Text/plain to image/vnd.cups-ubrl conversion support?

[zdohnal]

Hi,

reviewer during Fedora review found out that there is no conversion rule for text/plain document format to image/vnd.cups-ubrl format, but the printing works for the format if pstotiff from hplip is installed.

Should there be a direct conversion support in braille-printer-app as it is for text/plain -> application/vnd.cups-brf, or libcupsfilters+cups-filters will provide necessary conversions to an image document format?

[bkmgit]

To clarify, printing a text file to brl format works in Fedora 37, before braille-printer-app was made a separate application and uses pstotiff from hplip. It does not currently work in Fedora rawhide if pstotiff from hplip is installed.

[sthibaul]

? I don't understand the relation between printing a text file and pstotiff. Does the cups chain happen to convert text to ps then to tiff then to ubrl? That won't be good at all :)

To make things simpler, we can add a zero-cost brf2ubrl conversion that just translates from brf to unicode braille (basically what iconv -f brf -t utf-8 does)

[bkmgit]

A low cost conversion would be helpful. Conversion is text to pdf, ps to tiff then image to ubrl. Sample log below:

Feb 19 23:04:26 localhost.localdomain cupsd[869240]: [Job 11] Applying default options...
Feb 19 23:04:26 localhost.localdomain cupsd[869240]: [Job 11] Adding start banner page "none".
Feb 19 23:04:26 localhost.localdomain cupsd[869240]: [Job 11] Queued on "ubrl" by "fedora".
Feb 19 23:04:26 localhost.localdomain cupsd[869240]: [Job 11] Auto-typing file...
Feb 19 23:04:26 localhost.localdomain cupsd[869240]: [Job 11] Request file type is text/plain.
Feb 19 23:04:26 localhost.localdomain cupsd[869240]: [Job 11] File of type text/plain queued by "fedora".
Feb 19 23:04:26 localhost.localdomain cupsd[869240]: [Job 11] Adding end banner page "none".
Feb 19 23:04:26 localhost.localdomain cupsd[869240]: [Job 11] time-at-processing=1676837066
Feb 19 23:04:26 localhost.localdomain cupsd[869240]: [Job 11] 4 filters for job:
Feb 19 23:04:26 localhost.localdomain cupsd[869240]: [Job 11] texttopdf (text/plain to application/pdf, cost 32)
Feb 19 23:04:26 localhost.localdomain cupsd[869240]: [Job 11] pstotiff (application/pdf to image/tiff, cost 80)
Feb 19 23:04:26 localhost.localdomain cupsd[869240]: [Job 11] imagetoubrl (image/tiff to image/vnd.cups-ubrl, cost 70)
Feb 19 23:04:26 localhost.localdomain cupsd[869240]: [Job 11] - (image/vnd.cups-ubrl to printer/ubrl, cost 0)
Feb 19 23:04:26 localhost.localdomain cupsd[869240]: [Job 11] job-sheets=none,none
Feb 19 23:04:26 localhost.localdomain cupsd[869240]: [Job 11] argv[0]="ubrl"
Feb 19 23:04:26 localhost.localdomain cupsd[869240]: [Job 11] argv[1]="11"
Feb 19 23:04:26 localhost.localdomain cupsd[869240]: [Job 11] argv[2]="fedora"
Feb 19 23:04:26 localhost.localdomain cupsd[869240]: [Job 11] argv[3]="test.txt"
Feb 19 23:04:26 localhost.localdomain cupsd[869240]: [Job 11] argv[4]="1"
Feb 19 23:04:26 localhost.localdomain cupsd[869240]: [Job 11] argv[5]="finishings=3 number-up=1 print-color-mode=monochrome job-uuid=urn:uuid:cf725edc-4cc4-3732-6fbe-93664b4e4543 job-originating-host-name=localhost date-time-at-creation= date-time-at-processing= time-at-creation=1676837066 time-at-processing=1676837066 document-name-supplied=test.txt"
Feb 19 23:04:26 localhost.localdomain cupsd[869240]: [Job 11] argv[6]="/var/spool/cups/d00011-001"
Feb 19 23:04:26 localhost.localdomain cupsd[869240]: [Job 11] envp[0]="CUPS_CACHEDIR=/var/cache/cups"
