How to correctly draw a graph of data from a com port in Swift?

Question

infographics

There is a device that sends data via a serial port (type uint8), data transfer rate is 115200 baud, data is sent every 20 microseconds.
I began to draw in nsview, the data is added to an array, where the index is the x value, and the array element itself is the y value. I draw in the context of the nsview itself. If I draw test data (a predefined array) through a timer (with a frequency of 0.01s) then everything is OK when I draw from the port. The program freezes and starts drawing in pieces, and then it hangs altogether (there is a memory leak). It is worth noting that each new datum redraws the entire graph. Bezier didn't improve the situation either.