Created attachment 153258 [details]
shows gv with the horizontal line just after pressing the spacebar (scrolling a visual page down)

On gv, when you were reading a document and hit the spacbar, it would
scroll a visual page, with the same functionality that is in evince
currently where the first couple of lines from the bottom of the
previous view are kept in the top of the new view.  

Gv also included a really helpful horizontal line indicating where the
last line on the previous "page" was on the current "page".  This made
reading so much easier, as you weren't always have to search for the
place you were reading when you hit the spacebar.

I think this would be a huge UI improvement in evince, which is a
wonderful reader, and already has great features like remembering
which page you were on last when opening a document.

The line across the middle of the document display in the attached
screeshot of gv gives a good idea of what I am talking about.  It is
very basic, but incredibly useful.

Thanks, 

Rohan  

P.S. I have searched high and low to see if this is already included
in evince, but with no luck, and it this moment do not have the
knowledge or time to dive in and patch evince.