gimp-print-devel

Re: [Gimp-print-devel] Request for Technical Guidance on Using Gutenprint for Android USB Printing (Canon PIXMA iP4000R)

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

On Tue, Dec 02, 2025 at 03:33:29PM +0500, Ameer Hamza wrote:
> I am currently developing a *cross-platform printing application for
> Android (Flutter + Kotlin + USB OTG)* that aims to support a wide range of
> printers, including HP, Epson, Brother, and especially *Canon PIXMA
> BubbleJet printers*.

Can it really be called "cross-platform" if it only runs on Android?

> I want to use Gutenprint on *Android (ARM 64-bit)* to generate correct
> raster print data for Canon PIXMA printers, and then send that data
> directly to the printer using Android’s USB Host API (bulk endpoints).

Straightforward enough in principle.

>    bitmap → Gutenprint renderer → Canon BJ raster byte stream

You also need a way to enumerate available print options and a mechanism 
for specifying them when doing this rendering.

> *📌 My Questions* *1. What is the recommended way to compile Gutenprint for
> Android?*

You will need to either get your application build process to use the 
android NDK to build gutenprint mostly as-is, or you will need to port 
the gutenprint source code into the "native" build process for android 
applications.

>    Can the Canon BJ backend be compiled *standalone* (without full CUPS)?

"backend" has specific meaning with CUPS -- it refers to the part of the 
stack that passes data to the printer.

>    Which directories / source files are required for models like *iP4000R*?

It will probably be less work to include everything (and simply not use the 
extra models) than try to systematically disable the parts you don't 
want.

>    Are there build flags to disable unnecessary drivers?

No, but you can disable what shows up in the printer list by removing 
the xml files/entries (see src/xml/printers).  The names of those xml 
files also generally correspond to src/main/print-???.c which contain 
the family-specific rendering code. 
 
> *2. Which internal Gutenprint APIs should be used to render a page?*

...You probably want the *external* APIs rather than the *internal* 
ones. There is a "Developer's guide to gutenprint" document that is 
generated using the contents of docs/developer that would be quite 
informative.

>    Any structure or API that maps directly to the “Canon Print Pipeline”

No idea.

> A minimal example (pseudo-code or call sequence) would be extremely helpful.

The gutenprint CUPS integration (see src/cups/rastertogutenprint.c ) is 
an example of those APIs in action.

> *3. Does Gutenprint expose a stable internal API for:*

In the sense that the API hasn't meaningfully changed for a couple of 
decades, yes.

> *4. Is there any documentation, diagrams, or implementation notes available
> for:*

All we have is what is embodied into the source code.  Beyond that I 
suggest you reach out to Canon.

> *5. Licensing clarification*

>    What is the correct way to comply with GPL/LGPL requirements?

https://www.fsf.org/blogs/licensing/licensing-and-compliance-lab-the-most-frequently-asked-frequently-asked-questions

Please keep in mind that whatever you directly link with Gutenprint will 
be subject to the same source code disclosure requirements as Gutenprint 
itself.  

For this reason, folks integrating Gutenprint typically do so by 
invoking our CUPS driver binaries (eg rastertogutenprint) and 
using/parsing PPDs to handle option selection.  

That way you are only on the hook to supply the complete corresponding 
source code only for the gutenprint components you actually ship.

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

[Gimp-print-devel] Request for Technical Guidance on Using Gutenprint for Android USB Printing (Canon PIXMA iP4000R)

[Ameer H. <aso...@gm...>]

Dear Gutenprint Developers,

I hope you are doing well.

I am currently developing a *cross-platform printing application for
Android (Flutter + Kotlin + USB OTG)* that aims to support a wide range of
printers, including HP, Epson, Brother, and especially *Canon PIXMA
BubbleJet printers*.

On HP printers my solution works well (PJL + PDF printing through USB Host
API).
However, Canon PIXMA printers (such as *Canon PIXMA iP4000R*) require *BJ/BJL
raster protocols*, which are not publicly documented.

