How to make a GUI for USBCNC with Qt4 - Femtotech

The typedef is needed because the cncapi uses the integer type _int64 which Qt4 does not know. Now build the
project (Ctrl + B or click on the hammer icon in the lower left). You should get no errors but a lot of warnings which
are due to the syntax used by the cncapi. However, we may ignore them.
Now let’s see how to do something useful with the USBCNC SDK.
3.3 The USBCNC Server
On launching the USBCNC software (this standard can be called GUI), a process will run in background: it is the
CncServer.exe. In order to work properly, the standard GUI and all other GUIs, that we can build, have to be
connected to this server.
Open the mainwindow.ui form, drag and drop a Pushbutton and a Line Edit widgets and set the following properties:
Pushbutton
objectName btnConnect
text CONNECT
Line Edit
objectName txtServerStatus
readOnly true
At the moment we do not use any layout, but we will come back to this topic later.
Open the mainwindow.h and add the following code in the class definition:
private slots:
void on_btnConnect_clicked();
At this point, add the implementation in the mainwindow.cpp:
void MainWindow::on_btnConnect_clicked()
{
CNC_RC rc = CncConnectServer("");
ui->txtServerStatus->setText(CncGetRCText(rc));
}
The “on_” prefix allows to connect automatically a signal (clicked() in the example) to the slot declared. In this way
on clicking the pushbutton, the on_btnConnect_clicked() function is called.
CncConnectServer() is the first cncapi function that we use. In order to know something more about any cncapi items
just place the cursor on and press F2. The editor will show the definition in the header file. CncConnectServer() takes
one optional argument: the .ini file name. You should pass this parameter only for stand-alone applications which
will run without USBCNC4 software. In our example we have already the server running because the USBCNC4
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