Feb 19 23:04:26 localhost.localdomain cupsd[869240]: [Job 11] envp[1]="CUPS_DATADIR=/usr/share/cups"
Feb 19 23:04:26 localhost.localdomain cupsd[869240]: [Job 11] envp[2]="CUPS_DOCROOT=/usr/share/cups/www"
Feb 19 23:04:26 localhost.localdomain cupsd[869240]: [Job 11] envp[3]="CUPS_REQUESTROOT=/var/spool/cups"
Feb 19 23:04:26 localhost.localdomain cupsd[869240]: [Job 11] envp[4]="CUPS_SERVERBIN=/usr/lib/cups"
Feb 19 23:04:26 localhost.localdomain cupsd[869240]: [Job 11] envp[5]="CUPS_SERVERROOT=/etc/cups"
Feb 19 23:04:26 localhost.localdomain cupsd[869240]: [Job 11] envp[6]="CUPS_STATEDIR=/run/cups"
Feb 19 23:04:26 localhost.localdomain cupsd[869240]: [Job 11] envp[7]="HOME=/var/spool/cups/tmp"
Feb 19 23:04:26 localhost.localdomain cupsd[869240]: [Job 11] envp[8]="PATH=/usr/lib/cups/filter:/usr/bin:/usr/sbin:/bin:/usr/bin"
Feb 19 23:04:26 localhost.localdomain cupsd[869240]: [Job 11] envp[9]="SERVER_ADMIN=root"
Feb 19 23:04:26 localhost.localdomain cupsd[869240]: [Job 11] envp[10]="SOFTWARE=CUPS/2.4.2"
Feb 19 23:04:26 localhost.localdomain cupsd[869240]: [Job 11] envp[11]="TMPDIR=/var/spool/cups/tmp"
Feb 19 23:04:26 localhost.localdomain cupsd[869240]: [Job 11] envp[12]="USER=root"
Feb 19 23:04:26 localhost.localdomain cupsd[869240]: [Job 11] envp[13]="CUPS_MAX_MESSAGE=2047"
Feb 19 23:04:26 localhost.localdomain cupsd[869240]: [Job 11] envp[14]="CUPS_SERVER=/run/cups/cups.sock"
Feb 19 23:04:26 localhost.localdomain cupsd[869240]: [Job 11] envp[15]="CUPS_ENCRYPTION=IfRequested"
Feb 19 23:04:26 localhost.localdomain cupsd[869240]: [Job 11] envp[16]="IPP_PORT=631"
Feb 19 23:04:26 localhost.localdomain cupsd[869240]: [Job 11] envp[17]="CHARSET=utf-8"
Feb 19 23:04:26 localhost.localdomain cupsd[869240]: [Job 11] envp[18]="LANG=en_US.UTF-8"
Feb 19 23:04:26 localhost.localdomain cupsd[869240]: [Job 11] envp[19]="PPD=/etc/cups/ppd/ubrl.ppd"
Feb 19 23:04:26 localhost.localdomain cupsd[869240]: [Job 11] envp[20]="CONTENT_TYPE=text/plain"
Feb 19 23:04:26 localhost.localdomain cupsd[869240]: [Job 11] envp[21]="DEVICE_URI=cups-brf:/"
Feb 19 23:04:26 localhost.localdomain cupsd[869240]: [Job 11] envp[22]="PRINTER_INFO=ubrl"
Feb 19 23:04:26 localhost.localdomain cupsd[869240]: [Job 11] envp[23]="PRINTER_LOCATION="
Feb 19 23:04:26 localhost.localdomain cupsd[869240]: [Job 11] envp[24]="PRINTER=ubrl"
Feb 19 23:04:26 localhost.localdomain cupsd[869240]: [Job 11] envp[25]="PRINTER_STATE_REASONS=none"
Feb 19 23:04:26 localhost.localdomain cupsd[869240]: [Job 11] envp[26]="CUPS_FILETYPE=document"
Feb 19 23:04:26 localhost.localdomain cupsd[869240]: [Job 11] envp[27]="FINAL_CONTENT_TYPE=image/vnd.cups-ubrl"
Feb 19 23:04:26 localhost.localdomain cupsd[869240]: [Job 11] envp[28]="AUTH_I****"
Feb 19 23:04:26 localhost.localdomain cupsd[869240]: [Job 11] Started filter /usr/lib/cups/filter/texttopdf (PID 869272)
Feb 19 23:04:26 localhost.localdomain cupsd[869240]: [Job 11] Started filter /usr/lib/cups/filter/pstotiff (PID 869273)
Feb 19 23:04:26 localhost.localdomain cupsd[869240]: [Job 11] Started filter /usr/lib/cups/filter/imagetoubrl (PID 869274)
Feb 19 23:04:26 localhost.localdomain cupsd[869240]: [Job 11] Started backend /usr/lib/cups/backend/cups-brf (PID 869275)
Feb 19 23:04:26 localhost.localdomain cupsd[869240]: [Job 11] creating directory \"/home/fedora/BRF
Feb 19 23:04:26 localhost.localdomain cupsd[869240]: [Job 11] creating file \"/home/fedora/BRF/test.txt.XXXXXX.brf
Feb 19 23:04:27 localhost.localdomain cupsd[869240]: [Job 11] Attribute Defaultpage-ranges is \'\'
Feb 19 23:04:27 localhost.localdomain cupsd[869240]: [Job 11] Default page-ranges is \'\'
