pyFLTK - Using cross-language polymorphisms

Description

There are a number of FLTK classes that can be derived from in Python and that allow cross-language polymorphism. Cross-language polymorphisms allow to override a method in Python and have it called from underlying C++ code. This is for instance required to give an implementation for the pure virtual method Fl_Widget::draw. On deriving from a FLTK class do not forget to call the base class constructor, as shown in the example below.

Classes

Fl_Box

  • void Fl_Box::draw(void)
    It is possible to provide a custom made draw method for Fl_Box.

  • int Fl_Box::handle(int event)
    Optional implementation of an event handler. Must return 0 if the event was not handled, 1 otherwise.

Fl_Double_Window

  • void Fl_Double_Window::draw(void)
    It is possible to provide a custom made draw method for Fl_Double_Window.

  • int Fl_Double_Window::handle(int event)
    Optional implementation of an event handler. Must return 0 if the event was not handled, 1 otherwise.

Fl_Gl_Window

  • void Fl_Gl_Window::draw(void)
    It is possible to provide a custom made draw method for Fl_Gl_Window.

  • int Fl_Gl_Window::handle(int event)
    Optional implementation of an event handler. Must return 0 if the event was not handled, 1 otherwise.

Fl_Overlay_Window

  • void Fl_Overlay_Window::draw_overlay(void)
    It is possible to provide a custom made draw_overlay method for Fl_Overlay_Window. Overlays can be used for implementing visual feedback for rubber boxes etc.

Fl_Single_Window

  • void Fl_Single_Window::draw(void)
    It is possible to provide a custom made draw method for Fl_Single_Window.

  • int Fl_Single_Window::handle(int event)
    Optional implementation of an event handler. Must return 0 if the event was not handled, 1 otherwise.

Fl_Table

  • Fl_Table::draw_cell(TableContext,int X, int Y, int W, int H, str label)
    Fl_Table always needs an implementation of the method draw_cell.

Fl_Table_Row

  • Fl_Table_Row::draw_cell(TableContext,int X, int Y, int W, int H, str label)
    Fl_Table_Row always needs an implementation of the method draw_cell.

Fl_Widget

  • void Fl_Widget::draw(void)
    Fl_Widget always needs an implementation of the method draw.

  • int Fl_Widget::handle(int event)
    Optional implementation of an event handler. Must return 0 if the event was not handled, 1 otherwise.

Example

     from fltk import *

     class Drawing(Fl_Widget):
         def __init__(self, X, Y, W, H, L):
	     # always intialize the base class!
	     Fl_Widget.__init__(self, X, Y, W, H, L)

	 # override method draw
	 def draw(self):
	     # simply paints the canvas red
	     fl_color(FL_RED)
	     self.redraw()

	 # implement event handler
	 def handle(event):
	     if event == FL_PUSH:
	         print "FL_PUSH caught!"
		 return 1
	     else:
	         return 0


     window = Fl_Window(300,500)
     d = Drawing(10,10,280,280, "test")
     .
     .
     window.end()
     window.show(len(sys.argv),sys.argv)
     Fl.run()