During my research, I discovered that:

   -

   Gutenprint is the only open-source project that provides *full BJ Raster
   support* for older Canon PIXMA models.
   -

   Many Android printing apps (such as PrinterShare/NokoPrint) appear to
   rely on Gutenprint-based drivers.
   -

   The Gutenprint source tree contains the logic I need, but I am unsure
   how to correctly extract or port only the necessary Canon backend
   components.

I am reaching out to kindly request your technical guidance.
------------------------------
*📌 What I am trying to accomplish*

I want to use Gutenprint on *Android (ARM 64-bit)* to generate correct
raster print data for Canon PIXMA printers, and then send that data
directly to the printer using Android’s USB Host API (bulk endpoints).

I do *not* need CUPS or spoolers — only:

   -

   bitmap → Gutenprint renderer → Canon BJ raster byte stream
   -

   which I will send to the printer over USB

------------------------------
*📌 My Questions* *1. What is the recommended way to compile Gutenprint for
Android?*

   -

   Can the Canon BJ backend be compiled *standalone* (without full CUPS)?
   -

   Which directories / source files are required for models like *iP4000R*?
   -

   Are there build flags to disable unnecessary drivers?

*2. Which internal Gutenprint APIs should be used to render a page?*

For example:

   -

   The function(s) that take raster input (RGB/mono bitmap) and output
   encoded BJ Raster commands
   -

   Initialization / job-start / per-line / job-end functions
   -

   Any structure or API that maps directly to the “Canon Print Pipeline”

A minimal example (pseudo-code or call sequence) would be extremely helpful.
*3. Does Gutenprint expose a stable internal API for:*

   -

   setting DPI
   -

   page size
   -

   color/mono mode
   -

   selecting Canon model (e.g., iP4000R)
   -

   receiving the fully encoded output buffer?

*4. Is there any documentation, diagrams, or implementation notes available
for:*

   -

   Canon BJ Raster / BJL / BJPL protocol
   -

   Model-specific quirks (iP4000R in particular)

Even partial internal notes or hints would be very valuable.
*5. Licensing clarification*

If I statically or dynamically link the Gutenprint encoder library inside
an Android APK:

   -

   What is the correct way to comply with GPL/LGPL requirements?
   -

   Are there any restrictions on distributing Gutenprint inside a
   commercial Android application?

------------------------------
*📌 Summary of What I Need*

I would appreciate your guidance on:

   -

   How to build *only* the Canon BJ backend for Android
   -

   How to call the Gutenprint API to generate raster bytes
   -

   Whether there is an example or minimal program showing “bitmap → Canon
   print data”
   -

   Any documentation or tips available for Canon BJ protocols

I am happy to contribute back documentation, Android build instructions,
and sample code after I get it working.

Thank you very much for your time, the great work you have done, and any
help you can provide.
Gutenprint is an incredible project and it would be wonderful to make it
usable on Android.

Looking forward to your response.

Best regards,
*Muhammad Usman*
(Android USB Printing Developer)

[Gimp-print-devel] No duplex printing on Canon Maxify MB5150

[Dr R. W. <rai...@gm...>]

Greetings,

recently we had to revive  our printer and scanner  Canon Maxify MB5150.
While it immediately worked flawlessly  from two Windows laptops,  I had
problems with it on a third laptop running Gentoo Linux:

Initially I used  "bjnp://192.168.2.114"  as the printer's URI  but this
lead to repeated messages on the terminal that the colour ink cartridges
are empty and that the job will be restarted in 30 seconds.

That's right,  the colour ink cartridges are empty,  but the PDF file is
greyscale,  and so this should not matter.   Or does CUPS really want to
tell me "You have to buy ink you do not need"?

But since the  CUPS log file  also contained  plenty of earlier messages
"Printer drivers are deprecated  and will stop working  in a future ver-
sion of CUPS"  I changed the URI to  "ipp://192.168.2.114/ipp/print" and
set the CUPS default settings for this printer to "color, 2-sided print-
ing".

