OPENCV 桌面捕捉第二部分

Question

从这里 OPENCV Destop Capture and this hwnd2mat 函数继续之前的 post，在 opencv 中捕获桌面作为源的方法是使用此 hwnd2mat 函数从屏幕图像创建位图。完毕。这个函数已经从屏幕上创建了一个位图 image.but 它产生了奇怪的效果，比如视频中的拖尾，我只想要一个更可能像 this one 的普通视频源。我已经尝试找出导致它的原因，但我不知道了。

#include "opencv2/imgproc.hpp"
#include "opencv2/highgui.hpp"
#include <Windows.h>
#include <iostream>

using namespace std;
using namespace cv;

Mat hwnd2mat(HWND hwnd)
{
    HDC hwindowDC, hwindowCompatibleDC;

    int height, width, srcheight, srcwidth;
    HBITMAP hbwindow;
    Mat src;
    BITMAPINFOHEADER  bi;

    hwindowDC = GetDC(hwnd);
    hwindowCompatibleDC = CreateCompatibleDC(hwindowDC);
    SetStretchBltMode(hwindowCompatibleDC, COLORONCOLOR);

    RECT windowsize;    // get the height and width of the screen
    GetClientRect(hwnd, &windowsize);

    srcheight = windowsize.bottom;
    srcwidth = windowsize.right;
    height = windowsize.bottom / 1;  //change this to whatever size you want to resize to
    width = windowsize.right / 1;

    src.create(height, width, CV_8UC4);

    // create a bitmap
    hbwindow = CreateCompatibleBitmap(hwindowDC, width, height);
    bi.biSize = sizeof(BITMAPINFOHEADER);    //http://msdn.microsoft.com/en-us/library/windows/window/dd183402%28v=vs.85%29.aspx
    bi.biWidth = width;
    bi.biHeight = -height;  //this is the line that makes it draw upside down or not
    bi.biPlanes = 1;
    bi.biBitCount = 32;
    bi.biCompression = BI_RGB;
    bi.biSizeImage = 0;
    bi.biXPelsPerMeter = 0;
    bi.biYPelsPerMeter = 0;
    bi.biClrUsed = 0;
    bi.biClrImportant = 0;

    // use the previously created device context with the bitmap
    SelectObject(hwindowCompatibleDC, hbwindow);
    // copy from the window device context to the bitmap device context
    StretchBlt(hwindowCompatibleDC, 0, 0, width, height, hwindowDC, 0, 0, srcwidth, srcheight, SRCCOPY); //change SRCCOPY to NOTSRCCOPY for wacky colors !
    GetDIBits(hwindowCompatibleDC, hbwindow, 0, height, src.data, (BITMAPINFO *)&bi, DIB_RGB_COLORS);  //copy from hwindowCompatibleDC to hbwindow

    // avoid memory leak
    DeleteObject(hbwindow);
    DeleteDC(hwindowCompatibleDC);
    ReleaseDC(hwnd, hwindowDC);

    return src;
}

int main(int argc, char **argv)
{
    HWND hwndDesktop = GetDesktopWindow();
    namedWindow("output", CV_WINDOW_NORMAL);
    int key = 0;

    while (key != 30 )
    {
        Mat src = hwnd2mat(hwndDesktop);        
        // you can do some image processing here
        imshow("output", src);
        key = waitKey(30); // you can change wait time
    }
    ReleaseCapture();
    destroyAllWindows();
    return 0;
}

Answer 1

使用 GetDesktopWindow() 将产生无限镜像效果，相反，使用 window 你想要捕获的内容，而我，我正在使用 FindWindowEx()，并使用 Spy++ 查找 window 你想捕获，应该可以。但当然会转到下一个错误:)。

OPENCV 桌面捕捉第二部分

OPENCV desktop capture Part II

c++

opencv

video-capture

bitmap

visual-studio-2013