LOGOLib.ps

%!PS-Adobe-3.0
%
% LOGO library by Ruda Moura (Public Domain)
% July 3, 2018
%

% num inch num
% Convert from inches to points
/inch {72 mul} def

% num cm num
% Convert from cms to points
/cm {28.346456693 mul} def

% Maximum integer (2^32-1)
/maxint 16#7FFFFFFF def

% - urand real
% Return a uniform random number from [0, 1]
/urand {rand maxint div} def

% int random int
% Return a random integer from [0, num)
/random {rand exch mod} def

% - setrandomgraycolor -
% Select a random gray color to draw
/setrandomgraycolor {urand setgray} def

% - setrandomcolor -
% Select a random color to draw
/setrandomcolor {urand urand urand setrgbcolor} def

% - setrandomlinewidth -
% Select a random line width to draw
/setrandomlinewidth {urand setlinewidth} def

% - setrandomposition -
% Move "turtle" to a random position
/setrandomposition {9 inch random 11 inch random moveto} def

% x y setxy -
% Position "turtle" to x y
/setxy {moveto} bind def

% - home -
% Move "turtle" to the home position (the middle of the page)
/home {newpath 4 inch 5 inch moveto} bind def

% n forward -
% Move "turtle" forward by 'n' positions
/forward {
	0 exch userdict (draw) get
	{rlineto currentpoint stroke newpath moveto} {rmoveto} ifelse
} bind def

% n backward -
% Move "turtle" backward by 'n' positions
/backward {neg forward} bind def

% angle right -
% Rotate "turtle" to the right bindy 'angle' degrees
/right {neg rotate} bind def

% angle left -
% Rotate "turtle" to the left by 'angle' degrees
/left {rotate} bind def

% - penup -
% Set pen up
/penup {userdict (draw) false put} bind def

% - pendown -
% Set pen down
/pendown {userdict (draw) true put} bind def

% - showturle -
% Show "turtle"
/showturtle {userdict (turtle) true put} bind def

% - hideturtle -
% Hide "turtle"
/hideturtle {userdict (turtle) false put} bind def

% Abbreviations/aliases
/fd {forward}    bind def
/bd {backward}   bind def
/rt {right}      bind def
/lt {left}       bind def
/pu {penup}      bind def
/pd {pendown}    bind def
/st {showturtle} bind def
/ht {hideturtle} bind def

% Initialize
home
pendown
showturtle

% End of LOGO Library