How to change the scale of a page?

How to change the scale of a page?
I found Global.zoom Level =15, and i i changed the number to 50 and my page does not
Expanded on the screen and remained A4 format

Global.zoomLevel is the max zoom level i.e. 15 means 15x(2000%) zooming.

The page scale is calculated based on the pdf's max page size (width and height) and the view mode (vertical, single, double)
To change the scale of the page, you need to change the calculations done in the vLayout of the needed mode (PDFLayoutDual or PDFLayoutVert)
You may need to calculate the scale for every page based on its height/width, and save it into an array for example.

PDFLayoutDual or PDFLayoutVert) I want to set a permanent size so that all pdf documents regardless of the size were Stretch the width of the screen.
How to implement it?