Temporary save Image in pygame

Question

I am making an image cropper using pygame as interface and opencv for image processing. I have created function like crop(), colorfilter() etc but i load image as pygame.image.load() to show it on screen but when i perform crop() it is numpy.ndarray and pygame cannot load it getting error:

argument 1 must be pygame.Surface, not numpy.ndarray

how do i solve this problem. i need to blit() the cropped image. should save image and read it then delete it after its done as i want to apply more than one filters.

Answer 1

The following function converts a OpenCV (cv2) image respectively a numpy.array (that's the same) to a pygame.Surface:

import numpy as np

def cv2ImageToSurface(cv2Image):
    if cv2Image.dtype.name == 'uint16':
        cv2Image = (cv2Image / 256).astype('uint8')
    size = cv2Image.shape[1::-1]
    if len(cv2Image.shape) == 2:
        cv2Image = np.repeat(cv2Image.reshape(size[1], size[0], 1), 3, axis = 2)
        format = 'RGB'
    else:
        format = 'RGBA' if cv2Image.shape[2] == 4 else 'RGB'
        cv2Image[:, :, [0, 2]] = cv2Image[:, :, [2, 0]]
    surface = pygame.image.frombuffer(cv2Image.flatten(), size, format)
    return surface.convert_alpha() if format == 'RGBA' else surface.convert()

See How do I convert an OpenCV (cv2) image (BGR and BGRA) to a pygame.Surface object for a detailed explanation of the function.