4 files changed, 84 insertions, 7 deletions
diff --git a/Master/texmf-dist/doc/generic/pstricks-add/Changes b/Master/texmf-dist/doc/generic/pstricks-add/Changes
index ea4a67a0325..e9a470d06ba 100644
--- a/Master/texmf-dist/doc/generic/pstricks-add/Changes
+++ b/Master/texmf-dist/doc/generic/pstricks-add/Changes
@@ -1,4 +1,4 @@
-%% $Id: Changes 439 2010-12-18 18:45:23Z herbert $
+%% $Id: Changes 445 2011-01-18 18:43:16Z herbert $
 %%
 pstricks-add.pro ----------- 
 0.23 2009-12-20 - add RGBtoGRAY and WavelengthToGRAY
@@ -39,6 +39,8 @@ pstricks-add.sty ----------- (hv)
 
 
 pstricks-add.tex ----------- (Dominik Rodriguez/hv)
+ v 3.49  2011-01-18 - add macro \psEllipseTangents for drawing tangent
+                      lines of a point and an ellipse.
  v 3.48  2010-12-18 - add macro \psCircleTangents for drawing tangent
                       lines of a point and a circle or two circles.
  v 3.47  2010-12-14 - save the absolute coordinates of \psVector in node names
diff --git a/Master/texmf-dist/doc/generic/pstricks-add/pstricks-add-doc.pdf b/Master/texmf-dist/doc/generic/pstricks-add/pstricks-add-doc.pdf
index b2947990e5a..ba27a113b54 100644
--- a/Master/texmf-dist/doc/generic/pstricks-add/pstricks-add-doc.pdf
+++ b/Master/texmf-dist/doc/generic/pstricks-add/pstricks-add-doc.pdf
diff --git a/Master/texmf-dist/doc/generic/pstricks-add/pstricks-add-doc.tex b/Master/texmf-dist/doc/generic/pstricks-add/pstricks-add-doc.tex
index 8cdd5d020d9..88c43ec9e10 100644
--- a/Master/texmf-dist/doc/generic/pstricks-add/pstricks-add-doc.tex
+++ b/Master/texmf-dist/doc/generic/pstricks-add/pstricks-add-doc.tex
@@ -1,4 +1,4 @@
-%% $Id: pstricks-add-doc.tex 439 2010-12-18 18:45:23Z herbert $
+%% $Id: pstricks-add-doc.tex 445 2011-01-18 18:43:16Z herbert $
 \documentclass[11pt,english,BCOR10mm,DIV12,bibliography=totoc,parskip=false,smallheadings
     headexclude,footexclude,oneside]{pst-doc}
 \listfiles
@@ -336,12 +336,12 @@ and \verb=CircleT2=.
 \end{lstlisting}
 
 \bigskip
-When using the other variant of the macro two circles must be given. THe macro then defines
+When using the other variant of the macro two circles must be given. The macro then defines
 ten nodes, named \verb=CircleTC1= and \verb=CircleTC2= for the two intersection points,
  \verb=CircleTO1=, \verb=CircleTO2=, \verb=CircleTO3=, and \verb=CircleTO4= for the four
  nodes of the outer tangent lines and 
   \verb=CircleTI1=, \verb=CircleTI2=, \verb=CircleTI3=, and \verb=CircleTI4= for the
-  four nodes of the inenr tangent lines.
+  four nodes of the inner tangent lines.
 
 \bigskip
 \begin{pspicture}[showgrid](-2,-2)(10,10)
@@ -383,6 +383,47 @@ ten nodes, named \verb=CircleTC1= and \verb=CircleTC2= for the two intersection
 
