LASi is a library written by Larry Siden that provides a C++ stream output interface ( with operator << ) for creating Postscript documents that can contain characters from any of the scripts and symbol blocks supported in Unicode and by Owen Taylor's Pango layout engine. The library accommodates right-to-left scripts such as Arabic and Hebrew as easily as left-to-right scripts. Indic and Indic-derived Complex Text Layout (CTL) scripts, such as Devanagari, Thai, Lao, and Tibetan are supported to the extent provided by Pango and by the OpenType fonts installed on your system. All of this is provided without need for any special configuration or layout calculation on the programmer's part.

Although the capability to produce Unicode-based multilingual Postscript documents exists in large Open Source application framework libraries such as GTK+, QT, and KDE, LASi was designed for projects which require the ability to produce Postscript independent of any one application framework.