At least this solved the problem of the empty colour ink cartridges, but
while the command

   $ lpr -o sides=one-sided TwoPages-GreyScale.pdf

works as expected, the command

   $ lpr -o sides=two-sided-long-edge TwoPages-GreyScale.pdf

does wrap  each printed sheet around,  but without  printing anything on
its rear side.  The second page is then printed on the front side of the
next sheet, the net effect being two identical print outputs.

What am I missing?

Sincerely,
  Rainer

Re: [Gimp-print-devel] Dai Nippon Printing DS620

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

On Sun, Oct 05, 2025 at 10:31:46PM +0200, vlastimil.cocek--- via Gimp-print-devel wrote:

I guess I should have looked more closely before allowing this message 
through the moderation queue, but a screenshot of a GUI layout tool 
doesn't convey any sort of question or actionable information.

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

[Gimp-print-devel] Dai Nippon Printing DS620

[<vla...@vt...>]

‰PNG


Re: [Gimp-print-devel] Windows

[Erik B. B. A. <ba...@ta...>]

Yes
Sent from my iPhone

> On Oct 3, 2025, at 07:48, Adam via Gimp-print-devel <gim...@li...> wrote:
> 
> Hi, is this compatible with windows?
> 
> Thanks
> 
> Sent from my iPhone
> 
> 
> _______________________________________________
> Gimp-print-devel mailing list
> Gim...@li...
> https://lists.sourceforge.net/lists/listinfo/gimp-print-devel

Re: [Gimp-print-devel] Windows

[Erik B. B. A. <ba...@ta...>]

Sorry, I meant GIMP is compatible with windows. Gutenprint isn't as far as I know.


Sent from my iPhone

> On Oct 3, 2025, at 09:35, Erik Beck Bacon Account <ba...@ta...> wrote:
> 
> Yes
> Sent from my iPhone
> 
>> On Oct 3, 2025, at 07:48, Adam via Gimp-print-devel <gim...@li...> wrote:
>> 
>> Hi, is this compatible with windows?
>> 
>> Thanks
>> 
>> Sent from my iPhone
>> 
>> 
>> _______________________________________________
>> Gimp-print-devel mailing list
>> Gim...@li...
>> https://lists.sourceforge.net/lists/listinfo/gimp-print-devel

Re: [Gimp-print-devel] Windows

[gene h. <ghe...@sh...>]

On 10/3/25 07:48, Adam via Gimp-print-devel wrote:
> Hi, is this compatible with windows?
Never heard it claimed. Linux, maybe bsd only.
>
> Thanks
>
> Sent from my iPhone
>
>
> _______________________________________________
> Gimp-print-devel mailing list
> Gim...@li...
> https://lists.sourceforge.net/lists/listinfo/gimp-print-devel
> .

Cheers, Gene Heskett, CET.
-- 
"There are four boxes to be used in defense of liberty:
  soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author, 1940)
If we desire respect for the law, we must first make the law respectable.
  - Louis D. Brandeis
Don't poison our oceans, interdict drugs at the src.

[Gimp-print-devel] Windows

[Adam <ran...@ya...>]

Hi, is this compatible with windows?

Thanks

Sent from my iPhone

Re: [Gimp-print-devel] PANTUM wireless - about privacy

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

On Wed, Oct 01, 2025 at 04:06:34PM +0200, Karel wrote:
> I learned about the gutenprint project after the purchase of a wireless
> printer (Pantum BM2300AW) whose privacy terms and conditions I was not too
> happy about (possible privacy loopholes/leaks?).

This printer (along with nearly every model sold in the last five years 
or so) supports AirPrint, Mopria, and other "driverless" technologies that
allow it to be used without any special client-side drivers.

Of course, that doesn't help if the printer itself phones home about 
what you get up to.  You could try firewalling it off from the internet, or
other such approaches.

