Read and Write Exif Tags and Comments - Windows C DLL

#define LTV22_CONFIG  
#include "C:\LEADTOOLS22\Include\L_Bitmap.h" // use the actual path where LEADTOOLS is installed  
 
#pragma comment (lib, "C:\\LEADTOOLS22\\Lib\\CDLL\\x64\\Ltkrn_x.lib")  
#pragma comment (lib, "C:\\LEADTOOLS22\\Lib\\CDLL\\x64\\Ltfil_x.lib") // file loading and saving  
#pragma comment (lib, "C:\\LEADTOOLS22\\Lib\\CDLL\\x64\\Ltdis_x.lib") // image display 

switch (wmId) 
{ 
   case ID_FILE_EXIFCOMMENT: 
      ReadAndWriteExifComments(hWnd); 
      break; 
      // Keep rest of the code as is 

void ReadAndWriteExifComments(HWND hWnd) 
{ 
   L_TCHAR szSrcFile[260] = TEXT(""), szDestFile[260] = TEXT(""); 
   if (SUCCESS != GetBitmapLoadingName(hWnd, szSrcFile, ARRAYSIZE(szSrcFile))) 
      return; 
   if(LEADBmp.Flags.Allocated) 
      L_FreeBitmap(&LEADBmp); 
   L_LoadBitmap(szSrcFile, &LEADBmp, sizeof(LEADBmp), 24, ORDER_BGR, NULL, NULL); 
   InvalidateRect(hWnd, NULL, TRUE); 
   MessageBox(hWnd, TEXT("Image loaded and will be flipped.\nSelect output file"), TEXT("LEADTOOLS Demo"), MB_ICONINFORMATION); 
   // Flip the image. 
   L_FlipBitmap(&LEADBmp); 
   InvalidateRect(hWnd, NULL, TRUE); 
 
   // Specify output file 
   if (SUCCESS != GetBitmapSavingName(hWnd, szDestFile, ARRAYSIZE(szDestFile))) 
      return; 
 
   // Load the current comments from the file 
   for (int i = 0; i < CMNT_LAST; i++) 
   { 
      // Clear the comment 
      L_SetComment(i, NULL, 0); 
      // Use the return value to get the length of a comment in the file 
      L_INT CommentLength = L_ReadFileComment(szSrcFile, i, NULL, 0, NULL); 
      if (CommentLength > 0) 
      { 
         L_UCHAR* pCommentToGet = new L_UCHAR[CommentLength](); // parentheses initialize array to zeros 
         // Get the comment from the file 
         L_ReadFileComment(szSrcFile, i, pCommentToGet, CommentLength, NULL); 
         // Set the comment to be saved 
         L_SetComment(i, pCommentToGet, CommentLength); 
         delete[] pCommentToGet; 
      } 
   } 
 
   // Create the CMNT_USERCOMMENT comment as a byte array 
   // When writing a user comment, the first 8 bytes must contain the "ASCII" word.   
 
   L_SetComment(CMNT_USERCOMMENT, NULL, 0); 
   // IMPORTANT: initializing CommentToSet array causes remainder of array to contain null characters, which is needed for rest of code to work 
   L_UCHAR CommentToSet[80] = "ASCII"; 
   const L_CHAR* pUserComment = "The image has been flipped!"; 
   strcpy_s((char *)CommentToSet + 8, sizeof CommentToSet - 8, pUserComment); 
   // Set the CMNT_USERCOMMENT comment 
   L_SetComment(CMNT_USERCOMMENT, CommentToSet, (L_UINT)strlen(pUserComment) + 9); 
   L_SaveBitmap(szDestFile, &LEADBmp, FILE_EXIF, 24, 0, NULL); 
   L_UCHAR CommentCheck[80] = ""; 
   L_ReadFileComment(szDestFile, CMNT_USERCOMMENT, CommentCheck, sizeof CommentCheck, NULL); 
   char szMessageA[256] = "Comment read back from file:\n"; 
   strcat_s(szMessageA, sizeof szMessageA, (const char *)CommentCheck + 8); 
   // The returned string is in ASCII, so the "MessageBoxA" function is used to display it 
   MessageBoxA(hWnd, szMessageA, "LEADTOOLS Demo", MB_OK); 
} 

switch (wmId) 
{ 
case ID_FILE_EXIFTAG: 
   ReadAndWriteExifTags(hWnd); 
   break; 
   // Keep rest of the code as is 

void ReadAndWriteExifTags(HWND hWnd) 
{ 
   L_TCHAR szExifFile[260] = TEXT(""); 
   if (SUCCESS != GetBitmapLoadingName(hWnd, szExifFile, ARRAYSIZE(szExifFile))) 
      return; 
 
   FILEINFO info = { 0 }; // Important: Must initialize to zero 
   info.uStructSize = sizeof info; 
   L_FileInfo(szExifFile, &info, sizeof info, 0, NULL); 
   if (!L_TagsSupported(info.Format)) 
   { 
      MessageBox(hWnd, TEXT("File Format Does Not Support Tags"), TEXT("LEADTOOLS Demo"), MB_ICONERROR); 
      return; 
   } 
 
   // Add a private (custom) "Phone Number" tag 
   L_UINT16 PhoneNumber = 0x8001; 
   char TagData[] = "+1-800-637-4699"; 
   // Set the tag data to be saved 
   L_SetTag(PhoneNumber, TAG_ASCII, sizeof TagData, TagData); 
   // Save the the tag into the file 
   L_WriteFileTag(szExifFile, NULL); 
   // Clear the tag from memory 
   L_SetTag(0, 0, 0, NULL); 
 
   // Read the tags from the file and display them in the debugger window 
   L_UINT uTagCount = 0; 
   pLEADFILETAG pTags = NULL, pCurrentTag; 
   L_SIZE_T uTagDataSize = 0; 
   L_UCHAR* pTagsData = NULL; 
   L_ReadFileTags(szExifFile, 0, &uTagCount, &pTags, &uTagDataSize, &pTagsData, NULL); 
 
   if (uTagCount > 0) 
   { 
      // Show the tags 
      OutputDebugString(TEXT("Tags\n")); 
      for (L_UINT n = 0; n < uTagCount; n++) 
      { 
         pCurrentTag = &pTags[n]; 
 
         // If this tag is of type ASCII, get its data 
         L_CHAR* pszAscii = NULL; 
         if (pCurrentTag->uType == TAG_ASCII) 
         { 
            pszAscii = new L_CHAR[pCurrentTag->uDataSize + 1](); 
            memcpy(pszAscii, pTagsData + pCurrentTag->uDataOffset, pCurrentTag->uDataSize); 
         } 
         else 
         { 
            pszAscii = NULL; 
         } 
         CHAR szMessage[1024]; 
         wsprintfA(szMessage, "Id: 0x%X, data length: %u, data: %s\n", pCurrentTag->uTag, pCurrentTag->uDataSize, pszAscii != NULL ? pszAscii : "Binary data"); 
         if (pszAscii) 
            delete[] pszAscii; 
         OutputDebugStringA(szMessage); 
      } 
      L_FreeFileTags(uTagCount, pTags, uTagDataSize, pTagsData); 
   } 
}