Windows窗口截图

#include <Windows.h>
#include <gdiplus.h>
#include <stdio.h>

const Gdiplus::GdiplusStartupInput kGdiplusStartupInput;
const CLSID kPngEncoderId = { 0x557CF406, 0x1A04, 0x11D3, { 0x9A, 0x73, 0x00, 0x00, 0xF8, 0x1E, 0xF3, 0x2E } };

int main()
{
    ULONG_PTR hGdiplus;
    if (Gdiplus::GdiplusStartup(&hGdiplus, &kGdiplusStartupInput, nullptr) != Gdiplus::Status::Ok)
    {
        puts("GdiplusStartup() fail.");
        exit(1);
    }
    HWND hwd;
    scanf("%p", &hwd);
    if (!SetForegroundWindow(hwd))
    {
        puts("SetForegroundWindow() fail.");
        exit(1);
    }
    HDC hdc = GetDC(hwd);
    if (!hdc)
    {
        puts("GetDC() fail.");
        exit(1);
    }
    HDC hdd = CreateCompatibleDC(hdc);
    if (!hdd)
    {
        puts("CreateCompatibleDC() fail.");
        exit(1);
    }
    RECT rt;
    if (!GetWindowRect(hwd, &rt))
    {
        puts("GetWindowRect() fail.");
        exit(1);
    }
    int cx = rt.right - rt.left;
    int cy = rt.bottom - rt.top;
    HBITMAP hbm = CreateCompatibleBitmap(hdc, cx, cy);
    if (!hbm)
    {
        puts("CreateCompatibleBitmap() fail.");
        exit(1);
    }
    SelectObject(hdd, hbm);
    if (!PrintWindow(hwd, hdd, 0))
    {
        puts("PrintWindow() fail.");
        exit(1);
    }
    Gdiplus::Bitmap bitmap(hbm, nullptr);
    if (bitmap.Save(L"Screen Shot.png", &kPngEncoderId) != Gdiplus::Status::Ok)
    {
        puts("Bitmap::Save() fail.");
        exit(1);
    }
    DeleteDC(hdd);
    DeleteDC(hdc);
    Gdiplus::GdiplusShutdown(hGdiplus);
}