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

[Gimp-print-devel] PANTUM wireless - about privacy

[Karel <ka...@gm...>]

Hi,

I learned about the gutenprint project after the purchase of a wireless
printer (Pantum BM2300AW) whose privacy terms and conditions I was not too
happy about (possible privacy loopholes/leaks?).

So I started wondering if a "generic" driver exists for wireless printers
that might prevent such a potential privacy-unfriendly situation. I think
your project is not at that stage (I did not find reference to wireless
printing), but I just wanted to suggest to include a generic
privacy-friendly driver for wireless printers.

That said, receive my kindest greetings from Barcelona, Spain,

Karel De Pourcq

Re: [Gimp-print-devel] 2025 Gutenprint breaks drivers because it doesn't support old format

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

On Tue, Sep 30, 2025 at 07:44:06AM +0000, biker95 via Gimp-print-devel wrote:
> You did something in 2025 that made my EPSON driver or whatever incompatible. I remember trying to figure it out, and I think the problem was that you switched from the ppd3 format to 4 or whatever. or from 4 to 5.
> I mean, YOU should know what you did to break stuff.
> Anyway, what is the reason you can't or won't support older versions? Can I somehow help you? 
> Right now, my solution to this is downgrading gutenprint every time I want to print something, which is, frankly annoying.

To quote Gutenprint's license:

 BECAUSE THE PROGRAM IS LICENSED FREE OF CHARGE, THERE IS NO WARRANTY
 FOR THE PROGRAM, TO THE EXTENT PERMITTED BY APPLICABLE LAW.  EXCEPT WHEN
 OTHERWISE STATED IN WRITING THE COPYRIGHT HOLDERS AND/OR OTHER PARTIES
 PROVIDE THE PROGRAM "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED
 OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
 MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.  THE ENTIRE RISK AS
 TO THE QUALITY AND PERFORMANCE OF THE PROGRAM IS WITH YOU.  SHOULD THE
 PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL NECESSARY SERVICING,
 REPAIR OR CORRECTION.

> Yes, I could try to fix the problem maybe (my epson driver is only 
> available in that specific ppd format), but shouldn't not breaking 
> stuff be your job? I dunno...

Yes, you "could try to fix the problem maybe"

Meanwhile, it's not my, or anyone else's job, to care about entitled 
assholes who ask for help by swinging punches. They get to solve their 
own problems.

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

[Gimp-print-devel] 2025 Gutenprint breaks drivers because it doesn't support old format

[biker95 <bi...@pr...>]

Guys, I really need you to acknowledge me.

You did something in 2025 that made my EPSON driver or whatever incompatible. I remember trying to figure it out, and I think the problem was that you switched from the ppd3 format to 4 or whatever. or from 4 to 5.

I mean, YOU should know what you did to break stuff.

My printer suddenly didn't work one day.

Other people had the problem too.
https://bbs.archlinux.org/viewtopic.php?id=304707

Your ppd version doesn't work with gutenprint. Yea, sounds familiar.

Anyway, what is the reason you can't or won't support older versions? Can I somehow help you?

Right now, my solution to this is downgrading gutenprint every time I want to print something, which is, frankly annoying.

Yes, I could try to fix the problem maybe (my epson driver is only available in that specific ppd format), but shouldn't not breaking stuff be your job? I dunno...

I eagerly await your answer

[Gimp-print-devel] Problem driver Canon SELPHY DS810 - CUPS+Gutenprint v5.3.4 (color)

[Morgan Le R. <mor...@gm...>]

Hello Gutenprint team,

I am using a Canon Selphy DS810 printer. It works perfectly under 
Windows XP with the original Canon drivers, but I am trying to use it 
with CUPS on Ubuntu 24.04 LTS.

