GDI+: GdipGetPropertyItem

[José Roca]

The following example creates an Image object based on a JPEG file. The code gets the luminance table by passing the PropertyTagLuminanceTable constant to the GdipGetPropertyItem function.

C++

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

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

   UINT size = 0;
   PropertyItem* propertyItem = NULL;
   Image* image = new Image(L"FakePhoto.jpg");

   // Assume that the image has a property item of type PropertyItemEquipMake.
   // Get the size of that property item.
   size = image->GetPropertyItemSize(PropertyTagEquipMake);

   // Allocate a buffer to receive the property item.
   propertyItem = (PropertyItem*)malloc(size);

   // Get the property item.
   image->GetPropertyItem(PropertyTagEquipMake, size, propertyItem);

   // Display the members of the retrieved PropertyItem object.
   printf("The length of the property item is %u.\n", propertyItem->length);
   printf("The data type of the property item is %u.\n", propertyItem->type);

   if(propertyItem->type == PropertyTagTypeASCII)
      printf("The value of the property item is %s.\n", propertyItem->value);

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


PowerBASIC

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#COMPILE EXE
#DIM ALL
#INCLUDE "GDIPLUS.INC"

' ========================================================================================
' Main
' ========================================================================================
FUNCTION PBMAIN

   LOCAL hStatus AS LONG
   LOCAL token AS DWORD
   LOCAL StartupInput AS GdiplusStartupInput
   LOCAL pImage AS DWORD
   LOCAL strFileName AS STRING
   LOCAL nSize AS DWORD
   LOCAL buffer AS STRING
   LOCAL propItem AS PropertyItem
   LOCAL i AS LONG
   LOCAL pvShort AS INTEGER PTR

   ' // Initialize GDI+
   StartupInput.GdiplusVersion = 1
   hStatus = GdiplusStartup(token, StartupInput, BYVAL %NULL)
   IF hStatus THEN
      PRINT "Error initializing GDI+"
      EXIT FUNCTION
   END IF

   strFileName = UCODE$("climber.jpg")
   hStatus = GdipLoadImageFromFile(STRPTR(strFileName), pImage)

   ' // Get the size of that property item.
   hStatus = GdipGetPropertyItemSize(pImage, %PropertyTagLuminanceTable, nSize)

   ' // Use an string as the buffer.
   buffer = SPACE$(nSize)
   hStatus = GdipGetPropertyItem(pImage, %PropertyTagLuminanceTable, nSize, BYVAL STRPTR(buffer))
   IF hStatus = %StatusOk THEN
      LSET propItem = LEFT$(buffer, SIZEOF(PropertyItem))
      pvShort = propItem.value
      FOR i = 1 TO propItem.length \ 2  ' Divide the length by the size of an integer
         PRINT @pvShort[i-1] " ";
      NEXT
   END IF

   ' // Cleanup
   IF pImage THEN GdipDisposeImage(pImage)

   ' // Shutdown GDI+
   GdiplusShutdown token

   WAITKEY$

END FUNCTION
' ========================================================================================