live_video_spiral.py

import time
import sys
import numpy as np
import pvaccess as pva
import matplotlib.pyplot as plt
from matplotlib.pyplot import figure, draw, pause
from epics import caget, caput, camonitor, cainfo

data = np.empty((0, 4))
chunk_counter = -1

stop = False

def handle_close(evt):
     global stop
     stop = True

def reset_pv(pv):
     pv["value.column0"] = []
     pv["value.column1"] = []
     pv["value.column2"] = []
     pv["value.column3"] = []

     return pv

def callback(x):
     """Collect data."""
     global data
     global chunk_counter
     chunk_data = np.dstack(
         (x["value.column0"], x["value.column1"], x["value.column2"], x["value.column3"])
     ).squeeze()
     data = np.vstack((data, chunk_data))
     chunk_counter += 1
#     print(f"chunk {chunk_counter} received.")
     return chunk_counter

def get_new_data():

    channel = pva.Channel("CRYVISIL:STM:FASTSCAN:IMAGE_CHUNK")

    pv = channel.get("field(value)")
    pv = reset_pv(pv)
    channel.put(pv, "")

    channel.subscribe("callback", callback)

   # print("Starting monitor!")
    channel.startMonitor("field(value)")

    while data.shape[0] < 1:
        time.sleep(0.001)

 #   print("Stopping monitor!")
    channel.stopMonitor()
  #  print(f"{chunk_counter} chunks counted!")
    channel.unsubscribe("callback")
    x, y, z, zz = np.squeeze(np.hsplit(data,4))
    H, xedges, yedges = np.histogram2d(-y, x, bins=100, weights=z, normed=False)
    H_notweighted, xedges, yedges = np.histogram2d(-y, x, bins=100)
    H_scale = H / H_notweighted
    # plt.imshow(H_scale)
    # plt.show()
    return H_scale

fg = figure()
fg.canvas.mpl_connect("close_event", handle_close)
ax = fg.gca()
h = ax.imshow(get_new_data())
# for i in range(100):
#     data = np.empty((0, 4))
#     h.set_data(get_new_data())
#     draw(), pause(1e-3)
while not stop:
    if caget("CRYVISIL:AWG0:HoldDDS") == 13:
        data = np.empty((0, 4))
        h.set_data(get_new_data())
        draw(), pause(1e-3)
    elif caget("CRYVISIL:AWG0:HoldDDS") == 15:
        plt.close()
        break
    elif caget("CRYVISIL:AWG0:SmoothHoldDDS") == 1:
        data = np.empty((0, 4))
        h.set_data(get_new_data())
        draw(), pause(1e-3)