W3C home > Mailing lists > Public > www-style@w3.org > September 2013

css-shapes] Comments on CSS Shapes ED

From: Håkon Wium Lie <howcome@opera.com>
Date: Fri, 13 Sep 2013 11:56:22 +0200
Message-ID: <21042.57670.985222.914086@gargle.gargle.HOWL>
To: www-style@w3.org
I've reviewed 

   http://dev.w3.org/csswg/css-shapes/ 

as of today.

My previous review:

  http://lists.w3.org/Archives/Public/www-style/2011Dec/0482.html

resulted in a proposal which is now found here:

  http://dev.w3.org/csswg/css-page-floats/#exclusions-based-on-images

I still think that:

 - we should base runaround shapes on the actural rendered content,
   not external resources. That is, UAs would extract the runaround
   shapes from the luminence channel of the image (which is always
   available) or rendered text, and not rely on external alpha
   channels or shapes. E.g, I'd like to do:

     img.float { float: left; exclude-level: 0.5 }

   This is a simplification and avoids the use of the attr() function,
   which should not be necessary for common use.

 - the exclusions draft is limited to floats. It's good to start
   simple, but I would probably include backgrounds, too. E.g.:

     body { background: url(foo.jpg); background-exclude-level: 0.5 }

 - it's important to be able to run text around other text,
   especially initial caps. Declaring shapes is a cumbersome and
   unreliable way to do this -- it requires a tool to create the
   shape, and the specified font may not be available so the shape
   turns out to be wrong. Rather than using shapes, I think we should
   use the rendered content. Like this:

     http://dev.w3.org/csswg/css-page-floats/#exclusions-based-on-rendered-content

I also think that:

  - if there is an alpha channel available in the image, it makes
    sense to use it. Perhaps the switch could be automatic: if alpha
    is available, use it; otherwise use the luminence.

So, in summary I suggest:

  - let's do backgrounds in addition to floats
  - let's base runaround shapes on the actural rendered content, not external resources
  - let's postpone referring to external resources until a later level
  - let's use the alpha channel if it's available in the image itself

-h&kon
              Håkon Wium Lie                          CTO °þe®ª
howcome@opera.com                  http://people.opera.com/howcome
Received on Friday, 13 September 2013 09:56:53 UTC

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