Description This method will first shift the input image in the specified direction and after subtracts the shifted image from the original. This algorithm is often used to detect simple edges easily. This method works for only 1, 8 and 24 bit per pixel images.
Examples
The original 180 x 210 pixel image and the difference filtered image with nDirection = DIFF_NORTHWEST_SOUTHEAST.
Syntax RetVal = [BiFilter.]FilterDifference hDib nDirection iShowProgress hWnd
Returns RetVal LONGLONG The handle of new filtered DIB, 0 if an error occurred, or -1 if the BIFilter.dll does not installed.
Remarks hDib LONGLONG Handle of the image to filter.
nDirection short Shifting direction. progressbar and the preview dialog.
Available values:
DIFF_HORIZONTAL(0) Horizontal.
DIFF_VERTICAL(1) Vertical.
DIFF_NORTHWEST_SOUTHEAST(2) North-West.
DIFF_NORTHEAST_SOUTHWEST(3) North-East.
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 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 BIDlgs32.dll installed.
hWnd LONGLONG Handler of the parent window.
See Also