Image::GetPropertySize method (gdiplusheaders.h)

Article
10/13/2021

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

[out] totalBufferSize

Type: UINT*

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

[out] numProperties

Type: UINT*

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

Return value

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:

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

Requirement	Value
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