% name of textfile: Pxx Perspective Revisited(DL/Synergetics Feb 02 v1.0)
% ....

% =========

% This file requires the previous download of gonzo.ps
% available from http://www.tinaja.com/post01.asp

% Make sure the following line agrees with your gonzo.ps location
% Use DOUBLE SLASHES anytime you want a single slash in a PS string.

  (C:\\windows\\desktop\\gonzo\\gonzo.ps) run  % use internal gonzo

% ==========



gonzo begin
gutility begin
printerror
nuisance begin

%  Rewritten code does the 2 point "architect" perspective  transform

% 100 100 10 setgrid
% 26 17 showgrid



%% fudged figure


save /fudge exch store

0 0 translate  1 dup scale   % adjust position



% perspective transform is

%   x0 y0 z0 distances from observer to 0 0 0 perspective origin
%   x is left right y is in out z is up down
  
%    x' = y0(x-x0)/(y+y0)       % y must go first !!
%    y' = y0(z-z0)/(y+y0)

%  this example will use a fixed y for a flat panel.


      /x0 -250 def         % left right observer to 000 origin
      /y0 700 def       % in out observer to 000 origin    was 700
      /z0 400 def       % up-down observer to 000 origin

      /objrot 25 store  % rotation of object in x y plane

                          
  % This is the raw transform that accept three variables x,y,z  and returns 2D x' y'

   
      /ptransform {  /zz1 exch store  /yy1 exch store  /xx1 exch store  


                    /yy xx1 objrot sin mul   yy1 objrot cos mul add store  % rotate
                    /xx xx1 objrot cos mul   yy1 objrot sin mul sub store

                    y0 xx x0 sub yy y0 add div mul   % generate x'
              
                    y0 zz1 z0 sub yy y0 add div mul   % generate y'
          
                    } def

%  This is a perspective moveto

     /pmoveto { 3 copy  
                /lastzmt exch store  /lastz lastzmt store
                /lastymt exch store  /lasty lastymt store 
                /lastxmt exch store  /lastx lastxmt store  

                ptransform moveto                              



    } def

     /plineto {3 copy  
                /lastz exch store 
                /lasty exch store 
                /lastx exch store 

                ptransform lineto




} def

    /pcurveto  {/z3 exch store /y3 exch store /x3 exch store  % NOTE: NEEDS NINE VARS
                /z2 exch store /y2 exch store /x2 exch store
                /z1 exch store /y1 exch store /x1 exch store

                /lastz z3 store /lasty y3 store /lastx x3 store

                x1 y1 z1 ptransform
                x2 y2 z2 ptransform
                x3 y3 z3 ptransform

                curveto } def


      /pclosepath { lastxmt lastymt lastzmt 
                    ptransform lineto
                    closepath } def

% enter with yy pxzremap

/pxzremap {  /yy exch store mark

    {yy exch /pmoveto cvx }
    {yy exch /plineto cvx }

 { /zz3 exch store /xx3 exch store 
   /zz2 exch store /xx2 exch store 
   /zz1 exch store /xx1 exch store 
    xx1 yy zz1 xx2 yy zz2 xx3 yy zz3 /pcurveto cvx}

    {/pclosepath cvx }
    pathforall ] newpath cvx exec


      } def

/pyzremap {  /xx exch store mark     

    {/zz exch store neg /yy  exch store xx yy zz /pmoveto cvx } 
    {/zz exch store neg /yy  exch store xx yy zz /plineto cvx }

 { /zz3 exch store neg /yy3 exch store 
   /zz2 exch store neg /yy2 exch store 
   /zz1 exch store neg /yy1 exch store 
    xx yy1 zz1 xx yy2 zz3 xx yy3 zz3 /pcurveto cvx}

    {/pclosepath cvx }
    pathforall ] newpath cvx exec


      } def


/pxyremap {  /zz exch store mark

    {zz /pmoveto cvx }
    {zz /plineto cvx }

 { /yy3 exch store /xx3 exch store 
   /yy2 exch store /xx2 exch store 
   /yy1 exch store /xx1 exch store 
    xx1 yy1 zz xx2 yy2 zz xx3 yy3 zz /pcurveto cvx}

    {/pclosepath cvx }
    pathforall ] newpath cvx exec


      } def







% ptranslate accepts x y and z and moves the origin. Should be gsave bracketed
% ALGORITHM WRONG. MAGNIFIED FRONT RETAINED.


/ptranslate {/zf exch store /yf exch store /xf exch store 

      0 0 0 ptransform /yp exch store /xp exch store
      xf yf zf ptransform yp sub exch xp sub exch translate} def






/showxz {/yyy exch store false charpath yyy pxzremap} def

/showyz {/xxx exch store false charpath xxx pyzremap} def

/showxy {/zzz exch store false charpath zzz pxyremap} def

/font1 /StoneSerif-Bold 92 gonzofont
font1

0 600 translate 1 dup scale


     0.62 settint 
     0 0 mt 100 pu 100 pr 100 pd closepath 0 pxzremap 0.30 setgray fill
     8 8 mt 84 pu 84 pr 84 pd closepath 0 pxzremap 0.85 setgray fill

     14 18 moveto (A) 0 showxz 0.30 setgray fill
 
    % yz runs negative into picture so lettering is right reading

     0.33 settint 
     -100 0 mt 100 pu 100 pr 100 pd closepath 0 pyzremap 0.30 setgray fill
     -92 8 mt 84 pu 84 pr 84 pd closepath 0 pyzremap 0.85 setgray fill

     -86 18 moveto (B) 0 showyz 0.30 setgray fill


     0 settint 
     0 0 mt 100 pu 100 pr 100 pd closepath 100 pxyremap 0.30 setgray fill
     8 8 mt 84 pu 84 pr 84 pd closepath 100 pxyremap 0.85 setgray fill

     14 18 moveto (C) 100 showxy 0.30 setgray fill




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