The mouse event handler slows down the rendering of graphs with a large number of points (500K) in pyqtgraph - a solution?

Question

Python

The mouse event handler slows down the rendering of graphs with a large number of points (500K) in pyqtgraph.
How to win?
PS: noob in programming, all according to the developers, the developers are young, you have to look for solutions in parallel with them as you understand the subject.

Answer 1

Why draw graphs with a large number of points? At one time, we also faced a similar problem: a drop in performance, but as soon as we realized that the resolution of the chart area is simply not able to display them all: i.e., for example, there are 5-10 points of the chart per pixel, then we immediately found The solution is to output not raw data, but with filtering. Well, maybe this algorithm
will suit you .

Answer 2

You can use the formula for finding the distance R between two points (x1,y1) and (x2,y2), and use a comparison with a given Rmin.
If the distance is less than the specified Rmin - skip, more or equal - output and connect with the previous (displayed) line.
Also, in addition, you can connect the calculation of adaptive extremes.
It is simpler, faster and more accurate than the SwingingDoor algorithm.