[texhax] centering a box on the margin line

[Aditya Mahajan]

On Mon, 12 Nov 2007, Peter King wrote:

> There must be an easy way to do this in plain TeX, but I haven't come up
> with one. I have a rectangular graphic (actually a logo in an .eps file)
> that I want to center on the line of the left margin, thusly:
>
> ============================================
>  _____
>  | X |
>  |_Y_|
>
>    |Blah blah margin line on the left
>    |More text flush to margin line
>    |Even more text and random babbling
>
> ============================================
> Is there a straightforward way to do this? I suppose I could negative kern
> the epsfbox into the margin, or something like that. But surely centering
> a box on a given line (the margin line) must be an Old Solved Problem.
> Any help appreciated, even pointers on where to look. Thanks.

You can eclose the box in a \clap.

Aditya