[cl-typesetting-devel] Kerning question: hbox vs. paragraph

[Marc Battyani]

"Peter Heslin" <pj at heslin.eclipse.co.uk> wrote:
>
> I'm just playing around with cl-typesetting to get familiar with it,
> and it looks great!

:)

> Here's my question.  When text is typeset using the paragraph macro,
> the kerning is fine, but when using the hbox macro alone, it appears
> to be a little off.  Here's a minimal example:
>
> (defun test-kern ()
>   (with-document ()
>     (draw-pages (compile-text ()
>                               (hbox () "foo AWAY")
>                               (hbox () (put-string "foo"))
>                               (paragraph () "foo AWAY")))
>     (when pdf:*page* (finalize-page pdf:*page*))
>     (pdf:write-document #P"/tmp/test.pdf")))
>
> When you look at the PDF, the last string is typeset fine, but the
> first two are slightly off.  The middle "o" in "foo" is a bit too
> close the "f", and too far from the last "o".  Likewise in "AWAY", the
> "W" is not evenly spaced between the two "A"s in the first two
> strings.  In the paragraph example, it's fine. It is a subtle problem,
> but it's there.
>
> Looking quickly at the code in typo.lisp, I don't see any obvious
> reason for this difference.
>
> Is hbox not supposed to be used to typeset normal text?  Without
> documentation it's hard to tell ;-)

No. hbox and vbox are the raw level objects and should normally not be used in normal
usage.

Marc