texdraw non-update

git-svn-id: svn://tug.org/texlive/trunk@31894 c570f23f-e606-0410-a88d-b1316a301751

5 files changed, 2133 insertions, 505 deletions

diff --git a/Master/texmf-dist/tex/generic/texdraw/texdraw.tex b/Master/texmf-dist/tex/generic/texdraw/texdraw.tex
index 9b354424510..4201bf77c8d 100644
--- a/Master/texmf-dist/tex/generic/texdraw/texdraw.tex
+++ b/Master/texmf-dist/tex/generic/texdraw/texdraw.tex
@@ -18,563 +18,1117 @@
 %  Canada  H3A 2A7
 
 %  kabal@TSP.EE.McGill.CA
+ 
 \def\setRevDate $#1 #2 #3${#2}
 \def\TeXdrawId{\setRevDate $Date: 1995/12/19 16:40:42 $ TeXdraw V2R0}
+
+% ===============================================================
+
+% The TeXdraw macros allow PostScript line drawings and such to be
+% generated from within TeX and LaTeX.
+% (1) TeXdraw allows TeX text (either horizontal or rotated) to be
+%     superimposed on the figure.
+% (2) TeXdraw implements a \bsegment-\esegment environment which allows
+%     parameter changes and coordinate changes to be kept local.  In
+%     effect, these segments are self-contained relocatable procedures.
+% (3) TeX's macro facility can be used to modularize drawing units and
+%     produce more complex entities from simple elements.
+% (4) The drawing can be positioned on the page like any other TeX box.
+
+% TeXdraw coordinate units have positive X to the right and positive Y up.
+% The drawing units can be selected (initially inches).  In addition, two
+% scaling parameters - unit scale and segment scale - are available.  Their
+% effects are multiplicative.
+
+% Segments allow for relocatable drawing units.  Inside each segment the
+% coordinates are relative to the initial point, which becomes (0 0).
+% Scaling is local to segments.  Each segment inherits the unit scale
+% scaling from outside the segment, but any changes apply to that segment
+% and inferior segments.  The segment scale factor is reset to unity on
+% entry to each segment.
+
+% The coordinates given as command arguments are used to determine
+% the size of the drawing.  The width of the plot line, sizes of
+% arrowheads, arcs or text do not affect the size of the drawing.
+
+% TeXdraw writes PostScript commands to an intermediate file.  After the
+% drawing is finished, the PostScript file is included in the document as a
+% PostSript include file.
+
+%  This file is divided into 4 parts,
+%  - TeXdraw user interface
+%  - Utility definitions
+%  - Low level definitions
+%  - PostScript file macros
+
+
 \chardef\catamp=\the\catcode`\@
 \catcode`\@=11
-\long
+
+% ===============================================================
+% ===== TeXdraw user interface ==================================
+\long                              % \centertexdraw needs to be very \long
 \def\centertexdraw #1{\hbox to \hsize{\hss
-\btexdraw #1\etexdraw
-\hss}}
+                                      \btexdraw #1\etexdraw
+                                      \hss}}
+
+% ====== Begin TeXdraw
+% Inside the texdraw box:
+%   The \vbox should be of zero size; none of the TeXdraw drawing commands
+%   generate text, the TeXdraw text commands generate zero size boxes.
+
 \def\btexdraw {\x@pix=0             \y@pix=0
-\x@segoffpix=\x@pix  \y@segoffpix=\y@pix
-\t@exdrawdef
-\setbox\t@xdbox=\vbox\bgroup\offinterlineskip
-\global\d@bs=0
-\global\t@extonlytrue
-\global\p@osinitfalse
-\s@avemove \x@pix \y@pix
-\m@pendingfalse
-\global\p@osinitfalse
-\p@athfalse
-\the\everytexdraw}
+               \x@segoffpix=\x@pix  \y@segoffpix=\y@pix
+% Set the default values (define outside of the group so that \etexdraw can
+% see the scaling parameters)
+               \t@exdrawdef
+               \setbox\t@xdbox=\vbox\bgroup\offinterlineskip
+                   \global\d@bs=0           % pending segments
+                   \global\t@extonlytrue    % no PS commands yet
+                   \global\p@osinitfalse
+                   \s@avemove \x@pix \y@pix % capture the initial position
+                   \m@pendingfalse
+                   \global\p@osinitfalse    % capture the next move
+                   \p@athfalse
+                   \the\everytexdraw}
+
+% ====== End TeXdraw
+% Write out a trailer, close the file, bring in the PostScript code as
+% a \special include file.  The \special is offset to position on the page
+% to be (llx,ury) in PostScript coordinates.
+
+% The drawing is placed in a \vbox of appropriate size (zero depth).  The
+% temporary PostScript file is superimposed with offsets such that the
+% lower lefthand corner of the drawing is aligned with the lower lefthand of
+% the box.  Then, the position is temporarily offset to that corresponding
+% to (0 0) to place the TeX text.  Note that TeX text goes on top of the
+% PostScript drawing.
 \def\etexdraw {\ift@extonly \else
-\t@drclose
-\fi
-\egroup
-\ifdim \wd\t@xdbox>0pt
-\t@xderror {TeXdraw box non-zero size,
-possible extraneous text}%
-\fi
-\vbox {\offinterlineskip
-\pixtobp \xminpix \l@lxbp  \pixtobp \yminpix \l@lybp
-\pixtobp \xmaxpix \u@rxbp  \pixtobp \ymaxpix \u@rybp
-\hbox{\t@xdinclude 
-[{\l@lxbp},{\l@lybp}][{\u@rxbp},{\u@rybp}]{\p@sfile}}%
-\pixtodim \xminpix \t@xpos  \pixtodim \yminpix \t@ypos
-\kern \t@ypos
-\hbox {\kern -\t@xpos
-\box\t@xdbox
-\kern \t@xpos}%
-\kern -\t@ypos\relax}}
+                 \t@drclose      % close the PostScript file
+               \fi
+               \egroup           % ends the \vbox \bgroup
+               \ifdim \wd\t@xdbox>0pt
+                 \t@xderror {TeXdraw box non-zero size,
+                             possible extraneous text}%
+               \fi
+               \vbox {\offinterlineskip
+                      \pixtobp \xminpix \l@lxbp  \pixtobp \yminpix \l@lybp
+                      \pixtobp \xmaxpix \u@rxbp  \pixtobp \ymaxpix \u@rybp
+                      \hbox{\t@xdinclude 
+                        [{\l@lxbp},{\l@lybp}][{\u@rxbp},{\u@rybp}]{\p@sfile}}%
+                      \pixtodim \xminpix \t@xpos  \pixtodim \yminpix \t@ypos
+                      \kern \t@ypos
+                      \hbox {\kern -\t@xpos
+                             \box\t@xdbox       % TeX text
+                             \kern \t@xpos}%
+                      \kern -\t@ypos\relax}}
+
+% ===== Drawing scaling
+% The units in any segment may be scaled arbitrarily.  A unit scale is
+% local to a segment but affects enclosed segments unless specifically
+% overridden in that segment.  In addition there is a segment scale.  The
+% overall scale is the product of the two scaling factors.
+%
+% Scaling is handled entirely on the TeX side, the PostScript side gets
+% absolute pixel coordinates.
+
+% Drawing units, e.g. "in" or "cm"
 \def\drawdim #1 {\def\d@dim{#1\relax}}
+
+% \u@nitsc - unit scale
+% \s@egsc  - segment scale
+% \d@sc    - drawing scale, product of the unit scale and segment scale
+
+% Note that successive application of relative scale factors can lead
+% to poor accuracy of the final scale factor.  Each scale factor is
+% represented to about 5 decimal digits after the decimal point.
 \def\setunitscale #1 {\edef\u@nitsc{#1}%
-\realmult \u@nitsc \s@egsc \d@sc}
+                      \realmult \u@nitsc \s@egsc \d@sc}
 \def\relunitscale #1 {\realmult {#1}\u@nitsc \u@nitsc
-\realmult \u@nitsc \s@egsc \d@sc}
+                      \realmult \u@nitsc \s@egsc \d@sc}
 \def\setsegscale #1 {\edef\s@egsc {#1}%
-\realmult \u@nitsc \s@egsc \d@sc}
+                     \realmult \u@nitsc \s@egsc \d@sc}
 \def\relsegscale #1 {\realmult {#1}\s@egsc \s@egsc
-\realmult \u@nitsc \s@egsc \d@sc}
+                     \realmult \u@nitsc \s@egsc \d@sc}
+
+% ===== Drawing segments
+% The position is restored after a segment.
+% Segments use TeX grouping on the TeX side and gsave/grestore on the
+% PostScript side to keep changes local.  On the TeX side segments have
+% (0 0) as the initial point, while the PostScript side sees no scale
+% changes or translations.
 \def\bsegment {\ifp@ath
-\f@lushbs
-\f@lushmove
-\fi
-\begingroup
-\x@segoffpix=\x@pix
-\y@segoffpix=\y@pix
-\setsegscale 1
-\global\advance \d@bs by 1\relax}
+                 \f@lushbs
+                 \f@lushmove
+               \fi
+               \begingroup
+               \x@segoffpix=\x@pix
+               \y@segoffpix=\y@pix
+               \setsegscale 1
+               \global\advance \d@bs by 1\relax}
 \def\esegment {\endgroup
-\ifnum \d@bs=0
-\writetx {es}%
-\else
-\global\advance \d@bs by -1
-\fi}
+               \ifnum \d@bs=0
+                 \writetx {es}%
+               \else
+                 \global\advance \d@bs by -1
+               \fi}
+
+% Save a position
+% Save each coordinate as the macro "*name".  The macro is defined to
+% be the pixel coordinate value.
 \def\savecurrpos (#1 #2){\getsympos (#1 #2)\a@rgx\a@rgy
-\s@etcsn \a@rgx {\the\x@pix}%
-\s@etcsn \a@rgy {\the\y@pix}}
+                         \s@etcsn \a@rgx {\the\x@pix}%
+                         \s@etcsn \a@rgy {\the\y@pix}}
 \def\savepos (#1 #2)(#3 #4){\getpos (#1 #2)\a@rgx\a@rgy
-\coordtopix \a@rgx \t@pixa
-\advance \t@pixa by \x@segoffpix
-\coordtopix \a@rgy \t@pixb
-\advance \t@pixb by \y@segoffpix
-\getsympos (#3 #4)\a@rgx\a@rgy
-\s@etcsn \a@rgx {\the\t@pixa}%
-\s@etcsn \a@rgy {\the\t@pixb}}
+                            \coordtopix \a@rgx \t@pixa
+                            \advance \t@pixa by \x@segoffpix
+                            \coordtopix \a@rgy \t@pixb
+                            \advance \t@pixb by \y@segoffpix
+                            \getsympos (#3 #4)\a@rgx\a@rgy
+                            \s@etcsn \a@rgx {\the\t@pixa}%
+                            \s@etcsn \a@rgy {\the\t@pixb}}
+
+% ===== Line parameters
+% The following parameters apply to subsequent lines.  Each of these
+% commands invokes a stroke to draw the previous line segments,
+% establishes the current point and then changes the line parameter.
+% The parameters are kept local by the PostScript gsave/grestore
+% mechanism.  We use \writetx here, instead of \writeps, since we
+% do not want to flush any moves.
 \def\linewd #1 {\coordtopix {#1}\t@pixa
-\f@lushbs
-\writetx {\the\t@pixa\space sl}}
+                \f@lushbs
+                \writetx {\the\t@pixa\space sl}}
 \def\setgray #1 {\f@lushbs
-\writetx {#1 sg}}
+                 \writetx {#1 sg}}
 \def\lpatt (#1){\listtopix (#1)\p@ixlist
-\f@lushbs
-\writetx {[\p@ixlist] sd}}
+                \f@lushbs
+                \writetx {[\p@ixlist] sd}}
+
+% ===== Line drawing
+% PostScript uses the concept of a path consisting of line segments.
+% In this interface to PostScript, paths are continuous across the
+% beginning of segments.  Paths terminate at the end of a segment with
+% an implicit move.  In addition, paths are both terminated and started
+% with a move.  There is a current point at all times, starting with
+% initial position (0,0).
 \def\lvec (#1 #2){\getpos (#1 #2)\a@rgx\a@rgy
-\s@etpospix \a@rgx \a@rgy
-\writeps {\the\x@pix\space \the\y@pix\space lv}}
+                  \s@etpospix \a@rgx \a@rgy
+                  \writeps {\the\x@pix\space \the\y@pix\space lv}}
 \def\rlvec (#1 #2){\getpos (#1 #2)\a@rgx\a@rgy
-\r@elpospix \a@rgx \a@rgy
-\writeps {\the\x@pix\space \the\y@pix\space lv}}
+                   \r@elpospix \a@rgx \a@rgy
+                   \writeps {\the\x@pix\space \the\y@pix\space lv}}
 \def\move (#1 #2){\getpos (#1 #2)\a@rgx\a@rgy
-\s@etpospix \a@rgx \a@rgy
-\s@avemove \x@pix \y@pix}
+                  \s@etpospix \a@rgx \a@rgy
+                  \s@avemove \x@pix \y@pix}
 \def\rmove (#1 #2){\getpos (#1 #2)\a@rgx\a@rgy
-\r@elpospix \a@rgx \a@rgy
-\s@avemove \x@pix \y@pix}
+                   \r@elpospix \a@rgx \a@rgy
+                   \s@avemove \x@pix \y@pix}
+
+% ===== Circles, ellipses and arcs
+% Note that arcs do not update the size of the drawing.
+% \lcir, stroked circle
+%   r:#1 -  radius
+% \fcir, filled circle
+%   f:#1 - fill gray level, 0 is black, 1 is white
+%   r:#2 - radius
+% \ellip, stroked ellipse
+%   rx:#1 - x radius
+%   ry:#2 - y radius
+% \fellip, filled ellipse
+%   f:#1 - fill gray level, 0 is black, 1 is white
+%   rx:#1 - x radius
+%   ry:#2 - y radius
+% \larc, stroked counterclockwise arc, with the present position being
+%        the center of the arc.  Only the arc is drawn (not the line
+%        joining the center to the beginning of the arc)
+%   r:#1  - radius
+%   sd:#2 - start angle (degrees)
+%   ed:#3 - end angle (degrees)
 \def\lcir r:#1 {\coordtopix {#1}\t@pixa
-\writeps {\the\t@pixa\space cr}%
-\r@elupd \t@pixa \t@pixa
-\r@elupd {-\t@pixa}{-\t@pixa}}
+                \writeps {\the\t@pixa\space cr}%
+                \r@elupd \t@pixa \t@pixa
+                \r@elupd {-\t@pixa}{-\t@pixa}}
 \def\fcir f:#1 r:#2 {\coordtopix {#2}\t@pixa
-\writeps {\the\t@pixa\space #1 fc}%
-\r@elupd \t@pixa \t@pixa
-\r@elupd {-\t@pixa}{-\t@pixa}}
+                     \writeps {\the\t@pixa\space #1 fc}%
+                     \r@elupd \t@pixa \t@pixa
+                     \r@elupd {-\t@pixa}{-\t@pixa}}
 \def\lellip rx:#1 ry:#2 {\coordtopix {#1}\t@pixa
-\coordtopix {#2}\t@pixb
-\writeps {\the\t@pixa\space \the\t@pixb\space el}%
-\r@elupd \t@pixa \t@pixb
-\r@elupd {-\t@pixa}{-\t@pixb}}
+                     \coordtopix {#2}\t@pixb
+                     \writeps {\the\t@pixa\space \the\t@pixb\space el}%
+                     \r@elupd \t@pixa \t@pixb
+                     \r@elupd {-\t@pixa}{-\t@pixb}}
 \def\fellip f:#1 rx:#2 ry:#3 {\coordtopix {#2}\t@pixa
-\coordtopix {#3}\t@pixb
-\writeps {\the\t@pixa\space \the\t@pixb\space #1 fe}%
-\r@elupd \t@pixa \t@pixb
-\r@elupd {-\t@pixa}{-\t@pixb}}
+                     \coordtopix {#3}\t@pixb
+                     \writeps {\the\t@pixa\space \the\t@pixb\space #1 fe}%
+                     \r@elupd \t@pixa \t@pixb
+                     \r@elupd {-\t@pixa}{-\t@pixb}}
 \def\larc r:#1 sd:#2 ed:#3 {\coordtopix {#1}\t@pixa
-\writeps {\the\t@pixa\space #2 #3 ar}}
-\def\ifill f:#1 {\writeps {#1 fl}}
-\def\lfill f:#1 {\writeps {#1 fp}}
+                            \writeps {\the\t@pixa\space #2 #3 ar}}
+
+% ===== Fill commands
+% The form here completes a path with a closepath, applies the fill,
+% starts a newpath and moves to the current point.  The gray level has
+% 0 as black and 1 as white.  The current path is terminated.
