From: Masao Mutoh <mutoh@...>
Date: 2003-02-27T23:20:18+09:00
Subject: Re: Ruby-GNOME2: Getting double clicks?

Hi,

On Thu, 27 Feb 2003 04:16:27 +0900
"PS" <ps@inet-services.co.uk> wrote:

> I would appreciate any help in getting double mouse clicks to work in ruby
> Gtk2.
> 
> I have the following:
> 
> @tree.signal_connect( "button_press_event", Gdk::Event::BUTTON2_PRESS ){
> |widget,event,data| double_click_cb( widget, event, data ) }
> 
> is this right?

If you want to use double-click under Gtk::TreeView, 
"row-activated" signal may be better.

@tree.signal_connect("row-activated") do ... end


If you want to use it under Gtk::Button. You can write it as follows:

button.signal_connect("button_press_event") do |widget, event|
   if event.event_type == Gdk::Event::BUTTON2_PRESS
      p "double click"
   elsif event.event_type == Gdk::Event::BUTTON3_PRESS
      p "triple click"
   end
end

Other widget which doesn't get "button_press_event" may need to write
as follows:

window.add_events(Gdk::Event::BUTTON_PRESS_MASK)
window.signal_connect("button_press_event") do |widget, event|
   if event.event_type == Gdk::Event::BUTTON2_PRESS
      p "double click"
   elsif event.event_type == Gdk::Event::BUTTON3_PRESS
      p "triple click"
   end
end

> what goes in:
> 	def double_click_cb ( widget, event, data )
> 
> 	end

'data' is not supported in Ruby-GNOME2.

> Additionally what are the advantages/disadvantages of implementing
> callbacks as Proc rather than methods?

Hmm, it's a dificult question...

IMO,
callbacks as Proc: Smaller and not reuse it.
methods: Larger or reuse it.
         Usually I delegate processing to other object's 
         methods(like as MVC pattern).

In the both pattern, I don't like codes as follows.
-------
window.signal_connect("button_press_event") do |widget, event|
   if event.event_type == Gdk::Event::BUTTON2_PRESS
     double_click_cb(widget, event)
   end
end

def double_click_cb(widget, event)
end
-------

double_click_cb:
* the method name is not good because it means to use it 
  callback only.
* parameters are depend on callback.

So I think this method is difficult to reuse. 

It's better to pass the parameter which the method actually requires.
-------
window.signal_connect("button_press_event") do |widget, event|
   if event.event_type == Gdk::Event::BUTTON2_PRESS
     do_something("something value")
   end
end

def do_something(arg)
end

-------
-- 
.:% Masao Mutoh<mutoh@highway.ne.jp>