[cups] some IPP attributes don't work for some printers

Jacob Marble jacobmarble at google.com
Wed Sep 9 13:42:34 PDT 2015


Oh, I think I found the list. ppd-cache.c, around line 1120:

ColorModel
HPColorMode
BRMonoColor
CNIJSGrayScale
HPColorAsGray

Again, thanks.

Jacob

On Wed, Sep 9, 2015 at 1:40 PM, Jacob Marble <jacobmarble at google.com> wrote:

> Michael, just curious, what non-standard keywords does CUPS check for? I
> found one possible reference in cups/ppd-cache.c
> "com.apple.print.preset.output-mode"; are there others?
>
> Jacob
>
> On Wed, Sep 9, 2015 at 1:38 PM, Jacob Marble <jacobmarble at google.com>
> wrote:
>
>> Thanks
>>
>> Jacob
>>
>> On Wed, Sep 9, 2015 at 12:44 PM, Michael Sweet <msweet at apple.com> wrote:
>>
>>> Jacob,
>>>
>>> > On Sep 8, 2015, at 7:39 PM, Jacob Marble <jacobmarble at google.com>
>>> wrote:
>>> >
>>> > A PPD for a particular color printer lacks a ColorModel entry, but CUPS
>>> > indicates that color printing is possible with:
>>> >
>>> > color-supported=true
>>> > print-color-mode-default=color
>>> > print-color-mode-supported=color,monochrome
>>> >
>>> > So, instead of printing with the ColorModel attribute, I use
>>> > print-color-mode=monochrome. But. Color comes out of the printer.
>>> >
>>> > Digging into other PPD entries, I found this attribute, which *does*
>>> > control color vs monochrome in print tests:
>>> > *OpenUI *CMAndResolution/Print Color as Gray: PickOne
>>> >
>>> > Looks like this occurs in a dozen or so HP printers, out of my
>>> collection
>>> > of about 7000 PPDs from multiple manufacturers.
>>> >
>>> > How does CUPS decide that this printer should have the print-color-mode
>>> > attribute? Is this a bug in CUPS or in the PPD?
>>>
>>> The PPD.
>>>
>>> CUPS looks for the ColorDevice keyword in the PPD, and uses that to
>>> determine what values of the print-color-mode attribute  are supported.
>>> CUPS supports the standard ColorModel plus a handful of non-standard
>>> keywords that directly map to it for applying the print-color-mode value,
>>> but *not* CMAndResolution (which by its name is likely a non-standard
>>> combination of ColorModel and Resolution...)
>>>
>>> _________________________________________________________
>>> Michael Sweet, Senior Printing System Engineer, PWG Chair
>>>
>>> _______________________________________________
>>> cups mailing list
>>> cups at cups.org
>>> https://www.cups.org/mailman/listinfo/cups
>>>
>>
>>
>



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