Import heavy third-party modules lazily (matplotlib, numpy, cv2)

hardwarelibrary/cameras/camera.py

@@ -4,12 +4,6 @@
 from hardwarelibrary.physicaldevice import PhysicalDevice
 from hardwarelibrary.notificationcenter import NotificationCenter, Notification
 from threading import Thread, RLock
-try:
-    import cv2
-except Exception as err:
-    print("No support for OpenCVcameras")
-    pass
-
 import re
 
 class CameraDeviceNotification(Enum):
@@ -71,6 +65,8 @@ def stop(self):
             raise RuntimeError("No monitoring loop running")
 
     def captureLoopSynchronous(self):
+        import cv2
+
         frame = None
         NotificationCenter().postNotification(notificationName=CameraDeviceNotification.didStartCapture,
                                               notifyingObject=self)
@@ -114,6 +110,8 @@ def __init__(self, serialNumber:str = None, idProduct:int = None, idVendor:int =
             self.cvCameraIndex = int(serialNumber)
 
     def openCVProperties(self):
+        import cv2
+
         properties = {}
         for property in dir(cv2):
             if re.search('CAP_', property) is not None:
@@ -139,6 +137,8 @@ def isCompatibleWith(cls, serialNumber, idProduct, idVendor):
         return wasAcquired
 
     def doInitializeDevice(self):
+        import cv2
+
         super().doInitializeDevice()
         with self.lock:
             # FIXME: Open the first camera we find

hardwarelibrary/echodevice.py

@@ -8,8 +8,6 @@
 import time
 from struct import *
 
-from pyftdi.ftdi import Ftdi #FIXME: should not be here.
-
 
 class EchoDevice(PhysicalDevice):
     classIdProduct = 0x6001

hardwarelibrary/motion/sutterdevice.py

@@ -10,8 +10,6 @@
 import time
 from struct import *
 
-from pyftdi.ftdi import Ftdi #FIXME: should not be here.
-
 class SutterDevice(LinearMotionDevice):
     classIdVendor = 4930
     classIdProduct = 1

hardwarelibrary/oscilloscope/oscilloscopedevice.py

@@ -4,7 +4,6 @@
 from hardwarelibrary.communication.serialport import SerialPort
 from hardwarelibrary.physicaldevice import *
 from hardwarelibrary.notificationcenter import NotificationCenter, Notification
-import matplotlib.pyplot as plt
 
 class Channels(Enum):
     CH1     = "CH1"
@@ -35,6 +34,8 @@ def __init__(self, serialNumber:str = None, idProduct = 0x6001, idVendor = 0x040
         self.delay = None
 
     def displayWaveforms(self, channels=None):
+        import matplotlib.pyplot as plt
+
         if channels is None:
             channels = [Channels.CH1, Channels.CH2]
 

hardwarelibrary/spectrometers/__init__.py

@@ -22,12 +22,12 @@ def __init__(self):
 
 from .base import Spectrometer, getAllSubclasses
 from .oceaninsight import OISpectrometer, USB2000, USB4000, USB2000Plus, USB4000_2000Plus, USB650
-from .viewer import SpectraViewer
 
 def any() -> Spectrometer:
     return Spectrometer.any()
 
 def displayAny():
+    from .viewer import SpectraViewer
     spectrometer = Spectrometer.any()
     if spectrometer is not None:
         spectrometer.initializeDevice()

hardwarelibrary/spectrometers/base.py

@@ -1,5 +1,6 @@
+from __future__ import annotations
+
 import time
-import numpy as np
 from abc import abstractmethod
 from struct import *
 import csv
@@ -17,7 +18,6 @@
 
 from pathlib import *
 from hardwarelibrary.physicaldevice import PhysicalDevice, DeviceState
-from hardwarelibrary.spectrometers.viewer import *
 
 class NoSpectrometerConnected(RuntimeError):
     pass
@@ -32,6 +32,8 @@ class Spectrometer(PhysicalDevice):
     idVendor = None
     idProduct = None
     def __init__(self, serialNumber=None, idProduct:int = None, idVendor:int = None):
+        import numpy as np
+
         PhysicalDevice.__init__(self, serialNumber=serialNumber, idProduct=idProduct, idVendor=idVendor)
         self.model = ""
         self.wavelength = np.linspace(400,1000,1024)
@@ -57,6 +59,7 @@ def display(self):
         """
         if self.state != DeviceState.Ready:
             self.initializeDevice()
+        from hardwarelibrary.spectrometers.viewer import SpectraViewer
         viewer = SpectraViewer(spectrometer=self)
         viewer.display()
 

hardwarelibrary/spectrometers/oceaninsight.py

@@ -1,6 +1,5 @@
 try:
     import time
-    import numpy as np
     from struct import *
     import csv
     from typing import NamedTuple
@@ -17,18 +16,12 @@
     import usb.util
     import usb.backend.libusb1
 
-    import matplotlib.backends as backends
-    import matplotlib.pyplot as plt
-    import matplotlib.animation as animation
-    from matplotlib.widgets import Button, TextBox
-
 
 except Exception as err:
     print('** Error importing modules. {0}'.format(err))
     print('We will attempt to continue and hope for the best.')
 
 from hardwarelibrary.spectrometers.base import *
-from hardwarelibrary.spectrometers.viewer import *
 
 """
 This is a simple script to use an Ocean Insight USB2000 spectrometer. You can
@@ -627,6 +620,8 @@ def getSpectrumData(self):
             The spectrum, in 16-bit integers corresponding to each wavelength
             available in self.wavelength.
         """
+        import numpy as np
+
         spectrum = []
 
         for packet in range(32):
@@ -726,6 +721,8 @@ def getSpectrumData(self):
             The spectrum, in 16-bit integers corresponding to each wavelength
             available in self.wavelength.
         """
+        import numpy as np
+
         spectrum = []
 
         if not self.lastStatus.isHighSpeed:
@@ -847,6 +844,8 @@ class Emitter(NamedTuple):
         intensity:float = None
 
     def __init__(self):
+        import numpy as np
+
         self.model = "Debug - Nothing is connected"
         self.wavelength = np.linspace(400,1000,1024)
         self.integrationTime = 10
@@ -862,6 +861,8 @@ def getSerialNumber(self):
         return "000-000-000"
 
     def getSpectrum(self):
+        import numpy as np
+
         spectrum = []
         time = self.getIntegrationTime()
         for wavelength in self.wavelength:
@@ -880,6 +881,7 @@ def getSpectrum(self):
 
     def display(self):
         """ Display the spectrum with the SpectraViewer class."""
+        from hardwarelibrary.spectrometers.viewer import SpectraViewer
         viewer = SpectraViewer(spectrometer=self)
         viewer.display()