如何将 OpenCV (cv2) 图像（BGR 和 BGRA）转换为 pygame.Surface 对象

Question

我从 OpenCV/opencv-python (numpy.array) and I want to convert them to a pygame.Surface 对象创建图像：

def cv2ImageToSurface(cv2Image):

    pygameSurface = # ? create from "cv2Image"

    return pygameSurface 

surface = cv2ImageToSurface(cv2Image)

一些图像有 3 个通道 (BGR)，一些图像也有一个 alpha 通道 (BGRA)。在 cv2ImageToSurface 中我需要做什么才能将其中一种格式的图像转换为 pygame.Surface 对象？

Answer 1

numpy.array 的 shape 属性是每个维度中的元素数。第一个元素是高度，第二个元素是宽度，第三个元素是通道数。
一个pygame.Surface can be generated by pygame.image.frombuffer。第一个参数可以是 numpy.array，第二个参数是格式（RGB 或 RGBA）。

通过切片获取pygame.Surface对象的大小（宽度、高度）：

size = cv2Image.shape[1::-1]

根据第三个通道确定pygame.Surface对象的目标格式：

format = 'RGBA' if cv2Image.shape[2] == 4 else 'RGB'

由于源格式为BGR或BGRA，但目标格式为RGB或RGBA，必须交换红色和蓝色通道：

cv2Image[:, :, [0, 2]] = cv2Image[:, :, [2, 0]]

在灰度图像的情况下，必须使用 numpy.reshape and the gray channel must be expanded to a red-green and blue color channel using numpy.repeat 更改数组的形状：

cv2Image = np.repeat(cv2Image.reshape(size[1], size[0], 1), 3, axis = 2)

根据他的数据，pygame.Surface 对象可以通过 pygame.image.frombuffer:

生成

surface = pygame.image.frombuffer(cv2Image.flatten(), size, format)

为确保图像具有与显示器 Surface 相同的像素格式并获得最佳性能，应将 Surface 转换为convert or convert_alpha:

surface = surface.convert_alpha() if format == 'RGBA' else surface.convert()

完整功能cv2ImageToSurface:

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()

最小示例：

import os
import pygame
import cv2
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()

pygame.init()
window = pygame.display.set_mode((400, 400))
clock = pygame.time.Clock()

cv2Image1 = cv2.imread('woodtiles.jpg', cv2.IMREAD_GRAYSCALE)
cv2Image2 = cv2.imread('woodtiles.jpg', cv2.IMREAD_UNCHANGED)
cv2Image3 = cv2.imread('Apple1-256.png', cv2.IMREAD_UNCHANGED)
pygameSurface1 = cv2ImageToSurface(cv2Image1)
pygameSurface2 = cv2ImageToSurface(cv2Image2)
pygameSurface3 = cv2ImageToSurface(cv2Image3)

run = True
while run:
    clock.tick(60)
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            run = False

    window.fill(0)
    window.blit(pygameSurface1, pygameSurface1.get_rect(topleft = window.get_rect().inflate(-10, -10).topleft))
    window.blit(pygameSurface2, pygameSurface2.get_rect(center = window.get_rect().center))
    window.blit(pygameSurface3, pygameSurface3.get_rect(bottomright = window.get_rect().inflate(-10, -10).bottomright))
    pygame.display.flip()

pygame.quit()

如何将 OpenCV (cv2) 图像（BGR 和 BGRA）转换为 pygame.Surface 对象

How do I convert an OpenCV (cv2) image (BGR and BGRA) to a pygame.Surface object

python

pygame

numpy

pygame-surface

cv2