fxruby users - Oct 2006 - Painting a custom control

In this code, the closure I''ve attached to SEL_PAINT is never called.
What''s my newbie mistake?

Fox 1.4.34, FXRuby 1.4.7, Debian testing

#!/usr/bin/ruby1.8

require ''fox14''

include Fox

class CustomControl < FXFrame

  def initialize(*args)
    super
    connect(SEL_PAINT) do
      puts ''paint'' # Never called
    end
  end

  def getDefaultWidth
    50
  end

  def getDefaultHeight
    50
  end

end

class Main

  def run
    app = FXApp.new
    main = FXMainWindow.new(app, File.basename(__FILE__))
    CustomControl.new(main)
    main.show(PLACEMENT_SCREEN)
    app.create
    app.run
  end

end

Main.new.run if $0 == __FILE__

On Oct 21, 2006, at 12:07 PM, Wayne Conrad wrote:
> In this code, the closure I''ve attached to SEL_PAINT is never
called.
> What''s my newbie mistake?
The connect() method is used to define message handlers for messages  
sent from a widget to its target. FXFrame doesn''t send a SEL_PAINT  
message to its target, so that''s why your code never gets invoked.

If you simply want to override FXFrame''s default handling of  
SEL_PAINT, I think you''ll need to do something like this:

	class MyFrame < FXFrame
		def initialize(...)
			FXMAPFUNC(SEL_PAINT, 0, :onPaint)
		end
		def onPaint(sender, sel, event)
			# Respond to expose event here
		end
	end

Hope this helps,

Lyle

On Sat, Oct 21, 2006 at 12:53:39PM -0500, Lyle Johnson
wrote:
> Hope this helps,
It sure does.  My custom control is now drawing itself just fine.

It took me a small bit of fiddling, but not much, to figure out that
"include Responder" is required before I can call FXMAPFUNC.

I had thought that FXMAPFUNC was legacy stuff...  I misunderstood this
page:

        http://www.fxruby.org/doc/events.htm

FXMAPFUNC is mentioned in the discussion of flaws with earlier
releases of FXRuby, and not mentioned again after that.

One of the examples using FXMAPFUNC was called "scribble-orig.rb", and
the "scribble.rb" doesn''t use it.  That''s another
thing that made me
think that FXMAPFUNC was strictly a legacy function.

FXMAPFUNC doesn''t appear (that I can find) in the API docs for FXRuby
1.4 or 1.6-- another reason I thought it was deprecated.  Neither does
Responder.  Should they be in the API docs?

I''m not complaining... just explaining where a newby got misled.
You''ve been very helpful, and FXRuby has been the most enjoyable GUI
framework I''ve tried so far.  I''ve done Windows, OS/2 PM, TK,
and both
flavors of Java GUI.  The reason I don''t do GUIs is because the
frameworks drive me to drink.  FXRuby might change that.

Thanks again, Lyle.

        Wayne Conrad

On Oct 21, 2006, at 2:22 PM, Wayne Conrad wrote:
> It sure does.  My custom control is now drawing itself just fine.
Great!
> It took me a small bit of fiddling, but not much, to figure out that
> "include Responder" is required before I can call FXMAPFUNC.
Whoops. Sorry about that.
> I had thought that FXMAPFUNC was legacy stuff...  I misunderstood this
> page:
>
>         http://www.fxruby.org/doc/events.htm
>
> FXMAPFUNC is mentioned in the discussion of flaws with earlier
> releases of FXRuby, and not mentioned again after that.
>
> One of the examples using FXMAPFUNC was called
"scribble-orig.rb", and
> the "scribble.rb" doesn''t use it.  That''s
another thing that made me
> think that FXMAPFUNC was strictly a legacy function.
>
> FXMAPFUNC doesn''t appear (that I can find) in the API docs for
FXRuby
> 1.4 or 1.6-- another reason I thought it was deprecated.  Neither does
> Responder.  Should they be in the API docs?
Probably so, until the problem is completely solved.

FXMAPFUNC() is used to set up an instance''s message map (i.e. which  
messages it responds to, and which methods implement those message  
handlers). Now, for most of the "interesting" message types, a widget
will give its message target the "first shot" at handling any message
that it receives. So, for example, if an FXButton receives a  
SEL_LEFTBUTTONPRESS message from the application event loop, the  
first thing it does is send that message to its target, to see if the  
target wants to handle the message:

	class FXButton
		# this is pseudo-code
		def onLeftBtnPress(sender, sel, event)
			if (target != nil) && (target handles the message)
				# then we''re done
			else
				# do default handling
			end
		end
	end

If the target doesn''t handle it, FXButton''s default handling
kicks
in. Now, in order for the FXButton''s target to handle the message,  
the target''s message map has to be set up to declare that it can  
handle SEL_LEFTBUTTONPRESS messages and so forth. This is where the  
connect() method comes in -- it creates an anonymous object behind  
the scenes, and sets up that object''s message map appropriately,  
relieving you of the hassle.

The problem (as you ran into) is that not all messages are deemed  
"interesting" enough to forward to a widget''s target. FXFrame
is a
good example; that''s basically a container class for *other* widgets,  
and it by itself doesn''t have any really interesting behavior. (You  
hit on an exceptional case of course, which FOX can handle too.)
> I''m not complaining... just explaining where a newby got misled.
No, no need to apologize -- it''s still somewhat of a mess for cases  
like yours. Luckily those are somewhat rare. I need to come up with  
some simple way for a widget to register handlers for messages that  
it *receives* (as opposed to connect(), which has to do with handlers  
for messages that it *sends*).
> You''ve been very helpful, and FXRuby has been the most enjoyable
GUI
> framework I''ve tried so far.  I''ve done Windows, OS/2 PM,
TK, and both
> flavors of Java GUI.  The reason I don''t do GUIs is because the
> frameworks drive me to drink.  FXRuby might change that.
Thanks!

On Sat, Oct 21, 2006 at 07:53:38PM -0500, Lyle Johnson wrote: 
(An explanation of how some messages are "interesting" and are passed
on, and how FXMAPFUNC is *mostly* legacy code, but still needed in
some cases).

Lyle, Great explanation.  Understanding the model is most of the
battle.  Thanks!