[ SEA-GHOST MINI SHELL]

% Copyright (C) 2001-2018 Artifex Software, Inc.
% All Rights Reserved.
%
% This software is provided AS-IS with no warranty, either express or
% implied.
%
% This software is distributed under license and may not be copied,
% modified or distributed except as expressly authorized under the terms
% of the license contained in the file LICENSE in this distribution.
%
% Refer to licensing information at http://www.artifex.com or contact
% Artifex Software, Inc.,  1305 Grant Avenue - Suite 200, Novato,
% CA 94945, U.S.A., +1(415)492-9861, for further information.
%

% gs_dpnxt.ps
% NeXT Display PostScript extensions

% Define the operation values for compositing.  These must match the values
% in gsdpnext.h, which also are the ones from the NeXT documentation.
% We put them in systemdict, which seems like as good a place as any.
mark
  /Clear /Copy /Sover /Sin /Sout /Satop /Dover /Din /Dout /Datop /Xor
  /PlusD /PlusL /Highlight	% not sure about Highlight
counttomark { counttomark 1 sub def } repeat pop

% We implement readimage and sizeimage using the following 3 otherwise
% undocumented lower-level operators:
%
%	<x> <y> <width> <height> <matrix> .sizeimagebox
%	  <dev_x> <dev_y> <dev_width> <dev_height> <matrix>
%
%	- .sizeimageparams <bits/sample> <multiproc> <ncolors>
%
%	<device> <x> <y> <width> <max_height> <alpha?> <std_depth|null>
%	  <string> .getbitsrect <height> <substring>
%
% NOTE: These operators are subject to change without notice!

% Implement readimage using .getbitsrect.  Experimentation on a NeXT system
% shows that the data is always returned in order of increasing device Y,
% regardless of the CTM.
%
% Note that we can't make stack protection work for this operator,
% because it must remove its operands from the stack before calling
% the supplied procedure(s).

/readimage {		% <x> <y> <width> <height> <proc> [... <procN-1>]
                        %   <string> <alpha?> readimage -
  .sizeimageparams exch {
        % multiproc = true.  If N > 1, store the procedures in an array.
    exch pop 1 index { 1 add } if
        % Stack: ... string alpha? nprocs
    dup 1 eq {
      pop //false	% only 1 procedure, multiproc is irrelevant
    } {
      dup array 4 1 roll 3 add 2 roll astore 3 1 roll //true
    } ifelse
  } {
        % multiproc = false.
    pop pop //false
  } ifelse
        % Map the rectangle to device coordinates.
        % Stack: x y w h proc(s) str alpha? multi?
  8 -4 roll matrix .sizeimagebox pop 8 4 roll
        % Make sure we allocate the operand array in local VM
        % to avoid a possible invalidaccess.
  .currentglobal //false .setglobal 9 1 roll
  exch { 1 } { 0 } ifelse exch		% alpha is last, if present
  exch 4 1 roll 8 array astore exch .setglobal
  {	% Read out a block of scan lines and pass them to the procedure.
        % Stack: [x y w h alpha? proc(s) str multi?] -- we must consume this.
    dup 3 get 0 eq { pop exit } if
    aload 9 1 roll pop exch pop currentdevice 7 1 roll
        % Always read out the data as standard (not native) pixels.
    .sizeimageparams pop pop exch .getbitsrect
        % Stack: [x y w h alpha? proc(s) str multi?] hread substr
    3 -1 roll
        % Stack: hread substr [x y w h alpha? proc(s) str multi?]
    dup 1 2 copy get 5 index add put
        % Stack: hread substr [x y' w h alpha? proc(s) str multi?]
    dup 3 2 copy get 6 -1 roll sub put
        % Stack: substr [x y' w h' alpha? proc(s) str multi?]
    dup 5 get exch 7 get {
        % multiproc = true, pass each plane to a different procedure.
        % Stack: substr procs
      0 1 2 index length 1 sub {
        % Push 1 plane and its procedure under the top 2 elements.
        % Stack: ... substr procs plane#
        2 index length 2 index length idiv	% bytes per plane
        dup 2 index mul exch
        % Stack: ... substr procs plane# start length
        4 index 3 1 roll getinterval 4 1 roll
        2 copy get 4 1 roll pop
      } for
      exch pop length 2 mul .execn
    } {
        % multiproc = false, just call the procedure.
      exec
    } ifelse
  } //systemdict /exec get 3 packedarray cvx loop
} bind odef

%
%   <w>  <h>  <bpc>  <mtx>  <dsrc0> ... <multi>  <ncomp>   alphaimage   -
%
img_utils_dict begin
/.alphaimage  where
  {
    pop
    .currentglobal //true .setglobal
    /alphaimage
      {
        //true
          //.colorimage
        stopped
          { /alphaimage .systemvar $error /errorname get signalerror }
        if
      }
    .bind systemdict begin odef end
    .setglobal
  }
if
end

% Implement sizeimage using lower-level operators.

/sizeimage {		% <x> <y> <width> <height> <matrix> sizeimage
                        %   <devwidth> <devheight> <bits/sample> <matrix>
                        %   <multiproc> <ncolors>
  .sizeimagebox 5 -2 roll pop pop
  .sizeimageparams 3 -1 roll 4 1 roll
} bind odef