added tex2img example.

flows/jinja-yaml.yml

@@ -38,6 +38,87 @@ pages:
     - <regex>(?:linear\s+)?\s*map
     - <case_sens_regex>(?:operator\s+)?\s*map
 
+-
+    type: ChoiceQuestion
+    id: latex_image
+    title: Latex 2 image
+    value: 2
+    prompt: |
+
+        # Choice 
+
+        What format is the following image? From 
+        [TEXexample.net](http://www.texample.net/tikz/examples/complete-graph/)
+
+        {% set preamble %}
+            % Author: Quintin Jean-Noël
+            % <http://moais.imag.fr/membres/jean-noel.quintin/>
+            \documentclass{article}
+            \usepackage[fontsize=14px]{scrextend} % render with font size 14px
+            \usepackage{tikz}
+            %%%<
+            \usepackage{verbatim}
+            % The following three lines must be commented.
+            %\usepackage[active,tightpage]{preview}
+            %\PreviewEnvironment{tikzpicture}
+            %\setlength\PreviewBorder{5pt}%
+            %%%>
+            \begin{comment}
+            :Title: A complete graph
+            :Tags: Foreach;Graphs;To paths
+            :Author: Jean-Noël Quintin
+            :Slug: complete-graph
+            \end{comment}
+            \usetikzlibrary[topaths]
+            % A counter, since TikZ is not clever enough (yet) to handle
+            % arbitrary angle systems.
+            \newcount\mycount
+        {% endset %}
+
+        <p align='middle' >
+        {% call latex(compiler="latex", tex_preamble=preamble, image_format="png") %}
+
+            \begin{document}
+            \begin{tikzpicture}[transform shape]
+              %the multiplication with floats is not possible. Thus I split the loop in two.
+              \foreach \number in {1,...,8}{
+                  % Computer angle:
+                    \mycount=\number
+                    \advance\mycount by -1
+              \multiply\mycount by 45
+                    \advance\mycount by 0
+                  \node[draw,circle,inner sep=0.25cm] (N-\number) at (\the\mycount:5.4cm) {};
+                }
+              \foreach \number in {9,...,16}{
+                  % Computer angle:
+                    \mycount=\number
+                    \advance\mycount by -1
+              \multiply\mycount by 45
+                    \advance\mycount by 22.5
+                  \node[draw,circle,inner sep=0.25cm] (N-\number) at (\the\mycount:5.4cm) {};
+                }
+              \foreach \number in {1,...,15}{
+                    \mycount=\number
+                    \advance\mycount by 1
+              \foreach \numbera in {\the\mycount,...,16}{
+                \path (N-\number) edge[->,bend right=3] (N-\numbera)  edge[<-,bend
+                  left=3] (N-\numbera);
+              }
+            }
+            \end{tikzpicture}
+            \end{document}
+        {% endcall %}
+        </p>
+
+        Hints: You can use Jinja ``set`` block to set variable ``foo``, then use ``foo`` as keyword argument for the ``latex`` macro.
+
+    choices:
+          - png
+          - jpg
+          - ~CORRECT~ svg
+          - bmp
+          - gif
+
 
 completion_text: |