+
+\def\ifill f:#1 {\writeps {#1 fl}}     % Fill only
+\def\lfill f:#1 {\writeps {#1 fp}}     % Stroke and fill
+
+% ===== Text
+% TeX text superimposed on the drawing
+%  \htext (x y){text} or \htext {text}
+%  \vtext (x y){text} or \vtext {text}
+%  \rtext td:angle (x y){text} or \rtext td:angle {text}
+%  \textref h:#1 v:#2
+
+% The TeX text (or whatever) is placed in an \hbox.  The box is rotated
+% for vertical text.  The text is placed on the drawing at the specified
+% location (coordinates specified) or the current location (coordinates
+% not specified).  The text reference point is placed at that location.
+% For the purposes of determining the drawing size, the text box is of
+% zero size.
+
+% Horizontal text
+% Check if the argument starts with a left parenthesis
 \def\htext #1{\def\testit {#1}%
-\ifx \testit\l@paren
-\let\next=\h@move
-\else
-\let\next=\h@text
-\fi
-\next {#1}}
+              \ifx \testit\l@paren
+                \let\next=\h@move
+              \else
+                \let\next=\h@text
+              \fi
+              \next {#1}}
+
+% Rotated text
 \def\rtext td:#1 #2{\def\testit {#2}%
-\ifx \testit\l@paren
-\let\next=\r@move
-\else
-\let\next=\r@text
-\fi
-\next td:#1 {#2}}
+                    \ifx \testit\l@paren
+                      \let\next=\r@move
+                    \else
+                      \let\next=\r@text
+                    \fi
+                    \next td:#1 {#2}}
+
+% Vertical text
 \def\vtext {\rtext td:90 }
+
+% Text reference point
+%  h:#1  text horizontal reference point - L, C or R
+%  v:#2  text vertical reference point - T, C or B
 \def\textref h:#1 v:#2 {\ifx #1R%
-\edef\l@stuff {\hss}\edef\r@stuff {}%
-\else
-\ifx #1C%
-\edef\l@stuff {\hss}\edef\r@stuff {\hss}%
-\else
-\edef\l@stuff {}\edef\r@stuff {\hss}%
-\fi
-\fi
-\ifx #2T%
-\edef\t@stuff {}\edef\b@stuff {\vss}%
-\else
-\ifx #2C%
-\edef\t@stuff {\vss}\edef\b@stuff {\vss}%
-\else
-\edef\t@stuff {\vss}\edef\b@stuff {}%
-\fi
-\fi}
+                          \edef\l@stuff {\hss}\edef\r@stuff {}%
+                        \else
+                          \ifx #1C%
+                            \edef\l@stuff {\hss}\edef\r@stuff {\hss}%
+                          \else  % default L
+                            \edef\l@stuff {}\edef\r@stuff {\hss}%
+                          \fi
+                        \fi
+                        \ifx #2T%
+                          \edef\t@stuff {}\edef\b@stuff {\vss}%
+                        \else
+                          \ifx #2C%
+                            \edef\t@stuff {\vss}\edef\b@stuff {\vss}%
+                          \else  % default B
+                            \edef\t@stuff {\vss}\edef\b@stuff {}%
+                          \fi
+                        \fi}
+
+% ===== Arrow vectors
 \def\avec (#1 #2){\getpos (#1 #2)\a@rgx\a@rgy
-\s@etpospix \a@rgx \a@rgy
-\writeps {\the\x@pix\space \the\y@pix\space (\a@type)
-\the\a@lenpix\space \the\a@widpix\space av}}
+                  \s@etpospix \a@rgx \a@rgy
+                  \writeps {\the\x@pix\space \the\y@pix\space (\a@type) %
+                            \the\a@lenpix\space \the\a@widpix\space av}}
+
 \def\ravec (#1 #2){\getpos (#1 #2)\a@rgx\a@rgy
-\r@elpospix \a@rgx \a@rgy
-\writeps {\the\x@pix\space \the\y@pix\space (\a@type)
-\the\a@lenpix\space \the\a@widpix\space av}}
+                   \r@elpospix \a@rgx \a@rgy
+                   \writeps {\the\x@pix\space \the\y@pix\space (\a@type) %
+                             \the\a@lenpix\space \the\a@widpix\space av}}
+
+% Arrowhead size
+%  l:#1 - length of the arrowhead
+%  w:#2 - width of the base of the arrowhead
 \def\arrowheadsize l:#1 w:#2 {\coordtopix{#1}\a@lenpix
-\coordtopix{#2}\a@widpix}
+                              \coordtopix{#2}\a@widpix}
+% Arrowhead type
+%  t:#1 - arrowhead type, F  filled triangle (using current gray level)
+%                         T  empty closed triangle
+%                         W  white filled triangle
+%                         V  Vee shape, at the end of the vector
+%                         H  (or other character) Vee shape, vector stops
+%                            short of the Vee
 \def\arrowheadtype t:#1 {\edef\a@type{#1}}
+
+% ===== Bezier curve
+% The initial point is assumed to be the current point.  Only the last
+% coordinate affects the size of the plot.
 \def\clvec (#1 #2)(#3 #4)(#5 #6)%
-{\getpos (#1 #2)\a@rgx\a@rgy
-\coordtopix \a@rgx\t@pixa
-\advance \t@pixa by \x@segoffpix
-\coordtopix \a@rgy\t@pixb
-\advance \t@pixb by \y@segoffpix
-\getpos (#3 #4)\a@rgx\a@rgy
-\coordtopix \a@rgx\t@pixc
-\advance \t@pixc by \x@segoffpix
-\coordtopix \a@rgy\t@pixd
-\advance \t@pixd by \y@segoffpix
-\getpos (#5 #6)\a@rgx\a@rgy
-\s@etpospix \a@rgx \a@rgy
-\writeps {\the\t@pixa\space \the\t@pixb\space
-\the\t@pixc\space \the\t@pixd\space
-\the\x@pix\space \the\y@pix\space cv}}
+           {\getpos (#1 #2)\a@rgx\a@rgy
+            \coordtopix \a@rgx\t@pixa
+            \advance \t@pixa by \x@segoffpix
+            \coordtopix \a@rgy\t@pixb
+            \advance \t@pixb by \y@segoffpix
+            \getpos (#3 #4)\a@rgx\a@rgy
+            \coordtopix \a@rgx\t@pixc
+            \advance \t@pixc by \x@segoffpix
+            \coordtopix \a@rgy\t@pixd
+            \advance \t@pixd by \y@segoffpix
+            \getpos (#5 #6)\a@rgx\a@rgy
+            \s@etpospix \a@rgx \a@rgy
+            \writeps {\the\t@pixa\space \the\t@pixb\space
+                      \the\t@pixc\space \the\t@pixd\space
+                      \the\x@pix\space \the\y@pix\space cv}}
+
+% ===== Draw the bounding box
 \def\drawbb {\bsegment
-\drawdim bp
-\linewd 0.24
-\setunitscale {\p@sfactor}
-\writeps {\the\xminpix\space \the\yminpix\space mv}%
-\writeps {\the\xminpix\space \the\ymaxpix\space lv}%
-\writeps {\the\xmaxpix\space \the\ymaxpix\space lv}%
-\writeps {\the\xmaxpix\space \the\yminpix\space lv}%
-\writeps {\the\xminpix\space \the\yminpix\space lv}%
-\esegment}
+               \drawdim bp
+               \linewd 0.24       % line width 1/300 inch = 0.24 bp
+               \setunitscale {\p@sfactor}
+               \writeps {\the\xminpix\space \the\yminpix\space mv}%
+               \writeps {\the\xminpix\space \the\ymaxpix\space lv}%
+               \writeps {\the\xmaxpix\space \the\ymaxpix\space lv}%
+               \writeps {\the\xmaxpix\space \the\yminpix\space lv}%
+               \writeps {\the\xminpix\space \the\yminpix\space lv}%
+             \esegment}
+
+
+% ===============================================================
+% ===== Utility macros used by TeXdraw ==========================
+
+% ===== Decode coordinates
+% Get coordinates
+% This macro is used to get two arguments separated by a blank, with
+% possible leading and trailing blanks.  Symbolic coordinates are
+% converted to user coordinates.
+%  (#1 #2) - coordinates
+%  #3 - macro name to receive the x-coordinate value
+%  #4 - macro name to receive the y-coordinate value
 \def\getpos (#1 #2)#3#4{\g@etargxy #1 #2 {} \\#3#4%
-\c@heckast #3%
-\ifa@st
-\g@etsympix #3\t@pixa
-\advance \t@pixa by -\x@segoffpix
-\pixtocoord \t@pixa #3%
-\fi
-\c@heckast #4%
-\ifa@st
-\g@etsympix #4\t@pixa
-\advance \t@pixa by -\y@segoffpix
-\pixtocoord \t@pixa #4%
-\fi}
+                        \c@heckast #3%
+                        \ifa@st
+                          \g@etsympix #3\t@pixa
+                          \advance \t@pixa by -\x@segoffpix
+                          \pixtocoord \t@pixa #3%
+                        \fi
+                        \c@heckast #4%
+                        \ifa@st
+                          \g@etsympix #4\t@pixa
+                          \advance \t@pixa by -\y@segoffpix
+                          \pixtocoord \t@pixa #4%
+                        \fi}
+
+% Get symbolic coordinate names
+%  (#1 #2) - symbolic coordinates
+%  #3 - macro name to receive the symbolic x coordinate name
+%  #4 - macro name to receive the symbolic y coordinate name
 \def\getsympos (#1 #2)#3#4{\g@etargxy #1 #2 {} \\#3#4%
-\c@heckast #3%
-\ifa@st \else
-\t@xderror {TeXdraw: invalid symbolic coordinate}%
-\fi
-\c@heckast #4%
-\ifa@st \else
-\t@xderror {TeXdraw: invalid symbolic coordinate}%
-\fi}
+                     \c@heckast #3%
+                     \ifa@st \else
+                       \t@xderror {TeXdraw: invalid symbolic coordinate}%
+                     \fi
+                     \c@heckast #4%
+                     \ifa@st \else
+                       \t@xderror {TeXdraw: invalid symbolic coordinate}%
+                     \fi}
+
+% ===== Convert a list of values to pixel values
+%  (#1) - blank separated list of values in user coordinates
+%  #2 - macro name to receive the blank separated list of pixel values
 \def\listtopix (#1)#2{\def #2{}%
-\edef\l@ist {#1 }%
-\m@oretrue
-\loop
-\expandafter\g@etitem \l@ist \\\a@rgx\l@ist
-\a@pppix \a@rgx #2%
-\ifx \l@ist\empty
-\m@orefalse
-\fi
-\ifm@ore
-\repeat}
+                      \edef\l@ist {#1 }%    % append a blank to the string
+                      \m@oretrue
+                      \loop
+                        \expandafter\g@etitem \l@ist \\\a@rgx\l@ist
+                        \a@pppix \a@rgx #2%
+                        \ifx \l@ist\empty
+                          \m@orefalse
+                        \fi
+                      \ifm@ore
+                      \repeat}
+
+% ===== Real multiplication
+% This function uses the property that a box dimension may be scaled by
+% a real value.  The values are converted to dimensions in units of pt.
+% This choice gives us a reasonable dynamic range.  The final step is to
+% clean off the "pt" on the resulting dimension.  Note that these are fixed
+% point operations with each operand represented to an accuracy of about 5
+% decimal places.
+
+% Note we must use magnified points not "true" points, since the answer is
+% expressed in magnified points.  The result will be calculated in the same
+% manner no matter what the magnification is.
+%  #1 and #2 are multiplicands
+%  #3 macro name to capture the real result
 \def\realmult #1#2#3{\dimen0=#1pt
-\dimen2=#2\dimen0
-\edef #3{\expandafter\c@lean\the\dimen2}}
+                     \dimen2=#2\dimen0
+                     \edef #3{\expandafter\c@lean\the\dimen2}}
+
+% ===== Divide integers, real result
+%  #1 integer numerator value
+%  #2 integer denominator (divisor) value
+%  #3 macro name to capture the real result
 \def\intdiv #1#2#3{\t@counta=#1
-\t@countb=#2
-\ifnum \t@countb<0
-\t@counta=-\t@counta
-\t@countb=-\t@countb
-\fi
-\t@countd=1
-\ifnum \t@counta<0
-\t@counta=-\t@counta
-\t@countd=-1
-\fi
-\t@countc=\t@counta  \divide \t@countc by \t@countb
-\t@counte=\t@countc  \multiply \t@counte by \t@countb
-\advance \t@counta by -\t@counte
-\t@counte=-1
-\loop
-\advance \t@counte by 1
-\ifnum \t@counte<16
-\multiply \t@countc by 2
-\multiply \t@counta by 2
-\ifnum \t@counta<\t@countb \else
-\advance \t@countc by 1
-\advance \t@counta by -\t@countb
-\fi
-\repeat
-\divide \t@countb by 2
-\ifnum \t@counta<\t@countb
-\advance \t@countc by 1
-\fi
-\ifnum \t@countd<0
-\t@countc=-\t@countc
-\fi
-\dimen0=\t@countc sp
-\edef #3{\expandafter\c@lean\the\dimen0}}
+                   \t@countb=#2
+%  Limitations: #1 must be negatable, i.e. it must not be the largest
+%                  magnitude negative number
+%               #2 must be able to be multiplied by 2 without overflow
+%  Calculate a*65536/b  where the factor 65536 converts from pt to sp.
+%  This operation can also be interpretated as an extended precision
+%  numerator divided by the denominator.  The scheme used is basically a
+%  long division, except that it is bootstrapped by an integer divide.
+%  The computations are carried out with positive numerator and
+%  denominator, with the appropriate restoration of sign at the end.
