列出已安装的解码器

Windows GDI+ 提供 GetImageDecoders 函数，以便你可以确定计算机上可用的图像解码器。 GetImageDecoders 返回 ImageCodecInfo 对象的数组。 在调用 GetImageDecoders 之前，必须分配一个足够大的缓冲区来接收该数组。 可以调用 GetImageDecodersSize 来确定所需缓冲区的大小。

以下控制台应用程序列出了可用的图像解码器：

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

INT main()
{
   // Initialize GDI+.
   GdiplusStartupInput gdiplusStartupInput;
   ULONG_PTR gdiplusToken;
   GdiplusStartup(&gdiplusToken, &gdiplusStartupInput, NULL);

   UINT  num;        // number of image decoders
   UINT  size;       // size, in bytes, of the image decoder array

   ImageCodecInfo* pImageCodecInfo;

   // How many decoders are there?
   // How big (in bytes) is the array of all ImageCodecInfo objects?
   GetImageDecodersSize(&num, &size);

   // Create a buffer large enough to hold the array of ImageCodecInfo
   // objects that will be returned by GetImageDecoders.
   pImageCodecInfo = (ImageCodecInfo*)(malloc(size));

   // GetImageDecoders creates an array of ImageCodecInfo objects
   // and copies that array into a previously allocated buffer. 
   // The third argument, imageCodecInfo, is a pointer to that buffer. 
   GetImageDecoders(num, size, pImageCodecInfo);

   // Display the graphics file format (MimeType)
   // for each ImageCodecInfo object.
   for(UINT j = 0; j < num; ++j)
   { 
      wprintf(L"%s\n", pImageCodecInfo[j].MimeType);   
   }

   free(pImageCodecInfo);
   GdiplusShutdown(gdiplusToken);
   return 0;
}

运行上述控制台应用程序时，输出将类似于以下内容：

image/bmp
image/jpeg
image/gif
image/x-emf
image/x-wmf
image/tiff
image/png
image/x-icon