RE: [CSS21] shortening inline-height has no apparent effect

> Date: Mon, 28 May 2012 13:27:18 -0400
> Subject: RE: [CSS21] shortening inline-height has no apparent effect
> From: www-style@gtalbot.org
> To: tstartme@hotmail.com
> 
> 
> Le Lun 28 mai 2012 7:53, Roger Baker a écrit :
> > Hi Gérard,
> >
> > I've had a chance to try out your test. I downloaded and installed the
> > Ahem font. I changed the line-height of the div from 0 to 50px. Now, if I
> > may ask what is perhaps a stupid question: When you say "Measure the
> > yellow rectangle, how exactly do I do a measurement of something on a
> > screen?
> > Thank you,
> > Roger
> 
> There is a vertical ruler on the left side of that page. It's a rough
> measurement in some cases.

I was being silly and trying your test locally (I copied the document source to my computer), and of course my computer couldn't find the background url (the ruler) on *my* hard drive! I realized it's best to do your test online with Firebug, so that problem's solved. I did a little drawing experiment (scale drawing) based on your test to represent what I think is going on, and my results match the browser's rendering, so I think I understand now. I posted the drawing on Flickr: http://www.flickr.com/photos/29892546@N03/7296479510/in/photostream/lightbox/, if you or anyone else is able to take a peek and challenge my interpretation if they think I'm wrong.

> 
> Roger, I must say I am very busy these days... Please post your questions
> in the mailing list. Your questions are not stupid. In fact, they are
> relevant and I have been quite vocal and have been asking/rquesting about
> improving section 9.2.2, section 10.6 and section 10.8 of CSS 2.1.

I really appreciate your (and everyone else's) time. I think the CSS spec is a great document and I give a lot of credit to those who contributed to it. On the other hand, there does *appear* to be a bit too much red tape when it comes to making changes, particularly relatively minor amendments/clarifications/elucidations that don't change the essential substance of the text. Of course, I'm speaking basically as an outsider, and I don't understand the editing process.

Roger


> 
> Gérard
> 
> >
> >> Date: Mon, 21 May 2012 01:31:29 -0400
> >> Subject: Re: [CSS21] shortening inline-height has no apparent effect
> >> From: www-style@gtalbot.org
> >> To: jackalmage@gmail.com
> >> CC: tstartme@hotmail.com; www-style@w3.org
> >>
> >>
> >> Le Lun 14 mai 2012 10:56, Tab Atkins Jr. a écrit :
> >> > On Mon, May 14, 2012 at 4:29 PM, Roger Baker <tstartme@hotmail.com>
> >> wrote:
> >> >> Hi,
> >> >> Expanding the inline height of the inline box in the following
> >> example
> >> >> has
> >> >> the expected separation (effect due to expansion of its line box):
> >> >>
> >> >> http://jsfiddle.net/8XJhY/6/
> >> >>
> >> >> But *shortening* the inline height of the inline box does not bring
> >> the
> >> >> succeeding line box closer (does not appear to shorten its line box),
> >> >> for
> >> >> example:
> >> >>
> >> >> http://jsfiddle.net/8XJhY/1/
> >> >>
> >> >> Can someone help me explain this (or point me to the relevant section
> >> of
> >> >> the
> >> >> spec)?
> >> >
> >> > (Someone else can correct me if I'm wrong here - inline layout isn't
> >> > my specialty.)
> >>
> >> Tab,
> >>
> >> I am absolutely convinced that section 10.8 should have diagrams, code
> >> examples, explanations, etc. A wide majority of people do not, can not
> >> and
> >> will not understand section 10.8 without these.
> >>
> >>
> >> >
> >> > I believe that line boxes size themselves to the minimum of the
> >> > line-height of their containing block and the height of their
> >> > contents.
> >>
> >> You most likely meant maximum, not minimum.
> >>
> >> Also, an inline element may be of a certain height but
> >> vertical-align-ing
> >> it on the baseline will cause the line box to become taller (since some
> >> vertical space must be taken into account for the descender space). Or
> >> having an inline element vertical-align-ed at middle, etc.
> >>
> >>
> >> > So, adding a <span> with a large line-height (or just a
> >> > large font-size, or a tall image) will grow the line box, but adding
> >> > one with an extra-small height does nothing.
> >>
> >> line box height = max(line-height of containing block, distance between
> >> the uppermost box top and the lowermost box bottom among all inlines)
> >>
> >>
> >> Roger Baker, load the
> >> http://test.csswg.org/suites/css2.1/nightly-unstable/html4/inline-formatting-context-010b.htm
> >> test and then change line 49 from
> >>  line-height: 0px;
> >> to
> >>  line-height: 50px;
> >>
> >> and then measure the yellow rectangle height when a) the present,
> >> displayed black squares are bigger than 40px and b) when the present,
> >> displayed black squares are smaller than 40px: the line box a) grows in
> >> height and b) shrinks. The glyphs must be sitting on the baseline which
> >> is, for the Ahem font, at 20% of the glyph's height.
> >>
> >> The baseline could also be drawn in that example or it can be
> >> established,
> >> measured when there are several glyphs of different height. One other
> >> way
> >> to do this is to use the É glyph (for the Ahem font only) because
> >> "
> >> 'É' U+00C9 A rectangle exactly 0.8em high, 1em wide, and aligned so
> >>              that its bottom is flush with the baseline.
> >> "
> >> http://www.w3.org/Style/CSS/Test/Fonts/Ahem/
> >>
> >>
> >> Gérard
> >> --
> >> CSS 2.1 Test suite RC6, March 23rd 2011
> >> http://test.csswg.org/suites/css2.1/20110323/html4/toc.html
> >>
> >> Contributions to CSS 2.1 test suite
> >> http://www.gtalbot.org/BrowserBugsSection/css21testsuite/
> >>
> >> Web authors' contributions to CSS 2.1 test suite
> >> http://www.gtalbot.org/BrowserBugsSection/css21testsuite/web-authors-contributions-css21-testsuite.html
> >>
> >
> 
> 
> -- 
> CSS 2.1 Test suite RC6, March 23rd 2011
> http://test.csswg.org/suites/css2.1/20110323/html4/toc.html
> 
> Contributions to CSS 2.1 test suite
> http://www.gtalbot.org/BrowserBugsSection/css21testsuite/
> 
> Web authors' contributions to CSS 2.1 test suite
> http://www.gtalbot.org/BrowserBugsSection/css21testsuite/web-authors-contributions-css21-testsuite.html
>