+%    \t@counta == remainder, r, initially set to a
+%    \t@countb == denominator, b
+%    \t@countc == quotient, q
+%    \t@countd == +1, a and b have the same sign
+%                 -1, a and b have opposite signs
+%    \t@counte == temporary register
+                   \ifnum \t@countb<0
+                      \t@counta=-\t@counta
+                      \t@countb=-\t@countb
+                   \fi
+                   \t@countd=1                    % record the sign
+                   \ifnum \t@counta<0
+                      \t@counta=-\t@counta
+                      \t@countd=-1
+                   \fi
+%                                                 % q=a/b, r=a-q*b
+                   \t@countc=\t@counta  \divide \t@countc by \t@countb
+                   \t@counte=\t@countc  \multiply \t@counte by \t@countb
+                   \advance \t@counta by -\t@counte
+                   \t@counte=-1
+                   \loop
+                     \advance \t@counte by 1
+                   \ifnum \t@counte<16                  % loop 16 times
+                       \multiply \t@countc by 2           % q=2q
+                       \multiply \t@counta by 2           % r=2r
+                       \ifnum \t@counta<\t@countb \else   % if ( r >= b )
+                         \advance \t@countc by 1          %   q=q+1
+                         \advance \t@counta by -\t@countb %   r=r-b
+                       \fi
+                   \repeat
+                   \divide \t@countb by 2         % rounding
+                   \ifnum \t@counta<\t@countb     % if ( r >= b/2 ) q=q+1
+                     \advance \t@countc by 1
+                   \fi
+                   \ifnum \t@countd<0             % restore the sign
+                     \t@countc=-\t@countc
+                   \fi
+                   \dimen0=\t@countc sp           % express as a dimension
+                   \edef #3{\expandafter\c@lean\the\dimen0}}
+
+% ===============================================================
+% ===== Internal TeXdraw macros =================================
+
+% ===== Macros for converting between dimensions and units
+% Convert drawing units (coordinate value, scaled by the unit scale and
+% segment scale) to pixels.  We use rounding to get more accurate results.
+%  #1 dimension in drawing units
+%  #2 count in pixels (returned into a count)
 \def\coordtopix #1#2{\dimen0=#1\d@dim
-\dimen2=\d@sc\dimen0
-\t@counta=\dimen2
-\t@countb=\s@ppix
-\divide \t@countb by 2
-\ifnum \t@counta<0
-\advance \t@counta by -\t@countb
-\else
-\advance \t@counta by \t@countb
-\fi
-\divide \t@counta by \s@ppix
-#2=\t@counta}
+                     \dimen2=\d@sc\dimen0
+                     \t@counta=\dimen2          % scaled dimension in sp
+                     \t@countb=\s@ppix
+                     \divide \t@countb by 2
+                     \ifnum \t@counta<0         % rounding
+                       \advance \t@counta by -\t@countb
+                     \else
+                       \advance \t@counta by \t@countb
+                     \fi
+                     \divide \t@counta by \s@ppix
+                     #2=\t@counta}
+
+% Convert from absolute pixels to relative scaled coordinates
+%  #1 - input integer pixel value
+%  #2 - macro name to receive the character string corresponding to the
+%       floating point coordinate value
 \def\pixtocoord #1#2{\t@counta=#1%
-\multiply \t@counta by \s@ppix
-\dimen0=\d@sc\d@dim
-\t@countb=\dimen0
-\intdiv \t@counta \t@countb #2}
+                     \multiply \t@counta by \s@ppix
+                     \dimen0=\d@sc\d@dim
+                     \t@countb=\dimen0
+                     \intdiv \t@counta \t@countb #2}
+
+% Convert pixels to TeX dimensions.
+%  #1 - input integer pixel value
+%  #2 - returned dimension (returned into a dimension register)
 \def\pixtodim #1#2{\t@countb=#1%
-\multiply \t@countb by \s@ppix
-#2=\t@countb sp\relax}
+                   \multiply \t@countb by \s@ppix
+                   #2=\t@countb sp\relax}
+
+% Convert pixels to (integer) bp units
+%  #1 - input pixel value
+%  #2 - integer value, returned as a macro definition
 \def\pixtobp #1#2{\dimen0=\p@sfactor pt
-\t@counta=\dimen0
-\multiply \t@counta by #1%
-\ifnum \t@counta < 0
-\advance \t@counta by -32768
-\else
-\advance \t@counta by 32768
-\fi
-\divide \t@counta by 65536
-\edef #2{\the\t@counta}}
-\newcount\t@counta    \newcount\t@countb
+                  \t@counta=\dimen0
+                  \multiply \t@counta by #1%
+                  \ifnum \t@counta < 0             % rounding
+                    \advance \t@counta by -32768
+                  \else
+                    \advance \t@counta by 32768
+                  \fi
+                  \divide \t@counta by 65536
+                  \edef #2{\the\t@counta}}
+                  
+% ===== Allocations for registers and counts
+% == Temporary count registers
+\newcount\t@counta    \newcount\t@countb   % Use at lowest levels
 \newcount\t@countc    \newcount\t@countd
 \newcount\t@counte
-\newcount\t@pixa      \newcount\t@pixb
+\newcount\t@pixa      \newcount\t@pixb     % Use for pixel values
 \newcount\t@pixc      \newcount\t@pixd
+
+% == Temporary dimension registers
 \newdimen\t@xpos      \newdimen\t@ypos
+
+% == Position and parameter registers
+% The minimum and maximum extent in the X and Y direction in pixel units
+% (updated globally to reach outside segments)
 \newcount\xminpix      \newcount\xmaxpix
 \newcount\yminpix      \newcount\ymaxpix
+
+% == Arrowhead parameters
 \newcount\a@lenpix     \newcount\a@widpix
+
+% == Absolute pixel positions
 \newcount\x@pix        \newcount\y@pix
 \newcount\x@segoffpix  \newcount\y@segoffpix
 \newcount\x@savepix    \newcount\y@savepix
-\newcount\s@ppix
+
+% == Conversion factor
+\newcount\s@ppix       % sp/pixel 
+
+% == Pending segments count
 \newcount\d@bs
+
+% == Counter to form unique file names
 \newcount\t@xdnum
 \global\t@xdnum=0
+
+% == TeXdraw box
 \newbox\t@xdbox
+
+% == Output stream number for the PostScript file
 \newwrite\drawfile
+
+% == \newif
 \newif\ifm@pending
 \newif\ifp@ath
 \newif\ifa@st
 \newif\ifm@ore
 \newif \ift@extonly
 \newif\ifp@osinit
+
+% == \newtoks
 \newtoks\everytexdraw
+
+% ===== Character definitions
 \def\l@paren{(}
 \def\a@st{*}
+
+% ===== Special character macros
+% Need to be able to insert "%", "{" and "}" characters into the
+% PostScript file.
+% Define macros which have these characters with category "other".
+% We will assume, that these characters have the standard meanings --
+% after all, we use comments and braces in this code.
 \catcode`\%=12
-\def\p@b {%!}  \def\p@p {%%}
+  \def\p@b {%!}  \def\p@p {%%}
 \catcode`\%=14
 \catcode`\{=12  \catcode`\}=12  \catcode`\u=1 \catcode`\v=2
-\def\l@br u{v  \def\r@br u}v
+  \def\l@br u{v  \def\r@br u}v
 \catcode `\{=1  \catcode`\}=2   \catcode`\u=11 \catcode`\v=11
+
+% ===== Pixel conversion factors
+% The position is kept as an integer value (count).  It is set to a
+% resolution corresponding to 300 units/inch.  We refer to them as pixels,
+% but in fact the resolution is just that: movements are quantized to lie
+% on a grid with that resolution.
+
+% Using pixel units which correspond to the actual resolution of the device
+% has advantages in that all horizontal and vertical lines then will be
+% drawn with the same line thickness.  In addition the coordinates are
+% then integer values (no decimal point or leading zeros) which leads
+% to a more compact PostScript file.
+
+% The following macro sets the conversion from PostScript units (bp) to the
+% integer units (pixels).  The file inclusion \special environment in the
+% PostScript driver restores the context to default PostScript values
+% (bp or 72/in and origin in the lower lefthand corner).  A scaling value
+% of 0.24 converts to 300/inch.  Note that the PostScript commands written
+% to the temporary PostScript file do not depend on the TeX magnification
+% in effect.  Magnification should be handled by the dvi to PostScript
+% driver at the time that the file is included in the output.
+
+% Calculate the conversion factors
+% Let s@ppix = sp/pixel = u / p, where u = sp/unit and p = pix/unit (both
+% integer values).
+% We calculate s@ppix as
+%         s@ppix = [ (u+0.5p)/p ]
+% We also calculate the PostScript scale factor bp/pixel
+% Let b = sp/bp.  We want p@sfactor = s@ppix/b.  For 300 pixels/inch, this
+% gives p@sfactor=0.24.  Using rounding
+%         p@sfactor = [ (s@ppix+0.5b)/b ] .
+% To carry out the arithmetic, we will operate in sp units (integers) and
+% generate the answer in pt units (multiplying by sp/pt).  This result will
+% expressed as a character string representing a real number after the "pt"
+% designator is stripped off.
+
 {\catcode`\p=12 \catcode`\t=12
-\gdef\c@lean #1pt{#1}}
+ \gdef\c@lean #1pt{#1}}
+
 \def\sppix#1/#2 {\dimen0=1#2 \s@ppix=\dimen0
-\t@counta=#1%
-\divide \t@counta by 2
-\advance \s@ppix by \t@counta
-\divide \s@ppix by #1%
-\t@counta=\s@ppix
-\multiply \t@counta by 65536
-\advance \t@counta by 32891
-\divide \t@counta by 65782
-\dimen0=\t@counta sp
-\edef\p@sfactor {\expandafter\c@lean\the\dimen0}}
+                 \t@counta=#1%
+                 \divide \t@counta by 2
+                 \advance \s@ppix by \t@counta
+                 \divide \s@ppix by #1%             % \s@ppix available
+                 \t@counta=\s@ppix
+                 \multiply \t@counta by 65536       % 1 pt = 65536 sp
+                 \advance \t@counta by 32891        % 0.5 bp = 32890.88 sp
+                 \divide \t@counta by 65782         % 1 bp = 65781.76 sp
+                 \dimen0=\t@counta sp
+                 \edef\p@sfactor {\expandafter\c@lean\the\dimen0}}
+
+% ===== Low level coordinate decoding macros
+% Get two values, separated by a blank
+% Invoke as \g@etargxy <stuff> {} \\\ma\mb
 \def\g@etargxy #1 #2 #3 #4\\#5#6{\def #5{#1}%
-\ifx #5\empty
-\g@etargxy #2 #3 #4 \\#5#6%  leading blank
-\else
-\def #6{#2}%
-\def\next {#3}%
-\ifx \next\empty \else
-\t@xderror {TeXdraw: invalid coordinate}%
-\fi
-\fi}
+                           \ifx #5\empty
+                             \g@etargxy #2 #3 #4 \\#5#6%  leading blank
+                           \else
+                             \def #6{#2}%
+                             \def\next {#3}%
+                             \ifx \next\empty \else
+                               \t@xderror {TeXdraw: invalid coordinate}%
+                             \fi
+                           \fi}
+
+% Check for a leading asterisk
+% Sets \a@stfalse or \a@sttrue, test with \ifa@st
 \def\c@heckast #1{\expandafter
-\c@heckastll #1\\}
+                  \c@heckastll #1\\}
 \def\c@heckastll #1#2\\{\def\testit {#1}%
-\ifx \testit\a@st
-\a@sttrue
-\else
-\a@stfalse
-\fi}
+                        \ifx \testit\a@st
+                          \a@sttrue
+                        \else
+                          \a@stfalse
+                        \fi}
+
+% Decode a symbolic coordinate
+% Pixel value returned to a count
 \def\g@etsympix #1#2{\expandafter
-\ifx \csname #1\endcsname \relax
-\t@xderror {TeXdraw: undefined symbolic coordinate}%
-\fi
-#2=\csname #1\endcsname}
+               \ifx \csname #1\endcsname \relax
+                 \t@xderror {TeXdraw: undefined symbolic coordinate}%
+               \fi
+               #2=\csname #1\endcsname}
+
+% Set a macro named #1 to have value #2
 \def\s@etcsn #1#2{\expandafter
-\xdef\csname#1\endcsname {#2}}
+                  \xdef\csname#1\endcsname {#2}}
+
+% ===== Low level list decoding macros
+% Pick off the first item -> #3, rest of string -> #4
 \def\g@etitem #1 #2\\#3#4{\edef #4{#2}\edef #3{#1}}
 \def\a@pppix #1#2{\edef\next {#1}%
-\ifx \next\empty \else
-\coordtopix {#1}\t@pixa
-\ifx #2\empty
-\edef #2{\the\t@pixa}%
-\else
-\edef #2{#2 \the\t@pixa}%
-\fi
-\fi}
+                  \ifx \next\empty \else
+                    \coordtopix {#1}\t@pixa
+                    \ifx #2\empty
+                      \edef #2{\the\t@pixa}%
+                    \else
+                      \edef #2{#2 \the\t@pixa}%
+                    \fi
+                  \fi}
+
+% ===== Macros for updating the position
+% Calculate the position in pixels and update the maximum excursions
 \def\s@etpospix #1#2{\coordtopix {#1}\x@pix
-\advance \x@pix by \x@segoffpix
-\coordtopix {#2}\y@pix
-\advance \y@pix by \y@segoffpix
-\u@pdateminmax \x@pix \y@pix}
+                     \advance \x@pix by \x@segoffpix
+                     \coordtopix {#2}\y@pix
+                     \advance \y@pix by \y@segoffpix
+                     \u@pdateminmax \x@pix \y@pix}
+
 \def\r@elpospix #1#2{\coordtopix {#1}\t@pixa
-\advance \x@pix by \t@pixa
-\coordtopix {#2}\t@pixa
-\advance \y@pix by \t@pixa
-\u@pdateminmax \x@pix \y@pix}
+                     \advance \x@pix by \t@pixa
+                     \coordtopix {#2}\t@pixa
+                     \advance \y@pix by \t@pixa
+                     \u@pdateminmax \x@pix \y@pix}
+
 \def\r@elupd #1#2{\t@counta=\x@pix
-\advance\t@counta by #1%
-\t@countb=\y@pix
-\advance\t@countb by #2%
-\u@pdateminmax \t@counta \t@countb}
+                  \advance\t@counta by #1%
+                  \t@countb=\y@pix
+                  \advance\t@countb by #2%
+                  \u@pdateminmax \t@counta \t@countb}
+
 \def\u@pdateminmax #1#2{\ifnum #1>\xmaxpix
-\global\xmaxpix=#1%
-\fi
-\ifnum #1<\xminpix
-\global\xminpix=#1%
-\fi
-\ifnum #2>\ymaxpix
-\global\ymaxpix=#2%
-\fi
-\ifnum #2<\yminpix
-\global\yminpix=#2%
-\fi}
+                          \global\xmaxpix=#1%
+                        \fi
+                        \ifnum #1<\xminpix
+                          \global\xminpix=#1%
+                        \fi
+                        \ifnum #2>\ymaxpix
+                          \global\ymaxpix=#2%
+                        \fi
+                        \ifnum #2<\yminpix
+                          \global\yminpix=#2%
+                        \fi}
+
+% =====  Save moves / flush moves
+% A TeXdraw segment which generates only TeX text uses only move, begin
+% segment and end segment commands.  The goal is to avoid writing out
+% empty segments for such cases.  To this end, moves are held back and
+% only written out if necessary to set the position or terminate a path.
+% Also in this way, a TeXdraw drawing which generates only TeX text will
+% not generate a PostScript file.
+
+% Two flags are used.  Both flags are local to a segment.
+% - move pending:  Set when a move has been invoked but the move command
+%   has not been written out to the PostScript file
+% - path in progress:  Set when a PostScript path has been started but the
+%   path has not been terminated and stroked.
+% (1) Moves are kept back.  Using TeX's groups, a local flag and local
+%     position registers are used to keep track of whether the latest
+%     move applicable to a given segment has been written out or not.  In
+%     effect there is a stack of pending moves, one for each level of
+%     segment nesting.
+% (2) At the beginning of a segment, if a PS path is in progress and a
+%     a move is pending, the move is written out, terminating the path
+%     and stroking the path.  This is done to ensure that the path is
+%     stroked before lines and/or fills are executed in the segment.
