Fwd: [css3-gcpm] Spacing and alignment of leaders

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---------- Forwarded message ----------
From: Tab Atkins Jr. <jackalmage@gmail.com>
Date: Fri, Aug 8, 2008 at 9:28 AM
Subject: Re: [css3-gcpm] Spacing and alignment of leaders
To: marbux <marbux@gmail.com>




On Thu, Aug 7, 2008 at 11:12 PM, marbux <marbux@gmail.com> wrote:

>
> Forgive me if I am missing something (just getting started with CSS
> 3), but <http://www.w3.org/TR/2007/WD-css3-gcpm-20070504/#leaders>
> does not seem to specify a method for horizontal spacing and alignment
> of leaders. The section as now drafted seems to contemplate leaders
> without horizontal spacing and alignment.
>
> If correct, this repeats a visually ugly custom enforced by desktop
> word processors (e.g., an unbroken string of repeated periods) that is
> at odds with the typographical tradition of spacing between leader
> characters and each leader character's alignment with the
> corresponding leader character in other table of content entries. The
> ugliness stems from the visual heaviness of an unbroken string of
> leader characters, e.g.,
> ................................................
>
> In the hot type days, leader characters were normally separated using
> em and/or en spaces, and aligned horizontally. Numerals correspond in
> width to an en space, so if one has a variable page number length,
> e.g., pages 101, 89, and 5, the leader ending can be uniform; e.g.,
> assuming that variable justification is applied between Text and the
> leaders, that dot leaders are separated by one em space, and that one
> en space is desired between the last leader character and the longest
> page number:
>
> Text .[em].[em].[em][en]5
> Text .[em].[em].[em]89
> Text .[em].[em].[en]101
>
> produces right-aligned page numbers, a uniform gutter between the page
> numbers and the leaders, and horizontally aligned
> leaders. See Space Characters in Unicode,
> <http://www.cs.tut.fi/~jkorpela/chars/spaces.html<http://www.cs.tut.fi/%7Ejkorpela/chars/spaces.html>
> >.
>
> A similar effect might be programmatically attained using tab
> settings. However, it is the effect that is important, not the
> methodology. Horizontally separated and aligned leaders, being less
> visually overpowering, emphasize the text on the same line while still
> providing the desired visual guide to the correct page number on the
> right margin.


Wouldn't the horizontal spacing be rather simply solved by using
leader('.[em]')?  You can provide a generic string to the function.  You'd
have to escape the em space, obviously.

Of course, the leader alignment is a slightly different issue that is not
solved by this.

~TJ