From: Andreas Pinkert <the_supernova@...>
Date: 2007-06-24T21:10:05+09:00
Subject: Re: Trouble with scrolling on a TK frame

Thanks a lot!

I added only this line to my code and now it does what I want:
TkcWindow.new(canvas, 200,  200, :width=>100, :height=>280,
  	:window=>frame)

I have not found documentation on TkcWindow.
Where can I find such? I mean, I do not know what the API actually does.

regards,
Andreas.


Morton Goldberg wrote:


> On Jun 23, 2007, at 4:00 PM, Andreas Pinkert wrote:
> 
>> 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
> 
> 
> Perhaps this example will help. It's pretty rough, but I think it  might 
> point you in the right direction. It also illustrates some  alternative 
> ways of setting up widgets with Ruby/Tk. I'm not saying  these 
> alternatives are necessarily better what you did -- just  thought you 
> might like to know they exist. They do save on typing.
> 
> <code>
> # Demonstrates adding a vetical row of buttons to a scrolling canvas.
> 
> require 'tk'
> 
> Tk.root.title("Test")
> 
> canvas = TkCanvas.new(Tk.root) {
>    width   320
>    height  200
>    scrollregion '0 0 400 400'
>    pack(:side => :left, :fill => :both, :expand => :true )
> }
> 
> vbar = TkScrollbar.new(Tk.root) {
>    orient 'vert'
>    pack(:side => :right, :fill => :y)
>    }
> 
> canvas.yscrollbar(vbar)
> 
> frame = TkFrame.new(canvas) do |frm|
>    (1..10).each do |i|
>       TkButton.new(frm) {
>          text i
>          command { Tk.bell }
>          grid
>       }
>    end
> end
> 
> TkcLine.new(canvas, 0, 0, 400, 400)
> TkcLine.new(canvas, 0, 400, 400, 0)
> TkcWindow.new(canvas, 200,  200, :width=>100, :height=>280, :window=>frame)
> 
> Tk.mainloop
> </code>
> 
> I think the above does what you were asking for -- at least the  button 
> array scrolls with the canvas and the buttons beep when  clicked (which 
> proves that they function).
> 
> Regards, Morton
>