On Fri, Jul 01, 2016 at 06:22:02PM +0100, Arnt Gulbrandsen wrote:
> Hendrik Boom writes:
> >One thing I'm wondering about with GTK3 -- does GTK3 have the annoying
> >16-bit limitation on pixel counts? That has bitten me with GTK2. It
> >severely limits one's scrolling range.
>
> JFYI, it's not actually severe. Looks that way until you've crossed it,
> that's all.
>
> There's an easy workaround: Scroll in n-pixels steps instead of pixels. If
> you scroll in, say, 16-pixel steps, users won't notice the loss of accuracy,
> but you'll have an 19-bit or 20-bit range (the 16-bit limit is sometimes
> 15-bit because of sign bits). But it doesn't help you, because an 19-bit
> range is so large that users lose the ability to use the scrollbar
> effectively. Dragging the scrollbar one or a few pixels is an unmanageably
> large jump on the model. At a 19-bit range with a 900-pixel scrollbar+view,
> a single-pixel movement of the scrollbar moves the view by two thirds of the
> window.

It isn't a question of scrollbar resolution. It's a question of the
size of the scrolled region.

The various keyboard keys such as page up and page down still worked,
independent of the mouse and the scroll bars.

But I had a large scrolled region. When the pixel counter for the
scrolled region overflowed, GTK started drawing over previous
information at the top of the scrolled window again. Messy.

-- hendrik

>
> I think this workaround is so little-used and little-known precisely because
> it doesn't help. It just bypasses the 16-bit limitation and immediately
> gives you another, much less tractable, problem.
>
> Arnt
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