#!/bin/bash
OUT="$1"
[ -z "$OUT" ] && OUT=scan.png
echo Scanning to $OUT

# Scan area is specified in millimeters.
A4="-x 215 -y 297"
LETTER="-x 215.9 -y 279.4"
SIZE="$LETTER"

# FIXME: optimized for old CanoScan.  Brightness is very sensitive.
# MOD="--mode Color --brightness -60 --contrast 80"

# device `plustek:libusb:003:110' is a Canon CanoScan N670U/N676U/LiDE20 flatbed scanner
scanimage \
    --resolution 300 \
    $SIZE $MOD \
| pnmtopng >$OUT