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C++实现截图截屏的示例代码

2024-04-02 19:55

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1、截图工具

1.1 键盘截图(PrtScn键)

如何使用Microsoft Windows操作系统中的Print Screen(打印屏幕)键
(1)Print Screen键
按下之后,截取整个屏幕的画面到剪切板里。可以复制到其他软件里,比如系统的画图工具,Office Word等。

(2)Alt+Print Screen组合键
按下之后,截取当前活动窗口的画面到剪切板里。

在这里插入图片描述

1.2 win10自带截图(Win+Shift+S)

在这里插入图片描述

按下该组合键之后,使用鼠标在屏幕上画出想要截取的矩形区域,自动保存到系统剪切板里。

1.3 系统自带的截图小工具

在这里插入图片描述

1.4 ffmpeg

ffmpeg -i “输入视频” -fflags nobuffer -t 60 -ss 0 “输出地址”
说明:代表截取输入视频从0秒到60秒的片段,保存到输出地址。
-ss n : 起始时间为第n秒
-t n : 总共截取的片段时长为n秒

运行后会生成截图: out1.jpg out2.jpg out3.jpg …


ffmpeg -i fight.mp4 -r 1 -t 200 -ss 1 -f image2 out%d.jpg

1.5 ScreenToGif

在这里插入图片描述

1.6 Chrome

在这里插入图片描述

2、C++、GDI

2.1 微软官方例子

https://docs.microsoft.com/en-us/windows/win32/gdi/capturing-an-image


int CaptureAnImage(HWND hWnd)
{
    HDC hdcScreen;
    HDC hdcWindow;
    HDC hdcMemDC = NULL;
    HBITMAP hbmScreen = NULL;
    BITMAP bmpScreen;
    DWORD dwBytesWritten = 0;
    DWORD dwSizeofDIB = 0;
    HANDLE hFile = NULL;
    char* lpbitmap = NULL;
    HANDLE hDIB = NULL;
    DWORD dwBmpSize = 0;

    // Retrieve the handle to a display device context for the client 
    // area of the window. 
    hdcScreen = GetDC(NULL);
    hdcWindow = GetDC(hWnd);

    // Create a compatible DC, which is used in a BitBlt from the window DC.
    hdcMemDC = CreateCompatibleDC(hdcWindow);

    if (!hdcMemDC)
    {
        MessageBox(hWnd, L"CreateCompatibleDC has failed", L"Failed", MB_OK);
        goto done;
    }

    // Get the client area for size calculation.
    RECT rcClient;
    GetClientRect(hWnd, &rcClient);

    // This is the best stretch mode.
    SetStretchBltMode(hdcWindow, HALFTONE);

    // The source DC is the entire screen, and the destination DC is the current window (HWND).
    if (!StretchBlt(hdcWindow,
        0, 0,
        rcClient.right, rcClient.bottom,
        hdcScreen,
        0, 0,
        GetSystemMetrics(SM_CXSCREEN),
        GetSystemMetrics(SM_CYSCREEN),
        SRCCOPY))
    {
        MessageBox(hWnd, L"StretchBlt has failed", L"Failed", MB_OK);
        goto done;
    }

    // Create a compatible bitmap from the Window DC.
    hbmScreen = CreateCompatibleBitmap(hdcWindow, rcClient.right - rcClient.left, rcClient.bottom - rcClient.top);

    if (!hbmScreen)
    {
        MessageBox(hWnd, L"CreateCompatibleBitmap Failed", L"Failed", MB_OK);
        goto done;
    }

    // Select the compatible bitmap into the compatible memory DC.
    SelectObject(hdcMemDC, hbmScreen);

    // Bit block transfer into our compatible memory DC.
    if (!BitBlt(hdcMemDC,
        0, 0,
        rcClient.right - rcClient.left, rcClient.bottom - rcClient.top,
        hdcWindow,
        0, 0,
        SRCCOPY))
    {
        MessageBox(hWnd, L"BitBlt has failed", L"Failed", MB_OK);
        goto done;
    }

    // Get the BITMAP from the HBITMAP.
    GetObject(hbmScreen, sizeof(BITMAP), &bmpScreen);

    BITMAPFILEHEADER   bmfHeader;
    BITMAPINFOHEADER   bi;

    bi.biSize = sizeof(BITMAPINFOHEADER);
    bi.biWidth = bmpScreen.bmWidth;
    bi.biHeight = bmpScreen.bmHeight;
    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;

    dwBmpSize = ((bmpScreen.bmWidth * bi.biBitCount + 31) / 32) * 4 * bmpScreen.bmHeight;

    // Starting with 32-bit Windows, GlobalAlloc and LocalAlloc are implemented as wrapper functions that 
    // call HeapAlloc using a handle to the process's default heap. Therefore, GlobalAlloc and LocalAlloc 
    // have greater overhead than HeapAlloc.
    hDIB = GlobalAlloc(GHND, dwBmpSize);
    lpbitmap = (char*)GlobalLock(hDIB);

    // Gets the "bits" from the bitmap, and copies them into a buffer 
    // that's pointed to by lpbitmap.
    GetDIBits(hdcWindow, hbmScreen, 0,
        (UINT)bmpScreen.bmHeight,
        lpbitmap,
        (BITMAPINFO*)&bi, DIB_RGB_COLORS);

