Description This method increases the dynamic range of the gray levels. It multiplies pixels by ‘Const’ if the original pixel value is between ‘Begin’ and ‘End’. 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.
Syntax lRet = [BIFilter.]HistDIBStretch Dib Begin End Const iShowProgress hWnd
Remarks lRet LONGLONG Handle of the newly created DIB on success or 0 on failure.
Dib LONGLONG Source DIB.
Begin short Beginning of the range.
End short End of the range.
Const Long Quantity of the contrast stretch.
iShowProgress short 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 the conversion.
DISPLAY_PROGRESS (1) - The progressbar will display during the procedure.
DISPLAY_DIALOG (2) - The preview dialog will display before conversion. This dialog shows the part of the image before and after removing red eye.
DISPLAY_BOTH (3) - The progressbar and the preview dialog will display.
IMPORTANT: The preview dialog will only display, if there is BIDlgs32.dll installed.
hWnd LONGLONG Handler of the parent window.
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).
See Also