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LJp2FileFormat::ReadBox

Summary

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

Syntax

#include "ltwrappr.h"

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

Parameters

L_TCHAR * pszFile

Character string that contains the name of the JPEG 2000 file.

eJP2BOXTYPE eBoxType

Box type. It specifies the type of the box to be read from the file.

L_VOID ** plBox

Pointer to a pointer to be updated with the box data structure.

L_UINT32 uBoxIndex

0-based box index. It specifies the box to read.

Returns

Value	Meaning
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.

Platforms

Win32, x64.

Example

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

L_INT LJp2FileFormat__ReadBoxExample(L_UINT8 ** pMPEG7Data, L_SIZE_T* puSize) 
{ 
   LJp2FileFormat Engine; 
   L_INT  nRet = 0; 
   pL_JP2_MPEG7_BOX pMPEG7Box; 
   L_JP2_FILEINFO Jp2FileInfo; 
 
   Jp2FileInfo.uStructSize = sizeof(L_JP2_FILEINFO); 
   nRet = Engine.GetFileInfo(MAKE_IMAGE_PATH(TEXT("image1.jpx")),&Jp2FileInfo); 
   if(nRet != SUCCESS) 
      return nRet; 
 
   if(Jp2FileInfo.MPEG7.uNumOfBoxes == 0) 
      return 0; 
 
   nRet = Engine.ReadBox(MAKE_IMAGE_PATH(TEXT("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*/ 
   nRet = Engine.FreeBoxes( L_JPXB_MPEG7, pMPEG7Box, 1); 
   if(nRet != SUCCESS) 
      return nRet; 
 
   /*Free File Info structure*/ 
   nRet = Engine.FreeFileInfo( &Jp2FileInfo); 
   if(nRet != SUCCESS) 
      return nRet; 
 
   return SUCCESS; 
}