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From: mar@athena.mit.edu (Mark A. Rosenstein)
Newsgroups: comp.lang.postscript
Subject: Re: path to calligraphy penstroke
Message-ID: <1990May30.020154.7416@athena.mit.edu>
Date: 30 May 90 02:01:54 GMT
Article-I.D.: athena.1990May30.020154.7416
References: <12041@june.cs.washington.edu>
Sender: news@athena.mit.edu (News system)
Reply-To: mar@athena.mit.edu (Mark A. Rosenstein)
Organization: Massachusetts Institute of Technology
Lines: 114

I actually wrote a routine at one point to do calligraphy.  There are
three operators I defined: penwidth which takes 1 argument and sets
the width of the nib, penangle which takes 1 argument and sets the
angle of the nib, and penstroke, which strokes the current path with a
pen that has the last specified angle and width.  Like stroke, it does
a newpath after it has produced its line.  Here are the routines and a
sample usage.
					-Mark Rosenstein

		 Constants aren't and Variables wont

----------------

%!  penstroke routine

% data is kept in a private dictionary
/pendict 20 dict def
pendict begin
	/mtx matrix def
	/angle 30 def
	/width 1 def
	/dx 0 def
	/dy 0 def
	/trans { dy add exch dx add exch } def
	/calculate {
		/mtx [ angle cos angle sin dup neg 2 index 0 0 ] def
		/dx width 0 mtx transform /dy exch def def
	} def
end

% set the current angle of the pen nib
/penangle {
	pendict begin
		/angle exch def
		calculate
	end
} bind def

% set the width of the pen nib
/penwidth {
	pendict begin
		/width exch def
		calculate
	end
} bind def

% stroke the current path with the current nib
/penstroke { pendict begin
    {	/yo exch def
	/xo exch def
	/xx xo def
	/yy yo def
    } { gsave
	/y exch def
	/x exch def
	newpath xx yy moveto x y lineto 
	x y trans lineto
	xx yy trans lineto
	closepath fill
	/xx x def
	/yy y def
	grestore
    } {	gsave
	/y exch def
	/x exch def
	/y2 exch def
	/x2 exch def
	/y1 exch def
	/x1 exch def
	newpath xx yy moveto x1 y1 x2 y2 x y curveto
	x y trans lineto
	x2 y2 trans x1 y1 trans xx yy trans curveto
	closepath fill
	/xx x def
	/yy y def
	grestore
    } { gsave
	newpath xx yy moveto xo yo lineto
	xo yo trans lineto
	xx yy trans lineto
	closepath fill
	/xx xo def
	/yy yo def
	grestore
    } pathforall
    newpath
end } bind def


% Here is some sample usage:
/inch { 72 mul } def

10 penwidth 30 penangle

1 inch 2 inch translate

0 0 moveto 0 1 inch lineto
.5 inch 0 lineto
.5 inch 1 inch lineto penstroke

1.5 inch 0 moveto
1.5 inch .5 inch .5 inch -90 270 arc 
closepath penstroke

2 inch 0 moveto
2.6 inch 1 inch lineto
3.2 inch 0 lineto
closepath penstroke

1 inch 4 inch moveto
/Helvetica findfont 1 inch scalefont setfont
(TESTING) false charpath penstroke

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