ImageGear for C and C++ on Linux v20.0 - Updated
API Reference Guide > MD Component API Reference > MD Component Functions Reference > Image Processing Functions > MED_IP_reduce_depth_with_LUT

This function takes a 16-bit grayscale image and reduces it to a 8-bit grayscale one using provided (filled) LUT or current 16x8 display LUT.


Copy Code
        HIGEAR hIGear, 
        const LPBYTE lpLUT, 
        const DWORD dwEntries


Name Type Description
hIGear HIGEAR The HIGEAR handle to the image to convert.
lpLUT const LPBYTE A far pointer to the look-up table to use for reduction. Set to NULL if you want to use the display LUT.
dwEntries const DWORD A variable of type DWORD that specifies the number of entries in the LUT. This value is ignored if the display LUT is used.

Return Value:

Returns the number of ImageGear errors that occurred during the function call.

Supported Raster Image Formats:

Grayscale – 9…16 bpp.


The 16-bit image is discarded and replaced with the new 8-bit grayscale image.

To reduce memory requirements the LUT does not have to have a 16-bit input. dwEntries should hold the number of entries in the LUT. If there is a pixel found that can overflow the LUT it is ignored and replaced with a 0.

This function does not reduce 8-bit images. To reduce an 8-bit image, use the appropriate IG_IP_color_reduce_...() function from the baseline ImageGear API.

Once this function is called, the display LUT will be thrown away, since it is now an 8-bit image.

See also MED_IP_reduce_depth_with_downshift().

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