L_ScrambleBitmap

#include "l_bitmap.h"

L_LTKRN_API L_INT L_ScrambleBitmap(pBitmap, nColStart, nRowStart, nWidth, nHeight, uKey, uFlags)

pBITMAPHANDLE pBitmap;	pointer to a bitmap handle for the bitmap to be scrambled
L_INT nColStart;	starting column in pixels (0-based)
L_INT nRowStart;	starting row in pixels (0-based)
L_INT nWidth;	width of area to scramble in pixels
L_INT nHeight;	height of area to scramble in pixels
L_UINT uKey;	key that determines the scramble
L_UINT uFlags;	flag that determines whether to encrypt or decrypt the area.

Scrambles all or a portion of a bitmap.

Parameter	Description
pBitmap	Pointer to a bitmap handle for the bitmap to be scrambled.
nColStart	Starting column in pixels (0-based).
nRowStart	Starting row in pixels (0-based).
nWidth	Width of area to scramble in pixels.
nHeight	Height of area to scramble in pixels.
uKey	Key that determines the scramble. This is an unsigned integer with a minimum value of 0 and a maximum value of 4294967295 (0xffffffff).
uFlags	Flag that determines whether to encrypt or decrypt the area. Possible values are:
	Value	Meaning
	SB_ENCRYPT	Encrypts the area (the reverse of a decrypt).
	SB_DECRYPT	Decrypts the area (the reverse of an encrypt).
	SB_INTERSECT	Intersect the specified rectangle with the bitmaps rectangle.

Returns

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

Comments

Scrambling a rectangular area means that the pixels in that area are shuffled around into a pseudo-random location within the area.

Some properties of shuffling:

No colors are introduced,

Color counts remain unchanged

Given the same encrypt area (defined by nColStart, nRowStart, nWidth, nHeight) and the same key, setting (uFlags = SB_ENCRYPT) is the inverse of (uFlags = SB_DECRYPT)

Required DLLs and Libraries

LTKRN

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, Linux.

Example

This example scrambles the upper left quadrant of a bitmap using the key 123

L_INT ScrambleBitmapExample(pBITMAPHANDLE pBitmap) 
{ 
   L_INT nRet; 
   if (!pBitmap) 
      return ERROR_NO_BITMAP; 
   nRet = L_ScrambleBitmap(pBitmap, 0, 0, BITMAPWIDTH(pBitmap)/2, BITMAPHEIGHT(pBitmap)/2, 123, SB_ENCRYPT); 
   if(nRet != SUCCESS) 
      return nRet; 
   return SUCCESS; 
}

Help Version 19.0.2017.10.27

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LEADTOOLS Raster Imaging C API Help

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Redistributables/Files To Be Included With Your Application

Functions:	L_AnnGetMetafile, L_AnnSetMetafile, L_AnnGetPredefinedMetafile, L_AnnSetPredefinedMetafile, L_AnnEncryptApply, L_AnnSetEncryptOptions, L_AnnGetEncryptOptions
Topics:	Annotation Functions: Object Properties
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	Implementing an Automated Annotation Program
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