Image::GetPropertySize method

The Image::GetPropertySize method gets the total size, in bytes, of all the property items stored in this Image object. The Image::GetPropertySize method also gets the number of property items stored in this Image object.

Syntax

Status GetPropertySize(
  OUT UINT *totalBufferSize,
  OUT UINT *numProperties
);

Parameters

totalBufferSize

Type: UINT*

Pointer to a UINT that receives the total size, in bytes, of all the property items.

numProperties

Type: UINT*

Pointer to a UINT that receives the number of property items.

Return Value

Type: Type: Status

If the method succeeds, it returns Ok, which is an element of the Status enumeration.

If the method fails, it returns one of the other elements of the Status enumeration.

Remarks

Windows GDI+ stores an individual piece of metadata in a PropertyItem object. The Image::GetAllPropertyItems method returns an array of PropertyItem objects. Before you call Image::GetAllPropertyItems, you must allocate a buffer large enough to receive that array. You can call the Image::GetPropertySize method of an Image object to get the size, in bytes, of the required buffer. The Image::GetPropertySize method also gives you the number of properties (pieces of metadata) in the image.

Examples

The following example creates an Image object based on a JPEG file. The code calls the Image::GetAllPropertyItems method of that Image object to obtain its property items (metadata).

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

INT main()
{
   GdiplusStartupInput gdiplusStartupInput;
   ULONG_PTR gdiplusToken;
   GdiplusStartup(&gdiplusToken, &gdiplusStartupInput, NULL);

   // Create an Image object based on a JPEG file.
   Image* image = new Image(L"FakePhoto.jpg"); 

  // Find out how many property items are in the image, and find out the
   // required size of the buffer that will receive those property items.
   UINT totalBufferSize;
   UINT numProperties;
   image->GetPropertySize(&totalBufferSize, &numProperties);

   // Allocate the buffer that will receive the property items.
   PropertyItem* pAllItems = (PropertyItem*)malloc(totalBufferSize);

   // Fill the buffer.
   image->GetAllPropertyItems(totalBufferSize, numProperties, pAllItems);

   // Print the ID of each property item.
   for(UINT j = 0; j < numProperties; ++j)
   {
      printf("%x\n", pAllItems[j].id);
   }

   free(pAllItems);
   delete image;
   GdiplusShutdown(gdiplusToken);
   return 0;
}

The preceding code, along with a particular file, FakePhoto.jpg, produced the following output:

320
10f
110
9003
829a
5090
5091

The preceding output shows the hexadecimal value of each property identifier. You can look up those numbers in Gdiplusimaging.h and find out that they represent the following property tags.

Hexadecimal value Property tag
0x0320 PropertyTagImageTitle
0x010f PropertyTagEquipMake
0x0110 PropertyTagEquipModel
0x9003 PropertyTagExifDTOriginal
0x829a PropertyTagExifExposureTime
0x5090 PropertyTagLuminanceTable
0x5091 PropertyTagChrominanceTable
 

Requirements

   
Minimum supported client Windows XP, Windows 2000 Professional [desktop apps only]
Minimum supported server Windows 2000 Server [desktop apps only]
Target Platform Windows
Header gdiplusheaders.h (include Gdiplus.h)
Library Gdiplus.lib
DLL Gdiplus.dll

See Also

Image

Image::GetAllPropertyItems

Image::GetPropertyCount

Image::GetPropertyIdList

Image::GetPropertyItem

Image::GetPropertyItemSize

Image::RemovePropertyItem

Image::SetPropertyItem

PropertyItem

Reading and Writing Metadata