L_SpatialFilterBitmap

#include "l_bitmap.h"

L_INT EXT_FUNCTION L_SpatialFilterBitmap(pBitmap, pFilter)

pBITMAPHANDLE pBitmap;

/* pointer to the bitmap handle */

LPSPATIALFLT pFilter;

/* pointer to the spatial filter to use */

Imposes a spatial filter on a bitmap. You can supply your own filter or use one of the predefined filters.

Parameter

Description

pBitmap

Pointer to the bitmap handle that references the bitmap to be affected.

pFilter

Pointer to the spatial filter to use. For predefined filters, refer to List of Spatial Filters. To define your own filter, refer to SPATIALFLT.

Returns

SUCCESS

The function was successful.

< 1

An error occurred. Refer to Return Codes.

Comments

A spatial filter recomputes the brightness of each pixel in a bitmap by using a weighted averaging technique that considers the surrounding pixels. Spatial filters are used for operations such as sharpening an image or detecting edges within the image.

The L_SpatialFilterBitmap function works best with 24-bit, 16-bit, or grayscale bitmaps. If a bitmap uses a color palette, this function matches the new brightness value of each pixel to the nearest color in the existing palette.

To update a status bar or detect a user interrupt during execution of this function, refer to L_SetStatusCallback.

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 only in the Document/Medical toolkits.

This function does not support signed data images. It returns the error code ERROR_SIGNED_DATA_NOT_SUPPORTED if a signed data image is passed to this function.

Required DLLs and Libraries

LTIMG

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

Windows 95 / 98 / Me, Windows 2000 / XP, Windows CE.

See Also

Functions:

L_SharpenBitmap, L_PosterizeBitmap, L_MosaicBitmap, L_EmbossBitmap, L_AverageFilterBitmap, L_MedianFilterBitmap, L_AddBitmapNoise, L_IntensityDetectBitmap, L_BinaryFilterBitmap, L_MaxFilterBitmap, L_MinFilterBitmap, L_OilifyBitmap, L_SolarizeBitmap, L_DlgShiftDifferenceFilter, L_DlgGradientFilter, L_DlgLaplacianFilter, L_DlgSobelFilter, L_DlgPrewittFilter, L_DlgLineSegmentFilter, L_WindowLevel, L_SkeletonBitmap, L_CorrelationBitmap, L_HolesRemovalBitmapRgn, L_DiffuseGlowBitmap, L_HighPassFilterBitmap, L_MaskConvolutionBitmap

Topics:

Raster Image Functions: Filtering Images

 

Detecting and Enhancing Edges and Lines

 

Raster Image Functions: Detecting and Enhancing Edges and Lines

Example

For complete sample code, refer to the CHILD.C module of the DEMO example.

/* This example loads a bitmap and applies a Prewitt edge detection filter. */
BITMAPHANDLE LeadBitmap;   /* Bitmap handle to hold the loaded image. */
/* Load the bitmap, keeping the bits per pixel of the file */
L_LoadBitmap (TEXT("IMAGE1.CMP"), &LeadBitmap, sizeof(BITMAPHANDLE), 0, ORDER_BGR, NULL, NULL);
/* Apply a Prewitt edge detection filter */
L_SpatialFilterBitmap(&LeadBitmap, FLT_PREWITT_HORZ );