Re: Gtk scrollbar: thumb too short

["Stefan Monnier" <monnier+gnu/emacs@rum.cs.yale.edu>]

> Stefan Monnier wrote:
> 
> >>The advantages of being able to scroll so that the last line can be moved
> >>to the top can be questioned though.  It is not something other applications
> >>do.  Usually when the the last line is visible the thumb is at the bottom
> >>and you can not scroll so that the last line is moved to the top.
> >>But there is explicit code in Emacs for this behaviour so I figured
> >>that it had been decided some time ago.  It should perhaps be a
> >>settable customization?
> > 
> > 
> > Actually, this is also difficult to do.  What is the window-start
> > position that ensures that point-max is visible ?  The only
> > safe choice is when window-start == point-max.
> 
> When Emacs tells the different scroll bar implementations to adjust the thumb,
> it gives the size of the buffer (whole), the position of the top line
> (position) displayed, and the amount displayed in the window (portion).  All
> this in characters.  So one can figure out if the bottom is visible.

But the potion is not constant and cannot be determined without
first rendering the relevant part of the buffer.


	Stefan