With the driver /“Canon SELPHY DS810 - CUPS+Gutenprint v5.3.4 (color)”/, 
the printer works correctly in general: Cyan, Magenta, Yellow, Red, 
Green, and Blue color patches are rendered as expected. However, the 
black patch (K) is printed as brown instead of neutral black. Grayscale 
gradients look correct, but pure black does not.

I will attach a photo of the test print to illustrate the issue.

Since the Selphy DS810 uses a ribbon with only Cyan, Magenta, and Yellow 
dyes (no dedicated black channel), I wonder if this issue could be 
related to how the driver handles the black generation or color model 
conversion.

Could this be a limitation or bug in the current Gutenprint driver for 
this printer model?

Thank you very much for your work on Gutenprint, and for any advice you 
can provide.

Best regards,

[Gimp-print-devel] Borderless Printing for canon g1010

[ikandilauk <ika...@gm...>]

Hi, I'm Ivo. Your software helps me a lot. Thank you. I have one question.
I only found out recently that my printer (canon pixma g1010) is supposed
to be able to print borderless, but there's no option for a "A4 borderless"
paper for g1010 driver from gutenprint. Do you have any trick that I can
follow to print files as borderless with the gutenprint driver?

[Gimp-print-devel] SC-T3170x Driver

[Edward H. <cal...@ya...>]

Hi,

  I was wondering if you would have a driver for the EPSON SC-T3170x  
printer to run on a Linux Mint XFCE OS   or

for the Epson WF 3440 printer to run on Linux Mint OS.


Thanks so much for any help you can provide.

Regards, Edward Herman

Re: [Gimp-print-devel] Drivers for Sharp BP20M31

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

On Fri, Aug 22, 2025 at 04:24:17PM +0300, Efe Edizer via Gimp-print-devel wrote:
> I am in desperate need for a working Mac driver for my Sharp printer 
> as the manufacturer supplied ones do not work (installs, print job 
> disappears without error) and they likely are trying to exort money 
> from me to buy a PS license.

Postscript would alleviate all need for a manufacturer driver, as you 
can then use the Sharp-supplied PPD directly with CUPS.

That said, the printer does claim support for PCL6 as well, so you 
should be able to just use a generic PCL6 driver that supports 
large-format prints (ie 11x17"), such as Gutenprint's "Generic PCL 6 LF 
Printer wide margin".  That should get you the abilit to at least print 
properly, but anything unique to your model (eg additional input bin 
selection, and whatever else it does) probably won't work.

> Could you please help me with this issue?

Gutenprint's PCL driver hasn't seen any meaningful work since 2018.  
What exists today is likely all there ever will be.

But perhaps more importantly, for years now, we haven't had anyone with 
the technical _ability_ (much less the necessary skills) to produce a 
native MacOS package, much less one that runs properly on post-10.14 
Macs.

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

[Gimp-print-devel] Drivers for Sharp BP20M31

[Efe E. <edi...@me...>]

Hello,

I am in desperate need for a working Mac driver for my Sharp printer as the manufacturer supplied ones do not work (installs, print job disappears without error) and they likely are trying to exort money from me to buy a PS license.

I have tried the other drivers you have made for the Sharp printers and it at least communicates to the printer but only prints a section of the document in wrong orientation. Could you please help me with this issue? 

I would be incredibly thankful if you can. Hope you have a great day.

Best Regards,

Efe Edizer

[Gimp-print-devel] Driver for old Epson dot matrix printer for an Android app using Gutenprint

[58_Bee N. <bee...@gm...>]

To the Gutenprint Team,

My name is Nayaka. I am a user of a third-party Android application called
Nokoprint, which appears to be using your Gutenprint library for its
printer driver management.

I'm trying to print from a tablet to my old dot matrix printer, a *Epson
model LX-300+ II*. Unfortunately, the application does not have a suitable
driver for my printer.

After exploring the files on my tablet, I found a "drv_gutenprint" folder
within the app's data, which contains several XML files and sub-folders
that define the printer drivers, such as escp2, inks, and mediasizes. This
suggests that the application uses a Gutenprint-based driver system.

