C++实现截图截屏的示例代码_C/C++

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。

C++实现截图截屏的示例代码

1.2 win10自带截图(Win+Shift+S)

C++实现截图截屏的示例代码

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

C++实现截图截屏的示例代码

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

C++实现截图截屏的示例代码

1.6 Chrome

C++实现截图截屏的示例代码

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();

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原文链接：https://blog.csdn.net/hhy321/article/details/121548612