LJp2FileFormat::ReadBox

#include "ltwrappr.h"

L_INT LJp2FileFormat::ReadBox(pszFile, eBoxType, plBox, uBoxIndex)

L_TCHAR * pszFile;	/* JPEG 2000 file name */
eJP2BOXTYPE eBoxType;	/* box type */
L_VOID * * plBox;	/* pointer to a pointer */
L_UINT32 uBoxIndex;	/* box index */

Reads a box of type eBoxType at uBoxIndex from the specified JPEG 2000 file.

Parameter	Description
pszFile	Character string that contains the name of the JPEG 2000 file.
eBoxType	Box type. It specifies the type of the box to be read from the file.
plBox	Pointer to a pointer to be updated with the box data structure.
uBoxIndex	0-based box index. It specifies the box to read.

Returns

SUCCESS	The function was successful.
< 1	An error occurred. Refer to Return Codes.

Comments

LJp2FileFormat::ReadBox reads a box of type eBoxType at uBoxIndex from the specified JPEG 2000 file.

If the uBoxIndex is greater than the number of boxes, the function returns: ERROR_INV_PARAMETER.

L_JP2B_RESOLUTION and L_JPXB_RESOLUTION boxes cant be read using this function. All of the engines boxes will be reset and updated with the new loaded boxes only.

You must free the allocated box by calling the LJp2FileFormat::FreeBoxes function.

Required DLLs and Libraries

LTJP2
LFJ2K
LTIMGEFX

For a listing of the exact DLLs and Libraries needed, based on the toolkit version, refer to Files To Be Included With Your Application.

See Also

Functions:	LJp2FileFormat::FreeBoxes, LJp2FileFormat::ReadBoxMemory, LJp2FileFormat::AppendBoxes, LJp2FileFormat::AppendBoxesMemory
Topics:	Implementing JPEG 2000 Plug in Features
	Raster Image Functions: Working with JPEG 2000

Example

This example reads an MPEG7 box stored in a JPEG 2000 file.

L_LTJP2SAM_CLIB L_INT LJp2FileFormat__ReadBoxExample(L_UINT8 ** pMPEG7Data, L_SIZE_T* puSize)
{
   LJp2FileFormat Engine;
   L_INT  nRet;
   pL_JP2_MPEG7_BOX pMPEG7Box;
   L_JP2_FILEINFO Jp2FileInfo;
   Jp2FileInfo.uStructSize = sizeof(L_JP2_FILEINFO);
   Engine.GetFileInfo( TEXT("%UserProfile%\\My Documents\\LEADTOOLS Images\\image1.jpx"),&Jp2FileInfo);
   if(Jp2FileInfo.MPEG7.uNumOfBoxes == 0)
      return 0;
   nRet = Engine.ReadBox(TEXT("%UserProfile%\\My Documents\\LEADTOOLS Images\\image1.jpx"),L_JPXB_MPEG7, (L_VOID**)&pMPEG7Box,0);
   if(nRet != SUCCESS)
      return nRet;
   
   *pMPEG7Data = (L_UINT8*)malloc(pMPEG7Box->uDataSize);
   memcpy(*pMPEG7Data, pMPEG7Box->pData,pMPEG7Box->uDataSize);
   *puSize = pMPEG7Box->uDataSize;
   
   /*Free the read box*/
   Engine.FreeBoxes( L_JPXB_MPEG7, pMPEG7Box, 1);
   /*Free File Info structure*/
   Engine.FreeFileInfo( &Jp2FileInfo);
   return SUCCESS;
}