FLTK - Fast Light Tool Kit - https://github.com/fltk/fltk - cross platform GUI development

ManoloFLTK d428a00443 Have menu items drawn with same colors in all platforms (#969 ) Also, remove this text from the doc of Fl_Menu_::down_box() "If this is FL_NO_BOX then it acts like FL_THIN_UP_BOX and selection_color() acts like FL_WHITE, for back compatibility." that was true only for the Windows platform and that required selection_color to be replaced by white for menu items which is not what FLTK 1.4 expects. The new state of menu item drawings is as follows : - all platforms draw menu items with the same symbolic colors - selected items and menu titles are drawn with the selection color as background color - menu items are drawn by default with no box but can be given one by Fl_Menu_::down_box(Fl_Boxtype) - the text of selected items is drawn with the menu's color unless fl_contrast() finds it does not make enough contrast with the background (selection color) and substitutes it with a more adapted color - the Windows platform uses a visibly different hue for its default selection color from what other platforms use		1 year ago
.github	CMake/MSVC: Fix shared library build, add to GitHub CI build	1 year ago
CMake	CMake: improve output of fl_debug_target()	1 year ago
FL	Have menu items drawn with same colors in all platforms (#969 )	1 year ago
GL	Remove $Id$ tags, update URL's, and more	5 years ago
cairo	Introduce "Modern CMake" in FLTK	1 year ago
documentation	Wayland documentation: beef up description of registry_handle_global()	1 year ago
examples	Fix Visual Studio compiler warnings, make output visible...	1 year ago
fltk-options	Fix for Fl_Native_File_Chooser::filter_value() - cont'd (#899 )	1 year ago
fluid	Fix MSVC warnings (#966 )	1 year ago
jpeg	Update bundled libjpeg to version 9f	1 year ago
lib	Fix a typo, trailing whitespace, and dependencies	1 year ago
libdecor	Wayland: simpler implementation of "GTK Shell" protocol	1 year ago
misc	Update misc/README.txt	1 year ago
nanosvg	Update nanosvg/README.txt to reflect recent changes	2 years ago
png	Update bundled libpng to version 1.6.42	1 year ago
public	Activate GitLab CI and GitLab Pages (HTML docs).	7 years ago
src	Have menu items drawn with same colors in all platforms (#969 )	1 year ago
test	CMake: simplify compiler detection for '-Wshadow' test	1 year ago
util	Move src/cmap.cxx to util/cmap.cxx (utilities folder)	3 years ago
zlib	Update bundled zlib to version 1.3.1	1 year ago
.clang-format	Update .clang-format control file	3 years ago
.gitattributes	Remove experimental platforms Android, Pico, SDL (PR #376 )	3 years ago
.gitignore	CMake: Remove UseFLTK.cmake generation and usage	2 years ago
.gitlab-ci.yml	Introduce "Modern CMake" in FLTK	1 year ago
ANNOUNCEMENT	Fix ignored files, add 'build' directory to ignored files.	9 years ago
CHANGES.txt	Implement and document new class Fl_PDF_File_Surface	1 year ago
CHANGES_1.0.txt	Remove $Id$ tags, update URL's, and more	5 years ago
CHANGES_1.1.txt	Fix old URL's and forum/newsgroup names	5 years ago
CHANGES_1.3.txt	Remove $Id$ tags, update URL's, and more	5 years ago
CMakeLists.txt	CMake build summary: output libdecor location if found	1 year ago
COPYING	Remove $Id$ tags, update URL's, and more	5 years ago
CREDITS.txt	Update README.txt and CREDITS.txt	1 year ago
Makefile	Add configure option to build tests only on request (#940 )	1 year ago
README.CMake.txt	Fix: Fl_Native_File_Chooser::filter_value() [Kdialog] always returns 0 (#899 )	1 year ago
README.Cairo.txt	Introduce "Modern CMake" in FLTK	1 year ago
README.IDE.txt	Remove experimental platforms Android, Pico, SDL (PR #376 )	3 years ago
README.Unix.txt	Update documentation, remove/edit explicit FLTK versions	1 year ago
README.Wayland.txt	Documentation: bundled libdecor symbols are pefixed by "fl_"	1 year ago
README.Windows.txt	Generate FL/fl_config.h rather than FL/abi-version.h	4 years ago
README.abi-version.txt	Introduce "Modern CMake" in FLTK	1 year ago
README.experimental.txt	Remove experimental platforms Android, Pico, SDL (PR #376 )	3 years ago
README.macOS.md	Remove reference to automake which is not required	1 year ago
README.md	Fix trailing whitespace and dependencies	2 years ago
README.txt	Remove remaining references to xdbe on X11	1 year ago
autogen.sh	Fix README files and remove stale config.guess and config.sub	4 years ago
config.guess	Add autoconf cross-compilation support files.	4 years ago
config.sub	Add autoconf cross-compilation support files.	4 years ago
configh.cmake.in	Fix: Fl_Native_File_Chooser::filter_value() [Kdialog] always returns 0 (#899 )	1 year ago
configh.in	Fix: Fl_Native_File_Chooser::filter_value() [Kdialog] always returns 0 (#899 )	1 year ago
configure.ac	Add "fl_" prefix to libdecor symbols when using the built-in copy of libdecor	1 year ago
fl_config.cmake.in	Move FLTK_USE_SVG from config.h to FL/fl_config.h	1 year ago
fl_config.in	Move FLTK_USE_SVG from config.h to FL/fl_config.h	1 year ago
fltk-config.in	Fix more missing quotes in fltk-config.in (#714 )	2 years ago
fltk.list.in	Remove remaining 'pronounced "fulltick"' statements	2 years ago
fltk.spec.in	Remove remaining references to xdbe on X11	1 year ago
fltk.xpm	Fixed all Pixmaps to be '*const' (STR #3108 ).	6 years ago
fltk_version.dat	Rename file 'VERSION' to 'fltk_version.dat' (#191 )	4 years ago
forms.h	Initial revision	27 years ago
install-sh	Remove $Id$ tags, update URL's, and more	5 years ago
mac_endianness.h	Remove $Id$ tags, update URL's, and more	5 years ago
makeinclude.in	Add configure option to build tests only on request (#940 )	1 year ago
makesrcdist	Fix README files and remove stale config.guess and config.sub	4 years ago

README.md

README - Fast Light Tool Kit (FLTK) Version 1.4.0

WHAT IS FLTK?

The Fast Light Tool Kit is a cross-platform C++ GUI toolkit for
UNIX®/Linux® (X11 or Wayland), Microsoft® Windows®, and macOS®.
FLTK provides modern GUI functionality without the bloat and
supports 3D graphics via OpenGL® and its built-in GLUT
emulation. It was originally developed by Mr. Bill Spitzak
and is currently maintained by a small group of developers
across the world with a central repository on GitHub.

For more information see README.txt:
https://github.com/fltk/fltk/blob/master/README.txt