area, or pinch-to-zoom any area you want.
Crop: Tap relevant functions to automatically crop all blank
areas, or blank areas only on the left and right, or the marquee
area.
Margin: This is for the margin you want to keep for automatic
crop. You can adjust it to the size you want.
In zoom-in status, when the zoomed-in page exceeds the screen
area, you can drag the page around to check different areas. A
single tap only turns sub-pages. Tap the Virtual Buttons to turn
the whole page.