+% (3) At the beginning of a segment, if a PS path is not in progress,
+%     any pending moves are kept back.  Effectively, the move will be
+%     transferred into the segment.  It will be written out only when
+%     the position needs to be updated for some other command.  Such
+%     moves which are transferred into segments may have to be repeated
+%     outside the segment.  The move pending flag will be restored to
+%     the value outside the segment on exit from the segment.
+% (4) A begin segment command is not written out, but instead a global
+%     segment backlog counter is incremented.  The backlog of begin
+%     segment commands is written out when a drawing command is
+%     encountered.
+% The effect of the above on the TeXdraw commands is as follows.
+% (a) move:
+%     - set the current position
+%     - record the position of the saved move
+%     - set the move pending flag
+% (b) begin segment:
+%     - if a path is in progress
+%         - if a move is pending
+%           - if there is a backlog of segments
+%             - write out enough begin segments to clear the backlog
+%           - write out the pending move
+%           - reset the move pending flag (local to the containing segment,
+%             but affects inferior segments)
+%           - reset the path in progress flag
+%     - increment the segment backlog counter
+%     - begin a group
+% (c) end segment:
+%     - end a group
+%     - if there is no backlog of segments
+%       - write an end segment command
+%     - if there is a backlog of segments
+%       - decrement the backlog counter, thereby omitting an empty
+%         empty segment.
+%     - the move pending flag and path in progress flag are automatically
+%       restored on leaving the TeX group
+% (d) text:
+%     - create a text box
+% (e) line parameters:
+%     - if there is a backlog of segments
+%        - write out enough begin segments to clear the backlog
+%     - clear the path in progress flag
+%     - write the PS command changing the line parameter
+% (f) other drawing commands:
+%     - update the current position
+%     - if there is a backlog of segments
+%        - write out enough begin segments to clear the backlog
+%     - if there is a pending move
+%        - write out the pending move
+%        - reset the move pending flag (local to this segment, but affects
+%          inferior segments)
+%     - set the path in progress flag
+%     - write the drawing command
+% Notes:
+% (1) The es PS command strokes the path at the end of a segment to
+%     ensure that the correct line parameters are used for the segment.
+%     The path before the corresponding bs command is restored and
+%     continued.
+% (2) The \f@lushbs and \f@lushmove commands must be invoked before each
+%     drawing command written to the PS file.  The macro \writeps includes
+%     these operations.
+
+% Another awkward business has to do with initialization.  We want a
+% default (0 0) initial position so that the user can draw vectors
+% immediately.  However, if the user specifies another move before
+% beginning to draw, that position should be the initial position.  The
+% importance of this initial position is that the determination of the
+% maximum excursion must take this value into account.  We handle the
+% initialization in the \s@avemove and \f@lushmove macros.  The macro
+% \ifp@osinit indicates whether the next move should be captured as the
+% initial values for \xminpix, \yminpix, \xmaxpix, and \ymaxpix.  However,
+% if a \f@lushmove is invoked, then we assume that the appropriate initial
+% values has already been set.  The "mv" command in PostScript is defined
+% to stroke the current path (if any) and move to the pixel coordinates
+% specified.
+
+% Note that \m@pendingtrue and \m@pendingfalse define the flag locally.
+% In addition, \x@savepix and \y@savepix are local variables.  We make
+% use of the fact that the values of the flag and positions propagate
+% down to inferior segments but not up to superior segments.  This
+% behaviour Is consistent with the gsave/grestore operation on the
+% PostScript side.
 \def\s@avemove #1#2{\x@savepix=#1\y@savepix=#2%
-\m@pendingtrue
-\ifp@osinit \else
-\global\p@osinittrue
-\global\xminpix=\x@savepix \global\yminpix=\y@savepix
-\global\xmaxpix=\x@savepix \global\ymaxpix=\y@savepix
-\fi}
+                    \m@pendingtrue
+                    \ifp@osinit \else
+                      \global\p@osinittrue
+                      \global\xminpix=\x@savepix \global\yminpix=\y@savepix
+                      \global\xmaxpix=\x@savepix \global\ymaxpix=\y@savepix
+                    \fi}
+
 \def\f@lushmove {\global\p@osinittrue
-\ifm@pending
-\writetx {\the\x@savepix\space \the\y@savepix\space mv}%
-\m@pendingfalse
-\p@athfalse
-\fi}
+                 \ifm@pending
+                   \writetx {\the\x@savepix\space \the\y@savepix\space mv}%
+                   \m@pendingfalse
+                   \p@athfalse
+                 \fi}
+
+% =====  Flush begin segment
+% \f@lushbs flushes any saved up \bsegments.  Some of these may be
+% redundant, but we cannot know without looking ahead beyond the
+% \esegment.
 \def\f@lushbs {\loop
-\ifnum \d@bs>0
-\writetx {bs}%
-\global\advance \d@bs by -1
-\repeat}
+                 \ifnum \d@bs>0
+                   \writetx {bs}%
+                   \global\advance \d@bs by -1
+               \repeat}
+               
+% ===== Internal text macros
+% Horizontal text, use only 3 levels of box nesting here
 \def\h@move #1#2 #3)#4{\move (#2 #3)%
-\h@text {#4}}
+                       \h@text {#4}}
 \def\h@text #1{\pixtodim \x@pix \t@xpos
-\pixtodim \y@pix \t@ypos
-\vbox to 0pt{\normalbaselines
-\t@stuff
-\kern -\t@ypos
-\hbox to 0pt{\l@stuff
-\kern \t@xpos
-\hbox {#1}%
-\kern -\t@xpos
-\r@stuff}%
-\kern \t@ypos
-\b@stuff\relax}}
+               \pixtodim \y@pix \t@ypos
+               \vbox to 0pt{\normalbaselines
+                            \t@stuff
+                            \kern -\t@ypos
+                            \hbox to 0pt{\l@stuff
+                                         \kern \t@xpos
+                                         \hbox {#1}%
+                                         \kern -\t@xpos
+                                         \r@stuff}%
+                            \kern \t@ypos
+                            \b@stuff\relax}}
+
+% Rotated text
+% Uses 5 levels of box nesting here (so that the text reference point
+% is that <before> rotation).  This was done so that the reference point
+% definition makes sense with arbitrary angle rotation.  The text is
+% rotated with respect to the text reference point.  The result is zero
+% sized.  These macros generate in-line PostScript.
+% #1 - rotation angle in degrees
+% #2 - text to be rotated
 \def\r@move td:#1 #2#3 #4)#5{\move (#3 #4)%
-\r@text td:#1 {#5}}
+                             \r@text td:#1 {#5}}
 \def\r@text td:#1 #2{\vbox to 0pt{\pixtodim \x@pix \t@xpos
-\pixtodim \y@pix \t@ypos
-\kern -\t@ypos
-\hbox to 0pt{\kern \t@xpos
-\rottxt {#1}{\z@sb {#2}}%
-\hss}%
-\vss}}
+                                  \pixtodim \y@pix \t@ypos
+                                  \kern -\t@ypos
+                                  \hbox to 0pt{\kern \t@xpos
+                                               \rottxt {#1}{\z@sb {#2}}%
+                                               \hss}%
+                                  \vss}}
 \def\z@sb #1{\vbox to 0pt{\normalbaselines
-\t@stuff
-\hbox to 0pt{\l@stuff \hbox {#1}\r@stuff}%
-\b@stuff}}
+                          \t@stuff
+                          \hbox to 0pt{\l@stuff \hbox {#1}\r@stuff}%
+                          \b@stuff}}
+
+% ===== Rotate text, in-line PostScript code
 \ifx \rotatebox\@undefined
-\def\rottxt #1#2{\bgroup
-\special {ps: gsave currentpoint currentpoint translate
-#1\space neg rotate
-neg exch neg exch translate}%
-#2%
-\special {ps: currentpoint grestore moveto}%
-\egroup}
+  \def\rottxt #1#2{\bgroup
+                     \special {ps: gsave currentpoint currentpoint translate
+                               #1\space neg rotate
+                              neg exch neg exch translate}%
+                     #2%
+                     \special {ps: currentpoint grestore moveto}%
+                   \egroup}
 \else
-\let\rottxt=\rotatebox
+  \let\rottxt=\rotatebox
 \fi
+
+% ===== Error message
+% If not defined, use the plain TeX errmessage macro
 \ifx \t@xderror\@undefined
-\let\t@xderror=\errmessage
+  \let\t@xderror=\errmessage
 \fi
-\def\t@exdrawdef {\sppix 300/in
-\drawdim in
-\edef\u@nitsc {1}%
-\setsegscale 1
-\arrowheadsize l:0.16 w:0.08
-\arrowheadtype t:T
-\textref h:L v:B }
+
+% ===== Default values
+% These are reset each time TeXdraw is invoked
+\def\t@exdrawdef {\sppix 300/in            % 300 pixels/inch
+                  \drawdim in              % drawing units are inches
+                  \edef\u@nitsc {1}%       % unit scale 1 (has to be set
+                                           % before invoking \setsegscale)
+                  \setsegscale 1           % segment scale 1
+                  \arrowheadsize l:0.16 w:0.08
+                  \arrowheadtype t:T
+                  \textref h:L v:B }
+
+
+% ===============================================================
+% ===== PostScript file macros ==================================
+
+% ===== Include the TeXdraw graphics
+% The drawing in a box of appropriate size will be placed such that its
+% lower left hand corner will be at the current TeX position.
 \ifx \includegraphics\@undefined
-\def\t@xdinclude [#1,#2][#3,#4]#5{%
-\begingroup
-\message {<#5>}%
-\leavevmode
-\t@counta=-#1%
-\t@countb=-#2%
-\setbox0=\hbox{%
-\special {PSfile="#5"\space
-hoffset=\the\t@counta\space voffset=\the\t@countb}}%
-\t@ypos=#4 bp%
-\advance \t@ypos by -#2 bp%
-\t@xpos=#3 bp%
-\advance \t@xpos by -#1 bp%
-\dp0=0pt \ht0=\t@ypos  \wd0=\t@xpos
-\box0%
-\endgroup}
+  \def\t@xdinclude [#1,#2][#3,#4]#5{%
+    \begingroup                           % keep definitions local
+      \message {<#5>}%
+      \leavevmode
+      \t@counta=-#1%                      % integer bounding box coordinates
+      \t@countb=-#2%
+      \setbox0=\hbox{%
+        \special {PSfile="#5"\space
+                  hoffset=\the\t@counta\space voffset=\the\t@countb}}%
+      \t@ypos=#4 bp%
+        \advance \t@ypos by -#2 bp%
+      \t@xpos=#3 bp%
+        \advance \t@xpos by -#1 bp%
+      \dp0=0pt \ht0=\t@ypos  \wd0=\t@xpos
+      \box0%
+    \endgroup}
 \else
-\let\t@xdinclude=\includegraphics
+  \let\t@xdinclude=\includegraphics
 \fi
+
+% ===== Write to the PostScript file
+% Macro to write PostScript commands to the temporary PostScript file
+% To decrease the size of the PostScript file, moves are kept back to
+% allow redundant multiple moves to be removed.  In addition empty gsave/
+% grestore pairs are not written.  The PostScript file is not opened if
+% TeXdraw has not generated any PostScript commands, i.e. it has produced
+% only TeX text.
+% \writeps : flushes the pending move to make sure things are positioned
+%            correctly and flushes pending begin segments before calling
+%            \writetx to write to the PostScript file
+% \writetx : writes directly to the PostScript file.  This version is used
+%            only for those commands which just change line parameters
+%            without drawing.  This routine opens the file and writes the
+%            PS file header the first time it is called.
+% \w@rps :   lowest level direct write to the PostScript file
 \def\writeps #1{\f@lushbs
-\f@lushmove
-\p@athtrue
-\writetx {#1}}
+                \f@lushmove
+                \p@athtrue
+                \writetx {#1}}
 \def\writetx #1{\ift@extonly
-\global\t@extonlyfalse
-\t@xdpsfn \p@sfile
-\t@dropen \p@sfile
-\fi
-\w@rps {#1}}
+                  \global\t@extonlyfalse
+                  \t@xdpsfn \p@sfile
+                  \t@dropen \p@sfile
+                \fi
+                \w@rps {#1}}
 \def\w@rps #1{\immediate\write\drawfile {#1}}
+
+% ===== Open a PostScript file
+% Open a PostScript file, write the definitions used by TeXdraw.
