Python+OpenCV 实现图片无损旋转90°且无黑边

#!/usr/bin/python
# -*- coding: UTF-8 -*-
"""
This program is debugged by Harden Qiu.
You can send a e-mail to hardenqiu@foxmail.com for more details.
"""
import numpy as np
import cv2
def main():
  img = cv2.imread('.\\imgs\\img10.jpg')
  height, width = img.shape[:2]

  matRotate = cv2.getRotationMatrix2D((height * 0.5, width * 0.5), -90, 1)
  dst = cv2.warpAffine(img, matRotate, (width, height*2))
  rows, cols = dst.shape[:2]

  for col in range(0, cols):
    if dst[:, col].any():
      left = col
      break

  for col in range(cols-1, 0, -1):
    if dst[:, col].any():
      right = col
      break

  for row in range(0, rows):
    if dst[row,:].any():
      up = row
      break

  for row in range(rows-1,0,-1):
    if dst[row,:].any():
      down = row
      break

  res_widths = abs(right - left)
  res_heights = abs(down - up)
  res = np.zeros([res_heights ,res_widths, 3], np.uint8)

  for res_width in range(res_widths):
    for res_height in range(res_heights):
      res[res_height, res_width] = dst[up+res_height, left+res_width]

  cv2.imshow('res',res)

  cv2.imshow('img',img)
  cv2.imshow('dst', dst)
  cv2.waitKey(0)

if __name__ =='__main__':
  main()