Failed attempt to make the circle's border transparent

wahlergebnis.tex

@@ -18,6 +18,7 @@
 \usetikzlibrary{arrows}
 \usetikzlibrary{shadows}
 \usetikzlibrary{calc} % für ($ ... $)
+\usetikzlibrary{patterns}
 \pagestyle{empty}
 
 
@@ -44,13 +45,14 @@
 \newcommand{\piechart}[1]{
 \begin{tikzpicture}[segment/.style={
                         rounded corners=.2cm,
-                        draw = boxbg,
                         line width=.1cm,
                     },
+                    baseline = (B.center),
                    ]
     \pgfmathsetmacro{\curarc}{180} % starting angle
     \pgfmathsetmacro{\radius}{5.4}
     \useasboundingbox (-\radius cm,+\radius cm) rectangle (+\radius cm,0);
+    \coordinate (B) at (0,0);
     \pgfmathsetmacro{\smallradius}{1.26}
     \foreach \percent/\seats/\name/\curcolor [remember=\curarc] in {
       #1}
@@ -68,20 +70,31 @@
             ? (\labelarc - 180)
             : \labelarc}
     \pgfmathsetmacro{\middle}{0.5*\startarc+0.5*\endarc}
-    \def\mypath{(\startarc:\smallradius cm)
+    \edef\mypath{(\startarc:\smallradius cm)
         arc (\startarc:\endarc:\smallradius cm)
         -- (\endarc:\radius cm)
         arc (\endarc:\startarc:\radius
         cm) -- cycle}
-    %    \node {
-    %\begin{tikzfadingfrompicture}[name=fade right,scale=0.5]
-    %\fill[fill=transparent] (-\radius cm,+\radius cm) rectangle (+\radius cm,0);
-    %\draw[fill=white] \mypath;
-    %\draw[segment,draw=black,line width = 2mm] \mypath;
+    %\node {
+    %\begin{minipage}{\linewidth}
+    %\begin{tikzfadingfrompicture}[name=myfad, rounded corners = 0]
+    %\useasboundingbox (-\radius cm,+\radius cm) rectangle (+\radius cm,0);
+    %\fill[black,
+    %      ]  (-\radius cm,0) -| (\radius cm,\radius cm) -| cycle;
+    %\draw[fill=transparent,draw=transparent] (-\radius cm,\radius cm) rectangle (\radius cm,0);
+    %\draw[segment,fill=white,draw=transparent] \mypath;
+    %%\fill[red] \mypath;
     %\end{tikzfadingfrompicture}
+    %\end{minipage}
     %};
-    %\fill[path fading=fade right,fill=\curcolor] (-\radius cm,+\radius cm) rectangle (+\radius cm,0);
-    \draw[segment,fill=\curcolor] \mypath;
+    %\draw[path fading = myfad,
+    %      rounded corners= 0,
+    %      fit fading=true,
+    %      %fading transform={yshift=-0.5*\radius cm},
+    %      fill=\curcolor,
+    %      draw=none,
+    %      ]  (-\radius cm,0) -| (\radius cm,\radius cm) -| cycle;
+    \draw[segment,fill=\curcolor,draw=boxbg] \mypath;
       \node [anchor=center,rotate=\labelarc, shape border rotate=0]
       at (\middle:0.5*\radius+0.5*\smallradius) 
       {\sf{\color{percentcolor}
@@ -187,9 +200,13 @@
 
 \NewEnviron{twbox}[1]{%
 \begin{tikzpicture}[remember picture]%
-\draw node[draw=stuverot,fill=boxbg,%
+\draw node[draw=stuverot,
+           fill=boxbg,%
+           %top color = boxbg!90!black,
+           %bottom color = boxbg!90!white,
            very thick,rounded corners,%
            inner sep=1ex,
+           %pattern = checkerboard,
            ]%
     (lasttwbox)
 {%