Python+OpenCV+图片旋转并用原底色填充新四角

import cv2

from math import fabs, sin, cos, radians

import numpy as np

from scipy.stats import mode

def get_img_rot_broa(img, degree=45, filled_color=-1):

    """

    Desciption:

            Get img rotated a certain degree,

        and use some color to fill 4 corners of the new img.

    """

    # 获取旋转后4角的填充色

    if filled_color == -1:

        filled_color = mode([img[0, 0], img[0, -1],

                             img[-1, 0], img[-1, -1]]).mode[0]

    if np.array(filled_color).shape[0] == 2:

        if isinstance(filled_color, int):

            filled_color = (filled_color, filled_color, filled_color)

    else:

        filled_color = tuple([int(i) for i in filled_color])

    height, width = img.shape[:2]

    # 旋转后的尺寸

    height_new = int(width * fabs(sin(radians(degree))) +

                     height * fabs(cos(radians(degree))))

    width_new = int(height * fabs(sin(radians(degree))) +

                    width * fabs(cos(radians(degree))))

    mat_rotation = cv2.getRotationMatrix2D((width / 2, height / 2), degree, 1)

    mat_rotation[0, 2] += (width_new - width) / 2

    mat_rotation[1, 2] += (height_new - height) / 2

    # Pay attention to the type of elements of filler_color, which should be

    # the int in pure python, instead of those in numpy.

    img_rotated = cv2.warpAffine(img, mat_rotation, (width_new, height_new),

                                 borderValue=filled_color)

    # 填充四个角

    mask = np.zeros((height_new + 2, width_new + 2), np.uint8)

    mask[:] = 0

    seed_points = [(0, 0), (0, height_new - 1), (width_new - 1, 0),

                   (width_new - 1, height_new - 1)]

    for i in seed_points:

        cv2.floodFill(img_rotated, mask, i, filled_color)

    return img_rotated
巴特西

Python+OpenCV+图片旋转并用原底色填充新四角

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