[l2h] problem with vertical alignment of inlined math images

Bruce Miller bruce.miller at nist.gov
Thu Dec 11 15:24:27 CET 2003

Ross Moore wrote:
> Hi Bruce, Peter and others.

> On Thursday, December 11, 2003, at 01:24  AM, Bruce Miller wrote:
>> Peter Morling wrote:
>>> Hi,
>>> there is a problem with the vertical alignment of inlined math 
>>> images. 


> Yes.  It used to be that Netscape got this right, and IE aligned 
> according to the middle of the surrounding text.
> (as the CSS way, described below).
> However, this IE/CSS way *cannot* be correct for inline images, since
>    1.  you don't know the height of the text in advance --- that's under 
> the surfer's control;
>    2.  the height varies according to the presence of CAPITAL letters 
> and letters with descenders  (g,j,p,q,y);
>    3.  simply resizing the window, forcing text to re-flow, causes the 
> relative position of images to shift vertically
>           ---- a quite absurd situation.

Hmm, from this, I suspect the old IE way was to align the middle
of the image to the middle of the surrounding text --- a pretty fuzzy
font concept! --- which apparently included ascenders & descenders.

CSS aligns it to the baseline + half the x-height, which would
only be affected by the font in neighboring text, not the actual
letters.  So the window size, flow, etc, shouldn't generally matter.

> It is for these reasons that LaTeX2HTML continues to use the old 
> Netscape interpretation of  "align=middle".
> Any other is inherently impossible to predict how things will look.


> Precisely.
> If you specify *everything* with CSS, including the fonts and 
> font-sizes, and window-widths,
> then you can position images precisely.
> But that forces readers to view pages only with a very specific geometry.
> You lose the ability to freely adjust the window size and have all the 
> text re-flow to match.
> Also, the reader/surfer loses control of the font-size that is most 
> comfortable for themself.

Actually, it's not quite this bad.  I've created some material using
the CSS approach & varied the text size (Mozilla's control-mouse-wheel
to adjust font size is one of my favorite features! That and tabs!)
The alignment stays reasonable, if not perfect, over a pretty wide range.
--- The fixed size of the math images gets annoying _way_ before the
misalignment becomes bothersome!

>> Or, wait for the mozilla folks to fix it.  From the bugzilla log, it 
>> looks like after some initial resistance, they've accepted that it is 
>> a bug.
>     Agreed; it is a bug in the browser.

I agree; unless there were a drive to eliminate _all_ deprecated features
from l2h, it's not really worth changing.

If anything, I'd like to campaign to make images look worse, & mathml better,
to encourage the transition to the latter! :>

bruce.miller at nist.gov

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