IUP

IUP is a library of basic GUI elements using the languages C and Lua. It can be used to create fast, uncompiled graphical applications.

What makes IUP different from other similar libraries is the way it implements 4 important concepts:

• Controls creation time. When a widget is created, it is not immediately displayed in the OS. It is done by showing the dialog containing the widget or by manual call of the IupMap function for this dialog.
• The attributes system. In the IUP there are very few functions, because the main way to work with the widgets is to access their attributes (text type), using the functions IupSetAttribute and IupGetAttribute.
• Abstract Layout Positioning. Widgets in the IUP are never positioned by explicitly specifying coordinates, their positions are calculated dynamically, according to the abstract layout hierarchy defined using widget containers IupFill, IupHbox and IupVbox (however, explicit positioning is allowed within the widget containers of special type).
• Callback system. The LED language supports indirectly linking widgets with callback functions. To link a C function, the IupSetFunction name construction is used, followed by linking callback attributes using IupSetAttribute. It is also possible to link a widget directly to a callback function using IupSetCallback.