Re: Gtk scrollbar: thumb too short

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

> > > > IIUC, the scrollbar widget has the following:
> > > > 
> > > > 	total-size
> > > > 	minimum thumb size
> > > > 	thumb size
> > > > 	thumb position
> > > > 
> > > > Where minimum-thumb-size is (for all intents and purposes here) a constant.
> > > > Let's simplify things and subtract minimum thumb size from the current
> > > > thumb size and from the total, we get:
> > > > 
> > > > 	total-size
> > > > 	thumb size
> > > > 	thumb position
> > > >
> > > > where
> > > > 	
> > > > 	0 <= thumb-size <= total-size
> > > > 	thumb-size + thumb-position <= total-size
> > > 
> > > This isn't a "simplification", it is a different algorithm
> > > from what GTK+ uses. The scrollbar thumb size in GTK+
> > > is:
> > > 
> > >  MAX (min_size, total_size * document_page_size/document_size)
> > 
> > [ I assume that total_size = document_size to simplify the discussion ]
> 
> > So if min_size is 10, total_size is 100 and page_size is 1, how does
> > the user get to see the last page ?
> 
> The 0-99 possible values for position in the document are mapped
> linearly onto the 0-90 possible values for the position of the
> slider thumb.

My point exactly:
for all intents and purposes (other than actual drawing on
the screen which you might care about but we don't), we can
subtract 10 from all sizes and pretend the total_size is 90
and minimum_size is 0 (and can thus be ignored).


	Stefan