a gallery element contains another gallery, the
first picture element is meant to describe the gallery as a whole. The user
agent is free to show the sub-gallery inside the initial rectangle or
full-screen at its own discretion.
Example

<h2>My photos</h2>
<gallery content="photo" protected="true" embedded="false">
    <picture><img title="Mannheim" alt="Pictures of Mannheim"
srcset="test1s.png"/></picture>
    <gallery content="photo" protected="true">
        <figure>
            <picture><img title="Test photo 1" alt="The first test, showing
Mannheim at night" srcset="test1s.png"/></picture>
            <figcaption>A beautiful night</figcaption>
        </figure>
    </gallery>
</gallery>


A webpage may prevent the user-agent from opening any images in full-screen view
by specifying embedded="true", in which case the user agent should render the
image, with appropriate control inside the rectangle specified by the gallery
element.


Presentation

Defining the behavior of a gallery isn’t easy for all platforms. For example,
it’s not that easy to specify a universal size for thumbnails. A photographer
may require a much bigger thumbnail image for identification of a specific image
than an icon catalog designer.

The smallest reasonable size on a platform on the hand may require a larger
image for optimal navigation than what the designer intended. Or the platform
may be unable to show more than an overview before entering a separate mode for
navigation.

>From a design standpoint, the number of rows is often as important as the size
of the gallery. So how do we account for all these cases while giving designers
a predictable result that they can incorporate into their design?

Basically, we’ll need an element that will either
a)    Cover a specified area or
b)    Fit into a column with an intrinsic height
Which additionally
    Has a minimum specified size per element.

There’s also the issue to consider that not all images are the same.. Some may be
suitable for cropping, others may be suitable for scaling and so on and so
forth.
Getting the CSS right is obviously an issue, but a solvable one if there's any
interest in doing this.

So... is there?


Hans Schmucker
i@hansshmucker.de
Received on Thursday, 7 July 2016 14:54:58 UTC

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