Halftone method (ILEADRasterProcess)

Visual Basic example

Visual C++ 5.0 example

Delphi 4 example

C++ Builder example

 

Syntax

short Halftone (ILEADRaster *pRaster, HalftoneConstants Type, long iAngle, short iDim);

Overview

Refer to Examining and Altering Bitmaps.

Remarks

Converts a 1-, 4-, 8-, 16-, 24-, or 32-bit bitmap to a halftoned bitmap, with a specified pattern rotation. A halftoned bitmap is a 1-bit bitmap that has been dithered for black and white printing or display.

For the HALFTONE_USERDEF option, the number of bitmaps in the list must be at least equal to (iDim * iDim + 1). Bitmaps with higher indexes correspond to higher intensity values.

This method can process the whole image or a region of the image.

This method does not support 12 and 16-bit grayscale and 48 and 64-bit color images.

If the bitmap is originally 1-bit but is not black and white, this method changes it to black and white.

This method does not support signed data images. It returns the error code ERROR_SIGNED_DATA_NOT_SUPPORTED if a signed data image is passed to this method.

See Also

Elements:

GrayScale method, GrayScaleExt method

Topics:

Raster Images: Doing Color Expansion or Reduction