From: Andreas Pinkert <the_supernova@...>
Date: 2007-06-24T05:00:04+09:00
Subject: Trouble with scrolling on a TK frame

Hi together,

Fist: Against all common sense I post a question without having read for 
a few days in this group.
However, I used groups.google and the apropriate faqs in the www but all 
I could come up with were examples that do not exactly cover my problem, 
or python code which also doesn't help so much.

Here is my problem:
I want to have a GUI in a "Excel" - like way: displaying a long list of 
data made up from different widgets. Since this list will grow quite 
long, I need to scroll that list.

Here is what I gathered so far:
I understand that I cannot scroll a Frame (which I use to arrange my 
widgets in a grid) so I wanted to use a canvas (which can be scrolled) 
and paint my widgets to that.
However, now I can scroll the canvas but not the frame on top of that.

Here is the code I am unhappy with:

     require 'tk'
     root = TkRoot.new() { title "Canvas, Grid, and Scrollbars" }
     vbar = TkScrollbar.new(root) { orient 'vert' }
     canvas = TkCanvas.new(root) {
             width   320
             height  200
             scrollregion '0 0 400 400'
     }
     canvas.yscrollbar(vbar)

     TkGrid.grid(canvas, vbar, 'sticky'=>'ns')

     TkGrid.columnconfigure(root, 0, 'weight'=>1)
     TkGrid.rowconfigure(   root, 0, 'weight'=>1)

     TkcLine.new(canvas, 0, 0, 400, 400)
     TkcLine.new(canvas, 0, 400, 400, 0)

################
# commenting these lines will result in a scrollable cross on the canvas

     frame = TkFrame.new(canvas).grid

     for i in 1..10
       button = TkButton.new(frame, 'text'=>i)
       button.grid
     end
################

     Tk.mainloop


As a relative newbie to both TK and Ruby (I wrote a minor project with 
REXML about 5 years ago but never really returned to Ruby after that), 
any help would be very much appreciated.

Thanks and regards,
Andreas.