Feb 19 23:04:27 localhost.localdomain cupsd[869240]: [Job 11] Attribute DefaultPageSize is \'A4TF\'
Feb 19 23:04:27 localhost.localdomain cupsd[869240]: [Job 11] Default PageSize is \'A4TF\'
Feb 19 23:04:27 localhost.localdomain cupsd[869240]: [Job 11] Attribute HWMargins is \'28.34645652771 28.34645652771 28.34645652771 28.34645652771\'
Feb 19 23:04:27 localhost.localdomain cupsd[869240]: [Job 11] HW margins are 28.34645652771 28.34645652771 28.34645652771 28.34645652771
Feb 19 23:04:27 localhost.localdomain cupsd[869240]: [Job 11] Attribute Defaultpage-left is \'15\'
Feb 19 23:04:27 localhost.localdomain cupsd[869240]: [Job 11] Default page-left is \'15\'
Feb 19 23:04:27 localhost.localdomain cupsd[869240]: [Job 11] Attribute Defaultpage-right is \'15\'
Feb 19 23:04:27 localhost.localdomain cupsd[869240]: [Job 11] Default page-right is \'15\'
Feb 19 23:04:27 localhost.localdomain cupsd[869240]: [Job 11] Attribute Defaultpage-top is \'15\'
Feb 19 23:04:27 localhost.localdomain cupsd[869240]: [Job 11] Default page-top is \'15\'
Feb 19 23:04:27 localhost.localdomain cupsd[869240]: [Job 11] Attribute Defaultpage-bottom is \'15\'
Feb 19 23:04:27 localhost.localdomain cupsd[869240]: [Job 11] Default page-bottom is \'15\'
Feb 19 23:04:27 localhost.localdomain cupsd[869240]: [Job 11] hard margins are left 1000 right 1000 top 1000 bottom 1000
Feb 19 23:04:27 localhost.localdomain cupsd[869240]: [Job 11] graphical margins are left 1000 right 1000 top 1000 bottom 1000
Feb 19 23:04:27 localhost.localdomain cupsd[869240]: [Job 11] printable area is 19000x28480
Feb 19 23:04:27 localhost.localdomain cupsd[869240]: [Job 11] Attribute DefaultTextDotDistance is \'250\'
Feb 19 23:04:27 localhost.localdomain cupsd[869240]: [Job 11] Default TextDotDistance is \'250\'
Feb 19 23:04:27 localhost.localdomain cupsd[869240]: [Job 11] Attribute DefaultTextDots is \'6\'
Feb 19 23:04:27 localhost.localdomain cupsd[869240]: [Job 11] Default TextDots is \'6\'
Feb 19 23:04:27 localhost.localdomain cupsd[869240]: [Job 11] Attribute DefaultLineSpacing is \'500\'
Feb 19 23:04:27 localhost.localdomain cupsd[869240]: [Job 11] Default LineSpacing is \'500\'
Feb 19 23:04:27 localhost.localdomain cupsd[869240]: [Job 11] Attribute DefaultTopMargin is \'2\'
Feb 19 23:04:27 localhost.localdomain cupsd[869240]: [Job 11] Default TopMargin is \'2\'
Feb 19 23:04:27 localhost.localdomain cupsd[869240]: [Job 11] Attribute DefaultTopMargin is \'2\'
Feb 19 23:04:27 localhost.localdomain cupsd[869240]: [Job 11] Default TopMargin is \'2\'
Feb 19 23:04:27 localhost.localdomain cupsd[869240]: [Job 11] Attribute DefaultBottomMargin is \'2\'
Feb 19 23:04:27 localhost.localdomain cupsd[869240]: [Job 11] Default BottomMargin is \'2\'
Feb 19 23:04:27 localhost.localdomain cupsd[869240]: [Job 11] Attribute DefaultLeftMargin is \'2\'
Feb 19 23:04:27 localhost.localdomain cupsd[869240]: [Job 11] Default LeftMargin is \'2\'
Feb 19 23:04:27 localhost.localdomain cupsd[869240]: [Job 11] Attribute DefaultRightMargin is \'2\'
Feb 19 23:04:27 localhost.localdomain cupsd[869240]: [Job 11] Default RightMargin is \'2\'
Feb 19 23:04:27 localhost.localdomain cupsd[869240]: [Job 11] Attribute DefaultGraphicDotDistance is \'200\'
Feb 19 23:04:27 localhost.localdomain cupsd[869240]: [Job 11] Default GraphicDotDistance is \'200\'
Feb 19 23:04:27 localhost.localdomain cupsd[869240]: [Job 11] total graphical: 94x140
Feb 19 23:04:27 localhost.localdomain cupsd[869240]: [Job 11] graphical offset: 0x0
Feb 19 23:04:27 localhost.localdomain cupsd[869240]: [Job 11] rounded graphical top-left corner margin: 1000x1000
