利用GDI+图片格式转换(例如BMP转PNG)

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

#pragma comment(lib,"gdiplus")

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;

   //2.获取GDI+支持的图像格式编码器种类数以及ImageCodecInfo数组的存放大小
   GetImageEncodersSize(&num, &size);
   if(size == 0)
      return -1; // Failure

   //3.为ImageCodecInfo数组分配足额空间
   pImageCodecInfo = (ImageCodecInfo*)(malloc(size));
   if(pImageCodecInfo == NULL)
      return -1; // Failure

   //4.获取所有的图像编码器信息
   GetImageEncoders(num, size, pImageCodecInfo);

   //5.查找符合的图像编码器的Clsid
   for(UINT j = 0; j < num; ++j)
   {
      if( wcscmp(pImageCodecInfo[j].MimeType, format) == 0 )
      {
         *pClsid = pImageCodecInfo[j].Clsid;
         free(pImageCodecInfo);
         return j; // Success
      }
   }

   //6.释放步骤3分配的内存
   free(pImageCodecInfo);
   return -1; // Failure
}

INT main()
{
   GdiplusStartupInput gdiplusStartupInput;
   ULONG_PTR gdiplusToken;

   //1.初始化GDI+，以便后续的GDI+函数可以成功调用
   GdiplusStartup(&gdiplusToken, &gdiplusStartupInput, NULL);

   CLSID   encoderClsid;
   Status stat;

   //7.创建Image对象并加载图片
   Image*   image = new Image(L"f://11.bmp");

   // Get the CLSID of the PNG encoder.
   GetEncoderClsid(L"image/png", &encoderClsid);

   //8.调用Image.Save方法进行图片格式转换，并把步骤3)得到的图像编码器Clsid传递给它
   stat = image->Save(L"11.png", &encoderClsid, NULL);

   if(stat == Ok)
      printf("Bird.png was saved successfully/n");
   else
      printf("Failure: stat = %d/n", stat);

   //9.释放Image对象
   delete image;
   //10.清理所有GDI+资源
   GdiplusShutdown(gdiplusToken);
   return 0;
}

本文来自CSDN博客，转载请标明出处：http://blog.csdn.net/yuzl32/archive/2010/03/18/5389919.aspx