C++ BMP图片转换为PNG图片

#include <windows.h>  
#include <gdiplus.h>  
#include <stdio.h>  
using namespace Gdiplus; 

BOOL GetEncoderClsid(WCHAR* pFormat,CLSID* pClsid)
{
GdiplusStartupInput gdiplusStartupInput;
ULONG_PTR           gdiplusToken;
GdiplusStartup(&gdiplusToken, &gdiplusStartupInput, NULL);

UINT num = 0,size = 0;
        ImageCodecInfo* pImageCodecInfo = NULL;
GetImageEncodersSize(&num,&size);
if (size == 0)
{
return FALSE;
}
pImageCodecInfo = (Gdiplus::ImageCodecInfo*)(malloc(size));
if (pImageCodecInfo == NULL)
{
return FALSE;
}
GetImageEncoders(num,size,pImageCodecInfo);
BOOL bfound = FALSE;
for (UINT i = 0;!bfound && i < num;  i++)
{
if (_wcsicmp(pImageCodecInfo[i].MimeType,pFormat) == 0)
{
*pClsid = pImageCodecInfo[i].Clsid;
bfound = TRUE;
}
}
GdiplusShutdown(gdiplusToken);
free(pImageCodecInfo);
return bfound;
}


BOOL BMptoPNG(LPCWSTR StrBMp,LPCWSTR StrPNG)
{
GdiplusStartupInput gdiplusStartupInput;
ULONG_PTR           gdiplusToken;
Gdiplus::GdiplusStartup(&gdiplusToken, &gdiplusStartupInput, NULL);


CLSID encoderClsid;
Status stat;
Image* image = NULL;
image = Gdiplus::Bitmap::FromFile(StrBMp,TRUE);
if (!GetEncoderClsid(L"image/png",&encoderClsid))
{
return FALSE;
}
stat = image->Save(StrPNG,&encoderClsid,NULL);
if (stat != Gdiplus::Ok)
{
return FALSE;
}
//Gdiplus::GdiplusShutdown(gdiplusToken);
delete image;
return TRUE;
}