LAnnContainer::

#include "ltwrappr.h"

virtual L_INT LAnnContainer::EncryptApply(uEncryptFlags, uFlags)

Applies an encryptor annotation object to the underlying bitmap.

Returns

Comments

An encrypt object can have two states: it can be an encryptor or it can be a decryptor.

Use this function to apply encryptor(s), decryptor(s), or both. Applying an encryptor means that the part of the bitmap that is under the encryptor is scrambled according to the encryptor properties.

Once applied, the portion of the bitmap under the encrypt object becomes scrambled or unscrambled, and the encrypt object changes state (encryptors become decryptors, and decryptors be encryptors). Using different keys before calling this function gives different scrambling patterns The decryptor state differs from the encryptor state in that a decryptor cannot be moved, and cannot be changed to an encryptor. The scrambling can be removed by calling LAnnContainer::EncryptApply on the decryptor with the appropriate arguments. If successful, the decryptor again changes state to become an encryptor. An encryptor can be moved, and can be changed to a decryptor.

The encrypt object is useful for encrypting portions of a bitmap. After encrypting, the scrambled bitmap cannot easily be unscrambled without the associated annotation file. The scrambling can be removed by using the associated annotation file, or by using automation mode to manually change the encrypt state from encryptor to a decryptor, position the object correctly, and setting the key appropriately.

LAnnContainer::EncryptApply calls LBitmap::Scramble internally to shuffle the pixels. For more information, refer to LBitmap::Scramble.

Required DLLs and Libraries

Platforms

Win32, x64.

See Also

Example

// This example takes a pointer to an LAnnEncrypt object that is an encryptor, and does the following

// 1. Verifies that it is an encryptor that is associated with a bitmap

// 2. changes the key to 123

// 3. Applies the encryptor so that it changes state to a decryptor

// 4. Prompts the user to continuev

// 5. Removes the scrambling by applying the decryptor

L_INT LAnnContainer_EncryptApplyExample(LAnnContainer *pLContainer, LAnnEncrypt *pLEncrypt) 
{
   L_INT nRet;
   L_UINT uObjectType; 
   ANNENCRYPTOPTIONS EncryptOptions; 
   uObjectType = pLContainer->GetType();
   if (uObjectType != ANNOBJECT_CONTAINER) 
   {
      MessageBox(NULL, TEXT("This object is not an encryptor."), TEXT("Error"), MB_OK); 
      return FAILURE ; 
   }
   memset(&EncryptOptions, 0, sizeof(ANNENCRYPTOPTIONS)); 
   EncryptOptions.uStructSize = sizeof(ANNENCRYPTOPTIONS); 
   EncryptOptions.uFlags = ANNENCRYPT_ALL; 
   nRet = pLEncrypt->GetEncryptOptions(&EncryptOptions); 
   if(nRet != SUCCESS)
      return nRet;
 
   if (EncryptOptions.pEncryptBitmap == NULL) 
   {
      MessageBox(NULL, TEXT("The encrypt object is not associated with a bitmap."), TEXT("Error"), MB_OK); 
      return FAILURE ; 
   }
   if (EncryptOptions.bEncryptor == FALSE) 
   {
      MessageBox(NULL, TEXT("This object is a decryptor."), TEXT("Error"), MB_OK); 
      return FAILURE ; 
   }
   // Change the key to '123'
   EncryptOptions.uKey = 123; 
   EncryptOptions.uFlags = ANNENCRYPT_KEY; 
   nRet = pLEncrypt->SetEncryptOptions(&EncryptOptions, 0); 
   if(nRet != SUCCESS)
      return nRet;
   // Apply the encryptor
   nRet = pLContainer->EncryptApply(ANNENCRYPTAPPLY_ENCRYPTOR, 0); 
   if(nRet != SUCCESS)
      return nRet;
   nRet = MessageBox(NULL, TEXT("Encryptor has been applied. Would you like to remove the encryption?"), TEXT(""), MB_YESNO); 
   if (nRet == IDYES) 
   {
      pLContainer->EncryptApply(ANNENCRYPTAPPLY_DECRYPTOR, 0); 
   }
   return SUCCESS;
}