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L_AntiAliasBitmap

Summary

Applies an anti-aliasing filter to the specified bitmap.

Syntax

#include "l_bitmap.h"

L_LTIMGEFX_API L_INT L_AntiAliasBitmap(pBitmap, nThreshold, uDim, uFilter, uFlags)

Parameters

pBITMAPHANDLE pBitmap

Pointer to the bitmap handle that references the bitmap on which to apply the filter.

L_INT nThreshold

Threshold value that indicates which pixels to smooth. The application of the anti-aliasing filter on the image associates a value with each pixel. Only pixels with values above this threshold are smoothed.

L_UINT uDim

Value that indicates the size of the anti-aliasing mask. For example, a value of three indicates an anti-aliasing mask of 3 X 3.

L_UINT uFilter

Flag that indicates the type of anti-aliasing filter to use. Possible values are:

Value	Meaning
ANTIALIAS_1	[0x0000] Anti-alias the bitmap vertically and horizontally.
ANTIALIAS_2	[0x0001] Anti-alias the bitmap in all directions.
ANTIALIAS_3	[0x0002] Anti-alias the bitmap in all directions. The filter used for this option is different from the filter used for the ANTIALIAS_2 option.
ANTIALIAS_DIAG	[0x0003] Anti-alias the bitmap diagonally.
ANTIALIAS_HORZ	[0x0004] Anti-alias the bitmap horizontally.
ANTIALIAS_VERT	[0x0005] Anti-alias the bitmap vertically.

L_UINT32 uFlags

Reserved for future use. Must be 0.

Returns

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

Comments

This function can process the whole image or a region of the image.

This function supports 12 and 16-bit grayscale and 48 and 64-bit color images. Support for 12 and 16-bit grayscale and 48 and 64-bit color images is available in the Document and Medical Imaging toolkits.

The best results for anti-aliasing text can be obtained with the filter ANTIALIAS_2.

The value of the uDim parameter determines the extent of the anti-aliasing.

The threshold range for 16, 48 and 64-bit images is from 0 to 65535 for unsigned images, and from –32768 to +32767 for signed images. For 12-bit images, the threshold range is from 0 to 4095 for unsigned images, and from –2048 to +2047 for signed images. Otherwise, it is from 0 to 255. The threshold is applied to channels separately.

This function does not support 32-bit grayscale images. It returns the error code ERROR_GRAY32_UNSUPPORTED if a 32-bit grayscale image is passed to this function.

Anti Aliasing Function - Before

Anti Aliasing Function - After

View additional platform support for this Anti Aliasing function.

Required DLLs and Libraries

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, Linux.

Example

L_INT AntiAliasBitmapExample(L_VOID) 
{ 
   L_INT nRet; 
   BITMAPHANDLE LeadBitmap;   /* Bitmap handle to hold the loaded image. */ 
 
   /* Load the bitmap, keeping the bits per pixel of the file */ 
   nRet = L_LoadBitmap(MAKE_IMAGE_PATH(TEXT("Jagged.jpg")), &LeadBitmap, sizeof(BITMAPHANDLE), 0, ORDER_BGR, NULL, NULL); 
   if (nRet != SUCCESS) 
      return nRet; 
 
   /* do the anti-aliasing on the bitmap */ 
   nRet = L_AntiAliasBitmap(&LeadBitmap, 128, 3, ANTIALIAS_1, 0); 
   if (nRet != SUCCESS) 
      return nRet; 
 
   nRet = L_SaveBitmap(MAKE_IMAGE_PATH(TEXT("Result.BMP")), &LeadBitmap, FILE_BMP, 24, 0, NULL); 
   if (nRet != SUCCESS) 
      return nRet; 
 
   //free bitmap 
   if (LeadBitmap.Flags.Allocated) 
      L_FreeBitmap(&LeadBitmap); 
 
   return SUCCESS; 
}