[cups.development] Brother Label Printer, partial driver, need help

[Thomas Seiler]

Hi cups-dev list,

I hope to be in the right place to ask a few questions about
developing a driver for the Brother QL-500 / QL-550 label printer
series. If I am in the wrong place, then please ignore this email.

The QL-5x0 is a thermal label printer that can print 62mm wide labels
or continuous paper. The 550 model has also an included automatic
cutter. See here:
http://www.brother.co.uk/cms.cfm/s_page/55570/s_level/17300/s_product/QL550

I am working on integrating support for the QL-550 Label Printer into
the rastertodymo driver, the protocol of this make of label printer
was reverse-engineered some time ago
(http://etc.nkadesign.com/Printers/QL550LabelPrinterProtocol) but
nobody has yet written a cups driver.

I have written an ppd based on the dymo.ppd and modified model number, etc....
Then I added the the ql550 protocol parts in the switch statements of
rastertodymo.

Sofar I can print a document of size a4, like i.e. the test page and
the printer produces a label with length of an a4 page and prints the
left-most 62mm of the page on the label. Very nice.

BUT, if I try to print anything that is smaller than an a4 page, for
example an address label, then the printer prints nevertheless a label
that is as long as an a4 page is high.
When I try to print a pdf that is slightly smaller than a4 from
acrobat or via kprinter, I can furthermore see, that the actual label
is centred on a a4 page, so there is a white border above, on the left
and also below the actual page. The strange thing is that in the
properties dialog, I can see and select the Page sizes of the modified
ppd, they just don't have any effect, as far as I can tell.

As the rastertodymo only translates the raster information into the
proprietary protocol of the QL550, I believe that the problem happens
somewhere upstreams.

So clearly I fail to tell the cups RIP that this printer can not
handle a4 but only 62mm wide labels.

Could someone give me a pointer for these questions:
- How to write a ppd that contains the different label sizes that are
supported by the printer or else how to disable the centering of the
label inside the a4 page ?
- How can I add a the contiguous paper option, where the label length
is determined by the printed label size ?
- I have seen the cutter yes / no directive for ppds. How can I access
the setting inside rastertodymo in order to send the right commands ?
- What is the cups way of witing drivers that do bi-directional
communication with the printer ?

Normaly I would sent an email per question, but im not sure to be on
the right list, so i prefer to keep a low profile :)

Thanks and best regards,
Thomas Seiler

--
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If the human brain was simple enough for us to understand we'd be so
simple we couldn't understand.
Prove this by induction.