 
 \clearpage
+
+%--------------------------------------------------------------------------------------
+\section{\nxLcs{psEllipseTangents}: Calculating tangent lines of an ellipse}
+%--------------------------------------------------------------------------------------
+
+The macro calculates the two points on an ellipse where tangent lines from an outside  point
+ are drawn.
+
+\begin{BDef}
+\Lcs{psEllipseTangents}\Largr{$x_0,y_0$}\Largr{$a,b$}\Largr{$x_p,y_p$}\\
+\end{BDef}
+
+The first two pairs of coordinates are the same as the ones for the default ellipse.
+The names of the calculates node names are \verb=EllipseT1=
+and \verb=EllipseT2=.
+
+\bigskip
+\begin{pspicture}[showgrid](0,3)(10,10)
+\psdot(2,4)\psellipse(7,7)(3,1.5)
+\psEllipseTangents(7,7)(3,1.5)(2,4)
+\pcline[nodesep=-1cm,linecolor=blue](2,4)(EllipseT1)
+\pcline[nodesep=-1cm,linecolor=blue](2,4)(EllipseT2)
+\psdots(EllipseT1)(EllipseT2)
+\uput[-80](EllipseT1){T1}\uput[115](EllipseT2){T2}
+\end{pspicture}
+
+
+\begin{lstlisting}
+\begin{pspicture}[showgrid](0,3)(10,10)
+\psdot(2,4)\psellipse(7,7)(3,1.5)
+\psEllipseTangents(7,7)(3,1.5)(2,4)
+\pcline[nodesep=-1cm,linecolor=blue](2,4)(EllipseT1)
+\pcline[nodesep=-1cm,linecolor=blue](2,4)(EllipseT2)
+\psdots(EllipseT1)(EllipseT2)
+\uput[-80](EllipseT1){T1}\uput[115](EllipseT2){T2}
+\end{pspicture}
+\end{lstlisting}
+
+
+\clearpage
+
 %--------------------------------------------------------------------------------------
 \section{\nxLcs{psrotate}: Rotating objects}
 %--------------------------------------------------------------------------------------
diff --git a/Master/texmf-dist/tex/generic/pstricks-add/pstricks-add.tex b/Master/texmf-dist/tex/generic/pstricks-add/pstricks-add.tex
index 1505289d7ed..3d7da83946c 100644
--- a/Master/texmf-dist/tex/generic/pstricks-add/pstricks-add.tex
+++ b/Master/texmf-dist/tex/generic/pstricks-add/pstricks-add.tex
@@ -1,4 +1,4 @@
-%% $Id: pstricks-add.tex 439 2010-12-18 18:45:23Z herbert $
+%% $Id: pstricks-add.tex 445 2011-01-18 18:43:16Z herbert $
 %%
 %%
 %% This is file `pstricks-add.tex',
@@ -31,8 +31,8 @@
 \ifx\PSTXKeyLoaded\endinput\else  \input pst-xkey \fi
 \ifx\PSTmathLoaded\endinput\else  \input pst-math \fi
 %
-\def\fileversion{3.48}
-\def\filedate{2010/12/18}
+\def\fileversion{3.49}
+\def\filedate{2011/01/18}
 \message{`pstricks-add' v\fileversion, \filedate\space (dr,hv)}
 %
 \edef\PstAtCode{\the\catcode`\@} \catcode`\@=11\relax
@@ -2218,6 +2218,40 @@ dup #1Delta.X m 1 add get mul #1.X m get add #1Tick.X j 3 -1 roll put % s on sta
   \ignorespaces%  
 }
 %
+\def\psEllipseTangents(#1,#2)(#3,#4)(#5,#6){%  (xe,ye)(a,b)(xP,yP) % no optional arguments
+  \pst@killglue%
+  \pnode(! 
+     /A #3 def
+     /B #4 def
+     /A2 A dup mul def /B2 B dup mul def 
+     #5 #1 sub /Xp ED
+     #6 #2 sub /Yp ED 
+          A2 B2 mul Xp mul 
+          Yp 4 exp A 6 exp mul
+          B2 Yp dup mul mul A 6 exp mul sub
+          B2 Xp dup mul mul Yp dup mul mul A 4 exp mul add sqrt add 
+          Yp dup mul A2 mul B2 Xp dup mul mul add div /Xt ED % the x3 value
+          Xt dup mul A2 div neg 1 add sqrt B mul /Yt ED
+          Yt Yp sub Xt Xp sub mul 0 gt { % P is in 1st or 3rd quadrant 
+            Xt dup mul A2 div neg 1 add sqrt neg B mul /Yt ED } if
+          Xt #1 add Yt #2 add ) {EllipseT1}%
+  \pnode(! 
+     /A #3 def
+     /B #4 def
+     /A2 A dup mul def /B2 B dup mul def 
+     #5 #1 sub /Xp ED
+     #6 #2 sub /Yp ED
+     A2 B2 mul Xp mul 
+          Yp 4 exp A 6 exp mul
+          B2 Yp dup mul mul A 6 exp mul sub
+          B2 Xp dup mul mul Yp dup mul mul A 4 exp mul add sqrt sub 
+          Yp dup mul A2 mul B2 Xp dup mul mul add div /Xt ED % the x3 value
+          Xt dup mul A2 div neg 1 add sqrt B mul /Yt ED
+          Yt Yp sub Xt Xp sub mul 0 lt { % P is in 2nd or 4th quadrant
+            Xt dup mul A2 div neg 1 add sqrt neg B mul /Yt ED } if
+          Xt #1 add Yt #2 add ) {EllipseT2}%
+  \ignorespaces}% 
+%
 \def\resetOptions{%
   \def\pst@linetype{0}%
   \pstScalePoints(1,1){}{}%