I would like to ask if there is any documentation or guidance I can use to:

   1.

   Find or create a compatible printer driver for my Epson dot matrix
   printer.
   2.

   Understand the structure of the XML files used by the Gutenprint library
   on Android, so I can try to create a custom printer profile.

Could you provide any information on how to create the correct driver
configuration files, or if there is an existing driver for my printer model
that I can manually add to the application's folder?

Thank you for your time and assistance.

Sincerely,
Bee Nayaka Athalah Muchamad
@bee...@gm...

[Gimp-print-devel] Duplex problem

[Robert H. <rob...@ya...>]

I'm using CUPS+Gutenprint v5.3.3 to print via my Canon Pixma MP970 and its great to be able to use my old buy brilliant printer on my 64-bit iMac. Thank you. However there's no option to print duplex as it used to do when I used a Canon 32-bit driver on my old iMac. Is there a way to make this function again? 
Thanks
Robert 

Re: [Gimp-print-devel] Muratec MFX-2835r driver for Macbook

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

On Tue, Jul 08, 2025 at 11:22:08AM +0300, Sadettin Gürman wrote:
> We have a Muratec MFX-2835r printer. However, I cannot find a driver for
> Mac. I downloaded your 5.3.3 version, but I couldn't find it there either.
> Could you please help me?

What made you think this model would be supported?  It's not on
our "supported printers" list:

   https://gimp-print.sourceforge.io/p_Supported_Printers.php

The 2835R is a 'GDI' type of printer that uses a 
proprietary/non-standard communication protocol.  However it apparently 
has an _optional_ PCL mode.  I do not know if there is a way to tell if 
your printer has that option or not.

All I can suggest is that you try the "Laserjet 5Si" driver.  If it 
works, great.  If not, complain to Muratec, but given that this model 
was discontinued over two decades ago they will probably ignore you.

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

[Gimp-print-devel] Muratec MFX-2835r driver for Macbook

[Sadettin G. <sad...@gm...>]

Hello,
We have a Muratec MFX-2835r printer. However, I cannot find a driver for
Mac. I downloaded your 5.3.3 version, but I couldn't find it there either.
Could you please help me?

[Gimp-print-devel] conan mb 2150

[callison c. <fre...@th...>]

hi. great work. lala. and what not.


the canon maxify? maxi.. something mb2150 worked great. updated. now it
gives out empty papers. on linuxmint 21, tried 22 same. opensuse
tumbleweed: same. 

had to manually get the rpm package from canon. extract, installed, now
it works again.


that's all i got.


thanks.

[Gimp-print-devel] [PATCH] cups: fix a build race-condition around empty directories removal

[Yoann C. <yoa...@sm...>]

From: Yoann Congal <yoa...@sm...>

In automake, install-exec and install-data happen in parallel.
install-exec installs executables and install-data finishes with
install-data-hook that removes empty directories. If install-data-hook
happen before install-exec finishes, it might remove a directory while
it is used by the install process and make it fail.

Fix this by adding an explicit dependency between install-data-hook and
install-exec.

For example, here is the log of such a failure:
| make  install-data-hook
|  hosttools/mkdir -p 'image/usr/libexec/cups/backend'
| make[5]: Entering directory '$WORKDIR/build/src/cups'
| Expect a number of "rmdir: Directory not empty" warnings
|   /bin/bash ../../libtool   --mode=install $HOSTTOOLS/install -c backend_gutenprint '$WORKDIR/image/usr/libexec/cups/backend'
 # Start of the install process (from install-exec)
| These messages are harmless and should be ignored.
...
| rmdir $WORKDIR/image/usr/libexec/cups/backend
 # empty /usr/libexec/cups/backend is removed (from install-data-hook)
...
| libtool: install: $HOSTTOOLS/install -c backend_gutenprint $WORKDIR/image/usr/libexec/cups/backend
 # install in a non-existing directory: backend_gutenprint is installed
 # as /usr/libexec/cups/backend (this is now a file instead of a
 # directory)
| make  install-exec-hook
| make[5]: Entering directory '$WORKDIR/build/src/cups'
| chmod 700 $WORKDIR/image/usr/libexec/cups/backend/backend_gutenprint
| chmod: cannot access '$WORKDIR/image/usr/libexec/cups/backend/backend_gutenprint': Not a directory
 # chmod fails because /usr/libexec/cups/backend is a file and not a
 # directory
| make[5]: *** [Makefile:2166: install-exec-hook] Error 1