Feb 19 23:04:27 localhost.localdomain cupsd[869240]: [Job 11] resulting graphical area: 94x141
Feb 19 23:04:27 localhost.localdomain cupsd[869240]: [Job 11] Liblouis table directory is /usr/share/liblouis/tables
Feb 19 23:04:27 localhost.localdomain cupsd[869240]: [Job 11] Attribute DefaultLibLouis is \'Locale\'
Feb 19 23:04:27 localhost.localdomain cupsd[869240]: [Job 11] Default LibLouis is \'Locale\'
Feb 19 23:04:27 localhost.localdomain cupsd[869240]: [Job 11] looking for locale \'en_US\' and grade \'\'
Feb 19 23:04:27 localhost.localdomain cupsd[869240]: [Job 11] Page = 594x864; 0,0 to 594,864
Feb 19 23:04:29 localhost.localdomain cupsd[869240]: [Job 11] PID 869272 (/usr/lib/cups/filter/texttopdf) exited with no errors.
Feb 19 23:04:30 localhost.localdomain cupsd[869240]: [Job 11] GPL Ghostscript 9.56.1 (2022-04-04)
Feb 19 23:04:30 localhost.localdomain cupsd[869240]: [Job 11] Copyright (C) 2022 Artifex Software, Inc.  All rights reserved.
Feb 19 23:04:30 localhost.localdomain cupsd[869240]: [Job 11] This software is supplied under the GNU AGPLv3 and comes with NO WARRANTY:
Feb 19 23:04:30 localhost.localdomain cupsd[869240]: [Job 11] see the file COPYING for details.
Feb 19 23:04:32 localhost.localdomain cupsd[869240]: [Job 11] *** WARNING - you have selected SAFER, indicating you want Ghostscript
Feb 19 23:04:32 localhost.localdomain cupsd[869240]: [Job 11] to execute in a safer environment, but at the same time
Feb 19 23:04:32 localhost.localdomain cupsd[869240]: [Job 11] have selected WRITESYSTEMDICT. Unless you use this option with
Feb 19 23:04:32 localhost.localdomain cupsd[869240]: [Job 11] care and specifically, remember to execute code like:
Feb 19 23:04:32 localhost.localdomain cupsd[869240]: [Job 11] \"systemdict readonly pop\"
Feb 19 23:04:32 localhost.localdomain cupsd[869240]: [Job 11] it is possible that malicious code may be able to evade the
Feb 19 23:04:32 localhost.localdomain cupsd[869240]: [Job 11] limited security offered by the SAFER option.
Feb 19 23:04:32 localhost.localdomain cupsd[869240]: [Job 11] Processing pages 1 through 2.
Feb 19 23:04:32 localhost.localdomain cupsd[869240]: [Job 11] Page 1
Feb 19 23:04:32 localhost.localdomain cupsd[869240]: [Job 11] Page 2
Feb 19 23:04:32 localhost.localdomain cupsd[869240]: [Job 11] The following errors were encountered at least once while processing this file:
Feb 19 23:04:32 localhost.localdomain cupsd[869240]: [Job 11] circular reference to indirect object
Feb 19 23:04:32 localhost.localdomain cupsd[869240]: [Job 11] **** This file had errors that were repaired or ignored.
Feb 19 23:04:32 localhost.localdomain cupsd[869240]: [Job 11] **** Please notify the author of the software that produced this
Feb 19 23:04:32 localhost.localdomain cupsd[869240]: [Job 11] **** file that it does not conform to Adobe\'s published PDF
Feb 19 23:04:32 localhost.localdomain cupsd[869240]: [Job 11] **** specification.
Feb 19 23:04:34 localhost.localdomain cupsd[869240]: [Job 11] Attribute DefaultLibLouis2 is \'HyphLocale\'
Feb 19 23:04:34 localhost.localdomain cupsd[869240]: [Job 11] Default LibLouis2 is \'HyphLocale\'
Feb 19 23:04:34 localhost.localdomain cupsd[869240]: [Job 11] Attribute DefaultLibLouis3 is \'None\'
Feb 19 23:04:34 localhost.localdomain cupsd[869240]: [Job 11] Default LibLouis3 is \'None\'
Feb 19 23:04:34 localhost.localdomain cupsd[869240]: [Job 11] Attribute DefaultLibLouis4 is \'None\'
Feb 19 23:04:34 localhost.localdomain cupsd[869240]: [Job 11] Default LibLouis4 is \'None\'
