The zoom is a print mode that allows you to get a global view of the whole file or a memory map on a single screen. In this mode, each byte represents file_size/block_size bytes of the file. Use the pz command, or just use Z in the visual mode to toggle the zoom mode.
The cursor can be used to scroll faster through the zoom out view. Pressing z again will zoom-in at the cursor position.
[0x004048c5]> pz?
|Usage: pz [len] print zoomed blocks (filesize/N)
| e zoom.maxsz max size of block
| e zoom.from start address
| e zoom.to end address
| e zoom.byte specify how to calculate each byte
| pzp number of printable chars
| pzf count of flags in block
| pzs strings in range
| pz0 number of bytes with value '0'
| pzF number of bytes with value 0xFF
| pze calculate entropy and expand to 0-255 range
| pzh head (first byte value); This is the default mode
