After finishing a print job you get a second connected notification. We need to either move this to Connecting: and make it say connecting or find some way to tell if we are comming from a previous state of Connecting and show the dialog only if that is true.

I don't like the idea of a persistent notification if we already have the progress inside the main window. Because a print job can take hours, and the user won't allow a notification on the screen for that long.

I dont like as much when i tried it as the connected notification. Lets try this

add an new private of type AtCore::STATES to atcoreinstancewidget (i called mine m_laststate) then we do this

    case AtCore::IDLE: {
        if(m_laststate == AtCore::CONNECTING) {
            stateString = i18n("Connected to %1", m_core.serial()->portName());
            KNotification::event ...
       }
 .....
    };//end of switch
    m_laststate = newState;
    m_statusWidget->setState(stateString);
}

Then we will only see the dialog if the last state was connecting. This can also help with the error stuff later on too.

would you consider this style for the KNotification::event calls ?

KNotification::event("printerDisconnected" // event name
    , i18n("Disconnected")  //Title
    , i18n("Disconnected from %1." //Body 
              , m_comboProfile->currentText() // i18n line substutions
              // if there was a %2 its source would be here                                       
      )// end of the i18n (with vars) 
);// end of notification event.

I find this to be much more readable.

The persistent notifications like the file transfers for dolphin stay in the tray or notification area and provide visual progress if the application is minimized. the user can toggle if they are shown by clicking the notification icon in the tray area. Im suggesting we do exactly that . If your unsure about how this will function just copy a large file via dolphin and look at how its progress is handled.

If your using several printers from one instance the notifications will be a useful way to monitor the jobs at the same time. As well as allow the user to keep atelier minimized and just get a quick peek at the progress of any job. I really think we should at very least try this and see how it works for us.

Is it not possible to use modern signal slots syntax ?

The indentation level is wrong.

For this one nope. =/

This Event should be removed and a KJob event should instead be used . As stated in previous comments i feel that this notification is redundant since the user must click print to start the job there is no delay to start the job and the UI will reflect that the print job started.

A Kio::job appears to be the type of popup that dolphin uses for the file transfers.
The perfect print pop up (for me) would have the following:

• file being printed
• the device thats printing
• elapsed time / remaining time
• A progress bar
• An abort and pause / resume button.

Idk about that on other platforms than Linux, and that is not related to a notification system, that is about monitoring.

Since this only happens when first connected I think the message should be

"Connected to printer" Instead of "Printer is Idle"

be sure to indent for the for these continued lines of i18n (here and elsewhere)

, i18n("%1 ...%2"
   , %1 replacement
   , %2 replacement
 )//Closing the i18n call.

When we connect we only have a title I think disconnect should also have no body since its one line of needed info. If not then we should add a title to the connect one to be consistent.

Printing Started.

Printing Finished.

We should consider a notification here since using command injection can pause the machine without user interaction.