Signed-off-by: Yoann Congal <yoa...@sm...>
---
 src/cups/Makefile.am | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/cups/Makefile.am b/src/cups/Makefile.am
index c22a8632..9774abaa 100644
--- a/src/cups/Makefile.am
+++ b/src/cups/Makefile.am
@@ -206,8 +206,9 @@ uninstall-local: $(INSTALL_DATA_LOCAL_DEPS) $(INSTALL_BLACKLIST)
 	$(RM) -f "$(DESTDIR)$(cupsdata_blacklistdir)/net.sf.gimp-print.usb-quirks"
 	$(RM) -f "$(DESTDIR)$(pkglibdir)/backend/gutenprint$(GUTENPRINT_MAJOR_VERSION)$(GUTENPRINT_MINOR_VERSION)+usb"
 
-install-data-hook:
+install-data-hook: install-exec
 # Remove unused directories in install tree
+# Note: it removes "exec" directories, so it must happen after install-exec.
 	-@echo 'Expect a number of "rmdir: Directory not empty" warnings'
 	-@echo 'These messages are harmless and should be ignored.'
 	-rmdir $(DESTDIR)$(cups_modeldir)

Re: [Gimp-print-devel] Inquiry Regarding Custom Inkset Control and ESC/P2 vs. ESC/P-R Clarification

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

On Tue, Jun 10, 2025 at 02:53:28PM -0700, Kevin Hu via Gimp-print-devel wrote:
> Information about ESC/P-R appears scarce, especially regarding how it 
> differs from ESC/P2. Given that Gutenprint lists support for some 
> ESC/P-R printers (like the XP-15000), is it appropriate to assume that 
> ESC/P-R largely overlaps with ESC/P2 but includes additional 
> high-level commands, or is it fundamentally distinct?

It is my understanding that ESC/P-R presents only higher-level commands 
whereas ESC/P2 operates at a fairly low level.  /P2 gives you full 
control of the individual ink dots but requires you to handle all of the 
color->ink mapping, dot size/patterns, density, dithering, etc to yield 
usable output.  /P-R takes in a RGB (and presumably other colorspaces) 
raster and the desired output parameters (media, resolution, quality, 
etc etc) and the printer handles mapping that to the individual ink 
droplets.

Some printers support both command languages, but others only support 
one. (typically /P-R for modern consumer-grade models, /P2 for 
commercial/industrial gear)

> Despite thorough review of the documentation on rasterization and 
> color handling, I remain slightly concerned whether printers perform 
> any additional internal processing of the rasterized data we 
> send—particularly, could commanding specific CMY channels 
> inadvertently activate the K channel in the printer's internal 
> processing?

I can't speak authoratitively on all implementations of ESC/P2, but it 
is my understanding that they do not perform any internal processing of 
the data they are supplied.  Gutenprint itself will only utilize a K 
channel if so requested.

(ESC/P-R by defninition does all sorts of processing to map the input 
raster to ink dots. I have no idea how much customization is allowed)

> Does this mean that for printers with min_nozzles equal to
> the total nozzle count, all nozzles must actively be used at some point
> during each print cycle? Does this mean that for full control of individual
> channels, we need to select printers that do not require all of the nozzles
> used?

My understanding is that this means the printer may require that data 
for a given ink channel may always need to be present.  However, that data 
can be completely "blank", ie no ink gets deposited.

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