W3C home > Mailing lists > Public > www-style@w3.org > July 1998

RE: OBJECT, inheritance, and rendering

From: Braden N. McDaniel <braden@shadow.net>
Date: Fri, 31 Jul 1998 20:20:28 -0700
To: "'David Perrell'" <davidp@earthlink.net>, "'HTML'" <www-html@w3.org>, "'Style'" <www-style@w3.org>
Message-ID: <000301bdbcfb$559911b0$7422dbd0@bonezero>
> -----Original Message-----
> From: www-style-request@w3.org [mailto:www-style-request@w3.org]On
> Behalf Of David Perrell
> Sent: Friday, July 31, 1998 7:12 PM
> To: 'HTML'; 'Style'
> Subject: Re: OBJECT, inheritance, and rendering
> Braden N. McDaniel wrote:
> >And how is this not, functionally, a default style sheet?
> It does not follow that because a UA has default style values, every
> document has a default stylesheet. Note "cascading" in the
> name. The UA has
> default values which can vary from UA to UA, the user can modify these
> values, and a document can modify them further. If we accept
> your semantics
> it could be argued that the default stylesheet for the
> included document
> should consist of the values at the point of inclusion.

I didn't say there was a single default style sheet that could be defined
across all browsers and configurations. I suggested that the browser
settings (which may include user-configured settings, including a user style
sheet) prior to the application of any styles in or referenced by the
document function as a default style sheet. Nothing you say above appears to
contradict this interpretation, though you seem not to like my choice of
terminology. This is certainly not incompatible with "cascading," as you
seem to suggest.

Your connection of my semantics to style inheritance for inclusions strikes
me as quite bizarre--I just don't see it.

> >"Independent" is a strong word. How strongly do you mean it?
> Do you mean
> >here that the background color should be the UA default, or
> that it should
> >be "transparent", and the color specified in the host
> document should show
> >through?
> Default, or as specified by the user.

If specifed by the user in the browser settings, that modified setting
becomes the default as far as subsequently applied style sheets are
concerned, yes?

> The idea of a UA algorithmically
> modifying foreground colors in the included document to
> provide contrast on
> an unexpected background is unappealing to me.

It was just an idea; I would certainly be glad to see others. But you
haven't convinced me that this problem doesn't exist.

> >Given (1) the conventional behavior of transparency in
> inclusions, and (2),
> >the fact that the initial value for "background-color" is
> "transparent",
> the
> >former interpretation strikes me as inconsistent with the established
> >behavior for other media types.
> >From the CSS2 recommendation, section 9.1.1*: "There is at
> most one viewport
> per canvas..." The default color of the viewport's canvas is
> determined by
> the UA, and it is not conventionally transparent (when you
> declare HTML and
> BODY background to be transparent, do you see your desktop shining
> through?).

No; that behavior isn't in conflict with the specs, though, is it? I'm not
suggesting the current behavior of browsers in this case (for documents that
are not inclusions) is in confict with the spec either. As noted, the
initial value for "background-color" is transparent. The "base color" that
should show through by default is, AFAICT, undefined. So, as you note, this
is defined by the implementation. It could be puce, or it could be my
desktop, or it could be the wall behind my monitor--as far as the spec is

> A complete HTML document must be rendered within its own
> viewport.

But where is it said that the canvas of this viewport must show the
UA-default background color as its default background?

> When an OBJECT is an HTML document, the object
> becomes, in effect,
> an IFRAME.


> Rendering of HTML documents in the IFRAME element
> corresponds to
> what I'm suggesting is reasonable.

This may be supported by the behavior of current implementations, but I
can't find support for it in the specs.

> >And I submit that only the latter interpretation requires no
> change to the
> >CSS spec. It seems to me that the former interpretation
> would require that
> >the initial value for "background-color" be changed from
> "transparent" to
> >"implementation defined".
> Nope, only that the nested viewport have its own canvas, as
> specified in the
> CSS2 Recommendation.

It is not apparent to me that being a nested viewport implies that the
transparent background of the elements in the included document should show
through the UA's default background color rather than the background of the
host document.

> >As stated, per my interpretation of the specs, this is not entirely
> >accurate. The host document *can* affect the background color of the
> >included document, but not the foreground color.
> I see the included HTML document in a nested viewport with
> its own canvas,
> ala IFRAME. I believe this is, at the moment, the
> conventional behavior of
> transparency for text/html inclusions.

Conventional...? Do we have more than one implementation that has
interpreted this as you describe?

Received on Friday, 31 July 1998 23:13:17 UTC

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