Re[3]: Vertical alignment of formulas

[Hans Hagen <pragma@wxs.nl>]

At 14:05 18/09/2003 +0200, you wrote:

>In the end it always end up on the totally different views on
>displayed material that you and TeX have. We discussed this for
>the "autoindent" stuff, remember? You always consider displays
>a "separate entity" from the surrounding text, whereas TeX
>allows it to be separate or not (depending on \pars around it).
>TeX approach is both more flexible and more "correct".

hm, in this case i more tend to look at the grayness of a page and then 
decide on a space correction like this; (which is why i also have a 
threshold)

>Let's say for example that we're discussing Einstein's
>equation. The following three examples have different logical
>meaning and should therefore be formatted appropriately
>differently:
>
>=== EXAMPLE 1: Display part of the paragraph ===
>
>Einstein's equation $$E=mc^2$$ ties energy and mass of a body
>to etc
>
>=== EXAMPLE 2: Display part of the previous paragraph but not
>     of the following one ===
>
>A relation between mass and energy of a body is expressed by
>Einstein's equation $$E=mc^2.$$
>
>We shall see further on that etc
>
>=== EXAMPLE 3: Display part of the following paragraph but not
>     of the previous one ===
>
>some text etc.
>
>$$E=mc^2$$ is Einstein equation and it ties energy and mass
>of a body etc.
>
>================================================
>
>In Ex1, you want the displayed equation to have as little
>spacing as possible both above and below, and the following
>text should NOT start with an indent.
>
>In Ex2, you want the displayed equation to be as close as
>possible to the previous text, and to have some spacing below,
>to ensure that it's clearly distinguishable from the next
>paragraph, which is a new entity. Also, the following text
>should start with an indent.

yes, but a very short last line will make uit look quite ugly, i.e. there 
is already quite some space there; i'd rather tend to have a different 
threshold then (say 4em instead of 2em, which boils down to:

some long text
                 formula part of paragraph

some text
                 formula part of paragraph

some long text

                 formula not part of paragraph

some text
                 formula not part of paragraph

so, to let the horizontal distance between end of line text and begin of 
text also play a role.

text $$math$$ text

>and
>
>text\par $$math$$\par text
>
>are NOT the same thing and should be treated differently!

i know, but that's on the agenda; and even then, i'll add options to 
control the look and feel -)

(in practice i think that it also depends on the taste and specific 
formula, say x=2 vs x=sqrt(2) may demand their own spacing rules)

Hans

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