python ggplot，python cv2 opencv 圖片旋轉

import cv2
import numpy as npdef opencv_rotate(img, angle):"""圖片旋轉，默認應該是逆時針轉動:param img::param angle::return:"""h, w = img.shape[:2]  # 圖像的（行數，列數，色彩通道數）borderValue = (0, 0, 0, 0)# 顏色空間轉換?if img.shape[-1] == 3:img = cv2.cvtColor(img, cv2.COLOR_BGR2BGRA)elif img.shape[-1] == 1:img = cv2.cvtColor(img, cv2.COLOR_GRAY2BGR)center = (w / 2, h / 2)scale = 1.0# 2.1獲取M矩陣"""M矩陣[cosA -sinA (1-cosA)*centerX+sinA*centerYsinA cosA  -sinA*centerX+(1-cosA)*centerY]"""# cv2.getRotationMatrix2D(獲得仿射變化矩陣)M = cv2.getRotationMatrix2D(center, angle, scale)# 2.2 新的寬高，radians(angle) 把角度轉為弧度 sin(弧度)new_H = int(w * np.fabs(np.sin(np.radians(angle))) + h * np.fabs(np.cos(np.radians(angle))))new_W = int(h * np.fabs(np.sin(np.radians(angle))) + w * np.fabs(np.cos(np.radians(angle))))# 2.3 平移M[0, 2] += (new_W - w) / 2M[1, 2] += (new_H - h) / 2# cv2.warpAffine(進行仿射變化)rotate = cv2.warpAffine(img, M, (new_W, new_H), borderValue=borderValue)return rotateif __name__ == "__main__":img = cv2.imread('./xiaowei.png')# 顯示圖片查看# cv2.imshow('imshow', img)# cv2.waitKey(1)# cv2.destroyAllWindows()# 顯示圖片查看angle = -45res = opencv_rotate(img, angle)cv2.imwrite('./after.png', res)# print(f"res = {res}")