Sane-pixma button control is a small script that allows scanners supported by
the sane-pixma backend to be controlled by the physical buttons present on the
scanners. This allows the scanner to be operated on a headless machine or a
server without the need for another machine or network communications.

Sane-pixma button control allows for single- or multi-page PDF scans, PNG scans
and photocopying (i.e. printing a scan).

Requirements:
	sane-backends with libusb and libpng support.
	imagemagick.
	A sane-pixma backend compatible scanner.

Setup:
	The OUTPUT_DIR variable in the script must be set to a valid location.

	The POLLING_TIMEOUT variable dictates the amount of seconds the script
	sleeps before checking with the pixma-backend whether a button was pressed
	on the scanner.

	The KEEP_ORIGINAL variable can be set to `true` to also save the raw
	PNG scans.

	When using Ghostscript >= 9.24 as the backend for ImageMagick's `convert`,
	ensure that you allow conversion of PDFs by modifying the PDF policy in
	`/etc/ImageMagick-*/policy.xml`.

Usage:
	Running the script looks for the first available scanner device detected by
	scanimage. It will poll this scanner repeatedly to check whether a button
	has been pressed. The polling timeout can be set using the POLLING_TIMEOUT
	variable found in the script.
	Based upon the button that was pressed, the scanner will start scanning and
	output its contents into the directory defined by the OUTPUT_DIR variable.

This script has been tested using a Canon CanoScan LiDE 300, using a source
build of sane-backends 1.0.29 running on Debian 10 Buster.

CanoScan LiDE 300 button mapping and programmed actions:
	PDF:		4		Scan multi-page / batch PDF
	Auto Scan:	2		Scan one PNG
	Copy:		1		Scan one PNG and print via printer
	Send:		3		Scan final batch PDF page or scan a one page PDF

Released under the MIT License