pyFltk API Documentation

The FLTK project has excellent documentation. However, it is in C++. Rather than duplicating the documention in Python, it is much easier to simply provide a document translating the existing C++ API to Python.

Importing:

Since the naming of FLTK classes, functions and constants start with

Fl_Foo   (classes)
fl_foo() (functions)
Fl.foo() (functions)
FL_FOO   (constants)

It's okay to use:

from fltk import *

However, if you just use

import fltk

Then your code will look like

fltk.Fl_Foo
fltk.fl_foo()
fltk.Fl.foo()
fltk.FL_FOO

which seems unneccesary.

Hello World example translation

Let's start with Hello.cxx from FLTK Basics

#include <FL/Fl.H>
#include <FL/Fl_Window.H>
#include <FL/Fl_Box.H>

int main(int argc, char **argv) {
  Fl_Window *window = new Fl_Window(340,180);
  Fl_Box *box = new Fl_Box(20,40,300,100,"Hello, World!");
  box->box(FL_UP_BOX);
  box->labelfont(FL_BOLD+FL_ITALIC);
  box->labelsize(36);
  box->labeltype(FL_SHADOW_LABEL);
  window->end();
  window->show(argc, argv);
  return Fl::run();
}

This would translate into the code below:

from fltk import *

window = Fl_Window(340,180)
box = Fl_Box(20,40,300,100,"Hello, World!")
box.box(FL_UP_BOX)
box.labelfont(FL_BOLD+FL_ITALIC)
box.labelsize(36)
box.labeltype(FL_SHADOW_LABEL)
window.end()
window.show()
Fl.run()

However, to utilize command line args we would have to import sys in Python.

Code Translations:

Notice the initializer/constructor for creating a window:

Fl_Window(int w, int h, const char *title=0)

Fl_Window (int x, int y, int w, int h, const char *title=0)

Like in Python, =0 means the default argument value is 0. So the last arg is optional.