def truncated_z_sample(batch_size, truncation=1., seed=None):
  state = None if seed is None else np.random.RandomState(seed)
  values = truncnorm.rvs(-2, 2, size=(batch_size, dim_z), random_state=state)
  return truncation * values

def one_hot(index, vocab_size=vocab_size):
  index = np.asarray(index)
  if len(index.shape) == 0:
    index = np.asarray([index])
  assert len(index.shape) == 1
  num = index.shape[0]
  output = np.zeros((num, vocab_size), dtype=np.float32)
  output[np.arange(num), index] = 1
  return output

def imconvert_uint8(im):
  im = np.clip(((im + 1) / 2.0) * 256, 0, 255)
  im = np.uint8(im)
  return im

def imconvert_float32(im):
  im = np.float32(im)
  im = (im / 256) * 2.0 - 1
  return im

def imread(filename):
  img = cv2.imread(filename, cv2.IMREAD_UNCHANGED)
  if img is not None:
    if len(img.shape) > 2:
      img = img[...,::-1]
  return img
  
def imwrite(filename, img):
  if img is not None:
    if len(img.shape) > 2:
      img = img[...,::-1]
  return cv2.imwrite(filename, img)

def imgrid(imarray, cols=5, pad=1):
  if imarray.dtype != np.uint8:
    raise ValueError('imgrid input imarray must be uint8')
  pad = int(pad)
  assert pad >= 0
  cols = int(cols)
  assert cols >= 1
  N, H, W, C = imarray.shape
  rows = int(np.ceil(N / float(cols)))
  batch_pad = rows * cols - N
  assert batch_pad >= 0
  post_pad = [batch_pad, pad, pad, 0]
  pad_arg = [[0, p] for p in post_pad]
  imarray = np.pad(imarray, pad_arg, 'constant', constant_values=255)
  H += pad
  W += pad
  grid = (imarray
          .reshape(rows, cols, H, W, C)
          .transpose(0, 2, 1, 3, 4)
          .reshape(rows*H, cols*W, C))
  if pad:
    grid = grid[:-pad, :-pad]
  return grid

def imshow(a, format='png', jpeg_fallback=True):
  a = np.asarray(a, dtype=np.uint8)
  str_file = cStringIO.StringIO()
  PIL.Image.fromarray(a).save(str_file, format)
  im_data = str_file.getvalue()
  try:
    disp = IPython.display.display(IPython.display.Image(im_data))
  except IOError:
    if jpeg_fallback and format != 'jpeg':
      print ('Warning: image was too large to display in format "{}"; '
             'trying jpeg instead.').format(format)
      return imshow(a, format='jpeg')
    else:
      raise
  return disp