[paola]

Originally Posted by ShellShock

Thanks. Yes that is much better. I think I understand: I need to use 100% for my svg width and height to get the viewBox to fill the screen rather than using an absolute size; the viewBox and image dimensions need to match the real image file in order to preserve its aspect ratio. The image dimensions need to match the viewBox dimensions to get the image to fill the viewBox, and hence fill the screen.

Originally Posted by ShellShock

snip
Replace the two 660 with the real width of the image, and the two 880 with the real height of the image (Sigil displays the width and height if you open the image).

now I get it, thanks!