From: Hidetoshi NAGAI <nagai@...>
Date: 2008-02-08T06:28:04+09:00
Subject: Re: Ruby/Tk/Iwidgets tabnotebook (and scrollbar)

From: Karl Miller <karl.miller.km@gmail.com>
Subject: Re: Ruby/Tk/Iwidgets tabnotebook (and scrollbar)
Date: Wed, 6 Feb 2008 07:53:53 +0900
Message-ID: <7dbb75f30cad0a50c37526bc2bbdf7ea@ruby-forum.com>
> > Probably the following is better. Sorry.
> > 
> Yay! This worked very well. Thank you :)

The previous version does not work with some of widget options
(e.g. tn.equaltabs = false, tn.gap = 2, and so on).
And, 'show_tab' method should be implemented on Tk::Iwidgets::Tabset.
The following is the final version (I hope so ;-)). 
If it has no problem, I'll add 'show_tab' method to official files.

==================================================================
# Command to control the tabset
class Tk::Iwidgets::Tabnotebook
  def show_tab(idx)
    @tabset.show_tab(idx)
    self
  end
end

class Tk::Iwidgets::Tabset
  def show_tab(idx)
    if index(idx) == 0
      self.start = 0
      return
    end

    reutrn unless @canvas ||= self.winfo_children[0]

    delta = 1 if (delta = cget(:gap)) == 'overlap' ||
                   (delta = self.winfo_pixels(delta) + 1) <= 0

    case cget(:tabpos)
    when 's', 'n'
      if (head = tabcget(idx, :left)) < 0
        self.start -= head
        return
      end
      tabs_size = @canvas.winfo_width
      tab_start, tab_end = @canvas . 
        find_overlapping(head, 0, head + delta, @canvas.winfo_height) . 
        find_all{|id| @canvas.itemtype(id) == TkcPolygon} . 
        map!{|id| bbox = @canvas.bbox(id); [bbox[0], bbox[2]]} . max

    when 'e', 'w'
      if (head = tabcget(idx, :top)) < 0
        self.start -= head
        return
      end
      tabs_size = @canvas.winfo_height
      tab_start, tab_end = @canvas . 
        find_overlapping(0, head, @canvas.winfo_width, head + delta) . 
        find_all{|id| @canvas.itemtype(id) == TkcPolygon} . 
        map!{|id| bbox = @canvas.bbox(id); [bbox[1], bbox[3]]} . max
    end

    if (size = tab_end - tab_start + 1) > tabs_size
      self.start -= tab_start
    elsif head + size > tabs_size
      self.start -= head + size - tabs_size
    end

    self
  end
end

tn.component_widget('tabset').command{|idx|
  tn.view(idx)
  tn.show_tab(idx)
}

# An example to following to resizing of the Tabnotebook widget
tn.bind('Configure'){ 
  tn.show_tab(:select)
}
==================================================================
-- 
Hidetoshi NAGAI (nagai@ai.kyutech.ac.jp)