 \def\t@xdpsfn #1{%
-\global\advance \t@xdnum by 1
-\ifnum \t@xdnum<10
-\xdef #1{\jobname.ps\the\t@xdnum}
-\else
-\xdef #1{\jobname.p\the\t@xdnum}
-\fi
+  \global\advance \t@xdnum by 1
+  \ifnum \t@xdnum<10
+    \xdef #1{\jobname.ps\the\t@xdnum}
+  \else
+    \xdef #1{\jobname.p\the\t@xdnum}
+  \fi
 }
 \def\t@dropen #1{%
-\immediate\openout\drawfile=#1%
-\w@rps {\p@b PS-Adobe-3.0 EPSF-3.0}%
-\w@rps {\p@p BoundingBox: (atend)}%
-\w@rps {\p@p Title: TeXdraw drawing: #1}%
-\w@rps {\p@p Pages: 1}%
-\w@rps {\p@p Creator: \TeXdrawId}%
-\w@rps {\p@p CreationDate: \the\year/\the\month/\the\day}%
-\w@rps {50 dict begin}%
-\w@rps {/mv {stroke moveto} def}%
-\w@rps {/lv {lineto} def}%
-\w@rps {/st {currentpoint stroke moveto} def}%
-\w@rps {/sl {st setlinewidth} def}%
-\w@rps {/sd {st 0 setdash} def}%
-\w@rps {/sg {st setgray} def}%
-\w@rps {/bs {gsave} def /es {stroke grestore} def}%
-\w@rps {/fl \l@br gsave setgray fill grestore}%
-\w@rps    { currentpoint newpath moveto\r@br\space def}%
-\w@rps {/fp {gsave setgray fill grestore st} def}%
-\w@rps {/cv {curveto} def}%
-\w@rps {/cr \l@br gsave currentpoint newpath 3 -1 roll 0 360 arc}%
-\w@rps    { stroke grestore\r@br\space def}%
-\w@rps {/fc \l@br gsave setgray currentpoint newpath}%
-\w@rps    { 3 -1 roll 0 360 arc fill grestore\r@br\space def}%
-\w@rps {/ar {gsave currentpoint newpath 5 2 roll arc stroke grestore} def}%
-\w@rps {/el \l@br gsave /svm matrix currentmatrix def}%
-\w@rps    { currentpoint translate scale newpath 0 0 1 0 360 arc}%
-\w@rps    { svm setmatrix stroke grestore\r@br\space def}%
-\w@rps {/fe \l@br gsave setgray currentpoint translate scale newpath}%
-\w@rps    { 0 0 1 0 360 arc fill grestore\r@br\space def}%
-\w@rps {/av \l@br /hhwid exch 2 div def /hlen exch def}%
-\w@rps    { /ah exch def /tipy exch def /tipx exch def}%
-\w@rps    { currentpoint /taily exch def /tailx exch def}%
-\w@rps    { /dx tipx tailx sub def /dy tipy taily sub def}%
-\w@rps    { /alen dx dx mul dy dy mul add sqrt def}%
-\w@rps    { /blen alen hlen sub def}%
-\w@rps    { gsave tailx taily translate dy dx atan rotate}%
-\w@rps    { (V) ah ne {blen 0 gt {blen 0 lineto} if} {alen 0 lineto} ifelse}%
-\w@rps    { stroke blen hhwid neg moveto alen 0 lineto blen hhwid lineto}%
-\w@rps    { (T) ah eq {closepath} if}%
-\w@rps    { (W) ah eq {gsave 1 setgray fill grestore closepath} if}%
-\w@rps    { (F) ah eq {fill} {stroke} ifelse}%
-\w@rps    { grestore tipx tipy moveto\r@br\space def}%
-\w@rps {\p@sfactor\space \p@sfactor\space scale}%
-\w@rps {1 setlinecap 1 setlinejoin}%
-\w@rps {3 setlinewidth [] 0 setdash}%
-\w@rps {0 0 moveto}%
+  \immediate\openout\drawfile=#1%
+  \w@rps {\p@b PS-Adobe-3.0 EPSF-3.0}%
+  \w@rps {\p@p BoundingBox: (atend)}%
+  \w@rps {\p@p Title: TeXdraw drawing: #1}%
+  \w@rps {\p@p Pages: 1}%
+  \w@rps {\p@p Creator: \TeXdrawId}%
+  \w@rps {\p@p CreationDate: \the\year/\the\month/\the\day}%
+  \w@rps {50 dict begin}%
+  \w@rps {/mv {stroke moveto} def}%
+  \w@rps {/lv {lineto} def}%
+  \w@rps {/st {currentpoint stroke moveto} def}%
+  \w@rps {/sl {st setlinewidth} def}%
+  \w@rps {/sd {st 0 setdash} def}%
+  \w@rps {/sg {st setgray} def}%
+  \w@rps {/bs {gsave} def /es {stroke grestore} def}%
+  \w@rps {/fl \l@br gsave setgray fill grestore}%
+  \w@rps    { currentpoint newpath moveto\r@br\space def}%
+  \w@rps {/fp {gsave setgray fill grestore st} def}%
+  \w@rps {/cv {curveto} def}%
+  \w@rps {/cr \l@br gsave currentpoint newpath 3 -1 roll 0 360 arc}%
+  \w@rps    { stroke grestore\r@br\space def}%
+  \w@rps {/fc \l@br gsave setgray currentpoint newpath}%
+  \w@rps    { 3 -1 roll 0 360 arc fill grestore\r@br\space def}%
+  \w@rps {/ar {gsave currentpoint newpath 5 2 roll arc stroke grestore} def}%
+  \w@rps {/el \l@br gsave /svm matrix currentmatrix def}%
+  \w@rps    { currentpoint translate scale newpath 0 0 1 0 360 arc}%
+  \w@rps    { svm setmatrix stroke grestore\r@br\space def}%
+  \w@rps {/fe \l@br gsave setgray currentpoint translate scale newpath}%
+  \w@rps    { 0 0 1 0 360 arc fill grestore\r@br\space def}%
+  \w@rps {/av \l@br /hhwid exch 2 div def /hlen exch def}%
+  \w@rps    { /ah exch def /tipy exch def /tipx exch def}%
+  \w@rps    { currentpoint /taily exch def /tailx exch def}%
+  \w@rps    { /dx tipx tailx sub def /dy tipy taily sub def}%
+  \w@rps    { /alen dx dx mul dy dy mul add sqrt def}%
+  \w@rps    { /blen alen hlen sub def}%
+  \w@rps    { gsave tailx taily translate dy dx atan rotate}%
+  \w@rps    { (V) ah ne {blen 0 gt {blen 0 lineto} if} {alen 0 lineto} ifelse}%
+  \w@rps    { stroke blen hhwid neg moveto alen 0 lineto blen hhwid lineto}%
+  \w@rps    { (T) ah eq {closepath} if}%
+  \w@rps    { (W) ah eq {gsave 1 setgray fill grestore closepath} if}%
+  \w@rps    { (F) ah eq {fill} {stroke} ifelse}%
+  \w@rps    { grestore tipx tipy moveto\r@br\space def}%
+  \w@rps {\p@sfactor\space \p@sfactor\space scale}%
+  \w@rps {1 setlinecap 1 setlinejoin}%
+  \w@rps {3 setlinewidth [] 0 setdash}%
+  \w@rps {0 0 moveto}%
 }
+
+% Notes:
+% - mv (move to) This command includes a stroke before the moveto.  The
+%      stroke terminates a path and the move begins another path.
+% - bs (begin segment) encloses a segment in a gsave/grestore to keep
+%      changes to line parameters local.
+% - es (end segment) does a "stroke grestore" to make sure lines inside
+%      the segment use the line parameters local to that segment
+% - ar (arc) The path is generated and stroked inside a gsave/grestore,
+%      leaving the current path intact.
+% - cr (circle) The path is generated and stroked inside a gsave/grestore,
+%      leaving the current path intact.
+% - fc (filled circle) The path is generated and filled inside a gsave/
+%      grestore, keeping the fill level local to the circle.  The current
+%      path is left intact.
+% - el (ellipse) The path is generated and stroked inside a gsave/grestore,
+%      leaving the current path intact.  The elliptical path is defined
+%      with different x and y scaling, then stroked with default scaling
+%      to give a constant line thickness.
+% - fe (filled ellipse) The path is generated and filled inside a gsave/
+%      grestore, leaving the current path intact.
+% - fl (fill) The current path is closed and filled inside a gsave/restore,
+%      keeping the fill level local.  A newpath terminates the path.
+% - fp (fill path) The current path is closed and then filled inside a
+%      gsave/grestore.  Finally the closed path is stroked, implicitly
+%      terminating the path.
+% - av (arrow vector) The arrow vector is drawn inside a gsave/grestore.
+%      The line width and type are those currently in effect.  After the
+%      grestore, the current path is continued with a move to the tip of
+%      the vector.
+
+% ===== Close the PostScript file
+% Write a trailer with the BoundingBox, close the file.  Note that the
+% BoundingBox may be larger than the commands in the PostScript file
+% indicate.  This is due to the fact that multiple move commands in
+% a row are collapsed into a single move.  The BoundingBox information
+% includes the effect of the moves which were expunged.
 \def\t@drclose {%
-\bgroup
-\w@rps {stroke end showpage}%
-\w@rps {\p@p Trailer:}%
-\pixtobp \xminpix \l@lxbp  \pixtobp \yminpix \l@lybp
-\pixtobp \xmaxpix \u@rxbp  \pixtobp \ymaxpix \u@rybp
-\w@rps {\p@p BoundingBox: \l@lxbp\space \l@lybp\space
-\u@rxbp\space \u@rybp}%
-\w@rps {\p@p EOF}%
-\egroup
-\immediate\closeout\drawfile
+  \bgroup
+    \w@rps {stroke end showpage}%
+    \w@rps {\p@p Trailer:}%
+    \pixtobp \xminpix \l@lxbp  \pixtobp \yminpix \l@lybp
+    \pixtobp \xmaxpix \u@rxbp  \pixtobp \ymaxpix \u@rybp
+    \w@rps {\p@p BoundingBox: \l@lxbp\space \l@lybp\space
+                              \u@rxbp\space \u@rybp}%
+    \w@rps {\p@p EOF}%
+  \egroup
+  \immediate\closeout\drawfile
 }
+
+% ===============================================================
 \catcode`\@=\catamp
diff --git a/Master/texmf-dist/tex/generic/texdraw/txdexamp.latex b/Master/texmf-dist/tex/generic/texdraw/txdexamp.latex
new file mode 100644
index 00000000000..c3ea8b4eee9
--- /dev/null
+++ b/Master/texmf-dist/tex/generic/texdraw/txdexamp.latex
@@ -0,0 +1,514 @@
+% TeXdraw examples for latex
+
+% $Id: txdexamp.latex,v 2.0 1995/12/18 texdraw-V2R0 $
+
+% These examples are taken from the TeXdraw manual.
+
+%  Peter Kabal
+%  Department of Electrical Engineering
+%  McGill University
+%  3480 University
+%  Montreal, Quebec
+%  Canada  H3A 2A7
+
+%  kabal@TSP.EE.McGill.CA
+ 
+\documentclass [11pt]{article}
+\usepackage {texdraw}
+
+\input txdtools
+\let\et=\etexdraw
+\def\etexdraw{\drawbb\et}
+
+\begin{document}
+
+\noindent
+TeXdraw examples using LaTeX.
+
+\bigskip
+\begin{center}
+\begin{texdraw}
+  \avec (0 0.8) \textref h:C v:B \htext (0 0.9){\sl y}
+  \move (0 0) \avec (0.8 0) \textref h:L v:C \htext(0.9 0){\sl x}
+  \move (0 1.0)
+\end{texdraw}
+\end{center}
+
+\bigskip
+\begin{center}
+\begin{texdraw}
+  \drawdim{cm} \linewd 0.02
+  \move(2 2) \lvec(3 3) \lvec(2 4) \lvec(1 3) \lvec(2 2)
+  \textref h:C v:C \htext(2 3){$\sum \rho_n$}
+\end{texdraw}
+\end{center}
+
+\bigskip
+\begin{center}
+\begin{texdraw}
+  \drawdim in
+  \linewd 0.03 \setgray 0.6 \arrowheadtype t:F \avec(0.5 0.5)
+  \linewd 0.01 \setgray 0   \arrowheadtype t:V \avec(1.0 0.5)
+  \linewd 0.015 \lpatt(0.067 0.1) \lvec (1.5 0)
+  \linewd 0.02 \lpatt() \arrowheadtype t:T \avec(2.0 0.5)
+  \arrowheadtype t:H \avec(2.5 0.5)
+  \setgray 0.4 \arrowheadtype t:W \avec(3.0 0)
+  \textref h:R v:T \htext (0.35 0.50){\tt t:F}
+  \textref h:R v:T \htext (1.0 0.43){\tt t:V}
+  \textref h:R v:T \htext (1.82 0.50){\tt t:T}
+  \textref h:R v:T \htext (2.5 0.43){\tt t:H}
+  \textref h:R v:B \htext (2.8 0){\tt t:W}
+\end{texdraw}
+\end{center}
+
+\bigskip
+\begin{center}
+\begin{texdraw}
+  \newcommand{\bdot}{\bsegment
+                  \fcir f:0 r:0.02
+                \esegment}
+  \newcommand{\Ttext}[1]{\bsegment
+                  \textref h:C v:B \htext (0 +0.06){#1}
+                \esegment}
+  \newcommand{\Btext}[1]{\bsegment
+                  \textref h:C v:T \htext (0 -0.06){#1}
+                \esegment}
+  \newcommand{\Ltext}[1]{\bsegment
+                  \textref h:R v:C \htext (-0.08 0){#1}
+                \esegment}
+  \newcommand{\Rtext}[1]{\bsegment
+                  \textref h:L v:C \htext (+0.08 0){#1}
+                \esegment}
+  \move (-1.5 0)
+  \bsegment
+    \move (+1.55 +0.45) \move (-1.55 -0.45) \move (0 0)
+    \Ttext{Horizontal Text}
+    \bdot                   \Btext{\tt h:C v:C}
+    \move (-0.9 0)    \bdot \Ltext{\tt h:L v:C}
+    \move (+0.9 0)    \bdot \Rtext{\tt h:R v:C}
+    \move (0 +0.3)    \bdot \Ttext{\tt h:C v:T}
+    \move (0 -0.3)    \bdot \Btext{\tt h:C v:B}
+    \move (-0.9 -0.3) \bdot \Ltext{\tt h:L v:B}
+    \lvec (-0.9 +0.3) \bdot \Ltext{\tt h:L v:T}
+    \lvec (+0.9 +0.3) \bdot \Rtext{\tt h:R v:T}
+    \lvec (+0.9 -0.3) \bdot \Rtext{\tt h:R v:B}
+    \lvec (-0.9 -0.3)
+  \esegment
+  \newcommand{\atext}{\rtext td:45 }
+  \newcommand{\ATtext}[1]{\bsegment
+                   \setsegscale 0.707
+                   \textref h:C v:B \atext (-0.06 +0.06){#1}
+                 \esegment}
+  \newcommand{\ABtext}[1]{\bsegment
+                   \setsegscale 0.707
+                   \textref h:C v:T \atext (+0.060 -0.06){#1}
+                 \esegment}
+  \newcommand{\ALtext}[1]{\bsegment
+                   \setsegscale 0.707
+                   \textref h:R v:C \atext (-0.08 -0.08){#1}
+                 \esegment}
+  \newcommand{\ARtext}[1]{\bsegment
+                   \setsegscale 0.707
+                   \textref h:L v:C \atext (+0.08 +0.08){#1}
+                 \esegment}
+  \move (+1.5 0)
+  \bsegment
+    \move (+1.33 +1.33) \move (-1.33 -1.33) \move (0 0)
+    \setsegscale 0.707
+    \ATtext{Rotated Text}
+    \bdot                   \ABtext{\tt h:C v:C}
+    \move (-0.9 -0.9) \bdot \ALtext{\tt h:L v:C}
+    \move (+0.9 +0.9) \bdot \ARtext{\tt h:R v:C}
+    \move (-0.3 +0.3) \bdot \ATtext{\tt h:C v:T}
+    \move (+0.3 -0.3) \bdot \ABtext{\tt h:C v:B}
