old_contents: # -*- coding: utf-8 -*-
  """
  This example demonstrates the use of ImageView, which is a high-level widget for 
  displaying and analyzing 2D and 3D data. ImageView provides:
  
    1. A zoomable region (ViewBox) for displaying the image
    2. A combination histogram and gradient editor (HistogramLUTItem) for
       controlling the visual appearance of the image
    3. A timeline for selecting the currently displayed frame (for 3D data only).
    4. Tools for very basic analysis of image data (see ROI and Norm buttons)
  
  """
  ## Add path to library (just for examples; you do not need this)
  import initExample
  
  import numpy as np
  from pyqtgraph.Qt import QtCore, QtGui
  import pyqtgraph as pg
  
  app = QtGui.QApplication([])
  
  ## Create window with ImageView widget
  win = QtGui.QMainWindow()
  win.resize(800,800)
  imv = pg.ImageView()
  win.setCentralWidget(imv)
  win.show()
  win.setWindowTitle('pyqtgraph example: ImageView')
  
  ## Create random 3D data set with noisy signals
  img = pg.gaussianFilter(np.random.normal(size=(200, 200)), (5, 5)) * 20 + 100
  img = img[np.newaxis,:,:]
  decay = np.exp(-np.linspace(0,0.3,100))[:,np.newaxis,np.newaxis]
  data = np.random.normal(size=(100, 200, 200))
  data += img * decay
  data += 2
  
  ## Add time-varying signal
  sig = np.zeros(data.shape[0])
  sig[30:] += np.exp(-np.linspace(1,10, 70))
  sig[40:] += np.exp(-np.linspace(1,10, 60))
  sig[70:] += np.exp(-np.linspace(1,10, 30))
  
  sig = sig[:,np.newaxis,np.newaxis] * 3
  data[:,50:60,50:60] += sig
  
  
  ## Display the data and assign each frame a time value from 1.0 to 3.0
  imv.setImage(data, xvals=np.linspace(1., 3., data.shape[0]))
  
  ## Set a custom color map
  positions = [0, 0.5, 1]
  colors =  [(0,0,255), (0,255,255), (255,255,0)]
  cm = pg.ColorMap(positions, colors)
  imv.setColorMap(cm)
  
  ## Start Qt event loop unless running in interactive mode.
  if __name__ == '__main__':
      import sys
      if (sys.flags.interactive != 1) or not hasattr(QtCore, 'PYQT_VERSION'):
          QtGui.QApplication.instance().exec_()
  
new_contents: # -*- coding: utf-8 -*-
  """
  This example demonstrates the use of ImageView, which is a high-level widget for 
  displaying and analyzing 2D and 3D data. ImageView provides:
  
    1. A zoomable region (ViewBox) for displaying the image
    2. A combination histogram and gradient editor (HistogramLUTItem) for
       controlling the visual appearance of the image
    3. A timeline for selecting the currently displayed frame (for 3D data only).
    4. Tools for very basic analysis of image data (see ROI and Norm buttons)
  
  """
  ## Add path to library (just for examples; you do not need this)
  import initExample
  
  import numpy as np
  from pyqtgraph.Qt import QtCore, QtGui
  import pyqtgraph as pg
  
  app = QtGui.QApplication([])
  
  ## Create window with ImageView widget
  win = QtGui.QMainWindow()
  win.resize(800,800)
  imv = pg.ImageView()
  win.setCentralWidget(imv)
  win.show()
  win.setWindowTitle('pyqtgraph example: ImageView')
  
  ## Create random 3D data set with noisy signals
  img = pg.gaussianFilter(np.random.normal(size=(200, 200)), (5, 5)) * 20 + 100
  img = img[np.newaxis,:,:]
  decay = np.exp(-np.linspace(0,0.3,100))[:,np.newaxis,np.newaxis]
  data = np.random.normal(size=(100, 200, 200))
  data += img * decay
  data += 2
  
  ## Add time-varying signal
  sig = np.zeros(data.shape[0])
  sig[30:] += np.exp(-np.linspace(1,10, 70))
  sig[40:] += np.exp(-np.linspace(1,10, 60))
  sig[70:] += np.exp(-np.linspace(1,10, 30))
  
  sig = sig[:,np.newaxis,np.newaxis] * 3
  data[:,50:60,50:60] += sig
  
  
  ## Display the data and assign each frame a time value from 1.0 to 3.0
  imv.setImage(data, xvals=np.linspace(1., 3., data.shape[0]))
  
  ## Set a custom color map
  colors = [
      (0, 0, 0),
      (45, 5, 61),
      (84, 42, 55),
      (150, 87, 60),
      (208, 171, 141),
      (255, 255, 255)
  ]
  cmap = pg.ColorMap(pos=np.linspace(0.0, 1.0, 6), color=colors)
  imv.setColorMap(cmap)
  
  ## Start Qt event loop unless running in interactive mode.
  if __name__ == '__main__':
      import sys
      if (sys.flags.interactive != 1) or not hasattr(QtCore, 'PYQT_VERSION'):
          QtGui.QApplication.instance().exec_()
  
subject: Use colormap with better perceptual contrast