Feb 19 23:04:34 localhost.localdomain cupsd[869240]: [Job 11] Table1 en_US.tbl
Feb 19 23:04:34 localhost.localdomain cupsd[869240]: [Job 11] Table2 hyph_en_US.dic
Feb 19 23:04:34 localhost.localdomain cupsd[869240]: [Job 11] Table3 None
Feb 19 23:04:34 localhost.localdomain cupsd[869240]: [Job 11] Table4 None
Feb 19 23:04:34 localhost.localdomain cupsd[869240]: [Job 11] Attribute DefaultNegate is \'False\'
Feb 19 23:04:34 localhost.localdomain cupsd[869240]: [Job 11] Default Negate is \'False\'
Feb 19 23:04:34 localhost.localdomain cupsd[869240]: [Job 11] Attribute DefaultRotate is \'90>\'
Feb 19 23:04:34 localhost.localdomain cupsd[869240]: [Job 11] Default Rotate is \'90>\'
Feb 19 23:04:34 localhost.localdomain cupsd[869240]: [Job 11] Attribute Defaultmirror is \'False\'
Feb 19 23:04:34 localhost.localdomain cupsd[869240]: [Job 11] Default mirror is \'False\'
Feb 19 23:04:35 localhost.localdomain cupsd[869240]: [Job 11] Attribute Defaultfitplot is \'True\'
Feb 19 23:04:35 localhost.localdomain cupsd[869240]: [Job 11] Default fitplot is \'True\'
Feb 19 23:04:35 localhost.localdomain cupsd[869240]: [Job 11] Attribute DefaultEdge is \'Canny\'
Feb 19 23:04:35 localhost.localdomain cupsd[869240]: [Job 11] Default Edge is \'Canny\'
Feb 19 23:04:35 localhost.localdomain cupsd[869240]: [Job 11] Attribute DefaultEdgeFactor is \'1\'
Feb 19 23:04:35 localhost.localdomain cupsd[869240]: [Job 11] Default EdgeFactor is \'1\'
Feb 19 23:04:35 localhost.localdomain cupsd[869240]: [Job 11] Attribute DefaultCannyRadius is \'0\'
Feb 19 23:04:35 localhost.localdomain cupsd[869240]: [Job 11] Default CannyRadius is \'0\'
Feb 19 23:04:35 localhost.localdomain cupsd[869240]: [Job 11] Attribute DefaultCannySigma is \'1\'
Feb 19 23:04:35 localhost.localdomain cupsd[869240]: [Job 11] Default CannySigma is \'1\'
Feb 19 23:04:35 localhost.localdomain cupsd[869240]: [Job 11] Attribute DefaultCannyLower is \'10\'
Feb 19 23:04:35 localhost.localdomain cupsd[869240]: [Job 11] Default CannyLower is \'10\'
Feb 19 23:04:35 localhost.localdomain cupsd[869240]: [Job 11] Attribute DefaultCannyUpper is \'30\'
Feb 19 23:04:35 localhost.localdomain cupsd[869240]: [Job 11] Default CannyUpper is \'30\'
Feb 19 23:04:35 localhost.localdomain cupsd[869240]: [Job 11] Converting image
Feb 19 23:04:35 localhost.localdomain cupsd[869240]: [Job 11] Set job-printer-state-message to "Converting image", current level=INFO
Feb 19 23:04:35 localhost.localdomain cupsd[869240]: [Job 11] Calling convert -canny 0x1+10%+30% -negate -rotate 90> -page 94x140+0+0 -size 94x141 -resize 94x141  -flatten - ubrl:- from stdin
Feb 19 23:04:36 localhost.localdomain cupsd[869240]: [Job 11] PID 869273 (/usr/lib/cups/filter/pstotiff) exited with no errors.
Feb 19 23:04:46 localhost.localdomain cupsd[869240]: [Job 11] Ready
Feb 19 23:04:46 localhost.localdomain cupsd[869240]: [Job 11] Set job-printer-state-message to "Ready", current level=INFO
Feb 19 23:04:46 localhost.localdomain cupsd[869240]: [Job 11] PID 869274 (/usr/lib/cups/filter/imagetoubrl) exited with no errors.
Feb 19 23:04:46 localhost.localdomain cupsd[869240]: [Job 11] PID 869275 (/usr/lib/cups/backend/cups-brf) exited with no errors.
Feb 19 23:04:46 localhost.localdomain cupsd[869240]: ubrl benson 11 [19/Feb/2023:23:04:46 +0300] total 0 - localhost test.txt - -
Feb 19 23:04:46 localhost.localdomain cupsd[869240]: [Job 11] time-at-completed=1676837086
Feb 19 23:04:46 localhost.localdomain cupsd[869240]: [Job 11] Job completed.
Feb 19 23:04:47 localhost.localdomain cupsd[869240]: [Job 11] Unloading...

