Re: [gnus git] branch master updated: =1= shr.el (shr-tag-div): Added.

[Ted Zlatanov <tzz@lifelogs.com>]

On Wed, 27 Oct 2010 01:58:28 +0200 Lars Magne Ingebrigtsen <larsi@gnus.org> wrote: 

LMI> Very often the div is just used as a container, and the css spells
LMI> out that there should be no "rendering" effect of the div.  (Many
LMI> people haven't heard of span.  :-)) 

There are very good reasons to use DIV instead of SPAN elements for
layout.  I won't bore you with the details, but it's surprisingly
annoying to use SPANs in older browsers and in certain situations.

On Wed, 27 Oct 2010 02:28:32 +0200 Lars Magne Ingebrigtsen <larsi@gnus.org> wrote: 

LMI> Of course, we could start parsing the CSS, but then we'd have to have
LMI> something else that shr could stand for, because it wouldn't be "Simple
LMI> HTML Renderer" any more.  :-)

Parsing CSS is not hard.  HTML layout according to the CSS styles is
very hard and I don't think it should be attempted (I said a while back
that it would require many man-years to get it right).  But a few CSS
properties could be interpreted: some properties I list below for
appearance and "display" and "visibility" for layout.  The renderer
doesn't have to be perfect but it could be usable.

Here's the appearance properties list that IMO would make sense in Emacs:

border
background-color
color
text-decoration
text-transform
line-height
font-family
font-style
font-size
font-weight
list-style
list-style-type
list-style-image
list-style-position

For DIV vs SPAN, if "display" is "block" then the element should be
rendered by itself.  And DIV elements have display:block by default in
all user agents.  Also at a minimum "visibility:none" should be honored.

If you want to support CSS, you have to parse referenced CSS
stylesheets.  I think that's not a big burden for shr.el and would make
it much better.  But otherwise let's not try to support DIVs
specifically; stick to HTML 3.2 (http://www.w3.org/TR/REC-html32.html)
and don't do anything extra for unknown tags.

LMI> I took a stab at it for "color" in span, but I'm not particularly
LMI> satisfied with the result.  That is, somebody has <span color="blue">,
LMI> which renders the text totally unreadable for me, because I use a black
LMI> background.  So I was thinking about either backing that out again
LMI> or...  er...  well, I don't have an "or".  :-)

I think you need to interpret background-color?

Ted