title: Why cv2.resize() does not work for integer array?
body: <pre><code>[~] python3
  Python 3.6.8 (default, Jan 14 2019, 11:02:34) 
  [GCC 8.0.1 20180414 (experimental) [trunk revision 259383]] on linux
  Type "help", "copyright", "credits" or "license" for more information.
  &gt;&gt;&gt; import numpy as np, cv2
  &gt;&gt;&gt; a=np.arange(10,250,10).reshape((6,4))
  &gt;&gt;&gt; a
  array([[ 10,  20,  30,  40],
         [ 50,  60,  70,  80],
         [ 90, 100, 110, 120],
         [130, 140, 150, 160],
         [170, 180, 190, 200],
         [210, 220, 230, 240]])
  &gt;&gt;&gt; cv2.resize(a,(3,2))
  Traceback (most recent call last):
    File "&lt;stdin&gt;", line 1, in &lt;module&gt;
  cv2.error: OpenCV(4.1.0) /io/opencv/modules/imgproc/src/resize.cpp:3596: error: (-215:Assertion failed) func != 0 in function 'resize'
  </code></pre>
  
  <p>The problem persists both in Python 3.6 under Linux and in Python 3.7 under Windows 10. The error message under Windows 10 is:</p>
  
  <pre><code>OpenCV(3.4.1) Error: Assertion failed (func != 0) in cv::hal::resize, file C:\Miniconda3\conda-bld\opencv-suite_1533128839831\work\modules\imgproc\src\resize.cpp, line 3922
  Traceback (most recent call last):
    File "&lt;stdin&gt;", line 1, in &lt;module&gt;
  cv2.error: OpenCV(3.4.1) C:\Miniconda3\conda-bld\opencv-suite_1533128839831\work\modules\imgproc\src\resize.cpp:3922: error: (-215) func != 0 in function cv::hal::resize
  </code></pre>
  
  <p>If I change type to float64 or float32, e.g.</p>
  
  <pre><code>a=np.arange(10,250,10).reshape((6,4)).astype(np.float64)
  </code></pre>
  
  <p>then <code>cv2.resize</code> suddenly works.</p>