improved line breaks in rightline templates for quotations

beamerthemelines.sty

@@ -573,9 +573,17 @@
 % pbk , phv, pnc, qcs
 \newcommand{\openquote}[2]{\tikz[baseline]{%
     \useasboundingbox (0, 0) rectangle (1ex, 1.7ex);
-    \node[scale=#2, xshift=-0.45ex, yshift=-0.75ex] at (current bounding box.north east) {\usebeamerfont*{#1 symbol}\textquotedblleft};
+    \node[scale=#2, xshift=-0.28ex, yshift=-0.75ex] at (current bounding box.north east) {\usebeamerfont*{#1 symbol}\textquoteleft};
 }}
 \newcommand{\closequote}[2]{\tikz[baseline]{%
+    \useasboundingbox (0, 0) rectangle (1ex, 1.7ex);
+    \node[scale=#2, xshift=-0.28ex, yshift=-0.75ex] at (current bounding box.north east) {\usebeamerfont*{#1 symbol}\textquoteright};
+}}
+\newcommand{\opendblquote}[2]{\tikz[baseline]{%
+    \useasboundingbox (0, 0) rectangle (1ex, 1.7ex);
+    \node[scale=#2, xshift=-0.45ex, yshift=-0.75ex] at (current bounding box.north east) {\usebeamerfont*{#1 symbol}\textquotedblleft};
+}}
+\newcommand{\closedblquote}[2]{\tikz[baseline]{%
     \useasboundingbox (0, 0) rectangle (1ex, 1.7ex);
     \node[scale=#2, xshift=-0.45ex, yshift=-0.75ex] at (current bounding box.north east) {\usebeamerfont*{#1 symbol}\textquotedblright};
 }}
@@ -598,23 +606,26 @@
     \usebeamercolor{#1 source}%
     #2\insertquotesource#3%
   \fi}
+% linebreaking from 
+% https://tex.stackexchange.com/questions/13756/quote-environment-with-reference-at-the-end-right :
 \newcommand{\quote@source@rightline}[3]{%
   \ifx\insertquotesource\@empty\else%
-    \hfill%
+    \leavevmode\unskip\nobreak\hfil\penalty50\hskip2em\hbox{}\nobreak\hfil%
     \usebeamerfont{#1 source}%
     \usebeamercolor{#1 source}%
-    #2\insertquotesource#3%
+    \makebox{#2\insertquotesource#3}%
+    \parfillskip=0pt \finalhyphendemerits=0 \endgraf%
   \fi}
-% for improvement see
-% https://tex.stackexchange.com/questions/13756/quote-environment-with-reference-at-the-end-right
 
 % quotation environment
 
 \defbeamertemplate{quotation symbol}{default}{}
 \defbeamertemplate{quotation symbol}{openquote}[1][4]{\usebeamercolor[fg]{quotation symbol}\openquote{quotation}{#1}}
 \defbeamertemplate{quotation symbol}{closequote}[1][4]{\usebeamercolor[fg]{quotation symbol}\closequote{quotation}{#1}}
+\defbeamertemplate{quotation symbol}{opendblquote}[1][4]{\usebeamercolor[fg]{quotation symbol}\opendblquote{quotation}{#1}}
+\defbeamertemplate{quotation symbol}{closedblquote}[1][4]{\usebeamercolor[fg]{quotation symbol}\closedblquote{quotation}{#1}}
 
-\setbeamertemplate{quotation symbol}[openquote][4] % default, openquote, closequote
+\setbeamertemplate{quotation symbol}[opendblquote][4] % default, openquote, closequote, opendblquote, closedblquote
 
 \defbeamertemplate{quotation source}{default}{}
 \defbeamertemplate{quotation source}{left}{\quote@source@left{quotation}{}{}}
@@ -695,8 +706,10 @@
 \defbeamertemplate{quote symbol}{default}{}
 \defbeamertemplate{quote symbol}{openquote}[1][4]{{\usebeamercolor[fg]{quote symbol}\openquote{quote}{#1}}}
 \defbeamertemplate{quote symbol}{closequote}[1][4]{{\usebeamercolor[fg]{quote symbol}\closequote{quote}{#1}}}
+\defbeamertemplate{quote symbol}{opendblquote}[1][4]{{\usebeamercolor[fg]{quote symbol}\opendblquote{quote}{#1}}}
+\defbeamertemplate{quote symbol}{closedblquote}[1][4]{{\usebeamercolor[fg]{quote symbol}\closedblquote{quote}{#1}}}
 
-\setbeamertemplate{quote symbol}[openquote][4] % default, openquote, closequote
+\setbeamertemplate{quote symbol}[opendblquote][4] % default, openquote, closequote, opendblquote, closedblquote
 
 \defbeamertemplate{quote source}{default}{}
 \defbeamertemplate{quote source}{left}{\quote@source@left{quote}{}{}}

lines-example.tex

@@ -599,15 +599,24 @@
   \vfill
 }
 
-\newcommand{\quotesymboldemo}[1]{
+\newcommand{\quotesymboldemo}[2]{
-  \setbeamertemplate{quote symbol}[#1]
+  \setbeamertemplate{quote symbol}[#1]#2
   \begin{small}
-    \texttt{\textbackslash setbeamertemplate\{quote symbol\}[#1]}
+    \texttt{\textbackslash setbeamertemplate\{quote symbol\}[#1]#2}
   \end{small}
   \quotedemo
-  \setbeamertemplate{quote symbol}[openquote]
+  \setbeamertemplate{quote symbol}[opendblquote]
 }
 
+\begin{frame}[fragile]{Quote symbol settings}
+  \quotesymboldemo{default}{}
+  \quotesymboldemo{closequote}{}
+  \quotesymboldemo{openquote}{}
+  \quotesymboldemo{closedblquote}{}
+  \quotesymboldemo{opendblquote}{}
+  \quotesymboldemo{opendblquote}{[2]}
+\end{frame}
+
 \newcommand{\quotesymbolfontdemo}[1]{
   \setbeamerfont{quote symbol}{family*=#1}
   \begin{small}
@@ -617,14 +626,11 @@
   \setbeamerfont{quote symbol}{family*=pbk}
 }
 
-\begin{frame}[fragile]{Quote symbol settings}
+\begin{frame}[fragile]{Font settings for quote symbol}
-  \quotesymboldemo{default}
-  \quotesymboldemo{closequote}
-  \quotesymboldemo{openquote}
-  \quotesymbolfontdemo{phv}
-  \quotesymbolfontdemo{pnc}
   \quotesymbolfontdemo{pbk}
-  %\quotesymbolfontdemo{qcs}
+  \quotesymbolfontdemo{pnc}
+  \quotesymbolfontdemo{qcs}
+  \quotesymbolfontdemo{phv}
 \end{frame}
 
 \newcommand{\quotesourcedemo}[1]{
@@ -665,6 +671,11 @@
   \quotesourcedemo{rightlinebrackets}
   \quotesourcedemo{dashrightline}
   \quotesourcedemo{tilderightline}
+  In case the last line is too long, the source is printed on the next line:
+  \begin{quote}[Hamlet by William Shakespeare]
+    To be, or not to be, that is the question:
+    Whether 'tis nobler in the mind to suffer ...
+  \end{quote}
 \end{frame}
 
 \newcommand{\quotecolordemo}[2]{