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这篇文章主要介绍了C++如何实现截图截屏,具有一定借鉴价值,感兴趣的朋友可以参考下,希望大家阅读完这篇文章之后大有收获,下面让小编带着大家一起了解一下。
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。
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。
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
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; }
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);
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); }
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; }
QDesktopWidget *desk = QApplication::desktop(); QScreen * screen = QGuiApplication::primaryScreen(); QPixmap p = screen->grabWindow(desk->winId()); QImage image = p.toImage();
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