When I view the pdf vertically on one page , each page is centered incorrectly. In practice, it also sees the start of the next. In the attached image it is very clear. How do I set this thing so it does not happen again ? Not much I know the library, and then all the information is useful .
in vertical render mode, the default behavior is to fit the page using width and the page scroll is continuos, for that reason also the next page is visible.
I suggest to change the render mode, for example to "double page left" mode.
Using demo app, you can change the render mode in setting tab/default view mode.