[zdohnal]

To clarify, printing a text file to brl format works in Fedora 37, before braille-printer-app was made a separate application and uses pstotiff from hplip. It does not currently work in Fedora rawhide if pstotiff from hplip is installed.

But it works when pstotiff from hplip and braille-printer-app is installed... have you restarted cups after hplip installation? cupsd picks up available filters at the start of daemon.

[zdohnal]

? I don't understand the relation between printing a text file and pstotiff. Does the cups chain happen to convert text to ps then to tiff then to ubrl? That won't be good at all :)

Yes, because there is no text/plain -> image/vnd.cups-ubrl rule in braille.convs :)

To make things simpler, we can add a zero-cost brf2ubrl conversion that just translates from brf to unicode braille (basically what iconv -f brf -t utf-8 does)

That sounds good - IIUC text/plain files will be converted to application/vnd.cups-brf and then to image/vnd.cups-ubrl. It should work, but we have to test it as well.

[tillkamppeter]

Make absolutely sure that text gets directly converted do Braille, not rasterized and then the Raster image getting embossed in the low resolution of a Braille embosser, then the text is completely lost. Filter paths doing that need to get avoided under all circumstances.

[zdohnal]

@tillkamppeter is there a way how to forbid it? I mean if cupsd is able construct a filter chain based on known rules, it will automatically construct the chain, which can convert text into ubrl via tiff. Or is there a way how to disable it without editing rules/removing filter?

[sthibaul]

The cost of the chains will be enough to avoid the rasterization (which is already given a large cost)