+    \move (-0.6 -1.2) \bdot \ALtext{\tt h:L v:B}
+    \lvec (-1.2 -0.6) \bdot \ALtext{\tt h:L v:T}
+    \lvec (+0.6 +1.2) \bdot \ARtext{\tt h:R v:T}
+    \lvec (+1.2 +0.6) \bdot \ARtext{\tt h:R v:B}
+    \lvec (-0.6 -1.2)
+  \esegment
+\end{texdraw}
+\end{center}
+
+\vfill
+\newpage
+
+
+\bigskip
+\begin{center}
+\begin{texdraw}
+  \move(-0.75 -0.25) \lvec (-0.75 +0.5) \lvec (+0.75 +0.5)
+  \lvec(+0.75 -0.25) \ifill f:0.9         % fill the region
+  \move(0 0)
+             \avec(-0.75 -0.25) \textref h:R v:C \htext{H-text}
+  \move(0 0) \avec(-0.75 +0.25) \textref h:R v:B \htext{H-text}
+  \move(0 0) \avec(0 +0.5)      \textref h:L v:T \vtext{V-text}
+  \move(0 0) \avec(+0.75 +0.25) \textref h:L v:B \htext{H-text}
+  \move(0 0) \avec(+0.75 -0.25) \textref h:L v:C \htext{H-text}
+  \move (-1.15 -0.3) \move (+1.15 +0.92)  % increase the size of the drawing
+\end{texdraw}
+\end{center}
+
+\bigskip
+\begin{center}
+\begin{texdraw}
+  \linewd 0.02
+  \fcir f:0.7 r:1
+  \larc r:1 sd:45 ed:135
+  \lvec ( 0.707  0.707) \move (0 0) \lvec (-0.707 +0.707)
+\end{texdraw}
+\end{center}
+
+\bigskip
+\begin{center}
+\begin{texdraw}
+  \newcommand{\Ltext}[1]{\bsegment
+                  \textref h:R v:C \htext (-0.08 0){#1}
+                \esegment}
+  \newcommand{\Rtext}[1]{\bsegment
+                  \textref h:L v:C \htext (+0.08 0){#1}
+                \esegment}
+  \newcommand{\bdot}{\fcir f:0 r:0.02 }
+  \newcommand{\Ldot}[1]{\bdot \Ltext{#1}}
+  \newcommand{\Rdot}[1]{\bdot \Rtext{#1}}
+  \move (-2 0)
+  \bsegment
+    \lpatt (0.033)
+    \move (0 0) \Ldot{0} \lvec (0 1) \Ldot{1}
+    \lvec (1 1) \Rdot{2} \lvec (1 0) \Rdot{3}
+    \lpatt ()
+    \move (0 0) \clvec (0 1)(1 1)(1 0)
+  \esegment
+  \move (0 0)
+  \bsegment
+    \lpatt (0.033)
+    \move (0 0) \Ldot{0}  \lvec (0.5 0.8) \Ldot{1}
+    \lvec (1.5 0.8) \Rdot{2} \lvec (1 0) \Rdot{3}
+    \lpatt ()
+    \move (0 0) \clvec (0.5 1)(1.5 1)(1 0)
+  \esegment
+  \move ( 2 0)
+  \bsegment
+    \lpatt (0.033)
+    \move (0 0) \Ldot{0} \lvec (0 1) \Ldot{1}
+    \lvec (1 0) \Rdot{2} \lvec (1 1) \Rdot{3}
+    \lpatt ()
+    \move (0 0) \clvec (0 1)(1 0)(1 1)
+  \esegment
+\end{texdraw}
+\end{center}
+
+\bigskip
+\begin{center}
+\begin{texdraw}
+\move (0.5 0)
+\lvec (0 0.5) \clvec (0.5 0.85)(1 0.65)(1.5 1)
+\lvec (2 0.5) \clvec (1.5 0.15)(1 0.35)(0.5 0)
+\lfill f:0.8
+\end{texdraw}
+\end{center}
+
+\vfill
+\newpage
+
+
+\bigskip
+\newcommand{\tbox}[1]{\bsegment
+               \lvec (0 +0.25)    \lvec (0.75 +0.25)
+               \lvec (0.75 -0.25) \lvec (0 -0.25) \lvec (0 0)
+               \textref h:C v:C \htext (0.375 0){#1}
+               \savepos (0.75 0)(*ex *ey)
+             \esegment
+             \move (*ex *ey)}
+\begin{center}
+\begin{texdraw}
+  \ravec (1 0) \tbox{$H(z)$} \ravec (1 0)
+\end{texdraw}
+\end{center}
+
+\bigskip
+\def\cavec (#1 #2)(#3 #4)(#5 #6){
+  \clvec (#1 #2)(#3 #4)(#5 #6)
+  \cossin (#3 #4)(#5 #6)\cosa\sina
+  \rmove (0 0) % stroke the Bezier curve
+  \bsegment
+    \drawdim in \setsegscale 0.05
+    \move ({-\cosa} -\sina)  \avec (0 0)
+  \esegment}
+
+\def\caw (#1 #2){
+  \currentpos \xa\ya
+  \cossin ({\xa} \ya)(#1 #2)\cosa\sina
+
+% The nominal wiggly curve is (0 0) (1+dx dy) (-dx -dy) (1 0)
+% Find the rotated offset (dx dy) -> (du dv)
+  \rotatecoord (0.4 0.1)\cosa\sina \du\dv
+
+% calculate the length of the vector
+  \vectlen ({\xa} \ya)(#1 #2)\len
+
+% draw the curve in normalized units
+  \bsegment
+    \setsegscale {\len}
+    \realadd \cosa \du \tmpa  \realadd \sina \dv \tmpb
+    \cavec ({\tmpa} \tmpb)({-\du} -\dv)({\cosa} \sina)
+  \esegment
+
+  \move (#1 #2)}
+
+% rotate a coordinate (x y)
+% arguments: (x y) cosa sina x' y'
+%  x' = cosa * x - sina * y;  y' = sina * x + cosa * y
+\def\rotatecoord (#1 #2)#3#4#5#6{
+  \getpos (#1 #2)\xarg\yarg
+  \realmult \xarg {#3} \tmpa  \realmult \yarg {#4} \tmpb
+  \realadd \tmpa {-\tmpb} #5
+  \realmult \xarg {#4} \tmpa  \realmult \yarg {#3} \tmpb
+  \realadd \tmpa \tmpb #6}
+
+\begin{center}
+\begin{texdraw}
+  \arrowheadtype t:W
+  \move (0 0)
+  \cavec (1.4 0.1)(-0.4 -0.1)(1 0)
+  \move (1 0) \caw (1 1) \htext{tip at \tt (1 1)}
+  \move (1 0) \caw (2 1) \htext{tip at \tt (2 1)}
+  \move (1 0) \caw (2 0) \htext{tip at \tt (2 0)}
+  \move (0 1.13) \move (0 -0.04)
+\end{texdraw}
+\end{center}
+
+\vfill
+\newpage
+
+
+\bigskip
+\def\delay {\bsegment
+              \setsegscale 0.3
+              \lvec (0 +0.5) \lvec (1 +0.5) \lvec (1 -0.5)
+              \lvec (0 -0.5) \lvec (0 0)
+              \textref h:C v:C  \htext (0.5 0){$z^{-1}$}
+              \savepos (1 0)(*ex *ey)
+            \esegment
+            \move (*ex *ey)}
+\def\bdot {\fcir f:0 r:0.02 }
+\def\Ttext #1{\bsegment
+                \textref h:C v:B  \htext (0 +0.06){#1}
+              \esegment}
+\def\Btext #1{\bsegment
+                \textref h:C v:T  \htext (0 -0.06){#1}
+              \esegment}
+\def\Ltext #1{\bsegment
+                \textref h:R v:C  \htext (-0.06 0){#1}
+              \esegment}
+\def\Rtext #1{\bsegment
+                \textref h:L v:C  \htext (+0.06 0){#1}
+              \esegment}
+\def\cradius {0.08}
+\def\pluss {\bsegment
+              \setsegscale {\cradius}
+              \move (-0.5 0) \lvec (+0.5 0)
+              \move (0 -0.5) \lvec (0 +0.5)
+            \esegment}
+\def\pcir {\lcir r:{\cradius} \pluss}
+\def\puttext (#1 #2)#3{\bsegment
+                         \setsegscale {\cradius}
+                         \textref h:C v:C \htext (#1 #2){#3}
+                       \esegment}
+\def\putwnw #1{\puttext (-1.7 +1.2){#1}}
+\def\putwsw #1{\puttext (-1.7 -1.2){#1}}
+\def\putn   #1{\puttext ( 0   +2  ){#1}}
+\def\puts   #1{\puttext ( 0   -2  ){#1}}
+\def\avectoc (#1 #2){\currentpos \xa\ya
+                     \cossin ({\xa} \ya)(#1 #2)\cosa\sina
+                     \savepos (#1 #2)(*tx *ty)
+                     \bsegment
+                       \move (*tx *ty)
+                       \setsegscale {\cradius}
+                       \rmove ({-\cosa} -\sina)
+                       \savecurrpos (*ex *ey)
+                     \esegment
+                     \avec (*ex *ey)
+                     \move (#1 #2)}
+\def\avecfrc (#1 #2){\currentpos \xa\ya
+                     \cossin ({\xa} \ya)(#1 #2)\cosa\sina
+                     \bsegment
+                       \setsegscale {\cradius}
+                       \move ({\cosa} \sina)
+                       \savecurrpos (*ex *ey)
+                     \esegment
+                     \move (*ex *ey)
+                     \avec (#1 #2)}
+
+\begin{center}
+\begin{texdraw}
+\drawdim in
+\arrowheadtype t:F  \arrowheadsize l:0.08 w:0.04
+\def\pl {$\scriptscriptstyle +$} \def\mn {$\scriptscriptstyle -$}
+
+\move (0 +0.63) \move (0 -0.60) \move (0 0) % compensate for the text size
+
+% Input to the first stage
+\bsegment
+  \Ltext{$x(n)$}
+  \lvec (0.3 0) \bdot \lvec (0.3 +0.4)
+  \move (0.3 0) \lvec (0.3 -0.4)
+  \savepos (0.3 0)(*ex *ey)
+\esegment
+\move (*ex *ey)
+
+% first lattice stage
+\bsegment
+  \move (0 +0.4)  \avectoc (1.7 +0.4)
+  \pcir \putwnw{\pl} \puts{\mn}
+  \avecfrc (2.1 +0.4)
+  \move (0 -0.4)  \avec (0.4 -0.4) \delay \avectoc (1.7 -0.4)
+  \pcir \putwsw{\pl} \putn{\mn}
+  \avecfrc (2.1 -0.4)
+  \move (0.9 +0.4)  \bdot  \avectoc (1.7 -0.4)
+  \move (0.9 -0.4)  \bdot  \avectoc (1.7 +0.4)
+  \move (0.1 +0.42) \Ttext {$f_0(n)$}
+  \move (2.0 +0.42) \Ttext {$f_1(n)$}
+  \move (0.1 -0.4)  \Btext {$b_0(n)$}
+  \move (2.0 -0.4)  \Btext {$b_1(n)$}
+  \textref h:L v:B  \htext (1.15 +0.2){$K_1$}
+  \textref h:L v:T  \htext (1.15 -0.2){$K_1$}
+  \savepos (2.1 0)(*ex *ey)
+\esegment
+\move (*ex *ey)
+
+% center section
+\bsegment
+  \textref h:C v:C
+  \htext (0.3 +0.4){$\cdots$}
+  \htext (0.3 -0.4){$\cdots$}
+  \savepos (0.6 0)(*ex *ey)
+\esegment
+\move (*ex *ey)
+
+% last lattice stage
+\bsegment
+  \move (0 +0.4)  \avectoc (1.7 +0.4)
+  \pcir \putwnw{\pl} \puts{\mn}
+  \avecfrc (2.3 +0.4) \Rtext{$e(n)$}
+  \move (0 -0.4)  \avec (0.4 -0.4) \delay \avectoc (1.7 -0.4)
+  \pcir \putwsw{\pl} \putn{\mn}
+  \avecfrc (2.1 -0.4)
+  \move (0.9 +0.4)  \bdot  \avectoc (1.7 -0.4)
+  \move (0.9 -0.4)  \bdot  \avectoc (1.7 +0.4)
+  \move (0.1 +0.42) \Ttext {$f_{P-1}(n)$}
+  \move (2.0 +0.42) \Ttext {$f_P(n)$}
+  \move (0.1 -0.4)  \Btext {$b_{P-1}(n)$}
+  \move (2.0 -0.4)  \Btext {$b_P(n)$}
+  \textref h:L v:B  \htext (1.15 +0.2){$K_P$}
+  \textref h:L v:T  \htext (1.15 -0.2){$K_P$}
+\esegment
+\end{texdraw}
+\end{center}
+
+\bigskip
+\begin{center}
+\begin{texdraw}
+\arrowheadtype t:F  \arrowheadsize l:0.08 w:0.04
+\def\ds {\displaystyle}
+\def\ticklab (#1 #2)#3{\move(#1 #2)
+                       \bsegment
+                         \lvec (0 0.05)
+                         \textref h:C v:T \htext (0 -0.05){#3}
+                       \esegment}
+\def\Rtext #1{\bsegment
+                \textref h:L v:C \htext ( 0.08 0){#1}
+              \esegment}
+
+\move (2.4 -0.32)    % move to set the size
+
+\move (0 0)
+% Axes
+\avec (0  1.4)
+\move (0 0) \avec (2.2 0) \Rtext{$\omega$}
+\ticklab (0 0)   {0}
+\ticklab (0.8 0) {$\ds {\pi \over  2N} $}
+\ticklab (1.2 0) {$\omega_s$}
+\ticklab (1.6 0) {$\ds {\pi \over N} $}
+
+\linewd 0.025
+\move (0 1)
+\lvec (0.4 1)
+\lvec (0.44 0.998)
+\lvec (0.48 0.988)
+\lvec (0.52 0.973)
+\lvec (0.56 0.951)
+\lvec (0.60 0.923)
+\lvec (0.64 0.891)
+\lvec (0.68 0.852)
+\lvec (0.72 0.809)
+\lvec (0.76 0.760)
+\lvec (0.80 0.707)
+\lvec (0.84 0.649)
+\lvec (0.88 0.587)
+\lvec (0.92 0.522)
+\lvec (0.96 0.454)
+\lvec (1.00 0.382)
+\lvec (1.04 0.309)
+\lvec (1.08 0.233)
+\lvec (1.12 0.156)
+\lvec (1.16 0.078)
+\lvec (1.20 0)
+\lvec (1.9 0)
+\end{texdraw}
+\end{center}
+
+\bigskip
+\begin{center}
+\begin{texdraw}
+\arrowheadtype t:V \arrowheadsize l:0.08 w:0.04
+\linewd 0.01
+\setunitscale 1.5            % circle will have radius 1.5 inches
+
+\def\Btext #1{\bsegment
+                \textref h:C v:T \htext (0 -0.04){#1}
+              \esegment}
+\def\Ttext #1{\bsegment
+                \textref h:C v:B \htext (0  0.04){#1}
+              \esegment}
+\def\Ltext #1{\bsegment
+                \textref h:R v:C \htext (-0.04 0){#1}
+              \esegment}
+\def\bdot {\fcir f:0 r:0.0133 }
+\def\vtick {\bsegment
+              \move (0 -0.05) \lvec (0  0.05)
+            \esegment}
+\def\htick {\bsegment
+              \move (-0.05 0) \lvec ( 0.05 0)
+            \esegment}
+\def\Hlen #1#2{\bsegment
+                 \vtick \avec ({#1} 0) \vtick \avec (0 0)
+                 \relsegscale 0.5
+                 \move ({#1} 0) \Ttext {#2}
+               \esegment}
+\def\Vlen #1#2{\bsegment
+                 \htick \avec (0 {#1}) \htick \avec (0 0)
+                 \relsegscale 0.5
+                 \move (0 {#1}) \Ltext {#2}
+               \esegment}
+
+\lcir r:1                         % circle
+\move (-1.05 0) \lvec ( 1.05 0)   % axes
+\move (0 -1.05) \lvec (0  1.05)
+
+\move (0 0) \lvec (0.707 0.707) \bdot
+\rmove (0.02 0.02) \textref h:L v:B \htext {X}
+\move (0.707 -0.707) \bdot
+\textref h:R v:T \htext(-0.02 -0.02){O}
+
+\move (0.5 0)                     % center of ellipse
+\bsegment
+  \lellip rx:0.435 ry:0.804
+  \bdot \Btext {$\beta_2$}
+  \move (0 0.15) \Hlen {0.435}{$|\beta_1{+}\beta_3|$}
+  \move (-0.7 0) \Vlen {0.804}{$|\beta_1{-}\beta_3|$}
+\esegment
+\end{texdraw}
+\end{center}
+
+\end{document}
diff --git a/Master/texmf-dist/tex/generic/texdraw/txdexamp.tex b/Master/texmf-dist/tex/generic/texdraw/txdexamp.tex
new file mode 100644
index 00000000000..371b0e64969
--- /dev/null
+++ b/Master/texmf-dist/tex/generic/texdraw/txdexamp.tex
@@ -0,0 +1,485 @@
+% TeXdraw examples
+
+% $Id: txdexamp.tex,v 2.0 1995/12/18 texdraw-V2R0 $
+
+% These examples are taken from the TeXdraw manual.  Note that the fonts
+% for text will be different from those in the manual -- here we use the
+% plain TeX defaults.
+
+%  Peter Kabal
+%  Department of Electrical Engineering
+%  McGill University
+%  3480 University
+%  Montreal, Quebec
+%  Canada  H3A 2A7
+
+%  kabal@TSP.EE.McGill.CA
+ 
+\input texdraw
+\input txdtools
+\let\et=\etexdraw
+\def\etexdraw{\drawbb\et}
+
+\noindent
+TeXdraw examples using plain TeX.
