/~bencollver/log/2022-06-15-print-quest on tilde.pink

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	# 2022-06-15 - Print Quest

	I wanted to print from DOS applications, but i no longer have a
	hardware printer. After some tinkering, i came up with the following
	solution in FreeDOS. Note that this process does not work in dosbox
	nor in dosbox-x.

	The first thing i learned is that the most common type of printer for
	DOS is Epson Esc/P. See the link below for a detailed reference to
	Esc/P printer language.

	Esc/P Reference

	First, the ingredients for this recipe:

	Ghostscript (FreeDOS) (32-bit)
	Ladybug LOGO (Simtelnet)
	NetPBM (DJGPP) (32-bit)
	PRN2FILE (Garbo)
	SNARF screen shot utility (32-bit)
	EscParse Esc/P to PDF/PS/SVG converter by Nikita Zimin (32-bit)
	Filter to fix Epson printer graphics output by NetPBM

	I chose to use Ladybug LOGO, which i described in an earlier log
	entry:

	Ladybug Quest

	I unzipped all of the "ingredients" and made sure they were in my
	path.

	I saved a simple LOGO program called flwrlife.bug:

	C:\>cd \ladybug
	C:\ladybug>copy con flwrlife.bug
	to circle :size :angle
	repeat ( 360 / :angle ) [ fd :size rt :angle ]
	end
	home cs ht rt 90 repeat 6 [ circle 1 1 rt 60 ]
	^Z

	Note: Where it shows ^Z, i pressed Ctrl-Z and then Enter.

	I ran the snarf screen shot utility, then ran the LOGO program:

	C:\ladybug>snarf.exe
	C:\ladybug>ladybug.exe
	? load flwrlife.bug

	I pressed Alt+S to take a screenshot.

	Ladybug flower of life screenshot

	I quit LOGO:

	? bye

	I converted the screenshot to Esc/P data using NetPBM. By the way,
	when i run NetPBM's Epson graphics through a printer emulator, the
	graphical output is staggered and incoherent. For this reason i
	wrote escpfltr to add a carriage return before each line of graphics
	and unstagger them.

	C:\ladybug>bmptoppm.exe SNARF000.BMP >flwrlife.pnm
	bmptoppm.exe: Windows BMP, 320x200x4
	C:\ladybug>ppmtopgm.exe flwrlife.pnm >flwrlife.pgm
	C:\ladybug>pgmtopbm.exe flwrlife.pgm >flwrlife.pbm
	C:\ladybug>pnmmerge.exe pnminvert flwrlife.pbm >inverted.pbm
	C:\ladybug>pbmmerge.exe pbmtoepson inverted.pbm >inverted.esc
	C:\ladybug>escpfltr.com <inverted.esc >flwrlife.esc

	I found an old utility named prn2file that captures the print job
	being sent to the printer. It works even when there is no printer
	attached. I used options to save to C:\print.out using a 64KB
	buffer. Note that prn2file does not work in dosbox nor in dosbox-x.

	C:\ladybug>prn2file.com /b64 /f C:\print.out
	PRN2FILE 1.1 (c) 1987 Ziff Communications Co.
	Modifications (c) 1991 Automated Answers
	LPT1 Redirected to: C:\print.out

	Then i used the COPY command to "print" the screenshot. It is
	important to pass the /b option. This uses an ioctl() to set binary
	mode. Otherwise, DOS will truncate the print data the first time it
	sees a Ctrl-Z (ASCII character 26, SUB). I used prn2file to ensure
	that the whole print job was flushed to disk.

	C:\ladybug>copy /b flwrlife.esc prn
	C:\ladybug>prn2file.com
	PRN2FILE 1.1 (c) 1987 Ziff Communications Co.
	Modifications (c) 1991 Automated Answers
	LPT1 Redirected to: PRN

	Then i compared the captured print job data to the original file.

	C:\ladybug>comp flwrlife.esc \print.out
	Files compare OK.

	What can i do with these captured print jobs on DOS? The "escparse"
	utility can convert Esc/P to PDF. I could copy the PDF to a thumb
	drive and print it from another computer. Because the DOS PDF
	viewers don't work well for me, i'll also convert the PDF to JPEG
	page images to preview using the links browser.

	C:\ladybug>escparse.exe -pdf C:\print.out >flwrlife.pdf
	ESCParser utility by Nikita Zimin Jun 15 2022 17:08:37
	Pages total: 2
	Page 2
	C:\ladybug>gs.exe -r72x72 -dGraphicsAlphaBits=4 -dTextAlphaBits=4
	-sDEVICE=jpeg -dJPEGQ=90 -o page-%03d.jpg flwrlife.pdf
	GPL Ghostscript 8.71 (2010-02-10)
	Copyright (C) 2010 Artifex Software, Inc. All rights reserved.
	This software comes with NO WARRANTY: see the file PUBLIC for details.
	Processing pages 1 through 2.
	Page 1
	Page 2
	C:\ladybug>c:\freedos\net\links\links.exe -g -mode 640x480x64k
	page-001.jpg

	Screenshot of page image in links browser

	Now that was a pretty convoluted process but it has a few advantages.

	* This will run on bare metal. It does not require any VM software.
	* This generally works with DOS apps that use an Epson printer.

	Whew! That's enough for now.

	By the way, i have a follow-up article that mentions printing higher
	quality PostScript output instead of low-resolution Epson dot-matrix
	output.

	2022-05-15 - Print Quest Part 2

	tags: bencollver,retrocomputing,technical

	# Tags

	bencollver
	retrocomputing
	technical