#include "l_bitmap.h"

L_LTIMGEFX_API L_INT L_ContourFilterBitmap(pBitmap, nThreshold, nDeltaDirection, nMaximumError, nOption, uFlags)


pointer to a bitmap handle

L_INT16 nThreshold;

threshold value

L_INT16 nDeltaDirection;

maximum angle

L_INT16 nMaximumError;

maximum error

L_INT nOption;

flag that controls the resulting image

L_UINT32 uFlags;


Performs a contour segment filter on the source bitmap.

Parameter Description
pBitmap Pointer to a bitmap handle that references the bitmap that will be affected.
nThreshold Threshold of the gradient magnitude. Values below this will be considered as background, and will be set to 0. Values can be from 1 to 254. A lower threshold provides a better quality image. Default is 15.
nDeltaDirection Maximum angle for the thinning algorithm. Values can be from 1 to 64. Default is 35.
nMaximumError Maximum error for approximation algorithm. Values can be from 0 to 255. Default is 5. This parameter is only valid if nOption is CONTOUR_APPROX_COLOR.
nOption Flag that controls the resulting image. This value tells the method what process to complete before returning. Possible values are:
  Value Meaning
  CONTOUR_THIN [0] return after the thinning algorithm
  CONTOUR_LINK_BLACKWHITE [1] return after contour linking, using only black and white
  CONTOUR_LINK_GRAY [2] return after contour linking, using 256 grayscale
  CONTOUR_LINK_COLOR [3] return after contour linking, using colors
  CONTOUR_APPROX_COLOR [4] return after line segment approximation, using colors
uFlags Reserved for future use. Must be 0.



The function was successful.

< 1

An error occurred. Refer to Return Codes.


The bits per pixel of the affected bitmap will change according to the value of nOption.

If nOption is:

Bits per pixel will be:


8 bits per pixel grayscale


1 bit per pixel


8 bits per pixel grayscale


8 bits per pixel color


8 bits per pixel color

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.

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.

Required DLLs and Libraries


For a listing of the exact DLLs and Libraries needed, based on the toolkit version, refer to Files To Be Included With Your Application.


Win32, x64.

Help Version 19.0.2017.10.27
Products | Support | Contact Us | Copyright Notices
© 1991-2017 LEAD Technologies, Inc. All Rights Reserved.
LEADTOOLS Raster Imaging C API Help