Logging data to a file
QtChart keeps only enough data in memory to support the process of creating a visual plot of each trace in the chart window. There are, however, two ways you can save data to a file.
Saving existing trace data
QtChart stores data in "segments" of time which include average, minimum,and maximum values (see here for details).
The in-memory values can be saved to a text file by selecting the "Write Trace Data to File..." command from the "Edit" menu. This writes to a text file with the following for each trace:
This is a one-time action that writes the existing data to a file and then closes the file. No future data is written to the file.
Continuous logging of trace data
Data can also be continuous saved to a log file. This method produces a standard Comma Separated Value (.csv) text file with the following values written aproximately every 10 ms:
The logging of values starts at the time you enable logging and continues until you disable it.
To enable or disable continuous logging, select the "Log to File..." option from the "Edit" menu.