title: OpenCV-python: cv2.imshow() only showing top bar on mac
body: <p>So i setup OpenCV and python3 on my mac using the guide here:
  <a href="http://www.pyimagesearch.com/2016/12/05/macos-install-opencv-3-and-python-3-5/#comment-427533" rel="nofollow noreferrer">http://www.pyimagesearch.com/2016/12/05/macos-install-opencv-3-and-python-3-5/#comment-427533</a></p>
  
  <p>In one of his guide, he has an example code:</p>
  
  <pre><code>from __future__ import print_function
  import argparse
  import cv2
  
  ap = argparse.ArgumentParser()
  ap.add_argument("-i", "--image", required = True, help = "From Terminal")
  args = vars(ap.parse_args())
  
  
  image = cv2.imread(args["image"])
  cv2.imwrite("./Output/image1.jpg", image)
  cv2.imshow("Test_imShow", image)
  cv2.waitKey(0)
  </code></pre>
  
  <p>After i execute it in terminal with</p>
  
  <pre><code>python read_n_write.py --image ./Resource/Me.jpg
  </code></pre>
  
  <p>while the imwrite function successfully creates a duplicate of the read image, imshow failed to display it in the window. There's no background, just a floating top window bar. 
  <a href="https://i.stack.imgur.com/sfLOY.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/sfLOY.png" alt="enter image description here"></a></p>
  
  <p>I'm really confused here, after a bit of google, i've tried the suggested solution</p>
  
  <pre><code>cv2.startWindowThread()
  cv2.namedWindow("test")
  </code></pre>
  
  <p>Both won't work, any suggestions would be appreciated, thank you. </p>
  
  <hr>
  
  <p><strong>Edit 1:</strong>
  Big thanks to api55.  I used matplotlib</p>
  
  <pre><code>plt.imshow(canvas, interpolation='nearest')
  plt.show()
  </code></pre>
  
  <p>And it totally worked, still have no idea why cv2.imshow isn't working. So i will leave this question open.  </p>