Originally Posted by LCF
Emm... why do you need it? You'll only get to see white strip on the one side and loose some part of the page on the other.
It's probably me who missunderstood. I thought, that you have pages bigger than the screen, but cannot shift horizontally, because the zoom level is 100%. So I figured, that if you have smaller pages, then you can zoom them in and use the horizontal scrolling.
Perhaps you're right. There are instances that the text is big in it's own physical page and you want it smaller and when you do that it moves to one side and (gradual) shifting is not possible. But one can ignore thiz rare cases. However a "center view" key* could really come handy for even zooming in.
*Perhaps by sacrificing one of those bookmark keys or giving user the freedom to do so.