    // A file is created, this is where we will save the screen capture.
    hFile = CreateFile(L"captureqwsx.bmp",
        GENERIC_WRITE,
        0,
        NULL,
        CREATE_ALWAYS,
        FILE_ATTRIBUTE_NORMAL, NULL);

    // Add the size of the headers to the size of the bitmap to get the total file size.
    dwSizeofDIB = dwBmpSize + sizeof(BITMAPFILEHEADER) + sizeof(BITMAPINFOHEADER);

    // Offset to where the actual bitmap bits start.
    bmfHeader.bfOffBits = (DWORD)sizeof(BITMAPFILEHEADER) + (DWORD)sizeof(BITMAPINFOHEADER);

    // Size of the file.
    bmfHeader.bfSize = dwSizeofDIB;

    // bfType must always be BM for Bitmaps.
    bmfHeader.bfType = 0x4D42; // BM.

    WriteFile(hFile, (LPSTR)&bmfHeader, sizeof(BITMAPFILEHEADER), &dwBytesWritten, NULL);
    WriteFile(hFile, (LPSTR)&bi, sizeof(BITMAPINFOHEADER), &dwBytesWritten, NULL);
    WriteFile(hFile, (LPSTR)lpbitmap, dwBmpSize, &dwBytesWritten, NULL);

    // Unlock and Free the DIB from the heap.
    GlobalUnlock(hDIB);
    GlobalFree(hDIB);

    // Close the handle for the file that was created.
    CloseHandle(hFile);

    // Clean up.
done:
    DeleteObject(hbmScreen);
    DeleteObject(hdcMemDC);
    ReleaseDC(NULL, hdcScreen);
    ReleaseDC(hWnd, hdcWindow);

    return 0;
}

2.2 C++、GDI、CImage


HDC hdcSrc = GetDC(NULL);
int nBitPerPixel = GetDeviceCaps(hdcSrc, BITSPIXEL);
int nWidth = GetDeviceCaps(hdcSrc, HORZRES);
int nHeight = GetDeviceCaps(hdcSrc, VERTRES);
CImage image;
image.Create(nWidth, nHeight, nBitPerPixel);
BitBlt(image.GetDC(), 0, 0, nWidth, nHeight, hdcSrc, 0, 0, SRCCOPY);
ReleaseDC(NULL, hdcSrc);
image.ReleaseDC();
image.Save(s, Gdiplus::ImageFormatPNG);

3、C++、OpenGL


void CaptureOpenGLWindow(const char* savePath, int w, int h)
{
	GLubyte* pPixelData; 
	GLint    PixelDataLength;  

	// 分配内存和打开文件
	pPixelData = (GLubyte*)malloc(w*h*3);
	if (pPixelData == 0)
		return;
	
	glPixelStorei(GL_UNPACK_ALIGNMENT, 4); 
	glReadPixels(0, 0, w, h, GL_RGB, GL_UNSIGNED_BYTE, pPixelData);
	stbi_write_png(savePath, w, h, 3, pPixelData, 0);
	free(pPixelData);

	int iw = w, ih = h, n = 3;
	stbi_set_flip_vertically_on_load(true);
	unsigned char *idata = stbi_load(savePath, &iw, &ih, &n, 0);
	stbi_write_png(savePath, w, h, 3, idata, 0);
	stbi_image_free(idata);

}

4、C++、OpenCV


BITMAPINFOHEADER createBitmapHeader(int width, int height)
{
   BITMAPINFOHEADER  bi;

     // create a bitmap
     bi.biSize = sizeof(BITMAPINFOHEADER);
     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;

     return bi;
}

Mat captureScreenMat(HWND hwnd)
{
     Mat src;

     // get handles to a device context (DC)
     HDC hwindowDC = GetDC(hwnd);
     HDC hwindowCompatibleDC = CreateCompatibleDC(hwindowDC);
     SetStretchBltMode(hwindowCompatibleDC, COLORONCOLOR);

     // define scale, height and width
     int screenx = GetSystemMetrics(SM_XVIRTUALSCREEN);
     int screeny = GetSystemMetrics(SM_YVIRTUALSCREEN);
     int width = GetSystemMetrics(SM_CXVIRTUALSCREEN);
     int height = GetSystemMetrics(SM_CYVIRTUALSCREEN);

     // create mat object
     src.create(height, width, CV_8UC4);

     // create a bitmap
     HBITMAP hbwindow = CreateCompatibleBitmap(hwindowDC, width, height);
     BITMAPINFOHEADER bi = createBitmapHeader(width, height);

     // 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, screenx, screeny, width, height, 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()
{
      // capture image
      HWND hwnd = GetDesktopWindow();
      Mat src = captureScreenMat(hwnd);

      // save img
      cv::imwrite("Screenshot.png", src);

  	  // clean-ups
      buf.clear();
      return 0;
}

5、C++、QT


QDesktopWidget *desk = QApplication::desktop();
QScreen * screen = QGuiApplication::primaryScreen();
QPixmap p = screen->grabWindow(desk->winId());
QImage image = p.toImage();

到此这篇关于C++实现截图截屏的示例代码的文章就介绍到这了,更多相关C++ 截图截屏内容请搜索编程网以前的文章或继续浏览下面的相关文章希望大家以后多多支持编程网!

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