Re: [Gimp-print-devel] Citizen CX-02 incorrect paper dimensions in PPD

[Solomon P. <pi...@sh...>]

On Wed, Jul 31, 2024 at 06:13:11PM +0300, ValdikSS wrote:
> I'd expect 3.5x5 PageSize to contain "252 360" value instead of "261.120
> 460.800".
> If I modify .ppd file with the values calculated by multiplying inches by
> 72, CUPS starts to report these values as an IPP-defined media sizes.

Again, this printer does not support "standard paper sizes" -- it _only_ 
uses printer-specific rolls of media.

It reports as 251.120 because *that is the actual dimension the 
printer needs*

If we report it as something smaller, then CUPS will hand us a raster 
image that is smaller than the printer needs, and that will make users 
very unhappy.

> Michael Sweet, the developer of CUPS, told to report this as a bug to you:
> https://github.com/OpenPrinting/cups/issues/1017#issuecomment-2259205981
> 
> Also I'm not sure why there are same PageSize values used for different page
> sizes, for example:
> 
> *PageSize w243h432/3.375x6:	"<</PageSize[297.600 460.800]/ImagingBBox
> null>>setpagedevice"
> *PageSize w270h432/3.75x6:	"<</PageSize[297.600 460.800]/ImagingBBox
> null>>setpagedevice"
> *PageSize w288h432/4x6:	"<</PageSize[297.600 460.800]/ImagingBBox
> null>>setpagedevice"

Except it's _not_ the same PageSize; they have different identifiers.  
Additionally, the ImageableAreas corresponding to those identifiers are 
different.

But... so what?  Even if the parameters were 100% identical, they are 
uniquely named, and those unique names are what clients are supposed to 
use to disambiguate things.

> I see. Should PageSize/PaperDimension use extended values in this case?
> Isn't that controlled by ImageableArea?

I would think ImageableArea is more important than PageSize in this 
context, yes.

> Check the link above: instead of reporting e.g. na_index-4x6_4x6in, CUPS
> reporting custom_117.35x162.56mm_117.35x162.56mm

That's because from the printer's perspective, it's physicaly larger 
than a "true" 4x6in print.

It is my understanding that the ImageableArea must be entirely contained 
within the PageSize.  Given that we need an ImageableArea physically 
larger than a "true" 4x6in print... that means we can't claim to be 4x6.
So we don't.

...Putting aside the less-than-ideal name, does it actually _work_ and 
print as expected?

Because this appears to be purely a cosmetic issue, brought on by how 
CUPS auto-translates PPD PageSize+ImageableArea into IPP's 
media+media-col equivalents.

A native IPP gutenprint print application would presumably be able to do 
better here; however at the end of the day the CX-02 (and other printers 
of its general class) do not use "standard" paper sizes, and I don't 
know what the implications could be if we report the "nominal" media 
name while correcting/supplenting the specifics in other attributes.

Based on my direct experience with IPP, if you're not using "standard 
office-type" paper sizes then for a realistic chance of success, you're 
probably going to have to use a vendor "app" to do the printing instead 
of "standard" IPP -- and that's using _native_ IPP printers, taking 
gutenprint + CUPS out of the loop entirely!

(As an aside, it is both faster and more reliable to print to my Brother 
Laser printer via IPP->CUPS->Gutenprint->JetDirect than it is to use the 
printer's native driverless IPP functionality.  Even from an iPhone!)

This new IPP world is two orders of magnitude more complicated, and I'm 
just one person working on this stuff on a (very) part time, 
entirely-out-of-pocket basis.

> The clients are Windows 10/11, Android 10 (check the link for more info).

At the end of the day I simply *do not care one iota* for supporting or 
resolving printing problems on proprietary platforms or operating 
systems.  If those platform owners (and printer manufacturers!) care, 
then they can do (and/or properly fund) this work themselves.

I'm <this> close to saying "eff this BS" and walking away entirely, 
because it's at the point where replacing fence posts while having my 
blood rapidly drained by swarms of mosquitos a moderate drizzle is more 
personally rewarding than continuing to deal with trying to keep 
printing working.

(Apologies for the rant, but ..... )

 - Solomon
-- 
Solomon Peachy			      pizza at shaftnet dot org (email&xmpp)
                                      @pizza:shaftnet dot org   (matrix)
Dowling Park, FL                      speachy (libera.chat)