together with foomatic-rip to avoid the introduction of a dependency
on Perl. Now it has been re-written in C and so it can be part of
cups-filters without introducing new dependencies.
-
-
-#### BRAILLE EMBOSSING
-
-cups-filters also provides filters and drivers for braille
-embossers. It supports:
-
-- Text on all kinds of embossers with generic support
-- Text and graphics on the Index V3 embossers and above.
-
-This is configured in CUPS just like any printer. Options can then be configured
-in the standard printer panel, or passed as -o options to the lp command.
-
-
-##### Text support
-
-Text can be embossed either with no translation on the computer side (the
-embosser will translate), or with translation on the computer side (thanks to
-liblouis). It is a matter of running
-
- lp file.txt
-
-or even
-
- lp file.html
- lp file.odt
- lp file.doc
- lp file.rtf
- lp file.docx
- lp file.pdf
-
-Important: it is really preferrable to directly print the document files
-themselves, and not a pdf output, or printing from the application (which
-would first convert to pdf). That way, the braille conversion will have the
-proper document structure (paragraphs, titles, footnotes, etc.) to produce good
-quality.
-
-
-##### Vector Image support
-
-Vector images can be embossed by converting them to braille dots.
-
-This needs the inkscape package installed. Various input formats are then
-supported: .svg, .fig, .wmf, .emf, .cgm, .cmx
-
-The conversion assumes that the input is black-on-white. If it is
-white-on-black, the -o Negate option can be used.
-
-This image support is preferred over the generic image support described below,
-which has to reconstruct lines to be embossed.
-
-
-##### Image support
-
-Images can be embossed by converting them to braille dots.
-
-The orientation of the image can be controlled. By default it will be rotate to
-fit the image orientation, i.e. it will be rotate by 90 degree if it is wider
-than high and the paper is higher than wide, or if vice-versa. Other rotation
-modes are provided.
-
-By default, the image will be resized to fit the size of the paper. Disabling
-the resize (fitplot set to No) will crop the image to the paper size. This is
-useful for instance when a carefully-drawn image was designed especially for
-embossing, and thus its pixels should exactly match with braille dots. In such
-case, edge detection should very probably be disabled too.
-
-The image can be processed for edge detection. When no processing is done (edge
-detection is configured to "None"), the dark pixels are embossed if the Negate
-option is off, or the light pixels are embossed if the Negate option is on. When
-edge processing is done, only the edges of the images will be embossed. The
-Basic and the Canny algorithms bring differing results. The Basic algorithm
-can be tuned thanks to the edge factor only. The Canny algorithm can also be
-tuned: increasing the Upper value will reduce the amount of detected edges (and
-vice-versa), increasing the Lower value will reduce the lengths of the detected
-edges (and vice-versa). The Radius and Sigma parameter control the blurring
-performed before edge detection, to improve the result; the Radius parameter
-controls how large blurring should be performed, setting it to zero requests
-autodetection; the Sigma parameter determines how strongly blurring should be
-performed.
-
-A lot of images formats are support, so one can just run
-
- lp file.png
- lp file.gif
- lp file.jpg
- ...
-
-Here are complete examples for controlling the processing (all options can be
-omitted, the default values are shown here):
-
-Emboss the image without edge detection, as black on white or white on black:
-
- lp -o "Edge=None" file.png
- lp -o "Edge=None Negate" file.png
-
-Emboss the image with edge detection, the default tuning parameters are set
-here:
-
- lp -o "Edge=Edge EdgeFactor=1" file.png
- lp -o "Edge=Canny CannyRadius=0 CannySigma=1 CannyLower=10 CannyUpper=30" file.png
-
-Emboss the image as it is, without any resize or edge detection, as black on
-white or white on black:
-
- lp -o "nofitplot Edge=None" file.png
- lp -o "nofitplot Edge=None Negate" file.png
-
-
-##### Generic embosser support
-
-It should be possible to make all embossers use the generic driver. For this to
-work, one has to:
-
-- configure the embosser itself so that it uses an MIT/NABCC/BRF braille table
-- add in CUPS a printer with the "Generic" manufacturer and "Braille embosser"
- model
-- configure CUPS options according to the embosser settings, so that CUPS knows
- the page size, braille spacing, etc.
