In the Oriental TeX project we use a combined approach to get nicely typeset paragraphs. We use a font with so many features that it drives font programs crazy but it works out well. We combine that with a special paragraph optimizer that improves the quality using different feature sets. This is a typical example of a local optimization that only kicks in on demand.
In this talk I will show how input is converted into nice looking output and how the already acceptable output can be further improved. I will also show how we visualize the process.
A byproduct of this effort is the TeX pararagraph builder rewritten in Lua. I will discuss a few issues that showed up when converting the original code into Lua and some of the outcomes that will be fed back into the LuaTeX code base.