From: Olivier Andrieu <oandrieu at nerim.net>
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Date: Thu, 20 Apr 2006 01:24:21 +0200
To: Erik de Castro Lopo <ocaml-erikd at mega-nerd.com>,
        Robert Roessler <robertr@rftp.com>
Cc: lablgtk at math.nagoya-u.ac.jp
Subject: Re: Low level lablgtk2 hacking
In-Reply-To: <20060420060312.67f8a4ee.ocaml-erikd at mega-nerd.com>
References: <20060420060312.67f8a4ee.ocaml-erikd at mega-nerd.com>
        <4446BCBB.2050502@rftp.com>
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 Erik de Castro Lopo [Thursday 20 April 2006] :
 >
 > Hi all,
 > 
 > Is there some way to access GTK+/C functionality from Ocaml?
 > 
 > For instance I would like to be able to call the GTK+/C function
 > gtk_scrolled_window_set_policy() for a lablgtk2 scrolled_window
 > object. Unfortunately, the lablgtk2 scrolled_window class does
 > not seem to expose this functionality.

I see #set_hpolicy and #set_vpolicy methods in the
GBin.scrolled_window class.

 > I actually have a number of problems of this type. Is there a
 > general solution?

It depends :
- sometimes it's just that a high-level lablgtk class is missing
  something but the lower-level layer wraps it. You can usually
  arrange to call the low-level function directly.

- if the missing functionality is a property or a signal, you can
  (almost) always dynamically use it with the functions of the module
  Gobject 

- if the missing functionality is only available via a C function,
  then some C code is needed.


 Robert Roessler [Wednesday 19 April 2006] :
 > Actually, I *am* puzzled - the 2.6.0 release of LablGTK has the 
 > following in ml_gtkbin.c:
 > 
 > ML_3 (gtk_scrolled_window_set_policy, GtkScrolledWindow_val,
 >        Policy_type_val, Policy_type_val, Unit)
 > 
 > but I *think* that the only interface exposed is the ability to 
 > independently set the "h" and "v" policies for a "GtkScrolledWindow".
 > 
 > So either I am not getting the intent of the LablGTK interface/code, 
 > or this part of LablGTK is as yet unfinished.

That's because the class is using the properties "hscrollbar-policy" and
"vscrollbar-policy" of GtkScrolledWindow directly. Wrapping
gtk_scrolled_window_set_policy isn't really needed.

-- 
   Olivier