如何将 OpenCV (cv2) 图像(BGR 和 BGRA)转换为 pygame.Surface 对象 [英] How do I convert an OpenCV (cv2) image (BGR and BGRA) to a pygame.Surface object
问题描述
我从
import os导入pygame导入 cv2将 numpy 导入为 npdef cv2ImageToSurface(cv2Image):如果 cv2Image.dtype.name == 'uint16':cv2Image = (cv2Image/256).astype('uint8')大小 = cv2Image.shape[1::-1]如果 len(cv2Image.shape) == 2:cv2Image = np.repeat(cv2Image.reshape(size[1], size[0], 1), 3,axis = 2)格式 = 'RGB'别的:格式 = 'RGBA' 如果 cv2Image.shape[2] == 4 else 'RGB'cv2Image[:, :, [0, 2]] = cv2Image[:, :, [2, 0]]表面 = pygame.image.frombuffer(cv2Image.flatten(), size, format)返回surface.convert_alpha() if format == 'RGBA' else surface.convert()pygame.init()窗口 = pygame.display.set_mode((400, 400))时钟 = 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)运行 = 真运行时:时钟滴答(60)对于 pygame.event.get() 中的事件:如果 event.type == pygame.QUIT:运行 = 错误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()
I created images from OpenCV/opencv-python (numpy.array
) and I want to convert them to a pygame.Surface
object:
def cv2ImageToSurface(cv2Image):
pygameSurface = # ? create from "cv2Image"
return pygameSurface
surface = cv2ImageToSurface(cv2Image)
Some of the images have 3 channels (BGR) and some of the images also have an alpha channel (BGRA). What do I have to do in cv2ImageToSurface
to convert images with one of the formats into a pygame.Surface
object?
The shape
attribute of a numpy.array
is the number of elements in each dimension. The first element is the height, the second the width and the third the number of channels.
A pygame.Surface
can be generated by pygame.image.frombuffer
. The 1st argument can be a numpy.array
and the 2nd argument is the format (RGB
or RGBA
).
Get the size (widht, height) for the pygame.Surface
object by slicing:
size = cv2Image.shape[1::-1]
Determine the target format for the pygame.Surface
object, depending on the third channel:
format = 'RGBA' if cv2Image.shape[2] == 4 else 'RGB'
Since the source format is BGR or BGRA, but the target format is RGB or RGBA, the red and blue channels have to be swapped:
cv2Image[:, :, [0, 2]] = cv2Image[:, :, [2, 0]]
In the case of a grayscale image, the shape of the array must be changed using numpy.reshape
and the gray channel must be expanded to a red-green and blue color channel using numpy.repeat
:
cv2Image = np.repeat(cv2Image.reshape(size[1], size[0], 1), 3, axis = 2)
With his data the pygame.Surface
object can be generated by pygame.image.frombuffer
:
surface = pygame.image.frombuffer(cv2Image.flatten(), size, format)
To ensure that the image has the same pixel format as the display Surface and for optimal performance, the Surface should be converted with either convert
or convert_alpha
:
surface = surface.convert_alpha() if format == 'RGBA' else surface.convert()
Complete function 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()
Minimal example:
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()
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