From: MENON Jean-Francois <jean-francois.menon@...>
Date: 2002-08-27T18:16:22+09:00
Subject: Re: Tk scrollbar with elided text

Albert Wagner wrote:
> 
> I am using a TkText as a base for an editor, with folding implemented by using
> TkTags with the 'elide' option.  However, the vertical scrollbar behaviour is
> not what I expected.  The slider within the scroller changes size depending
> on whether elided text is or is not within the window.
>  For example:
> I have several blocks of text, each block consisting of a header line that is
> always visible and any number of body lines tagged so that they may be elided
> as a group.
> 
> If no bodies are elided, then the scrollbar works as expected.
> 
> If all bodies are elided, then the scrollbar moves slowly as if it is actually
> scrolling the elided lines and the slider changes size depending on whether a
> small number or large number of elided lines are within the window.
> 
> If there is a mix of blocks, with some bodies elided and some not, then the
> slider changes both size and speed depending on whether the bodies within the
> window or elided or not.
> 
> I know that this must sound confusing.  But perhaps some Tk user has
> encountered this before.  Here is my definition:
> 
>                 #-------------------------------------
>                 # Define Vertical Scrollbar
>                 @vbar = TkScrollbar.new(parent,
>                         'orient'  => 'vertical',
>                         'command' => proc{|*args|@doc.yview(*args)}
>                         ).grid(
>                         'in'            => @bigGrid,
>                         'padx'      => 1,
>                         'pady'      => 1,
>                         'row'       => 0,
>                         'col'       => 2,
>                         'rowspan'   => 1,
>                         'columnspan'=> 1,
>                         'sticky'    => 'news'
>                         )
> 
>                 # synchronize @doc and @lineDoc to use same scrollbar
>                 @doc.yscrollcommand(proc{|first, last|
>                         @vbar.set(first, last)
>                         @lineDoc.yview('moveto', first)}
>                         )
> # @doc is the main TkText and @lineDoc is a slave TkText containing line
> numbers.

maybe you should not use the standard 'yview' command of TkText, but
implement your own function
to calculate the good 'first' and 'last' values ?

jf



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