From octave-graphics-request at bevo dot che dot wisc dot edu  Fri Aug 25 13:32:37 2000
Subject: VTK for octave
From: "John W. Eaton" <jwe at bevo dot che dot wisc dot edu>
To: Kai Habel <kahacjde at calvados dot zrz dot TU-Berlin dot DE>
Cc: octave-graphics at bevo dot che dot wisc dot edu
Date: Fri, 25 Aug 2000 13:30:49 -0500 (CDT)

On 25-Aug-2000, Kai Habel <kahacjde at calvados dot zrz dot TU-Berlin dot DE> wrote:

| The first problem one gets is, the vtk function has its own loop and
| waits for inputs (mouse or keyboard), so as long as the vtk window is
| open the octave input is blocked.
| I don't know how to solve this kind of problems. Could we merge the vtk
| loop into octave's? Anyone with more insight?

Here is an example (using Tk) that shows how to handle keyboard input
with readline while also handling GUI events.  The idea is that you
register a function with readline to process events and also tell the
GUI toolkit to not do anything with keyboard input.  I think most
toolkits allow you to do something similar.

jwe

// Compiled with:
//
// g++ -o foo tkHelloWorld.c \
//   -ltk4.2 -ltcl7.6 -lX11 -lreadline -ldl -lieee -lm -lc
//
// and with the necessary -I and -L options to find the include and
// library files.

#include <iostream.h>

#include <tcl.h>
#include <tk.h>

#include <readline/readline.h>
#include <readline/history.h>

extern "C" void
do_nothing (ClientData, int)
{
}

extern "C" int
event_hook ()
{
  return Tcl_DoOneEvent (TCL_ALL_EVENTS);
}

extern "C" void rl_deprep_terminal (void);

void
clean_up_and_exit (ClientData)
{
  rl_deprep_terminal ();
  cout << "\n";
  exit (0);
}

int
main (int argc, char **argv)
{
  rl_event_hook = event_hook;

  int retval = 0;

  Tcl_CreateExitHandler (clean_up_and_exit, 0);

  Tcl_Interp *interp = Tcl_CreateInterp ();

  Tcl_Init (interp);

  if (Tk_Init (interp) == TCL_ERROR)
    {
      cerr << interp->result << "\n";

      retval = 1;
    }
  else
    {
      Tk_CreateFileHandler (0, TK_READABLE, do_nothing, 0);

      bool done = false;

      while (! done)
	{
	  char *line = readline ("tk> ");

	  if (line)
	    {
	      if (*line)
		{
		  add_history (line);

		  Tcl_Eval (interp, line);
		}
	    }
	  else
	    done = true;
	}
    }

  Tcl_DeleteInterp (interp);

  return retval;
}