C++ - Take Screenshot of the Windows Desktop using GDI+

Here is the complete C++ source code for taking screenshot in Windows:

#include <iostream>
#include <string>
#include <windows.h>
#include <gdiplus.h>

#pragma comment(lib, "gdiplus.lib")

using namespace std;
using namespace Gdiplus;

int GetEncoderClsid(WCHAR *format, CLSID *pClsid)
{
    unsigned int num = 0,  size = 0;
    GetImageEncodersSize(&num, &size);
    if(size == 0) return -1;
    ImageCodecInfo *pImageCodecInfo = (ImageCodecInfo *)(malloc(size));
    if(pImageCodecInfo == NULL) return -1;
    GetImageEncoders(num, size, pImageCodecInfo);
 
    for (unsigned int j = 0; j < num; ++j) {
        if(wcscmp(pImageCodecInfo[j].MimeType, format) == 0) {
            *pClsid = pImageCodecInfo[j].Clsid;
            free(pImageCodecInfo);
            return j;
        }  
    }
    free(pImageCodecInfo);
    return -1;
}

int SaveScreenshot(string filename, ULONG uQuality) // by Napalm
{
    ULONG_PTR gdiplusToken;
    GdiplusStartupInput gdiplusStartupInput;
    GdiplusStartup(&gdiplusToken, &gdiplusStartupInput, NULL);
    HWND hMyWnd = GetDesktopWindow();
    RECT r;
    int w, h;
    HDC dc, hdcCapture;
    int nBPP, nCapture, iRes;
    LPBYTE lpCapture;
    CLSID imageCLSID;
    Bitmap *pScreenShot;
 
    // get the area of my application's window    
    GetWindowRect(hMyWnd, &r);
    dc = GetWindowDC(hMyWnd);   // GetDC(hMyWnd) ;
    w = r.right - r.left;
    h = r.bottom - r.top;
    nBPP = GetDeviceCaps(dc, BITSPIXEL);
    hdcCapture = CreateCompatibleDC(dc);

    // create the buffer for the screenshot
    BITMAPINFO bmiCapture = { sizeof(BITMAPINFOHEADER), w, -h, 1, nBPP, BI_RGB, 0, 0, 0, 0, 0, };

    // create a container and take the screenshot
    HBITMAP hbmCapture = CreateDIBSection(dc, &bmiCapture, DIB_PAL_COLORS, (LPVOID *)&lpCapture, NULL, 0);

    // failed to take it
    if (!hbmCapture) {
        DeleteDC(hdcCapture);
        DeleteDC(dc);
        GdiplusShutdown(gdiplusToken);
        printf("failed to take the screenshot. err: %d\n", GetLastError());
        return 0;
    }

    // copy the screenshot buffer
    nCapture = SaveDC(hdcCapture);
    SelectObject(hdcCapture, hbmCapture);
    BitBlt(hdcCapture, 0, 0, w, h, dc, 0, 0, SRCCOPY);
    RestoreDC(hdcCapture, nCapture);
    DeleteDC(hdcCapture);
    DeleteDC(dc);

    // save the buffer to a file  
    pScreenShot = new Bitmap(hbmCapture, (HPALETTE)NULL);
    EncoderParameters encoderParams;
    encoderParams.Count = 1;
    encoderParams.Parameter[0].NumberOfValues = 1;
    encoderParams.Parameter[0].Guid  = EncoderQuality;
    encoderParams.Parameter[0].Type  = EncoderParameterValueTypeLong;
    encoderParams.Parameter[0].Value = &uQuality;
    GetEncoderClsid(L"image/jpeg", &imageCLSID);

    wchar_t *lpszFilename = new wchar_t[filename.length() + 1];
    mbstowcs( lpszFilename, filename.c_str(), filename.length() + 1);
 
    iRes = (pScreenShot->Save(lpszFilename, &imageCLSID, &encoderParams) == Ok);
    delete pScreenShot;
    DeleteObject(hbmCapture);
    GdiplusShutdown(gdiplusToken);
    return iRes;
}

// Example program code:

int main() {
    string path = "screenshot.jpg";
    ULONG quality = 100;
    SaveScreenshot(path, quality);
 
    return 0;
}

If you have any problem running this code, please comment below. I will be glad to help you out.

Tags: screenshot in C++, screenshot using gdiplus, gdiplus library