VC6.0中gdiPlus的使用以及一个bmp转jpg的小例子

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VC6.0中gdiPlus的使用以及一个bmp转jpg的小例子

http://mingarlic.blog.163.com/blog/static/31148911200710261318324/

#include <GdiPlus.h>

using namespace Gdiplus;

GdiplusStartupInput m_gdiplusStartupInput;
ULONG_PTR m_gdiplusToken;

int GetEncoderClsid(const WCHAR* format, CLSID* pClsid);

void BMP2JPG(CString strBMPFile,CString strJPGFile);

GdiplusStartup(&m_gdiplusToken, &m_gdiplusStartupInput, NULL);

BMP2JPG("...","...");

GdiplusShutdown(m_gdiplusToken);

int GetEncoderClsid(const WCHAR* format, CLSID* pClsid)
{
UINT num = 0; // number of image encoders
UINT size = 0; // size of the image encoder array in bytes

ImageCodecInfo* pImageCodecInfo = NULL;

GetImageEncodersSize(&num, &size);
if(size == 0)
return -1; // Failure

pImageCodecInfo = (ImageCodecInfo*)(malloc(size));
if(pImageCodecInfo == NULL)
return -1; // Failure

GetImageEncoders(num, size, pImageCodecInfo);

for(UINT j = 0; j < num; ++j)
{
if( wcscmp(pImageCodecInfo[j].MimeType, format) == 0 )
{
*pClsid = pImageCodecInfo[j].Clsid;
free(pImageCodecInfo);
return j; // Success
}
}

free(pImageCodecInfo);
return -1; // Failure
}

void BMP2JPG(CString strBMPFile,CString strJPGFile)
{
CLSID encoderClsid;
WCHAR strGuid[39];
if(GetEncoderClsid(L"image/jpeg", &encoderClsid) >= 0)
StringFromGUID2(encoderClsid, strGuid, 39);

Image image(strBMPFile.AllocSysString());
image.Save(strJPGFile.AllocSysString(),&encoderClsid,NULL);

}

//在GDI+中，需要定义一个ULONG_PTR。

#ifndef ULONG_PTR

#define ULONG_PTR unsigned long*

#endif