Documentation of hpgl

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Function Synopsis

hpgl( pj )

Help text

HPGL Method to add control characters to beginning of HPGL files.
   As produced by MATLAB, the HPGL files are missing control codes needed
   for most operating systems to properly communicate with HPGL plotters.
   These control codes are added to lines left blank in the HPGL file
   so that users may modify them match their hardware. The control
   codes given work with HP7475A and compatible plotters.

Cross-Reference Information

Listing of function hpgl

function hpgl( pj )

%   Copyright 1984-2000 The MathWorks, Inc. 
%   $Revision: 1.2 $  $Date: 2000/06/01 02:54:06 $

%Add Xon/Xoff handshaking parameters to HPGL files.
% If these settings are not appropriate for you hardware,
% modify it -- the first line of the HPGL file is 80 blanks
% to make this easier.
% To make no such modifications, replace the elseif above with
% elseif 0

%Open the HPGL file we just wrote out.
[ fid, msg ] = fopen( pj.FileName, 'r+' );
if ( fid == -1 )
    error( ['Could not open HPGL file: ''' msg ''''] );
end

%The Escape code is ASCII 27
esc = setstr( 27 );

%Plotter initialization:
% Plotter On Instruction == ESC.Y;
% Set Handshake Mode 2 Instruction == ESC.I<options>;
%   3 optional arguments <blocksize>;<enquiry>;<acknowledgment>
%               blocksize == 200 bytes
%       enquiry character == defaults to NULL
%   acknowledgment string == ASCII character 17
% Set Extended Output and Handshake Mode Instruction == ESC.N<options>;
%   3 optional arguments <delay>;<trigger>
%     intercharacter delay == 50 milliseconds
%   Xoff trigger character == ASCII 19
% For more information, see your plotter manual or local hardware guru.
fprintf( fid, [esc '.Y;' esc '.I200;;17:' esc '.N50;19:;'] );

err = fseek( fid, 0, 'eof' );
if ( err == -1 )
    error('Could not seek to EOF of HPGL file');
end

%Plotter off
% Can't turn off power, just puts plotter in passive state
fprintf( fid, [esc '.Z\n'] );

fclose( fid );