{Didier Verna}
{Interactive and real-time typesetting for demonstration and~experimentation}
{In general, typesetting experimentation is not a very practical thing to do.
\WYSIWYG\ typesetting systems are very reactive but do not offer highly
configurable algorithms, and \TeX, with its separate development /
compilation / visualization phases, is not as interactive as its
\WYSIWYG\ competitors. Being able to experiment with typesetting
algorithms interactively and in real-time is nevertheless desirable, for
instance for demonstration purposes, or for rapid prototyping and
debugging of new ideas.

We present \acro{ETAP} (Experimental Typesetting Algorithms Platform), a
tool written to ease typesetting experimentation and demonstration.
\acro{ETAP} currently provides several paragraph justification
algorithms, all with many configuration options such as kerning,
ligatures, flexible spaces, sloppiness, hyphenation, etc. The resulting
paragraph is displayed with many visual hints as well, such as
paragraph, character, and line boxes, baselines, over\slash underfullness
hints, hyphenation clues, etc. All these parameters, along with the
desired paragraph width, are adjustable interactively through a \GUI,
and the resulting paragraph is displayed and updated in real-time.

But \acro{ETAP} can also be used without, or in conjunction with the
\GUI, as a scriptable application. In particular, it is able to generate
all sorts of statistical reports or charts on the behavior of the
various algorithms, for instance, the number of over\slash underfull boxes per
paragraph width, the average compression or stretch ratio per line,
whatever else you want. This allows you to quickly demonstrate or
evaluate the comparative behavior or merits of the provided algorithms,
or whichever you may want to add to the pool.}