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| + | ====== edelib basics ====== | ||
| + | This tutorial describe the basics of coding and compiling programs that use FLTK and edelib. It is continuation of [[http://www.fltk.org/doc-1.1/basics.html#basics|FLTK Basics]] document, introducing basic edelib usage with FLTK. | ||
| + | |||
| + | ===== Writing Your First edelib Program ===== | ||
| + | edelib headers are stored in ''edelib'' directory and that is the main prefix used when headers are included. Unlike FLTK header files that ends with ''.H'' extension, edelib uses more common approach, ending header files with ''.h'' extension. | ||
| + | |||
| + | Although FLTK install header aliases ending with ''.h'' extension when manually compiled, binary packages often comes without them, so the best advice is end FLTK specific header with ''.H'' anyway. | ||
| + | |||
| + | Here the example that showing a simple "Hello, World!" program that uses FLTK and edelib to display the window. | ||
| + | |||
| + | <code cpp> | ||
| + | /* hello.cpp */ | ||
| + | |||
| + | #include <FL/Fl.H> | ||
| + | #include <FL/Fl_Box.H> | ||
| + | #include <edelib/Window.h> | ||
| + | |||
| + | EDELIB_NS_USING_AS(Window, MainWindow) | ||
| + | |||
| + | int main(int argc, char **argv) { | ||
| + | MainWindow *window = new MainWindow(300,180); | ||
| + | Fl_Box *box = new Fl_Box(20,40,260,100,"Hello, World!"); | ||
| + | box->box(FL_UP_BOX); | ||
| + | box->labelsize(36); | ||
| + | box->labelfont(FL_BOLD+FL_ITALIC); | ||
| + | box->labeltype(FL_SHADOW_LABEL); | ||
| + | window->end(); | ||
| + | window->show(argc, argv); | ||
| + | return Fl::run(); | ||
| + | } | ||
| + | </code> | ||
| + | |||
| + | As you can see, it is much the same as example program from FLTK documentation, with one difference: it uses edelib Window class. This class behaves pretty much the same as ''Fl_Window'' and ''Fl_Double_Window'' classes, plus adding some features like internal usage of XSETTINGS protocol and automatic loading of appropriate icon theme. | ||
| + | |||
| + | The first noticeable line in this code is: | ||
| + | |||
| + | <code cpp> | ||
| + | EDELIB_NS_USING_AS(Window, MainWindow) | ||
| + | </code> | ||
| + | This is actually a C++ macro that expands to something like: | ||
| + | |||
| + | <code cpp> | ||
| + | typedef edelib::Window MainWindow; | ||
| + | </code> | ||
| + | All edelib code is placed under ''edelib'' namespace and edelib is written so namespace name can be easily changed during compilation time. With this macro, the code will be compileable no matter what namespace name is used. Of course, you can always explicitly add namespace name (like ''edelib::Window'') if that suits you. | ||
| + | |||
| + | Rest of the code is pretty much the same as given in FLTK example program. | ||
| + | |||
| + | ===== Compiling ===== | ||
| + | |||
| + | FLTK comes with handy script called ''fltk-config''. It makes things easier by providing required include paths and linkage libraries to compiler, as shown in ''Compiling Programs with Standard Compilers'' in [[http://www.fltk.org/doc-1.1/basics.html#basics|FLTK Basics]]. | ||
| + | |||
| + | edelib does not comes with such script, but uses [[http://pkg-config.freedesktop.org/wiki|pkg-config]] tool. pkg-config became de facto standard for these things and every recent library is using it, so it is great chance you have it already installed. | ||
| + | |||
| + | To compile ''hello.cpp'' example, you would use: | ||
| + | |||
| + | <code> | ||
| + | g++ hello.cpp -o hello `pkg-config edelib-gui --cflags --libs` | ||
| + | </code> | ||
| + | |||
| + | ===== Troubleshooting ===== | ||
| + | If edelib was installed on uncommon path, ''pkg-config'' can fail with message like: | ||
| + | |||
| + | <code> | ||
| + | Package edelib-gui was not found in the pkg-config search path. | ||
| + | Perhaps you should add the directory containing `edelib-gui.pc' | ||
| + | to the PKG_CONFIG_PATH environment variable | ||
| + | No package 'edelib-gui' found | ||
| + | </code> | ||
| + | |||
| + | This means ''edelib-gui.pc'' wasn't found, so you should adjust PKG_CONFIG_PATH environment variable to point to directory where it exists. If edelib was installed in ''/usr/local'', which is default, you will do: | ||
| + | |||
| + | <code> | ||
| + | export PKG_CONFIG_PATH=/usr/local/lib/pkgconfig | ||
| + | </code> | ||
| + | |||
| + | One common pattern used in C++ programs, when namespaces are used, is to introduce all symbols with "using namespace <name>". You should be careful when using ''edelib::Window'' class with this. For example, if ''hello.cpp'' was written as: | ||
| + | |||
| + | <code cpp> | ||
| + | /* hello.cpp */ | ||
| + | |||
| + | #include <FL/Fl.H> | ||
| + | #include <FL/Fl_Box.H> | ||
| + | #include <edelib/Window.h> | ||
| + | |||
| + | using namespace edelib; | ||
| + | |||
| + | int main(int argc, char **argv) { | ||
| + | Window *window = new Window(300,180); | ||
| + | /* rest of the code... */ | ||
| + | } | ||
| + | </code> | ||
| + | it would fail during compilation with message like: | ||
| + | |||
| + | <code> | ||
| + | hello.cpp: In function 'int main(int, char**)': | ||
| + | hello.cpp:13: error: reference to 'Window' is ambiguous | ||
| + | /usr/include/X11/X.h:101: error: candidates are: typedef XID Window | ||
| + | ... | ||
| + | </code> | ||
| + | because X11 already provides ''Window'' name, implicitly introduced by edelib/Window.h header. This is known bug and will be fixed in upcomming versions. | ||
| + | |||
| + | For now, either explicitly use ''edelib::Window'' type or use ''EDELIB_NS_USING_AS()'' macro. | ||
