python-如何调整图像大小并保持宽高比

ratio = math.hypot(x2 - x1, y2 - y1) / math.hypot(x4 - x3, y4 - y3)
print("img1", math.hypot(x2 - x1, y2 - y1),"img 2", math.hypot(x4 - x3, y4 - y3)*ratio)

n = int(ratio * new_img_2.shape[0])
img = cv2.resize(new_img_2, (n, n), cv2.INTER_CUBIC)

import cv2

# Resizes a image and maintains aspect ratio
def maintain_aspect_ratio_resize(image, width=None, height=None, inter=cv2.INTER_AREA):
    # Grab the image size and initialize dimensions
    dim = None
    (h, w) = image.shape[:2]

    # Return original image if no need to resize
    if width is None and height is None:
        return image

    # We are resizing height if width is none
    if width is None:
        # Calculate the ratio of the height and construct the dimensions
        r = height / float(h)
        dim = (int(w * r), height)
    # We are resizing width if height is none
    else:
        # Calculate the ratio of the 0idth and construct the dimensions
        r = width / float(w)
        dim = (width, int(h * r))

    # Return the resized image
    return cv2.resize(image, dim, interpolation=inter)

if __name__ == '__main__':
    image = cv2.imread('../color_palette.jpg')
    cv2.imshow('image', image)
    cv2.waitKey(0)

    resized = maintain_aspect_ratio_resize(image, width=400)
    cv2.imshow('resized', resized)
    cv2.waitKey(0)

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