Visual cue to help keeping track of text during partial scrolling of page

[GoogleCodeExporter]

This is actually a request for enhancement, but let me disguise it as an error 
report. Here's how EB works now:

What steps will reproduce the problem?
1. Open a document with a zoom level so that the page does not fit the screen
2. when you are at the last readable line withing the screen, you tap forward
3. the page is scrolled by the amount specified in the preference but user has 
lost track of where he/she was reading. It is very unnerving.

What is the expected output? What do you see instead?

I expect some sort of aid to keep track of the last line I was reading before 
scrolling (in what I will call the 'old view').
I suggest to implement a visual cue in the form of an animation to superpose to 
the 'new view' (i.e. scrolled page). 

The animation must be very simple and consists of a lightly highlighted line 
(well, a thick one, about the height of the font) that appears shortly in the 
old view (some tens of milliseconds, experimenting might be necessary) and, in 
the new view will 'slowly' scroll form the old position of last read line (or 
simply the bottom of top of the screen) to the new position of the last read 
line (or simply the amount of scrolling applied).

The 'animation' can simply be that of a linear movement (but a slightly 
accelerated or decelerated movement could look better) and should last enough 
for the user to take notice of it. Possibly several tens of a second - 
experimenting might be required.

This will make it harder to lose track of where the user was, when he/she 
scrolled the page.

Color should be 'pastel-like', no strong color. Light grey should be fine in 
both day and night modes.

Original issue reported on code.google.com by peltio on 21 Mar 2014 at 4:12

[GoogleCodeExporter]

[deleted comment]

[GoogleCodeExporter]

Oh, in the last part I meant "tenths of a second" (0.4 - 0.6 s?), while in the 
text above I confirm "scores of milliseconds" (what is the minimum time to have 
persistence of vision?).

Original comment by peltio on 21 Mar 2014 at 4:16

[GoogleCodeExporter]

Hi! I fully understand your problem, which was mine a few weeks ago. Your 
proposal makes sense, but it seems to me rather complicated for the devs. I 
simply solved it by specifying 95% in the preference for scrolling. The next 
place for reading after scrolling is always the topmost part of the screen, no 
more identification problem.

Original comment by philippe...@gmail.com on 27 Mar 2014 at 1:00

[GoogleCodeExporter]

Hi! I fully understand your problem, which was mine a few weeks ago. Your 
proposal makes sense, but it seems to me rather complicated for the devs. I 
simply solved it by specifying 95% in the preference for scrolling. The next 
place for reading after scrolling is always the topmost part of the screen, no 
more identification problem.

Original comment by philippe...@gmail.com on 27 Mar 2014 at 1:01

[GoogleCodeExporter]

So do I.

Original comment by Andrei.K...@gmail.com on 27 Mar 2014 at 2:28

[GoogleCodeExporter]

The 95% solution might be good for novels and fiction books. Not so for 
technical and scientific books, where one usually need to see previous passages 
and not only what is ahead. It is unnerving enough having to go back and forth 
between pages when that happen and is unavoidable, that it is a pity making 
that mandatory when it is avoidable.

Besides, what's the use of allowing the user to choose the scrolling percentage 
he/she desires?
A complicated (and computing intensive) solution could be animating the whole 
page scroll, but just moving an overlay line (or a partially transparent 
rectangular area growing from the new border to the position of the previous 
border) could be easier.

Original comment by peltio on 28 Mar 2014 at 2:15

[GoogleCodeExporter]

What's more: the animation might be overkill. Just showing a blinking line 
before the page change and a blinking line in the new position once the page 
has scrolled could work as well.
This feature could be enabled/disabled as a general preference (where the 
percentage of scrolling is set).

Original comment by peltio on 28 Mar 2014 at 2:24