Lazarus Component Library

The Lazarus Component Library, abbreviated LCL is a visual software component library for the Lazarus IDE.

The LCL consists of a collection of units that provide components and classes especially for visual tasks. It is based on the Free Pascal libraries RTL and FCL. By binding platform-specific widgetsets it supports platform-sensitive software development for several operating systems including Android, Desktop Linux, Mac OS X and Windows. Lazarus source code files is under a mix of licenses: GNU General Public License, version 2 (GPLv2), a modified LGPL, and the MPL.

It was reported on the GitHub Lazarus repository on 26 August 2013 (latest information as of September 2014^[update]) that the LCL supported Linux (gtk, gtk2 and qt4), all flavors of Windows including WinCE, Mac OS X (carbon, gtk, qt4), and FreeBSD (gtk, gtk2), with experimental support for Solaris and the native Pascal backend fpgui which runs on Windows, WinCE and Linux.

...
Wikipedia