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)