Anelok: weird ways to scroll

EdorFaus edorfaus at
Mon Jan 19 00:36:27 UTC 2015


On 01/03/2015 03:40 AM, Werner Almesberger wrote:
>  Key	Mode
>  ---	---------------------------------------------------
>   1	smooth and centered, the default
>   2	list scrolls in the same direction in all zones (2)
>   3	list changes scroll direction depending on zone
> Note that I didn't fully debug modes 2 and 3, so there are some jumps
> when changing zones.

I didn't really understand this explanation of modes 2 and 3, but the
image helped.

Even ignoring the zone-switching bug, I agree that modes 2 and 3 are
much weirder than mode 1.

Mode 3 would probably just confuse me, since it acts as if I'm scrolling
the wrong way, then jumps around to "fix" it.

Mode 2 seems like the pointer skips past one item (it moves by two item
heights) - but the list jumps at the same time so that it doesn't
actually skip anything...

Yet, they both have the list scroll smoothly while you're on a single
item. Just not when moving from one item to the next.

Frankly, I think it would be clearer (at least to me) if the cursor
and/or list just jumped one item at a time without the smooth scrolling
in between. A bit old-fashioned, perhaps, but still clearer IMO.

Mode 1, on the other hand, doesn't really seem odd at all.

There, the list moves consistently, and smoothly, without jumping
around, and the cursor only jumps one line at a time, when the currently
active item changes. (The video you posted clearly shows that the way it
jumps is not a problem, and rather makes sense.)

Having the list be empty at both ends doesn't really seem odd either,
IMO, it just reinforces that the active item is always at the middle of
the screen, which I think is good for consistency.

>     - let the cursor move freely and have another marker that jumps
>       from item to item (e.g., invert the entry). That would probably
>       clutter the display quickly.

I had an idea for a marker that might work, without inverting the entry
or otherwise causing long white lines, though I'm less sure about the
clutter aspect. The marker would be a vertical line right next to the
item, exactly one item high, and following the item like the cursor does
now - with the cursor pointing at it, possibly touching it.

This kind of solution would also have the advantage of showing how close
you are to switching which item is active, which could help to avoid
accidentally selecting the wrong item (by scrolling a little more just
as you clicked).

(Though I suppose your approach with delays and thresholds would also
prevent that.)

To be perfectly honest though, I'm not sure if something like this would
really be better than your current mode 1.

What you have very clearly shows that you are at the end of the list,
without having to look at the cursor, and is in some ways more
consistent than moving the cursor instead just because you're at the end
of the list.

On the other hand, this would make more use of the available space on
the screen, by showing more items than the current mode does.

So, which is better?

I suspect it might come down to personal preference, actually...


Hm, I just had a tangentially-related idea...

Is it possible to update the screen fast enough to get a level of gray
due to persistence of vision? (Think PWM on a per-pixel level.)

If so, that could be used to highlight things, such as the selected
item. Wouldn't even require long white lines, just use a checkerboard
pattern with the PWM to make the area gray.

I suspect it's not feasible in practice, though, even if it's possible.
(Among other reasons, it would probably take too much power...)


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