1 - Introduction to FLTK

History of FLTK

Many of the ideas in FLTK were developed on a NeXT (but not using NextStep) in 1987 in a C toolkit Bill called "views". Here he came up with passing events downward in the tree and having the handle routine return a value indicating the used the event, and the table-driven menus. In general he was trying to prove that complex UI ideas could be entirely implemented in a user space toolkit, with no knowledge or support by the system.

After going to film school for a few years, Bill worked at Sun Microsystems on the (doomed) NeWS project. Here he found an even better and cleaner windowing system, and he reimplemented "views" atop that. NeWS did have an unnecessarily complex method of delivering events which hurt it. But the designers did admit that perhaps the user could write just as good of a button as they could, and officially exposed the lower level interface.

With the death of NeWS Bill realized that he would have to live with X. The biggest problem with X is the "window manager", which means that the toolkit can no longer control the window borders or drag the window around.

At Digital Domain Bill discovered another toolkit, "Forms". Forms was similar to his work, but provided many more widgets, since it was used in many real applications, rather then as theoretical work. He decided to use Forms, except he integrated his table-driven menus into it. Several very large programs were created using this version of Forms.

The need to switch to OpenGL and GLX, portability, and a desire to use C++ subclassing required a rewrite of Forms. This produced the first version of FLTK. The conversion to C++ required so many changes it made it impossible to recompile any Forms objects. Since it was incompatible anyway, Bill decided to incorporate his older ideas as much as possible by simplifying the lower level interface and the event passing mechanisim.

Bill received permission to release it for free on the Internet, with the GNU general public license. Response from Internet users indicated that the Linux market dwarfed the SGI and high-speed GL market, so he rewrote it to use X for all drawing, greatly speeding it up on these machines. That is the version you have now.

Digital Domain has since withdrawn support for FLTK. While Bill is no longer able to actively develop it, he still contributes to FLTK in his free time and is a part of the FLTK development team.

Features

Here are some of the core features unique to FLTK:

• sizeof(Fl_Widget) == 40 to 48.
• The "core" (the "hello" program compiled & linked with a static FLTK library using gcc on a 486 and then stripped) is 39.5K.
• A program including every widget is less than 108K. Does not use macros, templates, multiple inheritance, or exceptions.
• Written directly atop Xlib (or WIN32) for maximum speed, and carefully optimized for code size and performance.
• Precise low-level compatability between the X11 and WIN32 version (only about 10% of the code is different).
• Interactive user interface builder program. Output is human-readable and editable C++ source code.
• Support for the X11 double buffering extension (emulation if not available and under Windows.)
• Support for X11 overlay hardware (emulation if none and under WIN32.)
• Very small & fast portable 2-D drawing library to hide Xlib and WIN32.
• OpenGL/Mesa drawing area widget.
• Support for OpenGL overlay hardware on both X11 and WIN32. Emulation if none.
• Text input fields with Emacs key bindings, X cut & paste, and foreign letter compose!
• Compatibility header file for the GLUT library.
• Compatibility header file for the XForms library.
• Much too much to list here...

Licensing

What Does "FLTK" Mean?

Building and Installing FLTK Under UNIX

FLTK uses GNU autoconf to configure itself for your UNIX platform. The main things that the configure script will look for are the X11, OpenGL (or Mesa), and JPEG header and library files. If these cannot be found in the standard include/library locations you'll need to define the CFLAGS, CXXFLAGS, and LDFLAGS environment variables. For the Bourne and Korn shells you'd use:

CFLAGS=-Iincludedir; export CFLAGS
CXXFLAGS=-Iincludedir; export CXXFLAGS
LDFLAGS=-Llibdir; export LDFLAGS

setenv CFLAGS "-Iincludedir"
setenv CXXFLAGS "-Iincludedir"
setenv LDFLAGS "-Llibdir"

CXX=xlC; export xlC
setenv CXX "xlC"

You can run configure yourself to get the exact setup you need. Type "./configure <options>", where options are:

--enable-debug

Enable debugging code & symbols

--enable-shared

Enable generation of shared libraries

--bindir=/path

Set the location for executables [default = /usr/local/bin]

--libdir=/path

Set the location for libraries [default = /usr/local/lib]

--includedir=/path

Set the location for include files. [default = /usr/local/include]

--prefix=/dir

Set the directory prefix for files [default = /usr/local]

To install the library, become root and type "make install". This will copy the "fluid" executable to "bindir", the header files to "includedir", and the library files to "libdir".

Building FLTK Under Microsoft Windows

The second method is to use a GNU-based development tool with the files in the "makefiles" directory. To build using one of these tools simply copy the appropriate makeinclude and config files to the main directory and do a make:

copy makefiles\Makefile.<env> Makefile
make

Building FLTK Under OS/2

To build the XFree86 version of FLTK for OS/2, copy the appropriate makeinclude and config files to the main directory and do a make:

copy makefiles\Makefile.os2x Makefile
make

Internet Resources

WWW

http://fltk.easysw.com

FTP

ftp://ftp.easysw.com/pub/fltk

ftp://ftp.funet.fi/mirrors/ftp.easysw.com/pub/fltk

ftp.northamerica.net/pub/ESP/fltk

EMail

fltk@easysw.com [see instructions below]

fltk-bugs@easysw.com [for reporting bugs]

To join the FLTK mailing list, send a message to "majordomo@easysw.com" with "subscribe fltk" in the message body. A digest of this list is available by subscribing to the "fltk-digest" mailing list.

Reporting Bugs

For general support and questions, please use the FLTK mailing list at "fltk@easysw.com".