[cups.general] Why not "recommend" PPDs in the NickName?

Johannes Meixner jsmeix at suse.de
Thu Jan 25 07:05:03 PST 2007


Hello,

On Jan 25 08:07 Michael Sweet wrote (shortened):
> My own list includes the general level of feature support (a percentage
> roughly corresponding to your "supported fully" vs. "supported
> partially" status) along with an indication for the type of printing the
> driver is optimized for (either a bitfield or percentage for text,
> business graphics, and photos.) and the type of driver (PS, CUPS, Foomatic)

perhaps I misunderstand what you mean but I think there should
be always a (translatable) text so that a printer setup tool
can show some meaningful info to the user.

What I have in mind is to agree on a fixed list of main keywords
and option keywords in the PPDs and use a syntax similar to the
syntax for "PaperDimension" so that bitfields or percentage values
are available for tools as well as (translatable) text for the user.

Personally I prefer probabilities instead of percentage values
(where 1 means "perfect" and 0 means "useless") and perhaps
optionally additional weights with default weight = 1.

For example something like:

*DriverName ljet4/ljet4 (generic PCL5e driver): "ljet4"
*DriverType GhostscriptBuiltin/builtin Ghostscript driver: "0.4"
*DriverMaxRes 600/up to 600 dpi: "0.5 2"
*DriverColor BW/black and white only: "0.1 2"
*DriverUsage Text/very good for text: "0.9"
*DriverUsage Lineart/good for line art: "0.8"
*DriverUsage Graphics/acceptable for graphics: "0.4"
*DriverUsage Photo/bad for photos: "0.1"
*DriverCosts Low/causes low system load: "0.8"
*DriverSpeed High/fast output: "0.9 3"

so that the overall probability to choose this driver is

( 0.4 + 0.5 * 2 + 0.1 * 2 + 0.9 + 0.8 + 0.4 + 0.1 + 0.8 + 0.9 * 3 )
 / ( 1 + 2 + 2 + 1 + 1 + 1 + 1 + 1 + 3 )
 = 7.3 / 13 = 0.56

Note that the low probability for black and white only
does not have a bad effect for a black and white only printer
because in this case there should be only black and white only
drivers available for the printer.

> Then when the user adds a particular printer and there are multiple
> drivers available, we can ask the user (if we haven't already) what kind
> of printing they will be doing and then narrow the list of drivers
> presented to the user.

Yes!
And the printer setup tool can use totally different weights
if the user is looking e.g. for a driver to print only text
so that the printer setup tool may calculate in this case the
  *DriverUsage Text/very good for text: "0.9"
with a weight of e.g. 100 which results a 0.86 probability
to choose this driver (and other drivers which provide
less than average quality for text (i.e. < 0.5) will get much
lower probability to be choosen if there is a heavy weight
for "DriverUsage Text".


Kind Regards
Johannes Meixner
-- 
SUSE LINUX Products GmbH, Maxfeldstrasse 5      Mail: jsmeix at suse.de
90409 Nuernberg, Germany                    WWW: http://www.suse.de/





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