+
+\bigskip
+\centertexdraw{
+  \avec (0 0.8) \textref h:C v:B \htext (0 0.9){\sl y}
+  \move (0 0) \avec (0.8 0) \textref h:L v:C \htext(0.9 0){\sl x}
+  \move (0 1.0)}
+
+\bigskip
+\centertexdraw{
+  \drawdim{cm} \linewd 0.02
+  \move(2 2) \lvec(3 3) \lvec(2 4) \lvec(1 3) \lvec(2 2)
+  \textref h:C v:C \htext(2 3){$\sum \rho_n$}
+}
+
+\bigskip
+\centertexdraw{
+  \drawdim in
+  \linewd 0.03 \setgray 0.6 \arrowheadtype t:F \avec(0.5 0.5)
+  \linewd 0.01 \setgray 0   \arrowheadtype t:V \avec(1.0 0.5)
+  \linewd 0.015 \lpatt(0.067 0.1) \lvec (1.5 0)
+  \linewd 0.02 \lpatt() \arrowheadtype t:T \avec(2.0 0.5)
+  \arrowheadtype t:H \avec(2.5 0.5)
+  \setgray 0.4 \arrowheadtype t:W \avec(3.0 0)
+  \textref h:R v:T \htext (0.35 0.50){\tt t:F}
+  \textref h:R v:T \htext (1.0 0.43){\tt t:V}
+  \textref h:R v:T \htext (1.82 0.50){\tt t:T}
+  \textref h:R v:T \htext (2.5 0.43){\tt t:H}
+  \textref h:R v:B \htext (2.8 0){\tt t:W}
+}
+
+\bigskip
+\centertexdraw{
+  \def\bdot {\bsegment
+               \fcir f:0 r:0.02
+             \esegment}
+  \def\Ttext #1{\bsegment
+                  \textref h:C v:B \htext (0 +0.06){#1}
+                \esegment}
+  \def\Btext #1{\bsegment
+                  \textref h:C v:T \htext (0 -0.06){#1}
+                \esegment}
+  \def\Ltext #1{\bsegment
+                  \textref h:R v:C \htext (-0.08 0){#1}
+                \esegment}
+  \def\Rtext #1{\bsegment
+                  \textref h:L v:C \htext (+0.08 0){#1}
+                \esegment}
+  \move (-1.5 0)
+  \bsegment
+    \move (+1.55 +0.45) \move (-1.55 -0.45) \move (0 0)
+    \Ttext{Horizontal Text}
+    \bdot                   \Btext{\tt h:C v:C}
+    \move (-0.9 0)    \bdot \Ltext{\tt h:L v:C}
+    \move (+0.9 0)    \bdot \Rtext{\tt h:R v:C}
+    \move (0 +0.3)    \bdot \Ttext{\tt h:C v:T}
+    \move (0 -0.3)    \bdot \Btext{\tt h:C v:B}
+    \move (-0.9 -0.3) \bdot \Ltext{\tt h:L v:B}
+    \lvec (-0.9 +0.3) \bdot \Ltext{\tt h:L v:T}
+    \lvec (+0.9 +0.3) \bdot \Rtext{\tt h:R v:T}
+    \lvec (+0.9 -0.3) \bdot \Rtext{\tt h:R v:B}
+    \lvec (-0.9 -0.3)
+  \esegment
+  \def\atext {\rtext td:45 }
+  \def\ATtext #1{\bsegment
+                   \setsegscale 0.707
+                   \textref h:C v:B \atext (-0.06 +0.06){#1}
+                 \esegment}
+  \def\ABtext #1{\bsegment
+                   \setsegscale 0.707
+                   \textref h:C v:T \atext (+0.060 -0.06){#1}
+                 \esegment}
+  \def\ALtext #1{\bsegment
+                   \setsegscale 0.707
+                   \textref h:R v:C \atext (-0.08 -0.08){#1}
+                 \esegment}
+  \def\ARtext #1{\bsegment
+                   \setsegscale 0.707
+                   \textref h:L v:C \atext (+0.08 +0.08){#1}
+                 \esegment}
+  \move (+1.5 0)
+  \bsegment
+    \move (+1.33 +1.33) \move (-1.33 -1.33) \move (0 0)
+    \setsegscale 0.707
+    \ATtext{Rotated Text}
+    \bdot                   \ABtext{\tt h:C v:C}
+    \move (-0.9 -0.9) \bdot \ALtext{\tt h:L v:C}
+    \move (+0.9 +0.9) \bdot \ARtext{\tt h:R v:C}
+    \move (-0.3 +0.3) \bdot \ATtext{\tt h:C v:T}
+    \move (+0.3 -0.3) \bdot \ABtext{\tt h:C v:B}
+    \move (-0.6 -1.2) \bdot \ALtext{\tt h:L v:B}
+    \lvec (-1.2 -0.6) \bdot \ALtext{\tt h:L v:T}
+    \lvec (+0.6 +1.2) \bdot \ARtext{\tt h:R v:T}
+    \lvec (+1.2 +0.6) \bdot \ARtext{\tt h:R v:B}
+    \lvec (-0.6 -1.2)
+  \esegment
+}
+
+\vfill
+\eject
+
+
+\bigskip
+\centertexdraw{
+  \move(-0.75 -0.25) \lvec (-0.75 +0.5) \lvec (+0.75 +0.5)
+  \lvec(+0.75 -0.25) \ifill f:0.9         % fill the region
+  \move(0 0)
+             \avec(-0.75 -0.25) \textref h:R v:C \htext{H-text}
+  \move(0 0) \avec(-0.75 +0.25) \textref h:R v:B \htext{H-text}
+  \move(0 0) \avec(0 +0.5)      \textref h:L v:T \vtext{V-text}
+  \move(0 0) \avec(+0.75 +0.25) \textref h:L v:B \htext{H-text}
+  \move(0 0) \avec(+0.75 -0.25) \textref h:L v:C \htext{H-text}
+  \move (-1.15 -0.3) \move (+1.15 +0.92)  % increase the size of the drawing
+}
+
+\bigskip
+\centertexdraw{
+  \linewd 0.02
+  \fcir f:0.7 r:1
+  \larc r:1 sd:45 ed:135
+  \lvec ( 0.707  0.707) \move (0 0) \lvec (-0.707 +0.707)
+}
+
+\bigskip
+\centertexdraw{
+  \def\Ltext #1{\bsegment
+                  \textref h:R v:C \htext (-0.08 0){#1}
+                \esegment}
+  \def\Rtext #1{\bsegment
+                  \textref h:L v:C \htext (+0.08 0){#1}
+                \esegment}
+  \def\bdot {\fcir f:0 r:0.02 }
+  \def\Ldot #1{\bdot \Ltext{#1}}
+  \def\Rdot #1{\bdot \Rtext{#1}}
+  \move (-2 0)
+  \bsegment
+    \lpatt (0.033)
+    \move (0 0) \Ldot{0} \lvec (0 1) \Ldot{1}
+    \lvec (1 1) \Rdot{2} \lvec (1 0) \Rdot{3}
+    \lpatt ()
+    \move (0 0) \clvec (0 1)(1 1)(1 0)
+  \esegment
+  \move (0 0)
+  \bsegment
+    \lpatt (0.033)
+    \move (0 0) \Ldot{0}  \lvec (0.5 0.8) \Ldot{1}
+    \lvec (1.5 0.8) \Rdot{2} \lvec (1 0) \Rdot{3}
+    \lpatt ()
+    \move (0 0) \clvec (0.5 1)(1.5 1)(1 0)
+  \esegment
+  \move ( 2 0)
+  \bsegment
+    \lpatt (0.033)
+    \move (0 0) \Ldot{0} \lvec (0 1) \Ldot{1}
+    \lvec (1 0) \Rdot{2} \lvec (1 1) \Rdot{3}
+    \lpatt ()
+    \move (0 0) \clvec (0 1)(1 0)(1 1)
+  \esegment
+}
+
+\bigskip
+\centertexdraw{
+\move (0.5 0)
+\lvec (0 0.5) \clvec (0.5 0.85)(1 0.65)(1.5 1)
+\lvec (2 0.5) \clvec (1.5 0.15)(1 0.35)(0.5 0)
+\lfill f:0.8
+}
+
+\vfill
+\eject
+
+
+\bigskip
+\def\tbox #1{\bsegment
+               \lvec (0 +0.25)    \lvec (0.75 +0.25)
+               \lvec (0.75 -0.25) \lvec (0 -0.25) \lvec (0 0)
+               \textref h:C v:C \htext (0.375 0){#1}
+               \savepos (0.75 0)(*ex *ey)
+             \esegment
+             \move (*ex *ey)}
+\centertexdraw{
+  \ravec (1 0) \tbox{$H(z)$} \ravec (1 0)
+}
+
+\bigskip
+\def\cavec (#1 #2)(#3 #4)(#5 #6){
+  \clvec (#1 #2)(#3 #4)(#5 #6)
+  \cossin (#3 #4)(#5 #6)\cosa\sina
+  \rmove (0 0) % stroke the Bezier curve
+  \bsegment
+    \drawdim in \setsegscale 0.05
+    \move ({-\cosa} -\sina)  \avec (0 0)
+  \esegment}
+
+\def\caw (#1 #2){
+  \currentpos \xa\ya
+  \cossin ({\xa} \ya)(#1 #2)\cosa\sina
+
+% The nominal wiggly curve is (0 0) (1+dx dy) (-dx -dy) (1 0)
+% Find the rotated offset (dx dy) -> (du dv)
+  \rotatecoord (0.4 0.1)\cosa\sina \du\dv
+
+% calculate the length of the vector
+  \vectlen ({\xa} \ya)(#1 #2)\len
+
+% draw the curve in normalized units
+  \bsegment
+    \setsegscale {\len}
+    \realadd \cosa \du \tmpa  \realadd \sina \dv \tmpb
+    \cavec ({\tmpa} \tmpb)({-\du} -\dv)({\cosa} \sina)
+  \esegment
+
+  \move (#1 #2)}
+
+% rotate a coordinate (x y)
+% arguments: (x y) cosa sina x' y'
+%  x' = cosa * x - sina * y;  y' = sina * x + cosa * y
+\def\rotatecoord (#1 #2)#3#4#5#6{
+  \getpos (#1 #2)\xarg\yarg
+  \realmult \xarg {#3} \tmpa  \realmult \yarg {#4} \tmpb
+  \realadd \tmpa {-\tmpb} #5
+  \realmult \xarg {#4} \tmpa  \realmult \yarg {#3} \tmpb
+  \realadd \tmpa \tmpb #6}
+
+\centertexdraw{
+  \arrowheadtype t:W
+  \move (0 0)
+  \cavec (1.4 0.1)(-0.4 -0.1)(1 0)
+  \move (1 0) \caw (1 1) \htext{tip at \tt (1 1)}
+  \move (1 0) \caw (2 1) \htext{tip at \tt (2 1)}
+  \move (1 0) \caw (2 0) \htext{tip at \tt (2 0)}
+  \move (0 1.13) \move (0 -0.04)
+}
+
+\vfill
+\eject
+
+
+\bigskip
+\def\delay {\bsegment
+              \setsegscale 0.3
+              \lvec (0 +0.5) \lvec (1 +0.5) \lvec (1 -0.5)
+              \lvec (0 -0.5) \lvec (0 0)
+              \textref h:C v:C  \htext (0.5 0){$z^{-1}$}
+              \savepos (1 0)(*ex *ey)
+            \esegment
+            \move (*ex *ey)}
+\def\bdot {\fcir f:0 r:0.02 }
+\def\Ttext #1{\bsegment
+                \textref h:C v:B  \htext (0 +0.06){#1}
+              \esegment}
+\def\Btext #1{\bsegment
+                \textref h:C v:T  \htext (0 -0.06){#1}
+              \esegment}
+\def\Ltext #1{\bsegment
+                \textref h:R v:C  \htext (-0.06 0){#1}
+              \esegment}
+\def\Rtext #1{\bsegment
+                \textref h:L v:C  \htext (+0.06 0){#1}
+              \esegment}
+\def\cradius {0.08}
+\def\pluss {\bsegment
+              \setsegscale {\cradius}
+              \move (-0.5 0) \lvec (+0.5 0)
+              \move (0 -0.5) \lvec (0 +0.5)
+            \esegment}
+\def\pcir {\lcir r:{\cradius} \pluss}
+\def\puttext (#1 #2)#3{\bsegment
+                         \setsegscale {\cradius}
+                         \textref h:C v:C \htext (#1 #2){#3}
+                       \esegment}
+\def\putwnw #1{\puttext (-1.7 +1.2){#1}}
+\def\putwsw #1{\puttext (-1.7 -1.2){#1}}
+\def\putn   #1{\puttext ( 0   +2  ){#1}}
+\def\puts   #1{\puttext ( 0   -2  ){#1}}
+\def\avectoc (#1 #2){\currentpos \xa\ya
+                     \cossin ({\xa} \ya)(#1 #2)\cosa\sina
+                     \savepos (#1 #2)(*tx *ty)
+                     \bsegment
+                       \move (*tx *ty)
+                       \setsegscale {\cradius}
+                       \rmove ({-\cosa} -\sina)
+                       \savecurrpos (*ex *ey)
+                     \esegment
+                     \avec (*ex *ey)
+                     \move (#1 #2)}
+\def\avecfrc (#1 #2){\currentpos \xa\ya
+                     \cossin ({\xa} \ya)(#1 #2)\cosa\sina
+                     \bsegment
+                       \setsegscale {\cradius}
+                       \move ({\cosa} \sina)
+                       \savecurrpos (*ex *ey)
+                     \esegment
+                     \move (*ex *ey)
+                     \avec (#1 #2)}
+
+\centertexdraw{
+\drawdim in
+\arrowheadtype t:F  \arrowheadsize l:0.08 w:0.04
+\def\pl {$\scriptscriptstyle +$} \def\mn {$\scriptscriptstyle -$}
+
+\move (0 +0.63) \move (0 -0.60) \move (0 0) % compensate for the text size
+
+% Input to the first stage
+\bsegment
+  \Ltext{$x(n)$}
+  \lvec (0.3 0) \bdot \lvec (0.3 +0.4)
+  \move (0.3 0) \lvec (0.3 -0.4)
+  \savepos (0.3 0)(*ex *ey)
+\esegment
+\move (*ex *ey)
+
+% first lattice stage
+\bsegment
+  \move (0 +0.4)  \avectoc (1.7 +0.4)
+  \pcir \putwnw{\pl} \puts{\mn}
+  \avecfrc (2.1 +0.4)
+  \move (0 -0.4)  \avec (0.4 -0.4) \delay \avectoc (1.7 -0.4)
+  \pcir \putwsw{\pl} \putn{\mn}
+  \avecfrc (2.1 -0.4)
+  \move (0.9 +0.4)  \bdot  \avectoc (1.7 -0.4)
+  \move (0.9 -0.4)  \bdot  \avectoc (1.7 +0.4)
+  \move (0.1 +0.42) \Ttext {$f_0(n)$}
+  \move (2.0 +0.42) \Ttext {$f_1(n)$}
+  \move (0.1 -0.4)  \Btext {$b_0(n)$}
+  \move (2.0 -0.4)  \Btext {$b_1(n)$}
+  \textref h:L v:B  \htext (1.15 +0.2){$K_1$}
+  \textref h:L v:T  \htext (1.15 -0.2){$K_1$}
+  \savepos (2.1 0)(*ex *ey)
+\esegment
+\move (*ex *ey)
+
+% center section
+\bsegment
+  \textref h:C v:C
+  \htext (0.3 +0.4){$\cdots$}
+  \htext (0.3 -0.4){$\cdots$}
+  \savepos (0.6 0)(*ex *ey)
+\esegment
+\move (*ex *ey)
+
+% last lattice stage
+\bsegment
+  \move (0 +0.4)  \avectoc (1.7 +0.4)
+  \pcir \putwnw{\pl} \puts{\mn}
+  \avecfrc (2.3 +0.4) \Rtext{$e(n)$}
+  \move (0 -0.4)  \avec (0.4 -0.4) \delay \avectoc (1.7 -0.4)
+  \pcir \putwsw{\pl} \putn{\mn}
+  \avecfrc (2.1 -0.4)
+  \move (0.9 +0.4)  \bdot  \avectoc (1.7 -0.4)
+  \move (0.9 -0.4)  \bdot  \avectoc (1.7 +0.4)
+  \move (0.1 +0.42) \Ttext {$f_{P-1}(n)$}
+  \move (2.0 +0.42) \Ttext {$f_P(n)$}
+  \move (0.1 -0.4)  \Btext {$b_{P-1}(n)$}
+  \move (2.0 -0.4)  \Btext {$b_P(n)$}
+  \textref h:L v:B  \htext (1.15 +0.2){$K_P$}
+  \textref h:L v:T  \htext (1.15 -0.2){$K_P$}
+\esegment
+}
+
+\bigskip
+\centertexdraw{
+\arrowheadtype t:F  \arrowheadsize l:0.08 w:0.04
+\def\ds {\displaystyle}
+\def\ticklab (#1 #2)#3{\move(#1 #2)
