使用CreateMetaFile创建WMF文件，并转换为EMF文件

#include <iostream>
#include <stdio.h>
#include <WINDOWS.H>
#include <shellapi.h>
#include <gdiplus.h>
#include <Shlwapi.h>


#pragma comment (lib,"Shlwapi.lib")
#pragma comment(lib,"gdiplus.lib")
#pragma comment(lib, "shell32.lib")

using namespace Gdiplus;

int main(int argc, char **argv)
{
    static HMETAFILE hmf;
    static int       cxClient, cyClient;
    HBRUSH           hBrush;
    HDC              hdcMeta;

    METAFILEPICT mp;
    HDC hDC;
    BYTE* buffer;
    GdiplusStartupInput gdiplusStartupInput;
    ULONG_PTR gdiplusToken;
    GdiplusStartup(&gdiplusToken, &gdiplusStartupInput, NULL);


    hdcMeta = CreateMetaFile("12_.WMF");
    hBrush = CreateSolidBrush(RGB(0, 0, 255));

    Rectangle(hdcMeta, 0, 0, 100, 100);

    MoveToEx(hdcMeta, 0, 0, NULL);
    LineTo(hdcMeta, 100, 100);
    MoveToEx(hdcMeta, 0, 100, NULL);
    LineTo(hdcMeta, 100, 0);

    SelectObject(hdcMeta, hBrush);
    Ellipse(hdcMeta, 20, 20, 80, 80);
    hmf = CloseMetaFile(hdcMeta);
    UINT nSize = GetMetaFileBitsEx(hmf, 0, NULL);

    buffer = (BYTE*)malloc(nSize);int err_1 = GetLastError();

    UINT bytesCopy = GetMetaFileBitsEx(hmf, nSize, buffer);

    HENHMETAFILE hEMF = SetWinMetaFileBits(nSize, buffer, NULL, NULL);

    int err_2 = GetLastError();

    HENHMETAFILE newHEMF = CopyEnhMetaFile(hEMF, "new EMF.emf");

    DeleteMetaFile(hmf);

    GdiplusShutdown(gdiplusToken);
    return 0;
}

GetMetaFileBitsEx需要调用两次，第二次调用是为了填充buffer缓冲区