This function reduces the image to a fewer number of Bits Per Pixel.

Declaration:

AT_ERRCOUNT ACCUAPI IG_IP_color_reduce_diffuse ( 
        HIGEAR hIGear, 
        UINT nToBits, 
        INT level, 
        LPAT_RGBQUAD lpPalette 
);

Arguments:

Return Value:

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

Supported Raster Image Formats:

Indexed RGB – 4, 8 bpp;
Grayscale – 4, 8 bpp;
RGB – 24 bpp.

Sample:

None

Example:

HIGEAR hIGear;   /* HIGEAR handle of 4, 8, or 24 bit image */
/* Reduce image to 1-bit black-and-white: */
IG_IP_color_reduce_diffuse ( hIGear, 1, 128, NULL );

Remarks:

The target bit depth is specified by argument nToBits. In general, a color image will be reduced to a fewer number of colors, and a grayscale image will be reduced to a fewer number of shades of gray. Note that setting nToBits = 1 will reduce the image to monochrome or black-and-white.

When reducing the image to monochrome (black-and-white), the level parameter sets a threshold value for the target image:

• level = 128 means that black and white in the target image will be in equal proportion.
• level greater than 128 would mean more bright than dark.
• level less than 128 would mean more dark than bright.

The input number of Bits Per Pixel must be greater than nToBits, or an error will result.