[whatwg] img as a layout tool to describe the displayed region of a CSS background-image
Ian Hickson
ian at hixie.ch
Thu Jul 29 18:17:03 PDT 2010
On Wed, 28 Apr 2010, Ingo Chao wrote:
>
> http://dev.w3.org/html5/spec/Overview.html#the-img-element "The img must
> not be used as a layout tool. In particular, img elements should not be
> used to display transparent images, as they rarely convey meaning and
> rarely add anything useful to the document."
>
> An img with a given transparent image for src cuts an area of a sprite.
> ( = img as a layout tool to describe the displayed region of a CSS
> background-image.)
>
> Is this usage of the img element considered invalid (non-conforming)?
I do not understand the use case you descrbe.
On Wed, 28 Apr 2010, Ashley Sheridan wrote:
>
> If an image is transparent, it has no display value other than to
> reserve an area of space, which goes back to the original point that
> images should not be used for layout.
Right.
> If you're using a background image then that shouldn't need to convey
> any meaning to the viewer, it should only be for presentation purposes.
> The meaning of the content should remain the same if the background
> image is displayed or turned off regardless. You should consider
> re-structuring your page so that the presentation is separate from the
> content.
Indeed.
On Wed, 28 Apr 2010, Giorgio Maone wrote:
>
> I believe the spec is trying to stigmatize old-times spacer images used
> to layout other HTML elements, like
>
> <img src="spacer.gif" width="100" height="1">
>
> which are overly ugly and meaningless now that there's nothing you can't
> layout by CSS.
Amongst other things, yes.
On Wed, 28 Apr 2010, Ashley Sheridan wrote:
>
> But still, using a transparent image with some alt text to convey
> information about a background image is just as bad. It's breaking the
> relationship between content and the meaning of that content. A
> background image should be just that, and shouldn't have any impact on
> the meaning of information. Likewise, colour shouldn't be relied on to
> convey information, as there are cases where colours can't be displayed
> or aren't transferred if the information is grabbed as an excerpt to be
> used elsewhere.
Right.
On Wed, 28 Apr 2010, Steve Dennis wrote:
> On 28/04/2010, at 7:43 PM, Tab Atkins Jr. wrote:
> > On Wed, Apr 28, 2010 at 4:31 AM, Ingo Chao <i4chao at googlemail.com>
> > wrote:
> >> http://dev.w3.org/html5/spec/Overview.html#the-img-element
> >> "The img must not be used as a layout tool.
>
> I think this may be a little vague/broad. I understand the intention,
> but say for example I have a logo image in the top left of my header,
> and my header doesn't have a static height set (in case something in the
> header needs it to grow or shrink for instance), then the height of the
> logo image is dictating the height of its parent, and this would seem to
> me, to be using an img as a layout tool, in a sense.
A rather odd sense. :-)
> Sprites for icons, while widely used and considered fairly good
> practice, still seem pretty hack-ish to me. Icons can (arguably) help
> convey meaning in a document, and changing a background position to
> change that meaning doesn't seem like the best way of achieving this.
> I am of course thinking like 10 years into the future here, as sprites
> are perfectly fine for lots of uses today, but as concurrent connections
> become less of a problem, I think lots of us will look back on sprites
> the same way we see spacer.gifs, which were a necessary evil at the
> time.
Using CSS to display content is a misuse of the technology, certainly.
On Wed, 28 Apr 2010, Tab Atkins Jr. wrote:
>
> Don't overthink it. It's a very simple rule. ^_^ Having an img
> *interact* in the layout is both fine and obviously necessary. The
> restriction is to prevent someone from using an <img> element *solely*
> for layout purposes.
Right. (No, wait. I mean, "Indeed".)
--
Ian Hickson U+1047E )\._.,--....,'``. fL
http://ln.hixie.ch/ U+263A /, _.. \ _\ ;`._ ,.
Things that are impossible just take longer. `._.-(,_..'--(,_..'`-.;.'
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