#include "BIFILTER.H"


HANDLE CALLBACK HistDIBModify(                  HANDLE    hSrcDIB,
int               iShowProgress,
HWND       hParent)


This function compresses the dynamic range of pixel values. The result is put to a newly created DIB and the source DIB is unmodified. It works with 4, 8 or 24 bits/pixel. In case of 24 bits/pixel, the operation is made separately on the R, G, B channels. In case of 4 or 8 bits/pixel, the source DIB must contain grayscale image and the palette values in the source DIB must be monotone increasing. It makes no sense to use this function in case of 1 bits/pixel.




Source DIB



This parameter specifies the displaying of the progressbar and the preview dialog.

Available values:

DISPLAY_NONE (0)      -     The progressbar and the preview dialog will not display before filtering.

DISPLAY_PROGRESS (1) -The progressbar will display during filtering procedure.

DISPLAY_DIALOG (2) -     The preview dialog will display before filtering. This dialog shows the part of the image before and after filtering.

DISPLAY_BOTH (3)      -     The progressbar and the preview dialog will display.

IMPORTANT: The preview dialog will only display, if there is BiDlgs.dll installed.



Handler of the parent window.

Return values

Handle of the newly created DIB on success or NULL on failure.

Programming notes

This function performs the following intensity transformation to compress the dynamic range of pixel values:  ResPix = F * log (SrcPix + 1) where  ResPix is the result pixel value, SrcPix is the source pixel value and F is a scaling factor. F = 1 / log(256) if the image resolution is 8 bits/pixel or 24 bits/pixel. In case of 4 bits/pixel F = 1 / log(16)


Header :    Declared in BIFilter.h; include BIFilter.h.

Library :    Use BIFilter.lib.

DLLs :       BIFilter.dll.