-
-The generic driver can emboss text, as well as images, but images will probably
-be distorted by the Braille interline spacing.
-
-
-##### Index embossers support
-
-Supported models:
-
-- Basic-S V3/4
-- Basic-D V3/4
-- Everest-D V3/4
-- 4-Waves PRO V3
-- 4X4 PRO V3
-- Braille Box V4
-
-Index V3 embosser support has been well tested. It supports both text and
-graphics mode. Embossers with firmware 10.30 and above can be easily configured
-from CUPS (paper dimension, braille spacing, etc.).
-
-Index V4 embosser support has not been tested, but is very close to V3 support,
-so it is probably working fine already. Feedback would be very welcome.
-
-To connect an Index embosser through Ethernet, gather its IP adress, select the
-"AppSocket/HP JetDirect" network printer protocol, and set
-socket://the.embosser.IP.address:9100 as Connection URL.
-
-The density of dots for images can easily be chosen from the command line, for
-instance:
-
- lp -o "GraphicDotDistance=160" file.png
-
-to select 1.6mm dots spacing
-
-Troubleshooting: if your embosser starts every document with spurious
-"TM0,BM0,IM0,OM0" or "TM0,BI0", your embosser is most probably still using an
-old 10.20 firmware. Please either reflash the embosser with a firmware version
-10.30 or above, or select the 10.20 firmware version in the "index" panel of the
-cups printer options.
-
-
-##### Braille output options
-
-The output can be finely tuned from the standard printing panel, or from the
-command-line, the following example selects translation tables for French and
-Greek, with 2.5mm dot spacing and 5mm line spacing. All options can be omitted,
-the default values are shown here.
-
- lp -o "LibLouis=fr-fr-g1 LibLouis2=gr-gr-g1 TextDotDistance=250 LineSpacing=500" file.txt
-
-
-##### Reworking output before embossing
-
-One may want to check and modify the .brf or .ubrl output before sending it to
-the embosser. This can be achieved by first generating the .brf file:
-
- /usr/sbin/cupsfilter -m application/vnd.cups-brf -p /etc/cups/ppd/yourprinter.ppd yourdocument.txt > ~/test.brf
-
-One can choose a ppd file and additionally pass -o options to control the
-generated output. One can then modify the .brf file with a text editor. One can
-then emboss it:
-
- lp -o document-format=application/vnd.cups-brf ~/test.brf
-
-
-The same can be achieved for images:
-
- /usr/sbin/cupsfilter -m image/vnd.cups-ubrl -p /etc/cups/ppd/yourprinter.ppd yourimage.png > ~/test.ubrl
-
- lp -o document-format=image/vnd.cups-ubrl ~/test.ubrl
-
-
-##### BRF file output
-
-One can generate BRF files by adding a virtual BRF printer.
-
-When creating it in the cups interface, choose the CUPS-BRF local printer,
-select the Generic maker, and choose the Generic Braille embosser model.
-
-Printing to the resulting printer will generate a .brf file in a BRF
-subdirectory of the home directory.
-
-
-##### UBRL file output
-
-One can generate Unicode braille files, not useful for embossing, but which can
-be easily looked at by sighted people to check for the output.
-
-In the cups interface, create a printer with the CUPS-BRF local printer,
-the Generic maker, and choose the Generic UBRL generator model.
-
-Printing to the resulting printer will generate a .brf file in a BRF
-subdirectory of the home directory.
-
-
-##### Remark about the source code
-
-The file filter/braille/drivers/index/ubrlto4dot.c is used to generate
-the translation table in
-filter/braille/drivers/index/imageubrltoindexv[34]. It is included as
-"source code" for these two files, even if actually running the
-generation in the Makefile is more tedious than really useful.
-
-
-##### TODO
-
-- Test whether one wants to negate, e.g. to emboss as few dots as possible
-- textubrltoindex when liblouis tools will be able to emit 8dot braille
-
projects / thirdparty / cups-filters.git / commitdiff
