harvey/sys/src/cmd/gs/lib/stocht.ps

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% $Id: stocht.ps,v 1.3 2000/09/19 18:29:11 lpd Exp $
% helper file to simplify use of Stochastic Halftone - uses ht_ccsto.ps

% This file sets the /StochasticDefault /Halftone as the current
% and the /Default halftoning, loading the Stochastic halftone
% if required.

% Stochastic halftoning is recommended for inkjet printers, and may
% produce output as pleasing as the more computationally expensive
% "error diffusion" that *some* device drivers provide.

% For printing technologies other than inkjet, Stochastic halftoning
% may not look better than standard screening. In particular, thermal
% transfer and direct thermal tend to be better with standard ordered
% screening methods. Some laser printers may produce "smoother"
% looking gray shades with Stochastic halftoning. Try it, and if
% you like it, use it.

% Note that this /Default halftone can be overridden by PostScript
% operators that set the screening or halftone (such as setscreen).

% To make Stochastic Halftone be "sticky" so that other screening and
% halftone setting in the subsequent PostScript will be ignored, use:
%	-c "<< /HalftoneMode 1 >> setuserparams"
% on the command line prior to the file to be processed. For example,
%
% gs stocht.ps -c "<< /HalftoneMode 1 >> setuserparams" -f examples/tiger.ps

% Alternatively, the command to set the /HalftoneMode userparam can be
% concatenated to this file (see below).

% =====================================================================
% Try to get the previously defined resource
{ /StochasticDefault /Halftone findresource } stopped
{
  pop pop
  % Need to load the Stochastic Halftone using the lib file
  (ht_ccsto.ps) runlibfile
} if

% If we didn't error out by now, then go ahead and define the /Default
/StochasticDefault /Halftone findresource
/Default exch /Halftone defineresource
sethalftone	% Use the halftone

% Uncomment the next line to make the Stocahstic halftoning be "sticky"
% << /HalftoneMode 1 >> setuserparams