12.1.10.5.6. Auto-update plot

This demo shows two possibilities of how to create an auto updating plot, when the data does not come from a device allowing a live plot.

from numpy import random
import time
from itom import dataObject
from itom import plot1

Option 1: open plot with fixed interval, the plot shares its values from a given dataObject, update the dataObject regularily and call the replot slot of the plot to force an update of the canvas (without that slot, the canvas is updated once the user makes a zoom, clicks somewhere…)

d = dataObject.zeros([1, 3], "float64")
[i, h] = plot1(d, properties={"yAxisInterval": (0, 1)})

t = time.time()
for i in range(0, 50):
    d[0, :] = random.rand(3)
    h.call("replot")
    time.sleep(0.1)
print("finished in %.2f s using replot" % (time.time() - t))

finished in 5.07 s using replot

Option 2: similar to option 1, but the plot is continously given the same object again as source. Some caching mechanism provides a quick replot of the data. This option makes an automatic bounds-check of the new source and can therefore automatically reset automatic axes intervals

[i, h] = plot1(d)

t = time.time()
for i in range(0, 50):
    d[0, :] = random.rand(3)
    h["source"] = d
    time.sleep(0.1)
print("finished in %.2f s using autoupdate" % (time.time() - t))

finished in 5.12 s using autoupdate