+                       \bsegment
+                         \lvec (0 0.05)
+                         \textref h:C v:T \htext (0 -0.05){#3}
+                       \esegment}
+\def\Rtext #1{\bsegment
+                \textref h:L v:C \htext ( 0.08 0){#1}
+              \esegment}
+
+\move (2.4 -0.32)    % move to set the size
+
+\move (0 0)
+% Axes
+\avec (0  1.4)
+\move (0 0) \avec (2.2 0) \Rtext{$\omega$}
+\ticklab (0 0)   {0}
+\ticklab (0.8 0) {$\ds {\pi \over  2N} $}
+\ticklab (1.2 0) {$\omega_s$}
+\ticklab (1.6 0) {$\ds {\pi \over N} $}
+
+\linewd 0.025
+\move (0 1)
+\lvec (0.4 1)
+\lvec (0.44 0.998)
+\lvec (0.48 0.988)
+\lvec (0.52 0.973)
+\lvec (0.56 0.951)
+\lvec (0.60 0.923)
+\lvec (0.64 0.891)
+\lvec (0.68 0.852)
+\lvec (0.72 0.809)
+\lvec (0.76 0.760)
+\lvec (0.80 0.707)
+\lvec (0.84 0.649)
+\lvec (0.88 0.587)
+\lvec (0.92 0.522)
+\lvec (0.96 0.454)
+\lvec (1.00 0.382)
+\lvec (1.04 0.309)
+\lvec (1.08 0.233)
+\lvec (1.12 0.156)
+\lvec (1.16 0.078)
+\lvec (1.20 0)
+\lvec (1.9 0)
+}
+
+\bigskip
+\centertexdraw{
+\arrowheadtype t:V \arrowheadsize l:0.08 w:0.04
+\linewd 0.01
+\setunitscale 1.5            % circle will have radius 1.5 inches
+
+\def\Btext #1{\bsegment
+                \textref h:C v:T \htext (0 -0.04){#1}
+              \esegment}
+\def\Ttext #1{\bsegment
+                \textref h:C v:B \htext (0  0.04){#1}
+              \esegment}
+\def\Ltext #1{\bsegment
+                \textref h:R v:C \htext (-0.04 0){#1}
+              \esegment}
+\def\bdot {\fcir f:0 r:0.0133 }
+\def\vtick {\bsegment
+              \move (0 -0.05) \lvec (0  0.05)
+            \esegment}
+\def\htick {\bsegment
+              \move (-0.05 0) \lvec ( 0.05 0)
+            \esegment}
+\def\Hlen #1#2{\bsegment
+                 \vtick \avec ({#1} 0) \vtick \avec (0 0)
+                 \relsegscale 0.5
+                 \move ({#1} 0) \Ttext {#2}
+               \esegment}
+\def\Vlen #1#2{\bsegment
+                 \htick \avec (0 {#1}) \htick \avec (0 0)
+                 \relsegscale 0.5
+                 \move (0 {#1}) \Ltext {#2}
+               \esegment}
+
+\lcir r:1                         % circle
+\move (-1.05 0) \lvec ( 1.05 0)   % axes
+\move (0 -1.05) \lvec (0  1.05)
+
+\move (0 0) \lvec (0.707 0.707) \bdot
+\rmove (0.02 0.02) \textref h:L v:B \htext {X}
+\move (0.707 -0.707) \bdot
+\textref h:R v:T \htext(-0.02 -0.02){O}
+
+\move (0.5 0)                     % center of ellipse
+\bsegment
+  \lellip rx:0.435 ry:0.804
+  \bdot \Btext {$\beta_2$}
+  \move (0 0.15) \Hlen {0.435}{$|\beta_1{+}\beta_3|$}
+  \move (-0.7 0) \Vlen {0.804}{$|\beta_1{-}\beta_3|$}
+\esegment
+}
+
+\bye
diff --git a/Master/texmf-dist/tex/generic/texdraw/txdps.tex b/Master/texmf-dist/tex/generic/texdraw/txdps.tex
index 16eb8a926f7..e5ea49e9ed9 100644
--- a/Master/texmf-dist/tex/generic/texdraw/txdps.tex
+++ b/Master/texmf-dist/tex/generic/texdraw/txdps.tex
@@ -18,8 +18,17 @@
 %  Canada  H3A 2A7
 
 %  kabal@TSP.EE.McGill.CA
+ 
+% ===============================================================
+
 \chardef\catamp=\the\catcode`\@
 \catcode`\@=11
+
+% The TeXdraw macros assume that a PostScript currentpoint is always
+% defined. When using the following macros, always finish off with
+% by reestablishing a PostScript currentpoint. This can be done with
+% a \PSmoveto command.
+
 \def\PSsetlinecap #1 {\writeps{#1 setlinecap}}
 \def\PSsetlinejoin #1 {\writeps{#1 setlinejoin}}
 \def\PSstroke {\writeps{stroke}}
@@ -27,19 +36,20 @@
 \def\PSclosepath {\writeps{closepath}}
 \def\PSfill {\writeps{fill}}
 \def\PSlineto (#1 #2){\getpos (#1 #2)\a@rgx\a@rgy
-\s@etpospix \a@rgx \a@rgy
-\writeps {\the\x@pix\space \the\y@pix\space lineto}}
+                      \s@etpospix \a@rgx \a@rgy
+                      \writeps {\the\x@pix\space \the\y@pix\space lineto}}
 \def\PSmoveto (#1 #2){\getpos (#1 #2)\a@rgx\a@rgy
-\s@etpospix \a@rgx \a@rgy
-\writeps {\the\x@pix\space \the\y@pix\space moveto}}
+                      \s@etpospix \a@rgx \a@rgy
+                      \writeps {\the\x@pix\space \the\y@pix\space moveto}}
 \def\PSarc r:#1 sd:#2 ed:#3 (#4 #5){\getpos (#4 #5)\a@rgx\a@rgy
-\s@etpospix \a@rgx \a@rgy
-\coordtopix {#1}\t@pixa
-\writeps{\the\x@pix\space \the\y@pix\space
-\the\t@pixa\space #2 #3 arc}}
+                                    \s@etpospix \a@rgx \a@rgy
+                                    \coordtopix {#1}\t@pixa
+                                    \writeps{\the\x@pix\space \the\y@pix\space
+                                             \the\t@pixa\space #2 #3 arc}}
 \def\PSarcn r:#1 sd:#2 ed:#3 (#4 #5){\getpos (#4 #5)\a@rgx\a@rgy
-\s@etpospix \a@rgx \a@rgy
-\coordtopix {#1}\t@pixa
-\writeps{\the\x@pix\space \the\y@pix\space
-\the\t@pixa\space #2 #3 arcn}}
+                                     \s@etpospix \a@rgx \a@rgy
+                                     \coordtopix {#1}\t@pixa
+                                     \writeps{\the\x@pix\space \the\y@pix\space
+                                              \the\t@pixa\space #2 #3 arcn}}
+
 \catcode`\@=\catamp
diff --git a/Master/texmf-dist/tex/generic/texdraw/txdtools.tex b/Master/texmf-dist/tex/generic/texdraw/txdtools.tex
index c3d5ee1aa01..676660bca7d 100644
--- a/Master/texmf-dist/tex/generic/texdraw/txdtools.tex
+++ b/Master/texmf-dist/tex/generic/texdraw/txdtools.tex
@@ -18,63 +18,128 @@
 %  Canada  H3A 2A7
 
 %  kabal@TSP.EE.McGill.CA
+ 
+% ===============================================================
+
+% These macros use temporary count registers defined by TeXdraw
+%  \t@counta     \t@pixa
+%  \t@countb     \t@pixb
+%  \t@countc     \t@pixc
+%                \t@pixd
+
 \chardef\catamp=\the\catcode`\@
 \catcode`\@=11
+
+
+% ===== Real arithmetic
+% Real addition
+%  #1  - summand
+%  #2  - summand
+%  #3  - macro name to capture the real result
 \def\realadd #1#2#3{\dimen0=#1pt
-\dimen2=#2pt
-\advance \dimen0 by \dimen2
-\edef #3{\expandafter\c@lean\the\dimen0}}
+                    \dimen2=#2pt
+                    \advance \dimen0 by \dimen2
+                    \edef #3{\expandafter\c@lean\the\dimen0}}
+
+% Real division
+%  #1 - numerator
+%  #2 - denominator (divisor)
+%  #3 - macro name to capture the real result
 \def\realdiv #1#2#3{\dimen0=#1pt
-\t@counta=\dimen0
-\dimen0=#2pt
-\t@countb=\dimen0
-\intdiv \t@counta \t@countb #3}
+                    \t@counta=\dimen0
+                    \dimen0=#2pt
+                    \t@countb=\dimen0
+                    \intdiv \t@counta \t@countb #3}
+
+% ===== Integer arithmetic
+
+% Length of the hypotenuse
+% Find the length of a vector, lenhyp = sqrt(dx*dx + dy*dy)
+%  #1 - integer value, dx
+%  #2 - integer value, dy
+%  #3 - count register to capture the integer value
 \def\lenhyp #1#2#3{\t@counta=#1%
-\multiply \t@counta by \t@counta
-\t@countb=#2%
-\multiply \t@countb by \t@countb
-\advance \t@counta by \t@countb
-\sqrtnum \t@counta #3}
+                   \multiply \t@counta by \t@counta
+                   \t@countb=#2%
+                   \multiply \t@countb by \t@countb
+                   \advance \t@counta by \t@countb
+                   \sqrtnum \t@counta #3}
+
+% Square root of an integer
+% Newton-Raphson iteration to find the square root, integer argument
+% Let the current estimate of the square root of x be b(k).
+% Form an error function, e(k)=b(k)*b(k)-x. Follow the gradient of the
+% error to calculate the next guess,
+%
+%    e(k) - 0     d e(k)                          b(k) + x/b(k)
+%   ----------  = ------  = 2*b(k)  ==>  b(k+1) = -------------
+%   b(k)-b(k+1)   d b(k)                               2
+%
+% Note this iteration does not work for x=0, since the guess is then b(k)=0.
+% Rename the count registers to have more suggestive names
 \let\bk=\t@counta
 \let\bn=\t@countb
 \let\xval=\t@countc
 \def\sqrtnum #1#2{\xval=#1%
-\bk=\xval
-\loop
-\bn=\xval
-\divide \bn by \bk
-\advance \bn by \bk
-\advance \bn by 1
-\divide \bn by 2
-\ifnum \bn < \bk
-\bk=\bn
-\repeat
-#2=\bn}
+                  \bk=\xval
+                  \loop
+                    \bn=\xval
+                    \divide \bn by \bk
+                    \advance \bn by \bk
+                    \advance \bn by 1            % rounding
+                    \divide \bn by 2
+                  \ifnum \bn < \bk
+                    \bk=\bn
+                  \repeat
+                  #2=\bn}
+
+% ===== Coordinate macros
+
+% Return the coordinates of the current position
+%  #1 - macro name to capture the x-coordinate
+%  #2 - macro name to capture the y-coordinate
 \def\currentpos #1#2{\t@pixa=\x@pix
-\advance \t@pixa by -\x@segoffpix
-\pixtocoord \t@pixa #1
-\t@pixa=\y@pix
-\advance \t@pixa by -\y@segoffpix
-\pixtocoord \t@pixa #2}
+                     \advance \t@pixa by -\x@segoffpix
+                     \pixtocoord \t@pixa #1
+                     \t@pixa=\y@pix
+                     \advance \t@pixa by -\y@segoffpix
+                     \pixtocoord \t@pixa #2}
+
+% Length of a vector
+% Find the length of the vector between coordinate (#1 #2) and
+% coordiante (#3 #4). The length is expressed relative to the
+% current scaling.
+%  (#1 #2) - vector start coordinates
+%  (#3 #4) - vector end coordinates
+%  #5 - macro name to receive the length
 \def\vectlen (#1 #2)(#3 #4)#5{\getpos (#1 #2)\x@arga\y@arga
-\getpos (#3 #4)\x@argb\y@argb
-\coordtopix \x@arga \t@pixa
-\coordtopix \x@argb \t@pixb
-\advance \t@pixb by -\t@pixa
-\coordtopix \y@arga \t@pixc
-\coordtopix \y@argb \t@pixd
-\advance \t@pixd by -\t@pixc
-\lenhyp \t@pixb \t@pixd \t@pixc
-\pixtocoord \t@pixc #5}
+                              \getpos (#3 #4)\x@argb\y@argb
+                              \coordtopix \x@arga \t@pixa
+                              \coordtopix \x@argb \t@pixb
+                              \advance \t@pixb by -\t@pixa
+                              \coordtopix \y@arga \t@pixc
+                              \coordtopix \y@argb \t@pixd
+                              \advance \t@pixd by -\t@pixc
+                              \lenhyp \t@pixb \t@pixd \t@pixc
+                              \pixtocoord \t@pixc #5}
+
+% Cossine and sine
+% Find the cosine and sine of the angle of a vector directed from
+% the coordinate (#1 #2) to the coordinate (#3 #4).
+%  (#1 #2) - start coordinates
+%  (#3 #4) - end coordinates
+%  #5 - macro name to receive the cosine of the angle
+%  #6 - macro name to receive the sine of the angle
 \def\cossin (#1 #2)(#3 #4)#5#6{\getpos (#1 #2)\x@arga\y@arga
-\getpos (#3 #4)\x@argb\y@argb
-\coordtopix \x@arga \t@pixa
-\coordtopix \x@argb \t@pixb
-\advance \t@pixb by -\t@pixa
-\coordtopix \y@arga \t@pixc
-\coordtopix \y@argb \t@pixd
-\advance \t@pixd by -\t@pixc
-\lenhyp \t@pixb \t@pixd \t@pixc
-\intdiv \t@pixb\t@pixc #5%
-\intdiv \t@pixd\t@pixc #6}
+                               \getpos (#3 #4)\x@argb\y@argb
+                               \coordtopix \x@arga \t@pixa
+                               \coordtopix \x@argb \t@pixb
+                               \advance \t@pixb by -\t@pixa
+                               \coordtopix \y@arga \t@pixc
+                               \coordtopix \y@argb \t@pixd
+                               \advance \t@pixd by -\t@pixc
+                               \lenhyp \t@pixb \t@pixd \t@pixc
+                               \intdiv \t@pixb\t@pixc #5%
+                               \intdiv \t@pixd\t@pixc #6}
+
 \catcode`\@=\catamp