#include "BIFILTER.H"
HANDLE CALLBACK HistDIBStretch( HANDLE hSrcDIB,
BYTE nBegin,
BYTE nEnd,
float fConst,
int iShowProgress,
HWND hParent)
Description
This function increases the dynamic range of the gray levels. It multiplies pixels by ‘fConst’ if the original pixel value is between ‘nBegin’ and ‘nEnd’. 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.
Parameters
|
HANDLE |
hSrcDIB |
Source DIB |
|
BYTE |
nBegin |
The begin of range |
|
BYTE |
nEnd |
The end of range |
|
float |
fConst |
Quantity of the contrast stretch |
|
int |
iShowProgress |
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. |
|
HWND |
hParent |
Handler of the parent window. |
Return values
Handle of the newly created DIB on success or NULL on failure.
Programming notes
If the result of multiplication (pixelvalue * fConst) overflows, then the maximum pixel value is used instead of the result. Maximum pixel values: 4 bits/pixel: 15, 8 bits/pixel: 255, 24 bits/pixel: 255 for each channel. There are three channels on 24 bits/pixel (R, G, B).
Requirements
Header : Declared in BIFilter.h; include BIFilter.h.
Library : Use BIFilter.lib.
DLLs : BIFilter.dll.