Listing Installed Encoders

GDI+ provides the GetImageEncoders function so that you can determine which image encoders are available on your computer. GetImageEncoders returns an array of ImageCodecInfo objects. Before you call GetImageEncoders, you must allocate a buffer large enough to receive that array. You can call GetImageEncodersSize to determine the size of the required buffer.

The following console application lists the available image encoders:

#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 encoders
   UINT  size;       // size, in bytes, of the image encoder array

   ImageCodecInfo* pImageCodecInfo;

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

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

   // GetImageEncoders 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. 
   GetImageEncoders(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);   

   return 0;

When you run the preceding console application, the output will be similar to the following: