将 cv2 图像转换为 PySDL2 表面以进行位图传输到屏幕答案

【问题标题】：Converting cv2 images to PySDL2 surfaces for blitting to screen将 cv2 图像转换为 PySDL2 表面以进行位图传输到屏幕
【发布时间】：2019-08-21 23:33:55
【问题描述】：

我正在使用新的 PySDL2 包，试图将它与我现有的 OpenCV 代码接口。我想通过 cv2 python 接口从网络摄像头捕捉到 OpenCV 的图像，并使用 PySDL2 在屏幕上的窗口中显示它。我想我想出了如何正确地将 cv2 图像格式转换为 PySDL2 表面，但是在下面的代码末尾，我得到的只是一个黑色窗口。任何关于我出错的地方的指示将不胜感激！

#grab a frame from a webcam
import cv2
vc = cv2.VideoCapture(0)
junk,image = vc.read()

#convert image to sdl format (?)
import sdl2
sbuf = image.tostring()
simage = sdl2.SDL_CreateRGBSurfaceFrom(sbuf,image.shape[0],image.shape[1],24,3*image.shape[0],sdl2.SDL_PIXELFORMAT_BGRA8888,0xff0000, 0x00ff00, 0x0000ff, 0)

#create a window
sdl2.SDL_Init(sdl2.SDL_INIT_VIDEO)
windowSize = (640,480)
window = sdl2.SDL_CreateWindow(b"Hello World",sdl2.SDL_WINDOWPOS_CENTERED, sdl2.SDL_WINDOWPOS_CENTERED,windowSize[0], windowSize[1], sdl2.SDL_WINDOW_SHOWN)
windowSurface = sdl2.SDL_GetWindowSurface(window)

#try to blit the sdl-formatted image to the window
sdl2.SDL_BlitSurface(simage,None,windowSurface,None)
sdl2.SDL_UpdateWindowSurface(window)
sdl2.SDL_FreeSurface(simage)

# pump events to get the window to show and update
while True:
    sdl2.SDL_PumpEvents()

【问题讨论】：

标签： python opencv sdl pysdl2

【解决方案1】：

解决了！

#import necessary modules
import cv2
import sdl2
import sdl2.ext
import numpy

windowSize = (640,480)

#initialize the camera
vc = cv2.VideoCapture(0)
vc.set(cv2.cv.CV_CAP_PROP_FRAME_WIDTH, windowSize[0])
vc.set(cv2.cv.CV_CAP_PROP_FRAME_HEIGHT, windowSize[1])

#grab and show a first frame from the camera
junk,image = vc.read()
cv2.imshow('0',image)

#initialize sdl2
sdl2.ext.init()
window = sdl2.ext.Window("test", size=windowSize)
window.show()
windowSurf = sdl2.SDL_GetWindowSurface(window.window)
windowArray = sdl2.ext.pixels3d(windowSurf.contents)

while True: #keep reading to have a live feed from the cam
    junk,image = vc.read()
    image = numpy.insert(image,3,255,axis=2) #add alpha
    image = numpy.rot90(image) #rotate dims
    numpy.copyto(windowArray, image)
    window.refresh()

我不知道为什么需要使用 cv2.imshow 显示来自相机的第一帧，但没有这部分，sdl2 窗口永远不会出现。

【讨论】：

您忘记每帧轮询事件，导致窗口无法出现。 for event in sdl2.ext.get_events(): if event.type == sdl2.SDL_QUIT: exit()

【解决方案2】：

这条线可以帮助你：

windowArray[:,:,0:3] = img.swapaxes(0,1)

#!python3
import cv2
import sdl2
import sdl2.ext

def process_frame(img):
    # --- initialize
    sdl2.ext.init()
    window = sdl2.ext.Window("sdl",size=('width','height'))
    window.show()
    events = sdl2.ext.get_events()
    for event in events:
        if event.type == sdl2.SDL_QUIT:
            exit(0)
    # --- initialize
    windowArray = sdl2.ext.pixels3d(window.get_surface()) 

    # --- convert cv2 frame to sdl windowArray
    windowArray[:,:,0:3] = img.swapaxes(0,1)


vc = cv2.VideoCapture(0)     
while vc.isOpened():
    ret,frame = cap.read()
    if ret == True:
        process_frame(frame)
    else:
        break

【讨论】：

【解决方案3】：

我没有足够的声誉来添加评论，虽然它是很久以前的事了，希望这可以帮助某人，

您可以为创建窗口添加一个标志

window = sdl2.ext.Window("test", size=windowSize, flag=sdl2.SDL_WINDOW_SHOWN)

【讨论】：