hpcups ljcolor and ljmono drivers need cupsEvenDuplex=False

[Seb James]

This is an issue which has been covered to some extent in bug 406074 (https://bugs.launchpad.net/hplip/+bug/406074)

The problem seen is that when a single page postscript document is printed via ghostscript and hpcups to an HP printer (where the PPD sets duplex (long-edge) mode), an extraneous extra blank sheet of paper is emitted by the printer. In all other senses, the print renders correctly.

I am using the hpcups driver from hplip-3.9.12 with an HP P3005x printer and also with an HP CM1312cfi MFP.

The raster data input to the hpcups driver is being generated from ghostscript 8.64, which converts postscript input into vnd.cups-raster data.

The P3005x uses the ljmono driver - this is specified in hpcups.drv (hplip-3.9.12/prnt/drv/hpcups.drv) the CM1312cfi uses the ljcolor driver.

For the ljmono and also the ljcolor drivers in hpcups.drv, the attribute cupsEvenDuplex is set to "True". Bug 406074 prompted me to try changing these to "False". This resolves the issue for the single page documents, and two and three page documents also print correctly.

I checked hplip-3.10.2 and the cupsEvenDuplex attributes are set the same as in version 3.9.12.

So, should cupsEvenDuplex be set to True for the ljmono and ljcolor drivers in hpcups?

(It appears not, at least for my two printer models).