Claro Graphics provides a layout mechanism which is considerably different from other GUI toolkits. Layout Expression Language (LEL) uses a simplified textual format called a ‘lelex’ (think “regex for LEL”) to describe the way widgets will share the container’s available space. The lelex string doesn’t restrict the type of the widget or in any way describe the widget, it simply provides a method for naming a placeholder which a widget will later fill.

As an example, here’s the entire layout from the Canvas Clock Demo:

bounds_t b = { 50, 50, 220, 220 };
layout *lt = layout_create( "[][_<a|clock|<a][{40}Red|Green|Blue]", b, 10, 10 );

This small set of code replaces huge amounts of layout, boxing, packing, and containing code found in other frameworks. It also make resizing and altering a layout fast and trivial to deal with. The "[][_<a|clock|<a][{40}Red|Green|Blue]" contains the entire lelex for the interface and is quick to learn (unlike regular expressions).