Binary package “fluid” in ubuntu xenial

Fast Light Toolkit - user interface designer

 This package provides Fluid, an interactive GUI designer for FLTK,
 allowing graphical development of FLTK-based user
 interfaces. It natively works with (textual) .fl files, but also
 includes rough support for reading .fd files produced by fdesign (in
 The Fast Light Toolkit (FLTK) is a cross-platform graphical user interface
 toolkit originally based on libForms.