Now that I have Aseba Studio working, I tried to get connected to my Canon Wi-Fi printer, and it is once again quite difficult. Is there something rotten in Ubuntu’s world?
Let us start by the beginning, and describe my printer’s configuration: it is a Canon Pixma MG4250, connected by Wi-Fi to my Freebox Revolution. It is detected by system-config-printer, which by default chose automatically the corresponding driver, by failled at last step to define the new printer and returned cups-error-internal-error. My first reaction was of course to check the Web for others having a similar problem, and the way they solved it if any did, but I did not find anything relevant.
I then tried something else: instead of choosing the automatically detected printer, I gave the URI found on XUbuntu 16.04, which is cnijnet:/ followed by (what I think to be) the MAC address of the printer. I then had to choose a driver (where system-config-printer automatically did it in previous method), but adding the printer still failled at last step, this time with cups-error-not-possible.
At last, I applied the method which worked on XUbuntu 16.04, which is to use Canon driver. I chose the Debian archive from their page, and tried to install it. However, it needed three packages (libpango1.0, libpng12 and libtiff14) while only the first is still available on 18.04 (the two others are obsolete). A web search indicated that older packages can be used, I thus got those of the previous LTS (xenius) on the Ubuntu archive site (but the last one, libtiff14, needs a direct access to tiff directory of the French archive site, as the library is not referenced, only its dev part). Once those package are saved and installed (with a sudo dpkg -i ...), Canon’s installation script works fine, and adds the printer. Everything now works fine.
As I found abnormal the two errors sent by system-config-printer, I filled a bug report on launchpad.