FLTK includes all of the usual widgets to develop your
applications, and new widgets can be created easily through C++
subclassing. All widgets support keyboard shortcuts and can be
controlled both via the keyboard or mouse.
class supports push, check (Fl_Check_Button),
and "light" (Fl_Light_Button)
button styles; all styles can operate in momentary (press and
release), toggle (press on, press off), or radio (press one of
many) modes, so it is possible to create almost any kind of
button from a single widget.
widgets provide simple to complex text input and output
facilities. The Fl_Text_Display widget is based on a
C++ version of the NEdit software's extensible text editor
The Fl_Valuator class
provides a variety of numeric input controls including
scrollbars (Fl_Scrollbar) and
class provides several menu-based controls including menubars
and combo boxes (Fl_Choice).
The Fl_Browser_ class
is the basis for list controls. The Fl_Browser widget
shown at right lists lines of plain text. Other widgets list
files, widgets, and so forth.
User interfaces can be organized using scroll areas (Fl_Scroll), tabs (Fl_Tabs), tiles (Fl_Tile), and wizards
FLTK also provides standard dialogs for alerts, button
choosers, color choosers, file choosers, help browsers,
messages, passwords, and text input.
Finally, FLTK 1.1.x offers two appearance schemes: "standard"
and "plastic", and 1.3.x includes two additional schemes "gtk+"
Colors and fonts automatically adjust to the current user preferences.
Fast Light User-Interface Designer (FLUID)
FLUID allows you to develop complex applications quickly. You
can build complete applications within FLUID, drawing your
user-interface and creating functions, classes, and variables as
FLUID creates C++ source and header files that can be
compiled by themselves or included as part of a larger project.
In fact, several of the FLTK dialog widgets were created and are
maintained using FLUID.
The main FLUID window (at right) shows the widget browser along
with any classes, functions, and variables you have. You can
create simple user-interfaces using a function and global widget
variables or define C++ classes for a fully encapsulated
FLUID Widget Bin
Window for Sample Widgets Above
New items in the widget browser are added by via pop-up menus
or the widget bin (above) and can be placed in windows by
clicking and dragging. Each widget's attributes are controlled
through the widget attribute panel (right). Class, function, and
variable definitions are created using simple dialogs like the
The flPhoto user-interface was done completely
with FLUID and is pictured below.