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L_Jp2ReadBox

Summary

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

Syntax

#include "l_bitmap.h"

L_LTJP2_API L_INT EXT_FUNCTION L_Jp2ReadBox(hJp2, pszFile, eBoxType, plBox, uBoxIndex)

Parameters

L_HJP2 hJp2

JPEG 2000 engine handle that was created by the L_Jp2Create function.

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

L_Jp2ReadBox 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 L_Jp2FreeBoxes function.

Required DLLs and Libraries

LTJP2
LTIMGEFX
LFJ2K
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 Jp2ReadBoxExample(L_UINT8** pMPEG7Data, L_SIZE_T* puSize) 
{ 
   L_HJP2 hEngine; 
   L_INT  nRet; 
   pL_JP2_MPEG7_BOX pMPEG7Box; 
   L_JP2_FILEINFO Jp2FileInfo; 
 
   // Create JPEG  2000 engine handle 
   hEngine = L_Jp2Create(); 
 
   Jp2FileInfo.uStructSize = sizeof(L_JP2_FILEINFO); 
   L_Jp2GetFileInfo(hEngine, MAKE_IMAGE_PATH("image1.jpx"), &Jp2FileInfo); 
   if (Jp2FileInfo.MPEG7.uNumOfBoxes == 0) 
      return 0; 
 
   nRet = L_Jp2ReadBox(hEngine, MAKE_IMAGE_PATH("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 = L_Jp2FreeBoxes(hEngine, L_JPXB_MPEG7, pMPEG7Box, 1); 
   if (nRet != SUCCESS) 
      return nRet; 
 
   // Free File Info structure 
   nRet = L_Jp2FreeFileInfo(hEngine, &Jp2FileInfo); 
   if (nRet != SUCCESS) 
      return nRet; 
 
   // Destroy engine handle 
   nRet = L_Jp2Destroy(hEngine); 
   if (nRet != SUCCESS) 
      return nRet; 
 
   return SUCCESS; 
}